From eaaabc6c4f93d49f090ef7ff930fa2739428a36f Mon Sep 17 00:00:00 2001
From: Richard van der Hoff <richard@matrix.org>
Date: Mon, 23 Oct 2017 15:52:32 +0100
Subject: replace 'except:' with 'except Exception:'

what could possibly go wrong
---
 synapse/push/emailpusher.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'synapse/push/emailpusher.py')

diff --git a/synapse/push/emailpusher.py b/synapse/push/emailpusher.py
index a69dda7b09..58df98a793 100644
--- a/synapse/push/emailpusher.py
+++ b/synapse/push/emailpusher.py
@@ -121,7 +121,7 @@ class EmailPusher(object):
                         starting_max_ordering = self.max_stream_ordering
                         try:
                             yield self._unsafe_process()
-                        except:
+                        except Exception:
                             logger.exception("Exception processing notifs")
                         if self.max_stream_ordering == starting_max_ordering:
                             break
-- 
cgit 1.5.1


From 9255a6cb17716c022ebae1dbe9c142b78ca86ea7 Mon Sep 17 00:00:00 2001
From: Richard van der Hoff <richard@matrix.org>
Date: Fri, 27 Apr 2018 11:07:40 +0100
Subject: Improve exception handling for background processes

There were a bunch of places where we fire off a process to happen in the
background, but don't have any exception handling on it - instead relying on
the unhandled error being logged when the relevent deferred gets
garbage-collected.

This is unsatisfactory for a number of reasons:
 - logging on garbage collection is best-effort and may happen some time after
   the error, if at all
 - it can be hard to figure out where the error actually happened.
 - it is logged as a scary CRITICAL error which (a) I always forget to grep for
   and (b) it's not really CRITICAL if a background process we don't care about
   fails.

So this is an attempt to add exception handling to everything we fire off into
the background.
---
 synapse/app/appservice.py                 | 15 +++--
 synapse/app/federation_sender.py          | 27 +++++----
 synapse/app/pusher.py                     | 31 +++++-----
 synapse/app/synchrotron.py                | 95 ++++++++++++++++---------------
 synapse/app/user_dir.py                   | 13 ++++-
 synapse/appservice/scheduler.py           | 25 ++++----
 synapse/crypto/keyring.py                 | 93 +++++++++++++++---------------
 synapse/federation/transaction_queue.py   |  2 +
 synapse/federation/transport/server.py    | 13 ++++-
 synapse/groups/attestations.py            | 44 +++++++-------
 synapse/handlers/message.py               | 22 +++++--
 synapse/handlers/presence.py              | 19 +++++--
 synapse/handlers/receipts.py              | 61 ++++++++++----------
 synapse/handlers/typing.py                | 43 +++++++-------
 synapse/notifier.py                       | 13 +++--
 synapse/push/emailpusher.py               | 11 ++--
 synapse/push/httppusher.py                |  5 +-
 synapse/rest/media/v1/storage_provider.py |  9 ++-
 synapse/storage/event_push_actions.py     | 24 +++++---
 synapse/util/logcontext.py                |  7 ++-
 20 files changed, 335 insertions(+), 237 deletions(-)

(limited to 'synapse/push/emailpusher.py')

diff --git a/synapse/app/appservice.py b/synapse/app/appservice.py
index f2540023a7..58f2c9d68c 100644
--- a/synapse/app/appservice.py
+++ b/synapse/app/appservice.py
@@ -32,10 +32,10 @@ from synapse.replication.tcp.client import ReplicationClientHandler
 from synapse.server import HomeServer
 from synapse.storage.engines import create_engine
 from synapse.util.httpresourcetree import create_resource_tree
-from synapse.util.logcontext import LoggingContext, preserve_fn
+from synapse.util.logcontext import LoggingContext, run_in_background
 from synapse.util.manhole import manhole
 from synapse.util.versionstring import get_version_string
-from twisted.internet import reactor
+from twisted.internet import reactor, defer
 from twisted.web.resource import NoResource
 
 logger = logging.getLogger("synapse.app.appservice")
@@ -112,9 +112,14 @@ class ASReplicationHandler(ReplicationClientHandler):
 
         if stream_name == "events":
             max_stream_id = self.store.get_room_max_stream_ordering()
-            preserve_fn(
-                self.appservice_handler.notify_interested_services
-            )(max_stream_id)
+            run_in_background(self._notify_app_services, max_stream_id)
+
+    @defer.inlineCallbacks
+    def _notify_app_services(self, room_stream_id):
+        try:
+            yield self.appservice_handler.notify_interested_services(room_stream_id)
+        except Exception:
+            logger.exception("Error notifying application services of event")
 
 
 def start(config_options):
diff --git a/synapse/app/federation_sender.py b/synapse/app/federation_sender.py
index 0cc3331519..4f2a9ca21a 100644
--- a/synapse/app/federation_sender.py
+++ b/synapse/app/federation_sender.py
@@ -237,19 +237,22 @@ class FederationSenderHandler(object):
 
     @defer.inlineCallbacks
     def update_token(self, token):
-        self.federation_position = token
-
-        # We linearize here to ensure we don't have races updating the token
-        with (yield self._fed_position_linearizer.queue(None)):
-            if self._last_ack < self.federation_position:
-                yield self.store.update_federation_out_pos(
-                    "federation", self.federation_position
-                )
+        try:
+            self.federation_position = token
+
+            # We linearize here to ensure we don't have races updating the token
+            with (yield self._fed_position_linearizer.queue(None)):
+                if self._last_ack < self.federation_position:
+                    yield self.store.update_federation_out_pos(
+                        "federation", self.federation_position
+                    )
 
-                # We ACK this token over replication so that the master can drop
-                # its in memory queues
-                self.replication_client.send_federation_ack(self.federation_position)
-                self._last_ack = self.federation_position
+                    # We ACK this token over replication so that the master can drop
+                    # its in memory queues
+                    self.replication_client.send_federation_ack(self.federation_position)
+                    self._last_ack = self.federation_position
+        except Exception:
+            logger.exception("Error updating federation stream position")
 
 
 if __name__ == '__main__':
diff --git a/synapse/app/pusher.py b/synapse/app/pusher.py
index d5c3a85195..739d113ad5 100644
--- a/synapse/app/pusher.py
+++ b/synapse/app/pusher.py
@@ -144,20 +144,23 @@ class PusherReplicationHandler(ReplicationClientHandler):
 
     @defer.inlineCallbacks
     def poke_pushers(self, stream_name, token, rows):
-        if stream_name == "pushers":
-            for row in rows:
-                if row.deleted:
-                    yield self.stop_pusher(row.user_id, row.app_id, row.pushkey)
-                else:
-                    yield self.start_pusher(row.user_id, row.app_id, row.pushkey)
-        elif stream_name == "events":
-            yield self.pusher_pool.on_new_notifications(
-                token, token,
-            )
-        elif stream_name == "receipts":
-            yield self.pusher_pool.on_new_receipts(
-                token, token, set(row.room_id for row in rows)
-            )
+        try:
+            if stream_name == "pushers":
+                for row in rows:
+                    if row.deleted:
+                        yield self.stop_pusher(row.user_id, row.app_id, row.pushkey)
+                    else:
+                        yield self.start_pusher(row.user_id, row.app_id, row.pushkey)
+            elif stream_name == "events":
+                yield self.pusher_pool.on_new_notifications(
+                    token, token,
+                )
+            elif stream_name == "receipts":
+                yield self.pusher_pool.on_new_receipts(
+                    token, token, set(row.room_id for row in rows)
+                )
+        except Exception:
+            logger.exception("Error poking pushers")
 
     def stop_pusher(self, user_id, app_id, pushkey):
         key = "%s:%s" % (app_id, pushkey)
diff --git a/synapse/app/synchrotron.py b/synapse/app/synchrotron.py
index 2fddcd935a..777da564d7 100644
--- a/synapse/app/synchrotron.py
+++ b/synapse/app/synchrotron.py
@@ -340,55 +340,58 @@ class SyncReplicationHandler(ReplicationClientHandler):
 
     @defer.inlineCallbacks
     def process_and_notify(self, stream_name, token, rows):
-        if stream_name == "events":
-            # We shouldn't get multiple rows per token for events stream, so
-            # we don't need to optimise this for multiple rows.
-            for row in rows:
-                event = yield self.store.get_event(row.event_id)
-                extra_users = ()
-                if event.type == EventTypes.Member:
-                    extra_users = (event.state_key,)
-                max_token = self.store.get_room_max_stream_ordering()
-                self.notifier.on_new_room_event(
-                    event, token, max_token, extra_users
+        try:
+            if stream_name == "events":
+                # We shouldn't get multiple rows per token for events stream, so
+                # we don't need to optimise this for multiple rows.
+                for row in rows:
+                    event = yield self.store.get_event(row.event_id)
+                    extra_users = ()
+                    if event.type == EventTypes.Member:
+                        extra_users = (event.state_key,)
+                    max_token = self.store.get_room_max_stream_ordering()
+                    self.notifier.on_new_room_event(
+                        event, token, max_token, extra_users
+                    )
+            elif stream_name == "push_rules":
+                self.notifier.on_new_event(
+                    "push_rules_key", token, users=[row.user_id for row in rows],
                 )
-        elif stream_name == "push_rules":
-            self.notifier.on_new_event(
-                "push_rules_key", token, users=[row.user_id for row in rows],
-            )
-        elif stream_name in ("account_data", "tag_account_data",):
-            self.notifier.on_new_event(
-                "account_data_key", token, users=[row.user_id for row in rows],
-            )
-        elif stream_name == "receipts":
-            self.notifier.on_new_event(
-                "receipt_key", token, rooms=[row.room_id for row in rows],
-            )
-        elif stream_name == "typing":
-            self.typing_handler.process_replication_rows(token, rows)
-            self.notifier.on_new_event(
-                "typing_key", token, rooms=[row.room_id for row in rows],
-            )
-        elif stream_name == "to_device":
-            entities = [row.entity for row in rows if row.entity.startswith("@")]
-            if entities:
+            elif stream_name in ("account_data", "tag_account_data",):
                 self.notifier.on_new_event(
-                    "to_device_key", token, users=entities,
+                    "account_data_key", token, users=[row.user_id for row in rows],
                 )
-        elif stream_name == "device_lists":
-            all_room_ids = set()
-            for row in rows:
-                room_ids = yield self.store.get_rooms_for_user(row.user_id)
-                all_room_ids.update(room_ids)
-            self.notifier.on_new_event(
-                "device_list_key", token, rooms=all_room_ids,
-            )
-        elif stream_name == "presence":
-            yield self.presence_handler.process_replication_rows(token, rows)
-        elif stream_name == "receipts":
-            self.notifier.on_new_event(
-                "groups_key", token, users=[row.user_id for row in rows],
-            )
+            elif stream_name == "receipts":
+                self.notifier.on_new_event(
+                    "receipt_key", token, rooms=[row.room_id for row in rows],
+                )
+            elif stream_name == "typing":
+                self.typing_handler.process_replication_rows(token, rows)
+                self.notifier.on_new_event(
+                    "typing_key", token, rooms=[row.room_id for row in rows],
+                )
+            elif stream_name == "to_device":
+                entities = [row.entity for row in rows if row.entity.startswith("@")]
+                if entities:
+                    self.notifier.on_new_event(
+                        "to_device_key", token, users=entities,
+                    )
+            elif stream_name == "device_lists":
+                all_room_ids = set()
+                for row in rows:
+                    room_ids = yield self.store.get_rooms_for_user(row.user_id)
+                    all_room_ids.update(room_ids)
+                self.notifier.on_new_event(
+                    "device_list_key", token, rooms=all_room_ids,
+                )
+            elif stream_name == "presence":
+                yield self.presence_handler.process_replication_rows(token, rows)
+            elif stream_name == "receipts":
+                self.notifier.on_new_event(
+                    "groups_key", token, users=[row.user_id for row in rows],
+                )
+        except Exception:
+            logger.exception("Error processing replication")
 
 
 def start(config_options):
diff --git a/synapse/app/user_dir.py b/synapse/app/user_dir.py
index 5f845e80d1..5ba7e9b416 100644
--- a/synapse/app/user_dir.py
+++ b/synapse/app/user_dir.py
@@ -39,10 +39,10 @@ from synapse.storage.engines import create_engine
 from synapse.storage.user_directory import UserDirectoryStore
 from synapse.util.caches.stream_change_cache import StreamChangeCache
 from synapse.util.httpresourcetree import create_resource_tree
-from synapse.util.logcontext import LoggingContext, preserve_fn
+from synapse.util.logcontext import LoggingContext, run_in_background
 from synapse.util.manhole import manhole
 from synapse.util.versionstring import get_version_string
-from twisted.internet import reactor
+from twisted.internet import reactor, defer
 from twisted.web.resource import NoResource
 
 logger = logging.getLogger("synapse.app.user_dir")
@@ -164,7 +164,14 @@ class UserDirectoryReplicationHandler(ReplicationClientHandler):
             stream_name, token, rows
         )
         if stream_name == "current_state_deltas":
-            preserve_fn(self.user_directory.notify_new_event)()
+            run_in_background(self._notify_directory)
+
+    @defer.inlineCallbacks
+    def _notify_directory(self):
+        try:
+            yield self.user_directory.notify_new_event()
+        except Exception:
+            logger.exception("Error notifiying user directory of state update")
 
 
 def start(config_options):
diff --git a/synapse/appservice/scheduler.py b/synapse/appservice/scheduler.py
index 6da315473d..dfc8d1b42e 100644
--- a/synapse/appservice/scheduler.py
+++ b/synapse/appservice/scheduler.py
@@ -176,17 +176,20 @@ class _TransactionController(object):
 
     @defer.inlineCallbacks
     def _start_recoverer(self, service):
-        yield self.store.set_appservice_state(
-            service,
-            ApplicationServiceState.DOWN
-        )
-        logger.info(
-            "Application service falling behind. Starting recoverer. AS ID %s",
-            service.id
-        )
-        recoverer = self.recoverer_fn(service, self.on_recovered)
-        self.add_recoverers([recoverer])
-        recoverer.recover()
+        try:
+            yield self.store.set_appservice_state(
+                service,
+                ApplicationServiceState.DOWN
+            )
+            logger.info(
+                "Application service falling behind. Starting recoverer. AS ID %s",
+                service.id
+            )
+            recoverer = self.recoverer_fn(service, self.on_recovered)
+            self.add_recoverers([recoverer])
+            recoverer.recover()
+        except Exception:
+            logger.exception("Error starting AS recoverer")
 
     @defer.inlineCallbacks
     def _is_service_up(self, service):
diff --git a/synapse/crypto/keyring.py b/synapse/crypto/keyring.py
index fce83d445f..32cbddbc53 100644
--- a/synapse/crypto/keyring.py
+++ b/synapse/crypto/keyring.py
@@ -146,53 +146,56 @@ class Keyring(object):
             verify_requests (List[VerifyKeyRequest]):
         """
 
-        # create a deferred for each server we're going to look up the keys
-        # for; we'll resolve them once we have completed our lookups.
-        # These will be passed into wait_for_previous_lookups to block
-        # any other lookups until we have finished.
-        # The deferreds are called with no logcontext.
-        server_to_deferred = {
-            rq.server_name: defer.Deferred()
-            for rq in verify_requests
-        }
-
-        # We want to wait for any previous lookups to complete before
-        # proceeding.
-        yield self.wait_for_previous_lookups(
-            [rq.server_name for rq in verify_requests],
-            server_to_deferred,
-        )
-
-        # Actually start fetching keys.
-        self._get_server_verify_keys(verify_requests)
-
-        # When we've finished fetching all the keys for a given server_name,
-        # resolve the deferred passed to `wait_for_previous_lookups` so that
-        # any lookups waiting will proceed.
-        #
-        # map from server name to a set of request ids
-        server_to_request_ids = {}
-
-        for verify_request in verify_requests:
-            server_name = verify_request.server_name
-            request_id = id(verify_request)
-            server_to_request_ids.setdefault(server_name, set()).add(request_id)
-
-        def remove_deferreds(res, verify_request):
-            server_name = verify_request.server_name
-            request_id = id(verify_request)
-            server_to_request_ids[server_name].discard(request_id)
-            if not server_to_request_ids[server_name]:
-                d = server_to_deferred.pop(server_name, None)
-                if d:
-                    d.callback(None)
-            return res
-
-        for verify_request in verify_requests:
-            verify_request.deferred.addBoth(
-                remove_deferreds, verify_request,
+        try:
+            # create a deferred for each server we're going to look up the keys
+            # for; we'll resolve them once we have completed our lookups.
+            # These will be passed into wait_for_previous_lookups to block
+            # any other lookups until we have finished.
+            # The deferreds are called with no logcontext.
+            server_to_deferred = {
+                rq.server_name: defer.Deferred()
+                for rq in verify_requests
+            }
+
+            # We want to wait for any previous lookups to complete before
+            # proceeding.
+            yield self.wait_for_previous_lookups(
+                [rq.server_name for rq in verify_requests],
+                server_to_deferred,
             )
 
+            # Actually start fetching keys.
+            self._get_server_verify_keys(verify_requests)
+
+            # When we've finished fetching all the keys for a given server_name,
+            # resolve the deferred passed to `wait_for_previous_lookups` so that
+            # any lookups waiting will proceed.
+            #
+            # map from server name to a set of request ids
+            server_to_request_ids = {}
+
+            for verify_request in verify_requests:
+                server_name = verify_request.server_name
+                request_id = id(verify_request)
+                server_to_request_ids.setdefault(server_name, set()).add(request_id)
+
+            def remove_deferreds(res, verify_request):
+                server_name = verify_request.server_name
+                request_id = id(verify_request)
+                server_to_request_ids[server_name].discard(request_id)
+                if not server_to_request_ids[server_name]:
+                    d = server_to_deferred.pop(server_name, None)
+                    if d:
+                        d.callback(None)
+                return res
+
+            for verify_request in verify_requests:
+                verify_request.deferred.addBoth(
+                    remove_deferreds, verify_request,
+                )
+        except Exception:
+            logger.exception("Error starting key lookups")
+
     @defer.inlineCallbacks
     def wait_for_previous_lookups(self, server_names, server_to_deferred):
         """Waits for any previous key lookups for the given servers to finish.
diff --git a/synapse/federation/transaction_queue.py b/synapse/federation/transaction_queue.py
index 963d938edd..ded2b1871a 100644
--- a/synapse/federation/transaction_queue.py
+++ b/synapse/federation/transaction_queue.py
@@ -323,6 +323,8 @@ class TransactionQueue(object):
                     break
 
                 yield self._process_presence_inner(states_map.values())
+        except Exception:
+            logger.exception("Error sending presence states to servers")
         finally:
             self._processing_pending_presence = False
 
diff --git a/synapse/federation/transport/server.py b/synapse/federation/transport/server.py
index ff0656df3e..19d09f5422 100644
--- a/synapse/federation/transport/server.py
+++ b/synapse/federation/transport/server.py
@@ -25,7 +25,7 @@ from synapse.http.servlet import (
 )
 from synapse.util.ratelimitutils import FederationRateLimiter
 from synapse.util.versionstring import get_version_string
-from synapse.util.logcontext import preserve_fn
+from synapse.util.logcontext import run_in_background
 from synapse.types import ThirdPartyInstanceID, get_domain_from_id
 
 import functools
@@ -152,11 +152,18 @@ class Authenticator(object):
         # alive
         retry_timings = yield self.store.get_destination_retry_timings(origin)
         if retry_timings and retry_timings["retry_last_ts"]:
-            logger.info("Marking origin %r as up", origin)
-            preserve_fn(self.store.set_destination_retry_timings)(origin, 0, 0)
+            run_in_background(self._reset_retry_timings, origin)
 
         defer.returnValue(origin)
 
+    @defer.inlineCallbacks
+    def _reset_retry_timings(self, origin):
+        try:
+            logger.info("Marking origin %r as up", origin)
+            yield self.store.set_destination_retry_timings(origin, 0, 0)
+        except Exception:
+            logger.exception("Error resetting retry timings on %s", origin)
+
 
 class BaseFederationServlet(object):
     REQUIRE_AUTH = True
diff --git a/synapse/groups/attestations.py b/synapse/groups/attestations.py
index 1fb709e6c3..7187df2508 100644
--- a/synapse/groups/attestations.py
+++ b/synapse/groups/attestations.py
@@ -165,28 +165,32 @@ class GroupAttestionRenewer(object):
 
         @defer.inlineCallbacks
         def _renew_attestation(group_id, user_id):
-            if not self.is_mine_id(group_id):
-                destination = get_domain_from_id(group_id)
-            elif not self.is_mine_id(user_id):
-                destination = get_domain_from_id(user_id)
-            else:
-                logger.warn(
-                    "Incorrectly trying to do attestations for user: %r in %r",
-                    user_id, group_id,
+            try:
+                if not self.is_mine_id(group_id):
+                    destination = get_domain_from_id(group_id)
+                elif not self.is_mine_id(user_id):
+                    destination = get_domain_from_id(user_id)
+                else:
+                    logger.warn(
+                        "Incorrectly trying to do attestations for user: %r in %r",
+                        user_id, group_id,
+                    )
+                    yield self.store.remove_attestation_renewal(group_id, user_id)
+                    return
+
+                attestation = self.attestations.create_attestation(group_id, user_id)
+
+                yield self.transport_client.renew_group_attestation(
+                    destination, group_id, user_id,
+                    content={"attestation": attestation},
                 )
-                yield self.store.remove_attestation_renewal(group_id, user_id)
-                return
-
-            attestation = self.attestations.create_attestation(group_id, user_id)
 
-            yield self.transport_client.renew_group_attestation(
-                destination, group_id, user_id,
-                content={"attestation": attestation},
-            )
-
-            yield self.store.update_attestation_renewal(
-                group_id, user_id, attestation
-            )
+                yield self.store.update_attestation_renewal(
+                    group_id, user_id, attestation
+                )
+            except Exception:
+                logger.exception("Error renewing attestation of %r in %r",
+                                 user_id, group_id)
 
         for row in rows:
             group_id = row["group_id"]
diff --git a/synapse/handlers/message.py b/synapse/handlers/message.py
index 21628a8540..d168ff5b86 100644
--- a/synapse/handlers/message.py
+++ b/synapse/handlers/message.py
@@ -857,15 +857,25 @@ class EventCreationHandler(object):
         @defer.inlineCallbacks
         def _notify():
             yield run_on_reactor()
-            self.notifier.on_new_room_event(
-                event, event_stream_id, max_stream_id,
-                extra_users=extra_users
-            )
+            try:
+                self.notifier.on_new_room_event(
+                    event, event_stream_id, max_stream_id,
+                    extra_users=extra_users
+                )
+            except Exception:
+                logger.exception("Error notifying about new room event")
 
         preserve_fn(_notify)()
 
         if event.type == EventTypes.Message:
-            presence = self.hs.get_presence_handler()
             # We don't want to block sending messages on any presence code. This
             # matters as sometimes presence code can take a while.
-            preserve_fn(presence.bump_presence_active_time)(requester.user)
+            run_in_background(self._bump_active_time, requester.user)
+
+    @defer.inlineCallbacks
+    def _bump_active_time(self, user):
+        try:
+            presence = self.hs.get_presence_handler()
+            yield presence.bump_presence_active_time(user)
+        except Exception:
+            logger.exception("Error bumping presence active time")
diff --git a/synapse/handlers/presence.py b/synapse/handlers/presence.py
index a5e501897c..585f3e4da2 100644
--- a/synapse/handlers/presence.py
+++ b/synapse/handlers/presence.py
@@ -31,7 +31,7 @@ from synapse.storage.presence import UserPresenceState
 
 from synapse.util.caches.descriptors import cachedInlineCallbacks
 from synapse.util.async import Linearizer
-from synapse.util.logcontext import preserve_fn
+from synapse.util.logcontext import run_in_background
 from synapse.util.logutils import log_function
 from synapse.util.metrics import Measure
 from synapse.util.wheel_timer import WheelTimer
@@ -254,6 +254,14 @@ class PresenceHandler(object):
 
         logger.info("Finished _persist_unpersisted_changes")
 
+    @defer.inlineCallbacks
+    def _update_states_and_catch_exception(self, new_states):
+        try:
+            res = yield self._update_states(new_states)
+            defer.returnValue(res)
+        except Exception:
+            logger.exception("Error updating presence")
+
     @defer.inlineCallbacks
     def _update_states(self, new_states):
         """Updates presence of users. Sets the appropriate timeouts. Pokes
@@ -364,7 +372,7 @@ class PresenceHandler(object):
                     now=now,
                 )
 
-            preserve_fn(self._update_states)(changes)
+            run_in_background(self._update_states_and_catch_exception, changes)
         except Exception:
             logger.exception("Exception in _handle_timeouts loop")
 
@@ -422,20 +430,23 @@ class PresenceHandler(object):
 
         @defer.inlineCallbacks
         def _end():
-            if affect_presence:
+            try:
                 self.user_to_num_current_syncs[user_id] -= 1
 
                 prev_state = yield self.current_state_for_user(user_id)
                 yield self._update_states([prev_state.copy_and_replace(
                     last_user_sync_ts=self.clock.time_msec(),
                 )])
+            except Exception:
+                logger.exception("Error updating presence after sync")
 
         @contextmanager
         def _user_syncing():
             try:
                 yield
             finally:
-                preserve_fn(_end)()
+                if affect_presence:
+                    run_in_background(_end)
 
         defer.returnValue(_user_syncing())
 
diff --git a/synapse/handlers/receipts.py b/synapse/handlers/receipts.py
index 3f215c2b4e..2e0672161c 100644
--- a/synapse/handlers/receipts.py
+++ b/synapse/handlers/receipts.py
@@ -135,37 +135,40 @@ class ReceiptsHandler(BaseHandler):
         """Given a list of receipts, works out which remote servers should be
         poked and pokes them.
         """
-        # TODO: Some of this stuff should be coallesced.
-        for receipt in receipts:
-            room_id = receipt["room_id"]
-            receipt_type = receipt["receipt_type"]
-            user_id = receipt["user_id"]
-            event_ids = receipt["event_ids"]
-            data = receipt["data"]
-
-            users = yield self.state.get_current_user_in_room(room_id)
-            remotedomains = set(get_domain_from_id(u) for u in users)
-            remotedomains = remotedomains.copy()
-            remotedomains.discard(self.server_name)
-
-            logger.debug("Sending receipt to: %r", remotedomains)
-
-            for domain in remotedomains:
-                self.federation.send_edu(
-                    destination=domain,
-                    edu_type="m.receipt",
-                    content={
-                        room_id: {
-                            receipt_type: {
-                                user_id: {
-                                    "event_ids": event_ids,
-                                    "data": data,
+        try:
+            # TODO: Some of this stuff should be coallesced.
+            for receipt in receipts:
+                room_id = receipt["room_id"]
+                receipt_type = receipt["receipt_type"]
+                user_id = receipt["user_id"]
+                event_ids = receipt["event_ids"]
+                data = receipt["data"]
+
+                users = yield self.state.get_current_user_in_room(room_id)
+                remotedomains = set(get_domain_from_id(u) for u in users)
+                remotedomains = remotedomains.copy()
+                remotedomains.discard(self.server_name)
+
+                logger.debug("Sending receipt to: %r", remotedomains)
+
+                for domain in remotedomains:
+                    self.federation.send_edu(
+                        destination=domain,
+                        edu_type="m.receipt",
+                        content={
+                            room_id: {
+                                receipt_type: {
+                                    user_id: {
+                                        "event_ids": event_ids,
+                                        "data": data,
+                                    }
                                 }
-                            }
+                            },
                         },
-                    },
-                    key=(room_id, receipt_type, user_id),
-                )
+                        key=(room_id, receipt_type, user_id),
+                    )
+        except Exception:
+            logger.exception("Error pushing receipts to remote servers")
 
     @defer.inlineCallbacks
     def get_receipts_for_room(self, room_id, to_key):
diff --git a/synapse/handlers/typing.py b/synapse/handlers/typing.py
index 77c0cf146f..823e2e27e1 100644
--- a/synapse/handlers/typing.py
+++ b/synapse/handlers/typing.py
@@ -205,28 +205,31 @@ class TypingHandler(object):
 
     @defer.inlineCallbacks
     def _push_remote(self, member, typing):
-        users = yield self.state.get_current_user_in_room(member.room_id)
-        self._member_last_federation_poke[member] = self.clock.time_msec()
+        try:
+            users = yield self.state.get_current_user_in_room(member.room_id)
+            self._member_last_federation_poke[member] = self.clock.time_msec()
 
-        now = self.clock.time_msec()
-        self.wheel_timer.insert(
-            now=now,
-            obj=member,
-            then=now + FEDERATION_PING_INTERVAL,
-        )
+            now = self.clock.time_msec()
+            self.wheel_timer.insert(
+                now=now,
+                obj=member,
+                then=now + FEDERATION_PING_INTERVAL,
+            )
 
-        for domain in set(get_domain_from_id(u) for u in users):
-            if domain != self.server_name:
-                self.federation.send_edu(
-                    destination=domain,
-                    edu_type="m.typing",
-                    content={
-                        "room_id": member.room_id,
-                        "user_id": member.user_id,
-                        "typing": typing,
-                    },
-                    key=member,
-                )
+            for domain in set(get_domain_from_id(u) for u in users):
+                if domain != self.server_name:
+                    self.federation.send_edu(
+                        destination=domain,
+                        edu_type="m.typing",
+                        content={
+                            "room_id": member.room_id,
+                            "user_id": member.user_id,
+                            "typing": typing,
+                        },
+                        key=member,
+                    )
+        except Exception:
+            logger.exception("Error pushing typing notif to remotes")
 
     @defer.inlineCallbacks
     def _recv_edu(self, origin, content):
diff --git a/synapse/notifier.py b/synapse/notifier.py
index 0e40a4aad6..939723a404 100644
--- a/synapse/notifier.py
+++ b/synapse/notifier.py
@@ -21,7 +21,7 @@ from synapse.handlers.presence import format_user_presence_state
 from synapse.util import DeferredTimedOutError
 from synapse.util.logutils import log_function
 from synapse.util.async import ObservableDeferred
-from synapse.util.logcontext import PreserveLoggingContext, preserve_fn
+from synapse.util.logcontext import PreserveLoggingContext, run_in_background
 from synapse.util.metrics import Measure
 from synapse.types import StreamToken
 from synapse.visibility import filter_events_for_client
@@ -251,9 +251,7 @@ class Notifier(object):
     def _on_new_room_event(self, event, room_stream_id, extra_users=[]):
         """Notify any user streams that are interested in this room event"""
         # poke any interested application service.
-        preserve_fn(self.appservice_handler.notify_interested_services)(
-            room_stream_id
-        )
+        run_in_background(self._notify_app_services, room_stream_id)
 
         if self.federation_sender:
             self.federation_sender.notify_new_events(room_stream_id)
@@ -267,6 +265,13 @@ class Notifier(object):
             rooms=[event.room_id],
         )
 
+    @defer.inlineCallbacks
+    def _notify_app_services(self, room_stream_id):
+        try:
+            yield self.appservice_handler.notify_interested_services(room_stream_id)
+        except Exception:
+            logger.exception("Error notifying application services of event")
+
     def on_new_event(self, stream_key, new_token, users=[], rooms=[]):
         """ Used to inform listeners that something has happend event wise.
 
diff --git a/synapse/push/emailpusher.py b/synapse/push/emailpusher.py
index 58df98a793..ba7286cb72 100644
--- a/synapse/push/emailpusher.py
+++ b/synapse/push/emailpusher.py
@@ -77,10 +77,13 @@ class EmailPusher(object):
     @defer.inlineCallbacks
     def on_started(self):
         if self.mailer is not None:
-            self.throttle_params = yield self.store.get_throttle_params_by_room(
-                self.pusher_id
-            )
-            yield self._process()
+            try:
+                self.throttle_params = yield self.store.get_throttle_params_by_room(
+                    self.pusher_id
+                )
+                yield self._process()
+            except Exception:
+                logger.exception("Error starting email pusher")
 
     def on_stop(self):
         if self.timed_call:
diff --git a/synapse/push/httppusher.py b/synapse/push/httppusher.py
index 2cbac571b8..1420d378ef 100644
--- a/synapse/push/httppusher.py
+++ b/synapse/push/httppusher.py
@@ -94,7 +94,10 @@ class HttpPusher(object):
 
     @defer.inlineCallbacks
     def on_started(self):
-        yield self._process()
+        try:
+            yield self._process()
+        except Exception:
+            logger.exception("Error starting http pusher")
 
     @defer.inlineCallbacks
     def on_new_notifications(self, min_stream_ordering, max_stream_ordering):
diff --git a/synapse/rest/media/v1/storage_provider.py b/synapse/rest/media/v1/storage_provider.py
index c188192f2b..0252afd9d3 100644
--- a/synapse/rest/media/v1/storage_provider.py
+++ b/synapse/rest/media/v1/storage_provider.py
@@ -18,7 +18,7 @@ from twisted.internet import defer, threads
 from .media_storage import FileResponder
 
 from synapse.config._base import Config
-from synapse.util.logcontext import preserve_fn
+from synapse.util.logcontext import run_in_background
 
 import logging
 import os
@@ -87,7 +87,12 @@ class StorageProviderWrapper(StorageProvider):
             return self.backend.store_file(path, file_info)
         else:
             # TODO: Handle errors.
-            preserve_fn(self.backend.store_file)(path, file_info)
+            def store():
+                try:
+                    return self.backend.store_file(path, file_info)
+                except Exception:
+                    logger.exception("Error storing file")
+            run_in_background(store)
             return defer.succeed(None)
 
     def fetch(self, path, file_info):
diff --git a/synapse/storage/event_push_actions.py b/synapse/storage/event_push_actions.py
index e78f8d0114..c22762eb5c 100644
--- a/synapse/storage/event_push_actions.py
+++ b/synapse/storage/event_push_actions.py
@@ -448,6 +448,7 @@ class EventPushActionsWorkerStore(SQLBaseStore):
             "add_push_actions_to_staging", _add_push_actions_to_staging_txn
         )
 
+    @defer.inlineCallbacks
     def remove_push_actions_from_staging(self, event_id):
         """Called if we failed to persist the event to ensure that stale push
         actions don't build up in the DB
@@ -456,13 +457,22 @@ class EventPushActionsWorkerStore(SQLBaseStore):
             event_id (str)
         """
 
-        return self._simple_delete(
-            table="event_push_actions_staging",
-            keyvalues={
-                "event_id": event_id,
-            },
-            desc="remove_push_actions_from_staging",
-        )
+        try:
+            res = yield self._simple_delete(
+                table="event_push_actions_staging",
+                keyvalues={
+                    "event_id": event_id,
+                },
+                desc="remove_push_actions_from_staging",
+            )
+            defer.returnValue(res)
+        except Exception:
+            # this method is called from an exception handler, so propagating
+            # another exception here really isn't helpful - there's nothing
+            # the caller can do about it. Just log the exception and move on.
+            logger.exception(
+                "Error removing push actions after event persistence failure",
+            )
 
     @defer.inlineCallbacks
     def _find_stream_orderings_for_times(self):
diff --git a/synapse/util/logcontext.py b/synapse/util/logcontext.py
index d59adc236e..d6587e4409 100644
--- a/synapse/util/logcontext.py
+++ b/synapse/util/logcontext.py
@@ -305,7 +305,12 @@ def run_in_background(f, *args, **kwargs):
     deferred returned by the funtion completes.
 
     Useful for wrapping functions that return a deferred which you don't yield
-    on.
+    on (for instance because you want to pass it to deferred.gatherResults()).
+
+    Note that if you completely discard the result, you should make sure that
+    `f` doesn't raise any deferred exceptions, otherwise a scary-looking
+    CRITICAL error about an unhandled error will be logged without much
+    indication about where it came from.
     """
     current = LoggingContext.current_context()
     res = f(*args, **kwargs)
-- 
cgit 1.5.1


From 07cad26d65dcf237643a43ff2bdfac73ca7a7257 Mon Sep 17 00:00:00 2001
From: Amber Brown <hawkowl@atleastfornow.net>
Date: Mon, 25 Jun 2018 14:08:28 +0100
Subject: Remove all global reactor imports & pass it around explicitly (#3424)

---
 synapse/handlers/deactivate_account.py |  4 ++--
 synapse/handlers/message.py            |  4 ++--
 synapse/handlers/presence.py           |  4 ++--
 synapse/http/endpoint.py               | 16 +++++++++-------
 synapse/push/emailpusher.py            |  4 ++--
 synapse/push/httppusher.py             |  6 ++++--
 synapse/replication/tcp/client.py      |  6 +++---
 synapse/replication/tcp/resource.py    |  4 ++--
 synapse/util/__init__.py               |  3 +++
 9 files changed, 29 insertions(+), 22 deletions(-)

(limited to 'synapse/push/emailpusher.py')

diff --git a/synapse/handlers/deactivate_account.py b/synapse/handlers/deactivate_account.py
index 8ec5ba2012..6116842764 100644
--- a/synapse/handlers/deactivate_account.py
+++ b/synapse/handlers/deactivate_account.py
@@ -12,7 +12,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-from twisted.internet import defer, reactor
+from twisted.internet import defer
 
 from ._base import BaseHandler
 from synapse.types import UserID, create_requester
@@ -39,7 +39,7 @@ class DeactivateAccountHandler(BaseHandler):
 
         # Start the user parter loop so it can resume parting users from rooms where
         # it left off (if it has work left to do).
-        reactor.callWhenRunning(self._start_user_parting)
+        hs.get_reactor().callWhenRunning(self._start_user_parting)
 
     @defer.inlineCallbacks
     def deactivate_account(self, user_id):
diff --git a/synapse/handlers/message.py b/synapse/handlers/message.py
index 7b9946ab91..a812117dea 100644
--- a/synapse/handlers/message.py
+++ b/synapse/handlers/message.py
@@ -20,7 +20,7 @@ import sys
 from canonicaljson import encode_canonical_json
 import six
 from six import string_types, itervalues, iteritems
-from twisted.internet import defer, reactor
+from twisted.internet import defer
 from twisted.internet.defer import succeed
 from twisted.python.failure import Failure
 
@@ -157,7 +157,7 @@ class MessageHandler(BaseHandler):
             # remove the purge from the list 24 hours after it completes
             def clear_purge():
                 del self._purges_by_id[purge_id]
-            reactor.callLater(24 * 3600, clear_purge)
+            self.hs.get_reactor().callLater(24 * 3600, clear_purge)
 
     def get_purge_status(self, purge_id):
         """Get the current status of an active purge
diff --git a/synapse/handlers/presence.py b/synapse/handlers/presence.py
index 7fe568132f..7db59fba00 100644
--- a/synapse/handlers/presence.py
+++ b/synapse/handlers/presence.py
@@ -22,7 +22,7 @@ The methods that define policy are:
     - should_notify
 """
 
-from twisted.internet import defer, reactor
+from twisted.internet import defer
 from contextlib import contextmanager
 
 from six import itervalues, iteritems
@@ -179,7 +179,7 @@ class PresenceHandler(object):
         # have not yet been persisted
         self.unpersisted_users_changes = set()
 
-        reactor.addSystemEventTrigger("before", "shutdown", self._on_shutdown)
+        hs.get_reactor().addSystemEventTrigger("before", "shutdown", self._on_shutdown)
 
         self.serial_to_user = {}
         self._next_serial = 1
diff --git a/synapse/http/endpoint.py b/synapse/http/endpoint.py
index 87a482650d..928c1c7407 100644
--- a/synapse/http/endpoint.py
+++ b/synapse/http/endpoint.py
@@ -13,7 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 from twisted.internet.endpoints import HostnameEndpoint, wrapClientTLS
-from twisted.internet import defer, reactor
+from twisted.internet import defer
 from twisted.internet.error import ConnectError
 from twisted.names import client, dns
 from twisted.names.error import DNSNameError, DomainError
@@ -78,17 +78,18 @@ def matrix_federation_endpoint(reactor, destination, ssl_context_factory=None,
     else:
         return _WrappingEndpointFac(transport_endpoint(
             reactor, domain, port, **endpoint_kw_args
-        ))
+        ), reactor)
 
 
 class _WrappingEndpointFac(object):
-    def __init__(self, endpoint_fac):
+    def __init__(self, endpoint_fac, reactor):
         self.endpoint_fac = endpoint_fac
+        self.reactor = reactor
 
     @defer.inlineCallbacks
     def connect(self, protocolFactory):
         conn = yield self.endpoint_fac.connect(protocolFactory)
-        conn = _WrappedConnection(conn)
+        conn = _WrappedConnection(conn, self.reactor)
         defer.returnValue(conn)
 
 
@@ -98,9 +99,10 @@ class _WrappedConnection(object):
     """
     __slots__ = ["conn", "last_request"]
 
-    def __init__(self, conn):
+    def __init__(self, conn, reactor):
         object.__setattr__(self, "conn", conn)
         object.__setattr__(self, "last_request", time.time())
+        self._reactor = reactor
 
     def __getattr__(self, name):
         return getattr(self.conn, name)
@@ -131,14 +133,14 @@ class _WrappedConnection(object):
         # Time this connection out if we haven't send a request in the last
         # N minutes
         # TODO: Cancel the previous callLater?
-        reactor.callLater(3 * 60, self._time_things_out_maybe)
+        self._reactor.callLater(3 * 60, self._time_things_out_maybe)
 
         d = self.conn.request(request)
 
         def update_request_time(res):
             self.last_request = time.time()
             # TODO: Cancel the previous callLater?
-            reactor.callLater(3 * 60, self._time_things_out_maybe)
+            self._reactor.callLater(3 * 60, self._time_things_out_maybe)
             return res
 
         d.addCallback(update_request_time)
diff --git a/synapse/push/emailpusher.py b/synapse/push/emailpusher.py
index ba7286cb72..52d4f087ee 100644
--- a/synapse/push/emailpusher.py
+++ b/synapse/push/emailpusher.py
@@ -13,7 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from twisted.internet import defer, reactor
+from twisted.internet import defer
 from twisted.internet.error import AlreadyCalled, AlreadyCancelled
 
 import logging
@@ -199,7 +199,7 @@ class EmailPusher(object):
                     self.timed_call = None
 
         if soonest_due_at is not None:
-            self.timed_call = reactor.callLater(
+            self.timed_call = self.hs.get_reactor().callLater(
                 self.seconds_until(soonest_due_at), self.on_timer
             )
 
diff --git a/synapse/push/httppusher.py b/synapse/push/httppusher.py
index bf7ff74a1a..7a481b5a1e 100644
--- a/synapse/push/httppusher.py
+++ b/synapse/push/httppusher.py
@@ -15,7 +15,7 @@
 # limitations under the License.
 import logging
 
-from twisted.internet import defer, reactor
+from twisted.internet import defer
 from twisted.internet.error import AlreadyCalled, AlreadyCancelled
 
 from . import push_rule_evaluator
@@ -220,7 +220,9 @@ class HttpPusher(object):
                     )
                 else:
                     logger.info("Push failed: delaying for %ds", self.backoff_delay)
-                    self.timed_call = reactor.callLater(self.backoff_delay, self.on_timer)
+                    self.timed_call = self.hs.get_reactor().callLater(
+                        self.backoff_delay, self.on_timer
+                    )
                     self.backoff_delay = min(self.backoff_delay * 2, self.MAX_BACKOFF_SEC)
                     break
 
diff --git a/synapse/replication/tcp/client.py b/synapse/replication/tcp/client.py
index 6d2513c4e2..bb852b00af 100644
--- a/synapse/replication/tcp/client.py
+++ b/synapse/replication/tcp/client.py
@@ -15,7 +15,7 @@
 """A replication client for use by synapse workers.
 """
 
-from twisted.internet import reactor, defer
+from twisted.internet import defer
 from twisted.internet.protocol import ReconnectingClientFactory
 
 from .commands import (
@@ -44,7 +44,7 @@ class ReplicationClientFactory(ReconnectingClientFactory):
         self.server_name = hs.config.server_name
         self._clock = hs.get_clock()  # As self.clock is defined in super class
 
-        reactor.addSystemEventTrigger("before", "shutdown", self.stopTrying)
+        hs.get_reactor().addSystemEventTrigger("before", "shutdown", self.stopTrying)
 
     def startedConnecting(self, connector):
         logger.info("Connecting to replication: %r", connector.getDestination())
@@ -95,7 +95,7 @@ class ReplicationClientHandler(object):
         factory = ReplicationClientFactory(hs, client_name, self)
         host = hs.config.worker_replication_host
         port = hs.config.worker_replication_port
-        reactor.connectTCP(host, port, factory)
+        hs.get_reactor().connectTCP(host, port, factory)
 
     def on_rdata(self, stream_name, token, rows):
         """Called when we get new replication data. By default this just pokes
diff --git a/synapse/replication/tcp/resource.py b/synapse/replication/tcp/resource.py
index 63bd6d2652..95ad8c1b4c 100644
--- a/synapse/replication/tcp/resource.py
+++ b/synapse/replication/tcp/resource.py
@@ -15,7 +15,7 @@
 """The server side of the replication stream.
 """
 
-from twisted.internet import defer, reactor
+from twisted.internet import defer
 from twisted.internet.protocol import Factory
 
 from .streams import STREAMS_MAP, FederationStream
@@ -109,7 +109,7 @@ class ReplicationStreamer(object):
         self.is_looping = False
         self.pending_updates = False
 
-        reactor.addSystemEventTrigger("before", "shutdown", self.on_shutdown)
+        hs.get_reactor().addSystemEventTrigger("before", "shutdown", self.on_shutdown)
 
     def on_shutdown(self):
         # close all connections on shutdown
diff --git a/synapse/util/__init__.py b/synapse/util/__init__.py
index 2a3df7c71d..e9886ef299 100644
--- a/synapse/util/__init__.py
+++ b/synapse/util/__init__.py
@@ -34,6 +34,9 @@ def unwrapFirstError(failure):
 class Clock(object):
     """
     A Clock wraps a Twisted reactor and provides utilities on top of it.
+
+    Args:
+        reactor: The Twisted reactor to use.
     """
     _reactor = attr.ib()
 
-- 
cgit 1.5.1


From 49af4020190eae6b0c65897d96cd2be286364d2b Mon Sep 17 00:00:00 2001
From: Amber Brown <hawkowl@atleastfornow.net>
Date: Mon, 9 Jul 2018 16:09:20 +1000
Subject: run isort

---
 synapse/api/auth.py                                |  7 +--
 synapse/api/errors.py                              |  4 +-
 synapse/api/filtering.py                           | 14 ++---
 synapse/api/urls.py                                |  2 +-
 synapse/app/__init__.py                            |  4 +-
 synapse/app/_base.py                               | 11 ++--
 synapse/app/appservice.py                          |  5 +-
 synapse/app/client_reader.py                       |  5 +-
 synapse/app/event_creator.py                       |  9 ++--
 synapse/app/federation_reader.py                   |  5 +-
 synapse/app/federation_sender.py                   |  5 +-
 synapse/app/frontend_proxy.py                      |  9 ++--
 synapse/app/homeserver.py                          | 33 +++++++-----
 synapse/app/media_repository.py                    |  9 ++--
 synapse/app/pusher.py                              |  5 +-
 synapse/app/synchrotron.py                         | 11 ++--
 synapse/app/synctl.py                              |  5 +-
 synapse/app/user_dir.py                            |  5 +-
 synapse/appservice/__init__.py                     | 12 ++---
 synapse/appservice/api.py                          | 14 ++---
 synapse/appservice/scheduler.py                    |  4 +-
 synapse/config/_base.py                            |  3 +-
 synapse/config/api.py                              |  4 +-
 synapse/config/appservice.py                       | 14 ++---
 synapse/config/homeserver.py                       | 36 ++++++-------
 synapse/config/jwt.py                              |  1 -
 synapse/config/key.py                              | 21 ++++----
 synapse/config/logger.py                           |  6 ++-
 synapse/config/password_auth_providers.py          |  4 +-
 synapse/config/registration.py                     |  4 +-
 synapse/config/repository.py                       |  2 +-
 synapse/config/server.py                           |  1 +
 synapse/config/server_notices_config.py            |  3 +-
 synapse/config/tls.py                              | 11 ++--
 synapse/crypto/context_factory.py                  |  6 +--
 synapse/crypto/event_signing.py                    | 10 ++--
 synapse/crypto/keyclient.py                        | 14 ++---
 synapse/crypto/keyring.py                          | 44 ++++++++--------
 synapse/event_auth.py                              |  6 +--
 synapse/events/__init__.py                         |  3 +-
 synapse/events/builder.py                          |  5 +-
 synapse/events/snapshot.py                         |  4 +-
 synapse/events/utils.py                            |  9 ++--
 synapse/events/validator.py                        |  8 +--
 synapse/federation/federation_base.py              |  7 +--
 synapse/federation/federation_client.py            | 14 ++---
 synapse/federation/federation_server.py            | 18 +++----
 synapse/federation/persistence.py                  |  5 +-
 synapse/federation/send_queue.py                   | 14 ++---
 synapse/federation/transaction_queue.py            | 30 +++++------
 synapse/federation/transport/client.py             |  9 ++--
 synapse/federation/transport/server.py             | 21 ++++----
 synapse/federation/units.py                        |  3 +-
 synapse/groups/attestations.py                     |  5 +-
 synapse/groups/groups_server.py                    |  7 +--
 synapse/handlers/__init__.py                       | 10 ++--
 synapse/handlers/_base.py                          |  3 +-
 synapse/handlers/admin.py                          |  4 +-
 synapse/handlers/appservice.py                     | 13 +++--
 synapse/handlers/auth.py                           | 26 +++++-----
 synapse/handlers/deactivate_account.py             |  7 +--
 synapse/handlers/device.py                         | 16 +++---
 synapse/handlers/devicemessage.py                  |  3 +-
 synapse/handlers/directory.py                      |  9 ++--
 synapse/handlers/e2e_keys.py                       | 10 ++--
 synapse/handlers/events.py                         | 15 +++---
 synapse/handlers/federation.py                     | 40 ++++++++-------
 synapse/handlers/groups_local.py                   |  7 +--
 synapse/handlers/identity.py                       |  7 ++-
 synapse/handlers/initial_sync.py                   |  9 ++--
 synapse/handlers/message.py                        | 23 ++++-----
 synapse/handlers/presence.py                       | 21 ++++----
 synapse/handlers/profile.py                        |  3 +-
 synapse/handlers/read_marker.py                    |  5 +-
 synapse/handlers/receipts.py                       | 10 ++--
 synapse/handlers/register.py                       | 11 ++--
 synapse/handlers/room.py                           | 19 +++----
 synapse/handlers/room_list.py                      | 20 ++++----
 synapse/handlers/room_member.py                    | 14 +++--
 synapse/handlers/room_member_worker.py             |  5 +-
 synapse/handlers/search.py                         | 17 +++----
 synapse/handlers/set_password.py                   |  1 +
 synapse/handlers/sync.py                           | 24 ++++-----
 synapse/handlers/typing.py                         | 11 ++--
 synapse/handlers/user_directory.py                 |  7 +--
 synapse/http/additional_resource.py                |  3 +-
 synapse/http/client.py                             | 48 +++++++++---------
 synapse/http/endpoint.py                           | 12 ++---
 synapse/http/matrixfederationclient.py             | 48 +++++++++---------
 synapse/http/request_metrics.py                    |  2 +-
 synapse/http/server.py                             | 38 +++++++-------
 synapse/http/servlet.py                            |  3 +-
 synapse/http/site.py                               |  2 +-
 synapse/metrics/__init__.py                        | 11 ++--
 synapse/notifier.py                                | 21 ++++----
 synapse/push/action_generator.py                   |  6 +--
 synapse/push/baserules.py                          |  3 +-
 synapse/push/bulk_push_rule_evaluator.py           | 17 ++++---
 synapse/push/clientformat.py                       |  6 +--
 synapse/push/emailpusher.py                        |  7 ++-
 synapse/push/httppusher.py                         |  6 +--
 synapse/push/mailer.py                             | 33 ++++++------
 synapse/push/presentable_names.py                  |  6 +--
 synapse/push/push_rule_evaluator.py                |  4 +-
 synapse/push/push_tools.py                         |  5 +-
 synapse/push/pusher.py                             |  3 +-
 synapse/replication/http/__init__.py               |  1 -
 synapse/replication/http/membership.py             |  4 +-
 synapse/replication/http/send_event.py             | 12 +++--
 synapse/replication/slave/storage/_base.py         |  4 +-
 synapse/replication/slave/storage/appservice.py    |  3 +-
 synapse/replication/slave/storage/client_ips.py    |  3 +-
 synapse/replication/slave/storage/deviceinbox.py   |  7 +--
 synapse/replication/slave/storage/devices.py       |  5 +-
 synapse/replication/slave/storage/directory.py     |  3 +-
 synapse/replication/slave/storage/events.py        |  3 +-
 synapse/replication/slave/storage/filtering.py     |  3 +-
 synapse/replication/slave/storage/groups.py        |  5 +-
 synapse/replication/slave/storage/keys.py          |  3 +-
 synapse/replication/slave/storage/presence.py      |  8 +--
 synapse/replication/slave/storage/push_rule.py     |  5 +-
 synapse/replication/slave/storage/pushers.py       |  4 +-
 synapse/replication/slave/storage/receipts.py      |  4 +-
 synapse/replication/slave/storage/registration.py  |  3 +-
 synapse/replication/slave/storage/room.py          |  3 +-
 synapse/replication/slave/storage/transactions.py  |  3 +-
 synapse/replication/tcp/client.py                  |  9 ++--
 synapse/replication/tcp/protocol.py                | 40 +++++++++------
 synapse/replication/tcp/resource.py                | 17 ++++---
 synapse/replication/tcp/streams.py                 |  5 +-
 synapse/rest/__init__.py                           | 55 ++++++++------------
 synapse/rest/client/v1/admin.py                    | 10 ++--
 synapse/rest/client/v1/base.py                     | 10 ++--
 synapse/rest/client/v1/directory.py                |  9 ++--
 synapse/rest/client/v1/events.py                   |  8 +--
 synapse/rest/client/v1/initial_sync.py             |  1 +
 synapse/rest/client/v1/login.py                    | 30 +++++------
 synapse/rest/client/v1/logout.py                   |  5 +-
 synapse/rest/client/v1/presence.py                 | 13 ++---
 synapse/rest/client/v1/profile.py                  |  5 +-
 synapse/rest/client/v1/push_rule.py                | 16 +++---
 synapse/rest/client/v1/pusher.py                   | 15 +++---
 synapse/rest/client/v1/register.py                 | 19 +++----
 synapse/rest/client/v1/room.py                     | 24 +++++----
 synapse/rest/client/v1/voip.py                     |  9 ++--
 synapse/rest/client/v2_alpha/account.py            |  5 +-
 synapse/rest/client/v2_alpha/account_data.py       | 10 ++--
 synapse/rest/client/v2_alpha/auth.py               |  5 +-
 synapse/rest/client/v2_alpha/devices.py            |  1 +
 synapse/rest/client/v2_alpha/filter.py             | 10 ++--
 synapse/rest/client/v2_alpha/groups.py             |  4 +-
 synapse/rest/client/v2_alpha/keys.py               |  7 ++-
 synapse/rest/client/v2_alpha/notifications.py      | 11 ++--
 synapse/rest/client/v2_alpha/openid.py             | 10 ++--
 synapse/rest/client/v2_alpha/read_marker.py        |  6 +--
 synapse/rest/client/v2_alpha/receipts.py           |  6 +--
 synapse/rest/client/v2_alpha/register.py           | 22 ++++----
 synapse/rest/client/v2_alpha/report_event.py       |  6 +--
 synapse/rest/client/v2_alpha/sync.py               | 27 +++++-----
 synapse/rest/client/v2_alpha/tags.py               | 10 ++--
 synapse/rest/client/v2_alpha/thirdparty.py         |  1 +
 synapse/rest/client/v2_alpha/user_directory.py     |  1 +
 synapse/rest/client/versions.py                    |  4 +-
 synapse/rest/consent/consent_resource.py           | 12 ++---
 synapse/rest/key/v1/server_key_resource.py         | 10 ++--
 synapse/rest/key/v2/__init__.py                    |  1 +
 synapse/rest/key/v2/local_key_resource.py          | 10 ++--
 synapse/rest/key/v2/remote_key_resource.py         | 16 +++---
 synapse/rest/media/v0/content_repository.py        | 19 +++----
 synapse/rest/media/v1/_base.py                     | 19 +++----
 synapse/rest/media/v1/download_resource.py         |  6 +--
 synapse/rest/media/v1/filepath.py                  |  2 +-
 synapse/rest/media/v1/identicon_resource.py        |  1 +
 synapse/rest/media/v1/media_repository.py          | 51 ++++++++++---------
 synapse/rest/media/v1/media_storage.py             | 17 +++----
 synapse/rest/media/v1/preview_url_resource.py      | 25 ++++-----
 synapse/rest/media/v1/storage_provider.py          | 11 ++--
 synapse/rest/media/v1/thumbnail_resource.py        | 11 ++--
 synapse/rest/media/v1/thumbnailer.py               |  4 +-
 synapse/rest/media/v1/upload_resource.py           |  5 +-
 synapse/server.py                                  | 34 ++++++-------
 synapse/server_notices/consent_server_notices.py   |  3 +-
 synapse/state.py                                   | 22 ++++----
 synapse/storage/__init__.py                        | 59 ++++++++++------------
 synapse/storage/_base.py                           | 19 ++++---
 synapse/storage/account_data.py                    | 13 +++--
 synapse/storage/appservice.py                      |  6 ++-
 synapse/storage/background_updates.py              | 10 ++--
 synapse/storage/client_ips.py                      |  9 ++--
 synapse/storage/deviceinbox.py                     |  3 +-
 synapse/storage/devices.py                         | 11 ++--
 synapse/storage/directory.py                       |  9 ++--
 synapse/storage/end_to_end_keys.py                 |  8 +--
 synapse/storage/engines/__init__.py                |  7 ++-
 synapse/storage/engines/sqlite3.py                 |  4 +-
 synapse/storage/event_federation.py                | 16 +++---
 synapse/storage/event_push_actions.py              | 11 ++--
 synapse/storage/events.py                          | 34 ++++++-------
 synapse/storage/events_worker.py                   | 25 +++++----
 synapse/storage/filtering.py                       |  7 +--
 synapse/storage/group_server.py                    |  5 +-
 synapse/storage/keys.py                            | 14 ++---
 synapse/storage/prepare_database.py                |  1 -
 synapse/storage/presence.py                        | 10 ++--
 synapse/storage/profile.py                         |  2 +-
 synapse/storage/push_rule.py                       | 18 ++++---
 synapse/storage/pusher.py                          |  9 ++--
 synapse/storage/receipts.py                        | 16 +++---
 synapse/storage/registration.py                    |  6 +--
 synapse/storage/rejections.py                      |  4 +-
 synapse/storage/room.py                            | 12 ++---
 synapse/storage/roommember.py                      | 19 ++++---
 synapse/storage/schema/delta/25/fts.py             |  6 +--
 synapse/storage/schema/delta/27/ts.py              |  4 +-
 synapse/storage/schema/delta/30/as_users.py        |  2 +-
 synapse/storage/schema/delta/31/search_update.py   |  7 +--
 synapse/storage/schema/delta/33/event_fields.py    |  5 +-
 synapse/storage/schema/delta/33/remote_media_ts.py |  1 -
 synapse/storage/schema/delta/34/cache_stream.py    |  6 +--
 .../storage/schema/delta/34/received_txn_purge.py  |  4 +-
 synapse/storage/schema/delta/34/sent_txn_purge.py  |  4 +-
 synapse/storage/schema/delta/37/remove_auth_idx.py |  6 +--
 synapse/storage/schema/delta/42/user_dir.py        |  2 +-
 synapse/storage/search.py                          |  8 +--
 synapse/storage/signatures.py                      |  8 +--
 synapse/storage/state.py                           |  5 +-
 synapse/storage/stream.py                          | 16 +++---
 synapse/storage/tags.py                            | 10 ++--
 synapse/storage/transactions.py                    | 11 ++--
 synapse/storage/user_directory.py                  | 14 ++---
 synapse/storage/user_erasure_store.py              |  2 +-
 synapse/storage/util/id_generators.py              |  2 +-
 synapse/streams/config.py                          |  5 +-
 synapse/streams/events.py                          |  7 ++-
 synapse/types.py                                   |  3 +-
 synapse/util/__init__.py                           |  1 +
 synapse/util/async.py                              | 18 ++++---
 synapse/util/caches/__init__.py                    |  6 +--
 synapse/util/caches/descriptors.py                 | 22 ++++----
 synapse/util/caches/dictionary_cache.py            |  9 ++--
 synapse/util/caches/expiringcache.py               |  5 +-
 synapse/util/caches/lrucache.py                    |  2 +-
 synapse/util/caches/stream_change_cache.py         |  5 +-
 synapse/util/file_consumer.py                      |  4 +-
 synapse/util/frozenutils.py                        |  6 +--
 synapse/util/httpresourcetree.py                   |  4 +-
 synapse/util/logcontext.py                         |  6 +--
 synapse/util/logformatter.py                       |  3 +-
 synapse/util/logutils.py                           |  8 ++-
 synapse/util/manhole.py                            |  6 +--
 synapse/util/metrics.py                            |  8 +--
 synapse/util/msisdn.py                             |  1 +
 synapse/util/ratelimitutils.py                     | 13 +++--
 synapse/util/retryutils.py                         |  9 ++--
 synapse/util/rlimit.py                             |  3 +-
 synapse/util/stringutils.py                        |  1 +
 synapse/util/versionstring.py                      |  4 +-
 synapse/visibility.py                              |  4 +-
 tests/__init__.py                                  |  1 +
 tests/api/test_auth.py                             |  7 ++-
 tests/api/test_filtering.py                        | 15 +++---
 tests/appservice/test_appservice.py                |  9 ++--
 tests/appservice/test_scheduler.py                 | 15 ++++--
 tests/config/test_generate.py                      |  1 +
 tests/config/test_load.py                          |  3 ++
 tests/crypto/test_event_signing.py                 | 10 ++--
 tests/crypto/test_keyring.py                       | 10 ++--
 tests/events/test_utils.py                         |  4 +-
 tests/federation/test_federation_server.py         |  1 +
 tests/handlers/test_appservice.py                  |  8 +--
 tests/handlers/test_auth.py                        |  2 +
 tests/handlers/test_device.py                      |  2 +-
 tests/handlers/test_directory.py                   |  6 +--
 tests/handlers/test_e2e_keys.py                    |  5 +-
 tests/handlers/test_presence.py                    | 12 +++--
 tests/handlers/test_profile.py                     |  6 +--
 tests/handlers/test_register.py                    |  5 +-
 tests/handlers/test_typing.py                      | 19 ++++---
 tests/http/test_endpoint.py                        |  6 +--
 tests/replication/slave/storage/_base.py           | 15 +++---
 .../replication/slave/storage/test_account_data.py |  4 +-
 tests/replication/slave/storage/test_events.py     |  5 +-
 tests/replication/slave/storage/test_receipts.py   |  4 +-
 tests/rest/client/test_transactions.py             |  7 +--
 tests/rest/client/v1/test_events.py                |  6 +--
 tests/rest/client/v1/test_profile.py               |  5 +-
 tests/rest/client/v1/test_register.py              | 10 ++--
 tests/rest/client/v1/test_rooms.py                 | 11 ++--
 tests/rest/client/v1/test_typing.py                |  7 ++-
 tests/rest/client/v1/utils.py                      | 10 ++--
 tests/rest/client/v2_alpha/__init__.py             |  7 ++-
 tests/rest/client/v2_alpha/test_filter.py          | 11 ++--
 tests/rest/client/v2_alpha/test_register.py        | 11 ++--
 tests/rest/media/v1/test_media_storage.py          | 14 ++---
 tests/server.py                                    | 10 ++--
 tests/storage/test__base.py                        |  8 +--
 tests/storage/test_appservice.py                   | 20 +++++---
 tests/storage/test_background_update.py            |  6 +--
 tests/storage/test_base.py                         |  8 +--
 tests/storage/test_devices.py                      |  1 +
 tests/storage/test_directory.py                    |  4 +-
 tests/storage/test_event_push_actions.py           |  3 +-
 tests/storage/test_keys.py                         |  1 +
 tests/storage/test_presence.py                     |  4 +-
 tests/storage/test_profile.py                      |  2 +-
 tests/storage/test_redaction.py                    |  8 +--
 tests/storage/test_registration.py                 |  2 +-
 tests/storage/test_room.py                         |  4 +-
 tests/storage/test_roommember.py                   |  8 +--
 tests/storage/test_user_directory.py               |  1 +
 tests/test_distributor.py                          |  7 +--
 tests/test_dns.py                                  |  7 +--
 tests/test_event_auth.py                           |  3 +-
 tests/test_federation.py                           | 10 ++--
 tests/test_preview.py                              |  7 +--
 tests/test_server.py                               |  3 +-
 tests/test_state.py                                | 10 ++--
 tests/test_test_utils.py                           |  1 -
 tests/test_types.py                                |  6 +--
 tests/util/caches/test_descriptors.py              |  7 ++-
 tests/util/test_dict_cache.py                      |  4 +-
 tests/util/test_expiring_cache.py                  |  4 +-
 tests/util/test_file_consumer.py                   |  9 ++--
 tests/util/test_limiter.py                         |  4 +-
 tests/util/test_linearizer.py                      |  7 +--
 tests/util/test_logcontext.py                      |  8 +--
 tests/util/test_logformatter.py                    |  1 +
 tests/util/test_lrucache.py                        |  4 +-
 tests/util/test_rwlock.py                          |  4 +-
 tests/util/test_snapshot_cache.py                  |  5 +-
 tests/util/test_stream_change_cache.py             |  3 +-
 tests/util/test_treecache.py                       |  4 +-
 tests/util/test_wheel_timer.py                     |  4 +-
 tests/utils.py                                     |  3 +-
 334 files changed, 1609 insertions(+), 1528 deletions(-)

(limited to 'synapse/push/emailpusher.py')

diff --git a/synapse/api/auth.py b/synapse/api/auth.py
index 088b4e8b6d..6dec862fec 100644
--- a/synapse/api/auth.py
+++ b/synapse/api/auth.py
@@ -18,15 +18,16 @@ import logging
 from six import itervalues
 
 import pymacaroons
-from twisted.internet import defer
 from netaddr import IPAddress
 
+from twisted.internet import defer
+
 import synapse.types
 from synapse import event_auth
-from synapse.api.constants import EventTypes, Membership, JoinRules
+from synapse.api.constants import EventTypes, JoinRules, Membership
 from synapse.api.errors import AuthError, Codes
 from synapse.types import UserID
-from synapse.util.caches import register_cache, CACHE_SIZE_FACTOR
+from synapse.util.caches import CACHE_SIZE_FACTOR, register_cache
 from synapse.util.caches.lrucache import LruCache
 from synapse.util.metrics import Measure
 
diff --git a/synapse/api/errors.py b/synapse/api/errors.py
index 227a0713b2..6074df292f 100644
--- a/synapse/api/errors.py
+++ b/synapse/api/errors.py
@@ -17,11 +17,11 @@
 
 import logging
 
-from canonicaljson import json
-
 from six import iteritems
 from six.moves import http_client
 
+from canonicaljson import json
+
 logger = logging.getLogger(__name__)
 
 
diff --git a/synapse/api/filtering.py b/synapse/api/filtering.py
index aae25e7a47..25346baa87 100644
--- a/synapse/api/filtering.py
+++ b/synapse/api/filtering.py
@@ -12,16 +12,16 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-from synapse.api.errors import SynapseError
-from synapse.storage.presence import UserPresenceState
-from synapse.types import UserID, RoomID
-from twisted.internet import defer
-
-from canonicaljson import json
-
 import jsonschema
+from canonicaljson import json
 from jsonschema import FormatChecker
 
+from twisted.internet import defer
+
+from synapse.api.errors import SynapseError
+from synapse.storage.presence import UserPresenceState
+from synapse.types import RoomID, UserID
+
 FILTER_SCHEMA = {
     "additionalProperties": False,
     "type": "object",
diff --git a/synapse/api/urls.py b/synapse/api/urls.py
index bb46b5da8a..71347912f1 100644
--- a/synapse/api/urls.py
+++ b/synapse/api/urls.py
@@ -15,8 +15,8 @@
 # limitations under the License.
 
 """Contains the URL paths to prefix various aspects of the server with. """
-from hashlib import sha256
 import hmac
+from hashlib import sha256
 
 from six.moves.urllib.parse import urlencode
 
diff --git a/synapse/app/__init__.py b/synapse/app/__init__.py
index 9c2b627590..3b6b9368b8 100644
--- a/synapse/app/__init__.py
+++ b/synapse/app/__init__.py
@@ -14,9 +14,11 @@
 # limitations under the License.
 
 import sys
+
+from synapse import python_dependencies  # noqa: E402
+
 sys.dont_write_bytecode = True
 
-from synapse import python_dependencies   # noqa: E402
 
 try:
     python_dependencies.check_requirements()
diff --git a/synapse/app/_base.py b/synapse/app/_base.py
index a6925ab139..391bd14c5c 100644
--- a/synapse/app/_base.py
+++ b/synapse/app/_base.py
@@ -17,15 +17,18 @@ import gc
 import logging
 import sys
 
+from daemonize import Daemonize
+
+from twisted.internet import error, reactor
+
+from synapse.util import PreserveLoggingContext
+from synapse.util.rlimit import change_resource_limit
+
 try:
     import affinity
 except Exception:
     affinity = None
 
-from daemonize import Daemonize
-from synapse.util import PreserveLoggingContext
-from synapse.util.rlimit import change_resource_limit
-from twisted.internet import error, reactor
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/app/appservice.py b/synapse/app/appservice.py
index 4319ddce03..9a37384fb7 100644
--- a/synapse/app/appservice.py
+++ b/synapse/app/appservice.py
@@ -16,6 +16,9 @@
 import logging
 import sys
 
+from twisted.internet import defer, reactor
+from twisted.web.resource import NoResource
+
 import synapse
 from synapse import events
 from synapse.app import _base
@@ -36,8 +39,6 @@ from synapse.util.httpresourcetree import create_resource_tree
 from synapse.util.logcontext import LoggingContext, run_in_background
 from synapse.util.manhole import manhole
 from synapse.util.versionstring import get_version_string
-from twisted.internet import reactor, defer
-from twisted.web.resource import NoResource
 
 logger = logging.getLogger("synapse.app.appservice")
 
diff --git a/synapse/app/client_reader.py b/synapse/app/client_reader.py
index 654ddb8414..b0ea26dcb4 100644
--- a/synapse/app/client_reader.py
+++ b/synapse/app/client_reader.py
@@ -16,6 +16,9 @@
 import logging
 import sys
 
+from twisted.internet import reactor
+from twisted.web.resource import NoResource
+
 import synapse
 from synapse import events
 from synapse.app import _base
@@ -44,8 +47,6 @@ from synapse.util.httpresourcetree import create_resource_tree
 from synapse.util.logcontext import LoggingContext
 from synapse.util.manhole import manhole
 from synapse.util.versionstring import get_version_string
-from twisted.internet import reactor
-from twisted.web.resource import NoResource
 
 logger = logging.getLogger("synapse.app.client_reader")
 
diff --git a/synapse/app/event_creator.py b/synapse/app/event_creator.py
index 441467093a..374f115644 100644
--- a/synapse/app/event_creator.py
+++ b/synapse/app/event_creator.py
@@ -16,6 +16,9 @@
 import logging
 import sys
 
+from twisted.internet import reactor
+from twisted.web.resource import NoResource
+
 import synapse
 from synapse import events
 from synapse.app import _base
@@ -43,8 +46,10 @@ from synapse.replication.slave.storage.room import RoomStore
 from synapse.replication.slave.storage.transactions import TransactionStore
 from synapse.replication.tcp.client import ReplicationClientHandler
 from synapse.rest.client.v1.room import (
-    RoomSendEventRestServlet, RoomMembershipRestServlet, RoomStateEventRestServlet,
     JoinRoomAliasServlet,
+    RoomMembershipRestServlet,
+    RoomSendEventRestServlet,
+    RoomStateEventRestServlet,
 )
 from synapse.server import HomeServer
 from synapse.storage.engines import create_engine
@@ -52,8 +57,6 @@ from synapse.util.httpresourcetree import create_resource_tree
 from synapse.util.logcontext import LoggingContext
 from synapse.util.manhole import manhole
 from synapse.util.versionstring import get_version_string
-from twisted.internet import reactor
-from twisted.web.resource import NoResource
 
 logger = logging.getLogger("synapse.app.event_creator")
 
diff --git a/synapse/app/federation_reader.py b/synapse/app/federation_reader.py
index b2415cc671..7af00b8bcf 100644
--- a/synapse/app/federation_reader.py
+++ b/synapse/app/federation_reader.py
@@ -16,6 +16,9 @@
 import logging
 import sys
 
+from twisted.internet import reactor
+from twisted.web.resource import NoResource
+
 import synapse
 from synapse import events
 from synapse.api.urls import FEDERATION_PREFIX
@@ -41,8 +44,6 @@ from synapse.util.httpresourcetree import create_resource_tree
 from synapse.util.logcontext import LoggingContext
 from synapse.util.manhole import manhole
 from synapse.util.versionstring import get_version_string
-from twisted.internet import reactor
-from twisted.web.resource import NoResource
 
 logger = logging.getLogger("synapse.app.federation_reader")
 
diff --git a/synapse/app/federation_sender.py b/synapse/app/federation_sender.py
index 13d2b70053..18469013fa 100644
--- a/synapse/app/federation_sender.py
+++ b/synapse/app/federation_sender.py
@@ -16,6 +16,9 @@
 import logging
 import sys
 
+from twisted.internet import defer, reactor
+from twisted.web.resource import NoResource
+
 import synapse
 from synapse import events
 from synapse.app import _base
@@ -42,8 +45,6 @@ from synapse.util.httpresourcetree import create_resource_tree
 from synapse.util.logcontext import LoggingContext, run_in_background
 from synapse.util.manhole import manhole
 from synapse.util.versionstring import get_version_string
-from twisted.internet import defer, reactor
-from twisted.web.resource import NoResource
 
 logger = logging.getLogger("synapse.app.federation_sender")
 
diff --git a/synapse/app/frontend_proxy.py b/synapse/app/frontend_proxy.py
index d2bae4ad03..b5f78f4640 100644
--- a/synapse/app/frontend_proxy.py
+++ b/synapse/app/frontend_proxy.py
@@ -16,6 +16,9 @@
 import logging
 import sys
 
+from twisted.internet import defer, reactor
+from twisted.web.resource import NoResource
+
 import synapse
 from synapse import events
 from synapse.api.errors import SynapseError
@@ -25,9 +28,7 @@ from synapse.config.homeserver import HomeServerConfig
 from synapse.config.logger import setup_logging
 from synapse.crypto import context_factory
 from synapse.http.server import JsonResource
-from synapse.http.servlet import (
-    RestServlet, parse_json_object_from_request,
-)
+from synapse.http.servlet import RestServlet, parse_json_object_from_request
 from synapse.http.site import SynapseSite
 from synapse.metrics import RegistryProxy
 from synapse.metrics.resource import METRICS_PREFIX, MetricsResource
@@ -44,8 +45,6 @@ from synapse.util.httpresourcetree import create_resource_tree
 from synapse.util.logcontext import LoggingContext
 from synapse.util.manhole import manhole
 from synapse.util.versionstring import get_version_string
-from twisted.internet import defer, reactor
-from twisted.web.resource import NoResource
 
 logger = logging.getLogger("synapse.app.frontend_proxy")
 
diff --git a/synapse/app/homeserver.py b/synapse/app/homeserver.py
index ae5fc751d5..14e6dca522 100755
--- a/synapse/app/homeserver.py
+++ b/synapse/app/homeserver.py
@@ -18,27 +18,39 @@ import logging
 import os
 import sys
 
+from twisted.application import service
+from twisted.internet import defer, reactor
+from twisted.web.resource import EncodingResourceWrapper, NoResource
+from twisted.web.server import GzipEncoderFactory
+from twisted.web.static import File
+
 import synapse
 import synapse.config.logger
 from synapse import events
-from synapse.api.urls import CONTENT_REPO_PREFIX, FEDERATION_PREFIX, \
-    LEGACY_MEDIA_PREFIX, MEDIA_PREFIX, SERVER_KEY_PREFIX, SERVER_KEY_V2_PREFIX, \
-    STATIC_PREFIX, WEB_CLIENT_PREFIX
+from synapse.api.urls import (
+    CONTENT_REPO_PREFIX,
+    FEDERATION_PREFIX,
+    LEGACY_MEDIA_PREFIX,
+    MEDIA_PREFIX,
+    SERVER_KEY_PREFIX,
+    SERVER_KEY_V2_PREFIX,
+    STATIC_PREFIX,
+    WEB_CLIENT_PREFIX,
+)
 from synapse.app import _base
-from synapse.app._base import quit_with_error, listen_ssl, listen_tcp
+from synapse.app._base import listen_ssl, listen_tcp, quit_with_error
 from synapse.config._base import ConfigError
 from synapse.config.homeserver import HomeServerConfig
 from synapse.crypto import context_factory
 from synapse.federation.transport.server import TransportLayerServer
-from synapse.module_api import ModuleApi
 from synapse.http.additional_resource import AdditionalResource
 from synapse.http.server import RootRedirect
 from synapse.http.site import SynapseSite
 from synapse.metrics import RegistryProxy
 from synapse.metrics.resource import METRICS_PREFIX, MetricsResource
-from synapse.python_dependencies import CONDITIONAL_REQUIREMENTS, \
-    check_requirements
-from synapse.replication.http import ReplicationRestResource, REPLICATION_PREFIX
+from synapse.module_api import ModuleApi
+from synapse.python_dependencies import CONDITIONAL_REQUIREMENTS, check_requirements
+from synapse.replication.http import REPLICATION_PREFIX, ReplicationRestResource
 from synapse.replication.tcp.resource import ReplicationStreamProtocolFactory
 from synapse.rest import ClientRestResource
 from synapse.rest.key.v1.server_key_resource import LocalKey
@@ -55,11 +67,6 @@ from synapse.util.manhole import manhole
 from synapse.util.module_loader import load_module
 from synapse.util.rlimit import change_resource_limit
 from synapse.util.versionstring import get_version_string
-from twisted.application import service
-from twisted.internet import defer, reactor
-from twisted.web.resource import EncodingResourceWrapper, NoResource
-from twisted.web.server import GzipEncoderFactory
-from twisted.web.static import File
 
 logger = logging.getLogger("synapse.app.homeserver")
 
diff --git a/synapse/app/media_repository.py b/synapse/app/media_repository.py
index 19a682cce3..749bbf37d0 100644
--- a/synapse/app/media_repository.py
+++ b/synapse/app/media_repository.py
@@ -16,11 +16,12 @@
 import logging
 import sys
 
+from twisted.internet import reactor
+from twisted.web.resource import NoResource
+
 import synapse
 from synapse import events
-from synapse.api.urls import (
-    CONTENT_REPO_PREFIX, LEGACY_MEDIA_PREFIX, MEDIA_PREFIX
-)
+from synapse.api.urls import CONTENT_REPO_PREFIX, LEGACY_MEDIA_PREFIX, MEDIA_PREFIX
 from synapse.app import _base
 from synapse.config._base import ConfigError
 from synapse.config.homeserver import HomeServerConfig
@@ -43,8 +44,6 @@ from synapse.util.httpresourcetree import create_resource_tree
 from synapse.util.logcontext import LoggingContext
 from synapse.util.manhole import manhole
 from synapse.util.versionstring import get_version_string
-from twisted.internet import reactor
-from twisted.web.resource import NoResource
 
 logger = logging.getLogger("synapse.app.media_repository")
 
diff --git a/synapse/app/pusher.py b/synapse/app/pusher.py
index 13cfbd08b0..9295a51d5b 100644
--- a/synapse/app/pusher.py
+++ b/synapse/app/pusher.py
@@ -16,6 +16,9 @@
 import logging
 import sys
 
+from twisted.internet import defer, reactor
+from twisted.web.resource import NoResource
+
 import synapse
 from synapse import events
 from synapse.app import _base
@@ -37,8 +40,6 @@ from synapse.util.httpresourcetree import create_resource_tree
 from synapse.util.logcontext import LoggingContext, run_in_background
 from synapse.util.manhole import manhole
 from synapse.util.versionstring import get_version_string
-from twisted.internet import defer, reactor
-from twisted.web.resource import NoResource
 
 logger = logging.getLogger("synapse.app.pusher")
 
diff --git a/synapse/app/synchrotron.py b/synapse/app/synchrotron.py
index 82f06ea185..26b9ec85f2 100644
--- a/synapse/app/synchrotron.py
+++ b/synapse/app/synchrotron.py
@@ -17,6 +17,11 @@ import contextlib
 import logging
 import sys
 
+from six import iteritems
+
+from twisted.internet import defer, reactor
+from twisted.web.resource import NoResource
+
 import synapse
 from synapse.api.constants import EventTypes
 from synapse.app import _base
@@ -36,12 +41,12 @@ from synapse.replication.slave.storage.deviceinbox import SlavedDeviceInboxStore
 from synapse.replication.slave.storage.devices import SlavedDeviceStore
 from synapse.replication.slave.storage.events import SlavedEventStore
 from synapse.replication.slave.storage.filtering import SlavedFilteringStore
+from synapse.replication.slave.storage.groups import SlavedGroupServerStore
 from synapse.replication.slave.storage.presence import SlavedPresenceStore
 from synapse.replication.slave.storage.push_rule import SlavedPushRuleStore
 from synapse.replication.slave.storage.receipts import SlavedReceiptsStore
 from synapse.replication.slave.storage.registration import SlavedRegistrationStore
 from synapse.replication.slave.storage.room import RoomStore
-from synapse.replication.slave.storage.groups import SlavedGroupServerStore
 from synapse.replication.tcp.client import ReplicationClientHandler
 from synapse.rest.client.v1 import events
 from synapse.rest.client.v1.initial_sync import InitialSyncRestServlet
@@ -56,10 +61,6 @@ from synapse.util.logcontext import LoggingContext, run_in_background
 from synapse.util.manhole import manhole
 from synapse.util.stringutils import random_string
 from synapse.util.versionstring import get_version_string
-from twisted.internet import defer, reactor
-from twisted.web.resource import NoResource
-
-from six import iteritems
 
 logger = logging.getLogger("synapse.app.synchrotron")
 
diff --git a/synapse/app/synctl.py b/synapse/app/synctl.py
index 56ae086128..68acc15a9a 100755
--- a/synapse/app/synctl.py
+++ b/synapse/app/synctl.py
@@ -16,16 +16,17 @@
 
 import argparse
 import collections
+import errno
 import glob
 import os
 import os.path
 import signal
 import subprocess
 import sys
-import yaml
-import errno
 import time
 
+import yaml
+
 SYNAPSE = [sys.executable, "-B", "-m", "synapse.app.homeserver"]
 
 GREEN = "\x1b[1;32m"
diff --git a/synapse/app/user_dir.py b/synapse/app/user_dir.py
index f5726e3df6..637a89530a 100644
--- a/synapse/app/user_dir.py
+++ b/synapse/app/user_dir.py
@@ -17,6 +17,9 @@
 import logging
 import sys
 
+from twisted.internet import defer, reactor
+from twisted.web.resource import NoResource
+
 import synapse
 from synapse import events
 from synapse.app import _base
@@ -43,8 +46,6 @@ from synapse.util.httpresourcetree import create_resource_tree
 from synapse.util.logcontext import LoggingContext, run_in_background
 from synapse.util.manhole import manhole
 from synapse.util.versionstring import get_version_string
-from twisted.internet import reactor, defer
-from twisted.web.resource import NoResource
 
 logger = logging.getLogger("synapse.app.user_dir")
 
diff --git a/synapse/appservice/__init__.py b/synapse/appservice/__init__.py
index 328cbfa284..57ed8a3ca2 100644
--- a/synapse/appservice/__init__.py
+++ b/synapse/appservice/__init__.py
@@ -12,17 +12,17 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-from synapse.api.constants import EventTypes
-from synapse.util.caches.descriptors import cachedInlineCallbacks
-from synapse.types import GroupID, get_domain_from_id
-
-from twisted.internet import defer
-
 import logging
 import re
 
 from six import string_types
 
+from twisted.internet import defer
+
+from synapse.api.constants import EventTypes
+from synapse.types import GroupID, get_domain_from_id
+from synapse.util.caches.descriptors import cachedInlineCallbacks
+
 logger = logging.getLogger(__name__)
 
 
diff --git a/synapse/appservice/api.py b/synapse/appservice/api.py
index 47251fb6ad..6980e5890e 100644
--- a/synapse/appservice/api.py
+++ b/synapse/appservice/api.py
@@ -12,19 +12,19 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+import logging
+import urllib
+
+from prometheus_client import Counter
+
 from twisted.internet import defer
 
 from synapse.api.constants import ThirdPartyEntityKind
 from synapse.api.errors import CodeMessageException
-from synapse.http.client import SimpleHttpClient
 from synapse.events.utils import serialize_event
-from synapse.util.caches.response_cache import ResponseCache
+from synapse.http.client import SimpleHttpClient
 from synapse.types import ThirdPartyInstanceID
-
-import logging
-import urllib
-
-from prometheus_client import Counter
+from synapse.util.caches.response_cache import ResponseCache
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/appservice/scheduler.py b/synapse/appservice/scheduler.py
index 6eddbc0828..2430814796 100644
--- a/synapse/appservice/scheduler.py
+++ b/synapse/appservice/scheduler.py
@@ -48,14 +48,14 @@ UP & quit           +---------- YES                       SUCCESS
 This is all tied together by the AppServiceScheduler which DIs the required
 components.
 """
+import logging
+
 from twisted.internet import defer
 
 from synapse.appservice import ApplicationServiceState
 from synapse.util.logcontext import run_in_background
 from synapse.util.metrics import Measure
 
-import logging
-
 logger = logging.getLogger(__name__)
 
 
diff --git a/synapse/config/_base.py b/synapse/config/_base.py
index b748ed2b0a..3d2e90dd5b 100644
--- a/synapse/config/_base.py
+++ b/synapse/config/_base.py
@@ -16,11 +16,12 @@
 import argparse
 import errno
 import os
-import yaml
 from textwrap import dedent
 
 from six import integer_types
 
+import yaml
+
 
 class ConfigError(Exception):
     pass
diff --git a/synapse/config/api.py b/synapse/config/api.py
index 20ba33226a..403d96ba76 100644
--- a/synapse/config/api.py
+++ b/synapse/config/api.py
@@ -12,10 +12,10 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from ._base import Config
-
 from synapse.api.constants import EventTypes
 
+from ._base import Config
+
 
 class ApiConfig(Config):
 
diff --git a/synapse/config/appservice.py b/synapse/config/appservice.py
index 0c27bb2fa7..3b161d708a 100644
--- a/synapse/config/appservice.py
+++ b/synapse/config/appservice.py
@@ -12,18 +12,18 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from ._base import Config, ConfigError
+import logging
 
-from synapse.appservice import ApplicationService
-from synapse.types import UserID
+from six import string_types
+from six.moves.urllib import parse as urlparse
 
+import yaml
 from netaddr import IPSet
 
-import yaml
-import logging
+from synapse.appservice import ApplicationService
+from synapse.types import UserID
 
-from six import string_types
-from six.moves.urllib import parse as urlparse
+from ._base import Config, ConfigError
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/config/homeserver.py b/synapse/config/homeserver.py
index 1dea2ad024..2fd9c48abf 100644
--- a/synapse/config/homeserver.py
+++ b/synapse/config/homeserver.py
@@ -13,32 +13,32 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-from .tls import TlsConfig
-from .server import ServerConfig
-from .logger import LoggingConfig
-from .database import DatabaseConfig
-from .ratelimiting import RatelimitConfig
-from .repository import ContentRepositoryConfig
-from .captcha import CaptchaConfig
-from .voip import VoipConfig
-from .registration import RegistrationConfig
-from .metrics import MetricsConfig
 from .api import ApiConfig
 from .appservice import AppServiceConfig
-from .key import KeyConfig
-from .saml2 import SAML2Config
+from .captcha import CaptchaConfig
 from .cas import CasConfig
-from .password import PasswordConfig
+from .consent_config import ConsentConfig
+from .database import DatabaseConfig
+from .emailconfig import EmailConfig
+from .groups import GroupsConfig
 from .jwt import JWTConfig
+from .key import KeyConfig
+from .logger import LoggingConfig
+from .metrics import MetricsConfig
+from .password import PasswordConfig
 from .password_auth_providers import PasswordAuthProviderConfig
-from .emailconfig import EmailConfig
-from .workers import WorkerConfig
 from .push import PushConfig
+from .ratelimiting import RatelimitConfig
+from .registration import RegistrationConfig
+from .repository import ContentRepositoryConfig
+from .saml2 import SAML2Config
+from .server import ServerConfig
+from .server_notices_config import ServerNoticesConfig
 from .spam_checker import SpamCheckerConfig
-from .groups import GroupsConfig
+from .tls import TlsConfig
 from .user_directory import UserDirectoryConfig
-from .consent_config import ConsentConfig
-from .server_notices_config import ServerNoticesConfig
+from .voip import VoipConfig
+from .workers import WorkerConfig
 
 
 class HomeServerConfig(TlsConfig, ServerConfig, DatabaseConfig, LoggingConfig,
diff --git a/synapse/config/jwt.py b/synapse/config/jwt.py
index 47f145c589..51e7f7e003 100644
--- a/synapse/config/jwt.py
+++ b/synapse/config/jwt.py
@@ -15,7 +15,6 @@
 
 from ._base import Config, ConfigError
 
-
 MISSING_JWT = (
     """Missing jwt library. This is required for jwt login.
 
diff --git a/synapse/config/key.py b/synapse/config/key.py
index d1382ad9ac..279c47bb48 100644
--- a/synapse/config/key.py
+++ b/synapse/config/key.py
@@ -13,21 +13,24 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from ._base import Config, ConfigError
+import hashlib
+import logging
+import os
 
-from synapse.util.stringutils import random_string
 from signedjson.key import (
-    generate_signing_key, is_signing_algorithm_supported,
-    decode_signing_key_base64, decode_verify_key_bytes,
-    read_signing_keys, write_signing_keys, NACL_ED25519
+    NACL_ED25519,
+    decode_signing_key_base64,
+    decode_verify_key_bytes,
+    generate_signing_key,
+    is_signing_algorithm_supported,
+    read_signing_keys,
+    write_signing_keys,
 )
 from unpaddedbase64 import decode_base64
-from synapse.util.stringutils import random_string_with_symbols
 
-import os
-import hashlib
-import logging
+from synapse.util.stringutils import random_string, random_string_with_symbols
 
+from ._base import Config, ConfigError
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/config/logger.py b/synapse/config/logger.py
index 557c270fbe..a87b11a1df 100644
--- a/synapse/config/logger.py
+++ b/synapse/config/logger.py
@@ -16,15 +16,17 @@ import logging
 import logging.config
 import os
 import signal
-from string import Template
 import sys
+from string import Template
 
-from twisted.logger import STDLibLogObserver, globalLogBeginner
 import yaml
 
+from twisted.logger import STDLibLogObserver, globalLogBeginner
+
 import synapse
 from synapse.util.logcontext import LoggingContextFilter
 from synapse.util.versionstring import get_version_string
+
 from ._base import Config
 
 DEFAULT_LOG_CONFIG = Template("""
diff --git a/synapse/config/password_auth_providers.py b/synapse/config/password_auth_providers.py
index 6602c5b4c7..f4066abc28 100644
--- a/synapse/config/password_auth_providers.py
+++ b/synapse/config/password_auth_providers.py
@@ -13,10 +13,10 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from ._base import Config
-
 from synapse.util.module_loader import load_module
 
+from ._base import Config
+
 LDAP_PROVIDER = 'ldap_auth_provider.LdapAuthProvider'
 
 
diff --git a/synapse/config/registration.py b/synapse/config/registration.py
index c5384b3ad4..0fb964eb67 100644
--- a/synapse/config/registration.py
+++ b/synapse/config/registration.py
@@ -13,11 +13,11 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from ._base import Config
+from distutils.util import strtobool
 
 from synapse.util.stringutils import random_string_with_symbols
 
-from distutils.util import strtobool
+from ._base import Config
 
 
 class RegistrationConfig(Config):
diff --git a/synapse/config/repository.py b/synapse/config/repository.py
index 81ecf9778c..fc909c1fac 100644
--- a/synapse/config/repository.py
+++ b/synapse/config/repository.py
@@ -13,11 +13,11 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from ._base import Config, ConfigError
 from collections import namedtuple
 
 from synapse.util.module_loader import load_module
 
+from ._base import Config, ConfigError
 
 MISSING_NETADDR = (
     "Missing netaddr library. This is required for URL preview API."
diff --git a/synapse/config/server.py b/synapse/config/server.py
index 71fd51e4bc..18102656b0 100644
--- a/synapse/config/server.py
+++ b/synapse/config/server.py
@@ -17,6 +17,7 @@
 import logging
 
 from synapse.http.endpoint import parse_and_validate_server_name
+
 from ._base import Config, ConfigError
 
 logger = logging.Logger(__name__)
diff --git a/synapse/config/server_notices_config.py b/synapse/config/server_notices_config.py
index be1d1f762c..3c39850ac6 100644
--- a/synapse/config/server_notices_config.py
+++ b/synapse/config/server_notices_config.py
@@ -12,9 +12,10 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-from ._base import Config
 from synapse.types import UserID
 
+from ._base import Config
+
 DEFAULT_CONFIG = """\
 # Server Notices room configuration
 #
diff --git a/synapse/config/tls.py b/synapse/config/tls.py
index b66154bc7c..fef1ea99cb 100644
--- a/synapse/config/tls.py
+++ b/synapse/config/tls.py
@@ -13,15 +13,16 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from ._base import Config
-
-from OpenSSL import crypto
-import subprocess
 import os
-
+import subprocess
 from hashlib import sha256
+
 from unpaddedbase64 import encode_base64
 
+from OpenSSL import crypto
+
+from ._base import Config
+
 GENERATE_DH_PARAMS = False
 
 
diff --git a/synapse/crypto/context_factory.py b/synapse/crypto/context_factory.py
index 0397f73ab4..a1e1d0d33a 100644
--- a/synapse/crypto/context_factory.py
+++ b/synapse/crypto/context_factory.py
@@ -12,12 +12,12 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from twisted.internet import ssl
+import logging
+
 from OpenSSL import SSL, crypto
+from twisted.internet import ssl
 from twisted.internet._sslverify import _defaultCurveName
 
-import logging
-
 logger = logging.getLogger(__name__)
 
 
diff --git a/synapse/crypto/event_signing.py b/synapse/crypto/event_signing.py
index aaa3efaca3..8774b28967 100644
--- a/synapse/crypto/event_signing.py
+++ b/synapse/crypto/event_signing.py
@@ -15,15 +15,15 @@
 # limitations under the License.
 
 
-from synapse.api.errors import SynapseError, Codes
-from synapse.events.utils import prune_event
+import hashlib
+import logging
 
 from canonicaljson import encode_canonical_json
-from unpaddedbase64 import encode_base64, decode_base64
 from signedjson.sign import sign_json
+from unpaddedbase64 import decode_base64, encode_base64
 
-import hashlib
-import logging
+from synapse.api.errors import Codes, SynapseError
+from synapse.events.utils import prune_event
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/crypto/keyclient.py b/synapse/crypto/keyclient.py
index 2a0eddbea1..668b4f517d 100644
--- a/synapse/crypto/keyclient.py
+++ b/synapse/crypto/keyclient.py
@@ -13,14 +13,16 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from synapse.util import logcontext
-from twisted.web.http import HTTPClient
-from twisted.internet.protocol import Factory
-from twisted.internet import defer, reactor
-from synapse.http.endpoint import matrix_federation_endpoint
-from canonicaljson import json
 import logging
 
+from canonicaljson import json
+
+from twisted.internet import defer, reactor
+from twisted.internet.protocol import Factory
+from twisted.web.http import HTTPClient
+
+from synapse.http.endpoint import matrix_federation_endpoint
+from synapse.util import logcontext
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/crypto/keyring.py b/synapse/crypto/keyring.py
index 9b17ef0a08..e95b9fb43e 100644
--- a/synapse/crypto/keyring.py
+++ b/synapse/crypto/keyring.py
@@ -14,35 +14,37 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from synapse.crypto.keyclient import fetch_server_key
-from synapse.api.errors import SynapseError, Codes
-from synapse.util import unwrapFirstError, logcontext
-from synapse.util.logcontext import (
-    PreserveLoggingContext,
-    preserve_fn,
-    run_in_background,
-)
-from synapse.util.metrics import Measure
-
-from twisted.internet import defer
+import hashlib
+import logging
+import urllib
+from collections import namedtuple
 
-from signedjson.sign import (
-    verify_signed_json, signature_ids, sign_json, encode_canonical_json,
-    SignatureVerifyException,
-)
 from signedjson.key import (
-    is_signing_algorithm_supported, decode_verify_key_bytes,
+    decode_verify_key_bytes,
     encode_verify_key_base64,
+    is_signing_algorithm_supported,
+)
+from signedjson.sign import (
+    SignatureVerifyException,
+    encode_canonical_json,
+    sign_json,
+    signature_ids,
+    verify_signed_json,
 )
 from unpaddedbase64 import decode_base64, encode_base64
 
 from OpenSSL import crypto
+from twisted.internet import defer
 
-from collections import namedtuple
-import urllib
-import hashlib
-import logging
-
+from synapse.api.errors import Codes, SynapseError
+from synapse.crypto.keyclient import fetch_server_key
+from synapse.util import logcontext, unwrapFirstError
+from synapse.util.logcontext import (
+    PreserveLoggingContext,
+    preserve_fn,
+    run_in_background,
+)
+from synapse.util.metrics import Measure
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/event_auth.py b/synapse/event_auth.py
index cdf99fd140..b32f64e729 100644
--- a/synapse/event_auth.py
+++ b/synapse/event_auth.py
@@ -17,11 +17,11 @@ import logging
 
 from canonicaljson import encode_canonical_json
 from signedjson.key import decode_verify_key_bytes
-from signedjson.sign import verify_signed_json, SignatureVerifyException
+from signedjson.sign import SignatureVerifyException, verify_signed_json
 from unpaddedbase64 import decode_base64
 
-from synapse.api.constants import EventTypes, Membership, JoinRules
-from synapse.api.errors import AuthError, SynapseError, EventSizeError
+from synapse.api.constants import EventTypes, JoinRules, Membership
+from synapse.api.errors import AuthError, EventSizeError, SynapseError
 from synapse.types import UserID, get_domain_from_id
 
 logger = logging.getLogger(__name__)
diff --git a/synapse/events/__init__.py b/synapse/events/__init__.py
index cb08da4984..51f9084b90 100644
--- a/synapse/events/__init__.py
+++ b/synapse/events/__init__.py
@@ -13,9 +13,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from synapse.util.frozenutils import freeze
 from synapse.util.caches import intern_dict
-
+from synapse.util.frozenutils import freeze
 
 # Whether we should use frozen_dict in FrozenEvent. Using frozen_dicts prevents
 # bugs where we accidentally share e.g. signature dicts. However, converting
diff --git a/synapse/events/builder.py b/synapse/events/builder.py
index 13fbba68c0..e662eaef10 100644
--- a/synapse/events/builder.py
+++ b/synapse/events/builder.py
@@ -13,13 +13,12 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from . import EventBase, FrozenEvent, _event_dict_property
+import copy
 
 from synapse.types import EventID
-
 from synapse.util.stringutils import random_string
 
-import copy
+from . import EventBase, FrozenEvent, _event_dict_property
 
 
 class EventBuilder(EventBase):
diff --git a/synapse/events/snapshot.py b/synapse/events/snapshot.py
index 8e684d91b5..bcd9bb5946 100644
--- a/synapse/events/snapshot.py
+++ b/synapse/events/snapshot.py
@@ -13,10 +13,10 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from twisted.internet import defer
-
 from frozendict import frozendict
 
+from twisted.internet import defer
+
 
 class EventContext(object):
     """
diff --git a/synapse/events/utils.py b/synapse/events/utils.py
index 29ae086786..652941ca0d 100644
--- a/synapse/events/utils.py
+++ b/synapse/events/utils.py
@@ -13,14 +13,15 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from synapse.api.constants import EventTypes
-from . import EventBase
+import re
+
+from six import string_types
 
 from frozendict import frozendict
 
-import re
+from synapse.api.constants import EventTypes
 
-from six import string_types
+from . import EventBase
 
 # Split strings on "." but not "\." This uses a negative lookbehind assertion for '\'
 # (?<!stuff) matches if the current position in the string is not preceded
diff --git a/synapse/events/validator.py b/synapse/events/validator.py
index e0e5bf818c..cf184748a1 100644
--- a/synapse/events/validator.py
+++ b/synapse/events/validator.py
@@ -13,12 +13,12 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from synapse.types import EventID, RoomID, UserID
-from synapse.api.errors import SynapseError
-from synapse.api.constants import EventTypes, Membership
-
 from six import string_types
 
+from synapse.api.constants import EventTypes, Membership
+from synapse.api.errors import SynapseError
+from synapse.types import EventID, RoomID, UserID
+
 
 class EventValidator(object):
 
diff --git a/synapse/federation/federation_base.py b/synapse/federation/federation_base.py
index 4cc98a3fe8..f0c7a06718 100644
--- a/synapse/federation/federation_base.py
+++ b/synapse/federation/federation_base.py
@@ -16,14 +16,15 @@ import logging
 
 import six
 
+from twisted.internet import defer
+
 from synapse.api.constants import MAX_DEPTH
-from synapse.api.errors import SynapseError, Codes
+from synapse.api.errors import Codes, SynapseError
 from synapse.crypto.event_signing import check_event_content_hash
 from synapse.events import FrozenEvent
 from synapse.events.utils import prune_event
 from synapse.http.servlet import assert_params_in_request
-from synapse.util import unwrapFirstError, logcontext
-from twisted.internet import defer
+from synapse.util import logcontext, unwrapFirstError
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/federation/federation_client.py b/synapse/federation/federation_client.py
index 87a92f6ea9..62d7ed13cf 100644
--- a/synapse/federation/federation_client.py
+++ b/synapse/federation/federation_client.py
@@ -21,25 +21,25 @@ import random
 
 from six.moves import range
 
+from prometheus_client import Counter
+
 from twisted.internet import defer
 
 from synapse.api.constants import Membership
 from synapse.api.errors import (
-    CodeMessageException, HttpResponseException, SynapseError, FederationDeniedError
+    CodeMessageException,
+    FederationDeniedError,
+    HttpResponseException,
+    SynapseError,
 )
 from synapse.events import builder
-from synapse.federation.federation_base import (
-    FederationBase,
-    event_from_pdu_json,
-)
+from synapse.federation.federation_base import FederationBase, event_from_pdu_json
 from synapse.util import logcontext, unwrapFirstError
 from synapse.util.caches.expiringcache import ExpiringCache
 from synapse.util.logcontext import make_deferred_yieldable, run_in_background
 from synapse.util.logutils import log_function
 from synapse.util.retryutils import NotRetryingDestination
 
-from prometheus_client import Counter
-
 logger = logging.getLogger(__name__)
 
 sent_queries_counter = Counter("synapse_federation_client_sent_queries", "", ["type"])
diff --git a/synapse/federation/federation_server.py b/synapse/federation/federation_server.py
index 591d0026bf..48f26db67c 100644
--- a/synapse/federation/federation_server.py
+++ b/synapse/federation/federation_server.py
@@ -16,19 +16,19 @@
 import logging
 import re
 
-from canonicaljson import json
 import six
+from six import iteritems
+
+from canonicaljson import json
+from prometheus_client import Counter
+
 from twisted.internet import defer
 from twisted.internet.abstract import isIPAddress
 
 from synapse.api.constants import EventTypes
-from synapse.api.errors import AuthError, FederationError, SynapseError, NotFoundError
+from synapse.api.errors import AuthError, FederationError, NotFoundError, SynapseError
 from synapse.crypto.event_signing import compute_event_signature
-from synapse.federation.federation_base import (
-    FederationBase,
-    event_from_pdu_json,
-)
-
+from synapse.federation.federation_base import FederationBase, event_from_pdu_json
 from synapse.federation.persistence import TransactionActions
 from synapse.federation.units import Edu, Transaction
 from synapse.http.endpoint import parse_server_name
@@ -37,10 +37,6 @@ from synapse.util import async
 from synapse.util.caches.response_cache import ResponseCache
 from synapse.util.logutils import log_function
 
-from prometheus_client import Counter
-
-from six import iteritems
-
 # when processing incoming transactions, we try to handle multiple rooms in
 # parallel, up to this limit.
 TRANSACTION_CONCURRENCY_LIMIT = 10
diff --git a/synapse/federation/persistence.py b/synapse/federation/persistence.py
index 84dc606673..9146215c21 100644
--- a/synapse/federation/persistence.py
+++ b/synapse/federation/persistence.py
@@ -19,13 +19,12 @@ package.
 These actions are mostly only used by the :py:mod:`.replication` module.
 """
 
+import logging
+
 from twisted.internet import defer
 
 from synapse.util.logutils import log_function
 
-import logging
-
-
 logger = logging.getLogger(__name__)
 
 
diff --git a/synapse/federation/send_queue.py b/synapse/federation/send_queue.py
index 1d5c0f3797..5157c3860d 100644
--- a/synapse/federation/send_queue.py
+++ b/synapse/federation/send_queue.py
@@ -29,18 +29,18 @@ dead worker doesn't cause the queues to grow limitlessly.
 Events are replicated via a separate events stream.
 """
 
-from .units import Edu
+import logging
+from collections import namedtuple
 
-from synapse.storage.presence import UserPresenceState
-from synapse.util.metrics import Measure
-from synapse.metrics import LaterGauge
+from six import iteritems, itervalues
 
 from sortedcontainers import SortedDict
-from collections import namedtuple
 
-import logging
+from synapse.metrics import LaterGauge
+from synapse.storage.presence import UserPresenceState
+from synapse.util.metrics import Measure
 
-from six import itervalues, iteritems
+from .units import Edu
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/federation/transaction_queue.py b/synapse/federation/transaction_queue.py
index d72b057e28..5a956ecfb3 100644
--- a/synapse/federation/transaction_queue.py
+++ b/synapse/federation/transaction_queue.py
@@ -13,31 +13,29 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 import datetime
+import logging
 
-from twisted.internet import defer
+from six import itervalues
 
-from .persistence import TransactionActions
-from .units import Transaction, Edu
+from prometheus_client import Counter
+
+from twisted.internet import defer
 
-from synapse.api.errors import HttpResponseException, FederationDeniedError
-from synapse.util import logcontext, PreserveLoggingContext
-from synapse.util.retryutils import NotRetryingDestination, get_retry_limiter
-from synapse.util.metrics import measure_func
-from synapse.handlers.presence import format_user_presence_state, get_interested_remotes
 import synapse.metrics
-from synapse.metrics import LaterGauge
+from synapse.api.errors import FederationDeniedError, HttpResponseException
+from synapse.handlers.presence import format_user_presence_state, get_interested_remotes
 from synapse.metrics import (
+    LaterGauge,
+    events_processed_counter,
     sent_edus_counter,
     sent_transactions_counter,
-    events_processed_counter,
 )
+from synapse.util import PreserveLoggingContext, logcontext
+from synapse.util.metrics import measure_func
+from synapse.util.retryutils import NotRetryingDestination, get_retry_limiter
 
-from prometheus_client import Counter
-
-from six import itervalues
-
-import logging
-
+from .persistence import TransactionActions
+from .units import Edu, Transaction
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/federation/transport/client.py b/synapse/federation/transport/client.py
index 6db8efa6dd..4529d454af 100644
--- a/synapse/federation/transport/client.py
+++ b/synapse/federation/transport/client.py
@@ -14,16 +14,15 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import logging
+import urllib
+
 from twisted.internet import defer
-from synapse.api.constants import Membership
 
+from synapse.api.constants import Membership
 from synapse.api.urls import FEDERATION_PREFIX as PREFIX
 from synapse.util.logutils import log_function
 
-import logging
-import urllib
-
-
 logger = logging.getLogger(__name__)
 
 
diff --git a/synapse/federation/transport/server.py b/synapse/federation/transport/server.py
index c6d98d35cb..c9beca27c2 100644
--- a/synapse/federation/transport/server.py
+++ b/synapse/federation/transport/server.py
@@ -14,26 +14,27 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import functools
+import logging
+import re
+
 from twisted.internet import defer
 
+import synapse
+from synapse.api.errors import Codes, FederationDeniedError, SynapseError
 from synapse.api.urls import FEDERATION_PREFIX as PREFIX
-from synapse.api.errors import Codes, SynapseError, FederationDeniedError
 from synapse.http.endpoint import parse_and_validate_server_name
 from synapse.http.server import JsonResource
 from synapse.http.servlet import (
-    parse_json_object_from_request, parse_integer_from_args, parse_string_from_args,
     parse_boolean_from_args,
+    parse_integer_from_args,
+    parse_json_object_from_request,
+    parse_string_from_args,
 )
+from synapse.types import ThirdPartyInstanceID, get_domain_from_id
+from synapse.util.logcontext import run_in_background
 from synapse.util.ratelimitutils import FederationRateLimiter
 from synapse.util.versionstring import get_version_string
-from synapse.util.logcontext import run_in_background
-from synapse.types import ThirdPartyInstanceID, get_domain_from_id
-
-import functools
-import logging
-import re
-import synapse
-
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/federation/units.py b/synapse/federation/units.py
index 01c5b8fe17..bb1b3b13f7 100644
--- a/synapse/federation/units.py
+++ b/synapse/federation/units.py
@@ -17,10 +17,9 @@
 server protocol.
 """
 
-from synapse.util.jsonobject import JsonEncodedObject
-
 import logging
 
+from synapse.util.jsonobject import JsonEncodedObject
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/groups/attestations.py b/synapse/groups/attestations.py
index 6f11fa374b..09a5fbd44a 100644
--- a/synapse/groups/attestations.py
+++ b/synapse/groups/attestations.py
@@ -38,15 +38,14 @@ An attestsation is a signed blob of json that looks like:
 import logging
 import random
 
+from signedjson.sign import sign_json
+
 from twisted.internet import defer
 
 from synapse.api.errors import SynapseError
 from synapse.types import get_domain_from_id
 from synapse.util.logcontext import run_in_background
 
-from signedjson.sign import sign_json
-
-
 logger = logging.getLogger(__name__)
 
 
diff --git a/synapse/groups/groups_server.py b/synapse/groups/groups_server.py
index 62d20ad130..633c865ed8 100644
--- a/synapse/groups/groups_server.py
+++ b/synapse/groups/groups_server.py
@@ -16,11 +16,12 @@
 
 import logging
 
-from synapse.api.errors import SynapseError
-from synapse.types import GroupID, RoomID, UserID, get_domain_from_id
+from six import string_types
+
 from twisted.internet import defer
 
-from six import string_types
+from synapse.api.errors import SynapseError
+from synapse.types import GroupID, RoomID, UserID, get_domain_from_id
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/handlers/__init__.py b/synapse/handlers/__init__.py
index d358842b3e..4b9923d8c0 100644
--- a/synapse/handlers/__init__.py
+++ b/synapse/handlers/__init__.py
@@ -13,13 +13,13 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from .register import RegistrationHandler
-from .room import RoomContextHandler
-from .message import MessageHandler
-from .federation import FederationHandler
-from .directory import DirectoryHandler
 from .admin import AdminHandler
+from .directory import DirectoryHandler
+from .federation import FederationHandler
 from .identity import IdentityHandler
+from .message import MessageHandler
+from .register import RegistrationHandler
+from .room import RoomContextHandler
 from .search import SearchHandler
 
 
diff --git a/synapse/handlers/_base.py b/synapse/handlers/_base.py
index 2d1db0c245..b6a8b3aa3b 100644
--- a/synapse/handlers/_base.py
+++ b/synapse/handlers/_base.py
@@ -18,11 +18,10 @@ import logging
 from twisted.internet import defer
 
 import synapse.types
-from synapse.api.constants import Membership, EventTypes
+from synapse.api.constants import EventTypes, Membership
 from synapse.api.errors import LimitExceededError
 from synapse.types import UserID
 
-
 logger = logging.getLogger(__name__)
 
 
diff --git a/synapse/handlers/admin.py b/synapse/handlers/admin.py
index f36b358b45..5d629126fc 100644
--- a/synapse/handlers/admin.py
+++ b/synapse/handlers/admin.py
@@ -13,12 +13,12 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import logging
+
 from twisted.internet import defer
 
 from ._base import BaseHandler
 
-import logging
-
 logger = logging.getLogger(__name__)
 
 
diff --git a/synapse/handlers/appservice.py b/synapse/handlers/appservice.py
index 1c29c43a83..ec9fe01a5a 100644
--- a/synapse/handlers/appservice.py
+++ b/synapse/handlers/appservice.py
@@ -13,19 +13,18 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from twisted.internet import defer
+import logging
 
 from six import itervalues
 
+from prometheus_client import Counter
+
+from twisted.internet import defer
+
 import synapse
 from synapse.api.constants import EventTypes
+from synapse.util.logcontext import make_deferred_yieldable, run_in_background
 from synapse.util.metrics import Measure
-from synapse.util.logcontext import (
-    make_deferred_yieldable, run_in_background,
-)
-from prometheus_client import Counter
-
-import logging
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/handlers/auth.py b/synapse/handlers/auth.py
index cbef1f2770..402e44cdef 100644
--- a/synapse/handlers/auth.py
+++ b/synapse/handlers/auth.py
@@ -14,14 +14,24 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from twisted.internet import defer, threads
+import logging
 
+import attr
+import bcrypt
+import pymacaroons
 from canonicaljson import json
 
-from ._base import BaseHandler
+from twisted.internet import defer, threads
+from twisted.web.client import PartialDownloadError
+
+import synapse.util.stringutils as stringutils
 from synapse.api.constants import LoginType
 from synapse.api.errors import (
-    AuthError, Codes, InteractiveAuthIncompleteError, LoginError, StoreError,
+    AuthError,
+    Codes,
+    InteractiveAuthIncompleteError,
+    LoginError,
+    StoreError,
     SynapseError,
 )
 from synapse.module_api import ModuleApi
@@ -29,15 +39,7 @@ from synapse.types import UserID
 from synapse.util.caches.expiringcache import ExpiringCache
 from synapse.util.logcontext import make_deferred_yieldable
 
-from twisted.web.client import PartialDownloadError
-
-import logging
-import bcrypt
-import pymacaroons
-import attr
-
-import synapse.util.stringutils as stringutils
-
+from ._base import BaseHandler
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/handlers/deactivate_account.py b/synapse/handlers/deactivate_account.py
index a84b7b8b80..b3c5a9ee64 100644
--- a/synapse/handlers/deactivate_account.py
+++ b/synapse/handlers/deactivate_account.py
@@ -12,14 +12,15 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+import logging
+
 from twisted.internet import defer
 
-from ._base import BaseHandler
+from synapse.api.errors import SynapseError
 from synapse.types import UserID, create_requester
 from synapse.util.logcontext import run_in_background
-from synapse.api.errors import SynapseError
 
-import logging
+from ._base import BaseHandler
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/handlers/device.py b/synapse/handlers/device.py
index 11c6fb3657..0b4cd53456 100644
--- a/synapse/handlers/device.py
+++ b/synapse/handlers/device.py
@@ -12,21 +12,23 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+import logging
+
+from six import iteritems, itervalues
+
+from twisted.internet import defer
+
 from synapse.api import errors
 from synapse.api.constants import EventTypes
 from synapse.api.errors import FederationDeniedError
+from synapse.types import RoomStreamToken, get_domain_from_id
 from synapse.util import stringutils
 from synapse.util.async import Linearizer
 from synapse.util.caches.expiringcache import ExpiringCache
-from synapse.util.retryutils import NotRetryingDestination
 from synapse.util.metrics import measure_func
-from synapse.types import get_domain_from_id, RoomStreamToken
-from twisted.internet import defer
-from ._base import BaseHandler
-
-import logging
+from synapse.util.retryutils import NotRetryingDestination
 
-from six import itervalues, iteritems
+from ._base import BaseHandler
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/handlers/devicemessage.py b/synapse/handlers/devicemessage.py
index f147a20b73..2e2e5261de 100644
--- a/synapse/handlers/devicemessage.py
+++ b/synapse/handlers/devicemessage.py
@@ -18,10 +18,9 @@ import logging
 from twisted.internet import defer
 
 from synapse.api.errors import SynapseError
-from synapse.types import get_domain_from_id, UserID
+from synapse.types import UserID, get_domain_from_id
 from synapse.util.stringutils import random_string
 
-
 logger = logging.getLogger(__name__)
 
 
diff --git a/synapse/handlers/directory.py b/synapse/handlers/directory.py
index c5b6e75e03..ef866da1b6 100644
--- a/synapse/handlers/directory.py
+++ b/synapse/handlers/directory.py
@@ -14,15 +14,16 @@
 # limitations under the License.
 
 
+import logging
+import string
+
 from twisted.internet import defer
-from ._base import BaseHandler
 
-from synapse.api.errors import SynapseError, Codes, CodeMessageException, AuthError
 from synapse.api.constants import EventTypes
+from synapse.api.errors import AuthError, CodeMessageException, Codes, SynapseError
 from synapse.types import RoomAlias, UserID, get_domain_from_id
 
-import logging
-import string
+from ._base import BaseHandler
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/handlers/e2e_keys.py b/synapse/handlers/e2e_keys.py
index 62b4892a4e..5816bf8b4f 100644
--- a/synapse/handlers/e2e_keys.py
+++ b/synapse/handlers/e2e_keys.py
@@ -16,14 +16,14 @@
 
 import logging
 
+from six import iteritems
+
 from canonicaljson import encode_canonical_json, json
+
 from twisted.internet import defer
-from six import iteritems
 
-from synapse.api.errors import (
-    SynapseError, CodeMessageException, FederationDeniedError,
-)
-from synapse.types import get_domain_from_id, UserID
+from synapse.api.errors import CodeMessageException, FederationDeniedError, SynapseError
+from synapse.types import UserID, get_domain_from_id
 from synapse.util.logcontext import make_deferred_yieldable, run_in_background
 from synapse.util.retryutils import NotRetryingDestination
 
diff --git a/synapse/handlers/events.py b/synapse/handlers/events.py
index 8bc642675f..c3f2d7feff 100644
--- a/synapse/handlers/events.py
+++ b/synapse/handlers/events.py
@@ -13,20 +13,19 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import logging
+import random
+
 from twisted.internet import defer
 
-from synapse.util.logutils import log_function
-from synapse.types import UserID
-from synapse.events.utils import serialize_event
-from synapse.api.constants import Membership, EventTypes
+from synapse.api.constants import EventTypes, Membership
 from synapse.events import EventBase
+from synapse.events.utils import serialize_event
+from synapse.types import UserID
+from synapse.util.logutils import log_function
 
 from ._base import BaseHandler
 
-import logging
-import random
-
-
 logger = logging.getLogger(__name__)
 
 
diff --git a/synapse/handlers/federation.py b/synapse/handlers/federation.py
index 13117d70fe..d3ecebd29f 100644
--- a/synapse/handlers/federation.py
+++ b/synapse/handlers/federation.py
@@ -20,38 +20,42 @@ import itertools
 import logging
 import sys
 
-from signedjson.key import decode_verify_key_bytes
-from signedjson.sign import verify_signed_json
 import six
-from six.moves import http_client
 from six import iteritems
-from twisted.internet import defer
+from six.moves import http_client
+
+from signedjson.key import decode_verify_key_bytes
+from signedjson.sign import verify_signed_json
 from unpaddedbase64 import decode_base64
 
-from ._base import BaseHandler
+from twisted.internet import defer
 
+from synapse.api.constants import EventTypes, Membership, RejectedReason
 from synapse.api.errors import (
-    AuthError, FederationError, StoreError, CodeMessageException, SynapseError,
+    AuthError,
+    CodeMessageException,
     FederationDeniedError,
+    FederationError,
+    StoreError,
+    SynapseError,
 )
-from synapse.api.constants import EventTypes, Membership, RejectedReason
-from synapse.events.validator import EventValidator
-from synapse.util import unwrapFirstError, logcontext
-from synapse.util.metrics import measure_func
-from synapse.util.logutils import log_function
-from synapse.util.async import Linearizer
-from synapse.util.frozenutils import unfreeze
 from synapse.crypto.event_signing import (
-    compute_event_signature, add_hashes_and_signatures,
+    add_hashes_and_signatures,
+    compute_event_signature,
 )
+from synapse.events.utils import prune_event
+from synapse.events.validator import EventValidator
 from synapse.state import resolve_events_with_factory
 from synapse.types import UserID, get_domain_from_id
-
-from synapse.events.utils import prune_event
-
+from synapse.util import logcontext, unwrapFirstError
+from synapse.util.async import Linearizer
+from synapse.util.distributor import user_joined_room
+from synapse.util.frozenutils import unfreeze
+from synapse.util.logutils import log_function
+from synapse.util.metrics import measure_func
 from synapse.util.retryutils import NotRetryingDestination
 
-from synapse.util.distributor import user_joined_room
+from ._base import BaseHandler
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/handlers/groups_local.py b/synapse/handlers/groups_local.py
index dcae083734..53e5e2648b 100644
--- a/synapse/handlers/groups_local.py
+++ b/synapse/handlers/groups_local.py
@@ -14,14 +14,15 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from twisted.internet import defer
+import logging
+
 from six import iteritems
 
+from twisted.internet import defer
+
 from synapse.api.errors import SynapseError
 from synapse.types import get_domain_from_id
 
-import logging
-
 logger = logging.getLogger(__name__)
 
 
diff --git a/synapse/handlers/identity.py b/synapse/handlers/identity.py
index 277c2b7760..8c8aedb2b8 100644
--- a/synapse/handlers/identity.py
+++ b/synapse/handlers/identity.py
@@ -24,10 +24,13 @@ from canonicaljson import json
 from twisted.internet import defer
 
 from synapse.api.errors import (
-    MatrixCodeMessageException, CodeMessageException
+    CodeMessageException,
+    Codes,
+    MatrixCodeMessageException,
+    SynapseError,
 )
+
 from ._base import BaseHandler
-from synapse.api.errors import SynapseError, Codes
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/handlers/initial_sync.py b/synapse/handlers/initial_sync.py
index 71af86fe21..fb11716eb8 100644
--- a/synapse/handlers/initial_sync.py
+++ b/synapse/handlers/initial_sync.py
@@ -13,6 +13,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import logging
+
 from twisted.internet import defer
 
 from synapse.api.constants import EventTypes, Membership
@@ -21,9 +23,7 @@ from synapse.events.utils import serialize_event
 from synapse.events.validator import EventValidator
 from synapse.handlers.presence import format_user_presence_state
 from synapse.streams.config import PaginationConfig
-from synapse.types import (
-    UserID, StreamToken,
-)
+from synapse.types import StreamToken, UserID
 from synapse.util import unwrapFirstError
 from synapse.util.async import concurrently_execute
 from synapse.util.caches.snapshot_cache import SnapshotCache
@@ -32,9 +32,6 @@ from synapse.visibility import filter_events_for_client
 
 from ._base import BaseHandler
 
-import logging
-
-
 logger = logging.getLogger(__name__)
 
 
diff --git a/synapse/handlers/message.py b/synapse/handlers/message.py
index cbadf3c88e..f27f4d3546 100644
--- a/synapse/handlers/message.py
+++ b/synapse/handlers/message.py
@@ -16,32 +16,29 @@
 import logging
 import sys
 
-from canonicaljson import encode_canonical_json, json
 import six
-from six import string_types, itervalues, iteritems
+from six import iteritems, itervalues, string_types
+
+from canonicaljson import encode_canonical_json, json
+
 from twisted.internet import defer
 from twisted.internet.defer import succeed
 from twisted.python.failure import Failure
 
-from synapse.api.constants import EventTypes, Membership, MAX_DEPTH
-from synapse.api.errors import (
-    AuthError, Codes, SynapseError,
-    ConsentNotGivenError,
-)
+from synapse.api.constants import MAX_DEPTH, EventTypes, Membership
+from synapse.api.errors import AuthError, Codes, ConsentNotGivenError, SynapseError
 from synapse.api.urls import ConsentURIBuilder
 from synapse.crypto.event_signing import add_hashes_and_signatures
 from synapse.events.utils import serialize_event
 from synapse.events.validator import EventValidator
-from synapse.types import (
-    UserID, RoomAlias, RoomStreamToken,
-)
-from synapse.util.async import ReadWriteLock, Limiter
+from synapse.replication.http.send_event import send_event_to_master
+from synapse.types import RoomAlias, RoomStreamToken, UserID
+from synapse.util.async import Limiter, ReadWriteLock
+from synapse.util.frozenutils import frozendict_json_encoder
 from synapse.util.logcontext import run_in_background
 from synapse.util.metrics import measure_func
-from synapse.util.frozenutils import frozendict_json_encoder
 from synapse.util.stringutils import random_string
 from synapse.visibility import filter_events_for_client
-from synapse.replication.http.send_event import send_event_to_master
 
 from ._base import BaseHandler
 
diff --git a/synapse/handlers/presence.py b/synapse/handlers/presence.py
index 7db59fba00..3732830194 100644
--- a/synapse/handlers/presence.py
+++ b/synapse/handlers/presence.py
@@ -22,27 +22,26 @@ The methods that define policy are:
     - should_notify
 """
 
-from twisted.internet import defer
+import logging
 from contextlib import contextmanager
 
-from six import itervalues, iteritems
+from six import iteritems, itervalues
+
+from prometheus_client import Counter
+
+from twisted.internet import defer
 
-from synapse.api.errors import SynapseError
 from synapse.api.constants import PresenceState
+from synapse.api.errors import SynapseError
+from synapse.metrics import LaterGauge
 from synapse.storage.presence import UserPresenceState
-
-from synapse.util.caches.descriptors import cachedInlineCallbacks
+from synapse.types import UserID, get_domain_from_id
 from synapse.util.async import Linearizer
+from synapse.util.caches.descriptors import cachedInlineCallbacks
 from synapse.util.logcontext import run_in_background
 from synapse.util.logutils import log_function
 from synapse.util.metrics import Measure
 from synapse.util.wheel_timer import WheelTimer
-from synapse.types import UserID, get_domain_from_id
-from synapse.metrics import LaterGauge
-
-import logging
-
-from prometheus_client import Counter
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/handlers/profile.py b/synapse/handlers/profile.py
index 3465a787ab..859f6d2b2e 100644
--- a/synapse/handlers/profile.py
+++ b/synapse/handlers/profile.py
@@ -17,8 +17,9 @@ import logging
 
 from twisted.internet import defer
 
-from synapse.api.errors import SynapseError, AuthError, CodeMessageException
+from synapse.api.errors import AuthError, CodeMessageException, SynapseError
 from synapse.types import UserID, get_domain_from_id
+
 from ._base import BaseHandler
 
 logger = logging.getLogger(__name__)
diff --git a/synapse/handlers/read_marker.py b/synapse/handlers/read_marker.py
index 5142ae153d..995460f82a 100644
--- a/synapse/handlers/read_marker.py
+++ b/synapse/handlers/read_marker.py
@@ -13,13 +13,14 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from ._base import BaseHandler
+import logging
 
 from twisted.internet import defer
 
 from synapse.util.async import Linearizer
 
-import logging
+from ._base import BaseHandler
+
 logger = logging.getLogger(__name__)
 
 
diff --git a/synapse/handlers/receipts.py b/synapse/handlers/receipts.py
index 2e0672161c..cb905a3903 100644
--- a/synapse/handlers/receipts.py
+++ b/synapse/handlers/receipts.py
@@ -12,17 +12,15 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-from synapse.util import logcontext
-
-from ._base import BaseHandler
+import logging
 
 from twisted.internet import defer
 
-from synapse.util.logcontext import PreserveLoggingContext
 from synapse.types import get_domain_from_id
+from synapse.util import logcontext
+from synapse.util.logcontext import PreserveLoggingContext
 
-import logging
-
+from ._base import BaseHandler
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/handlers/register.py b/synapse/handlers/register.py
index e76ef5426d..7caff0cbc8 100644
--- a/synapse/handlers/register.py
+++ b/synapse/handlers/register.py
@@ -18,14 +18,19 @@ import logging
 
 from twisted.internet import defer
 
+from synapse import types
 from synapse.api.errors import (
-    AuthError, Codes, SynapseError, RegistrationError, InvalidCaptchaError
+    AuthError,
+    Codes,
+    InvalidCaptchaError,
+    RegistrationError,
+    SynapseError,
 )
 from synapse.http.client import CaptchaServerHttpClient
-from synapse import types
-from synapse.types import UserID, create_requester, RoomID, RoomAlias
+from synapse.types import RoomAlias, RoomID, UserID, create_requester
 from synapse.util.async import Linearizer
 from synapse.util.threepids import check_3pid_allowed
+
 from ._base import BaseHandler
 
 logger = logging.getLogger(__name__)
diff --git a/synapse/handlers/room.py b/synapse/handlers/room.py
index ab72963d87..f67512078b 100644
--- a/synapse/handlers/room.py
+++ b/synapse/handlers/room.py
@@ -15,23 +15,20 @@
 # limitations under the License.
 
 """Contains functions for performing events on rooms."""
-from twisted.internet import defer
+import logging
+import math
+import string
+from collections import OrderedDict
 
-from ._base import BaseHandler
+from twisted.internet import defer
 
-from synapse.types import UserID, RoomAlias, RoomID, RoomStreamToken
-from synapse.api.constants import (
-    EventTypes, JoinRules, RoomCreationPreset
-)
+from synapse.api.constants import EventTypes, JoinRules, RoomCreationPreset
 from synapse.api.errors import AuthError, Codes, StoreError, SynapseError
+from synapse.types import RoomAlias, RoomID, RoomStreamToken, UserID
 from synapse.util import stringutils
 from synapse.visibility import filter_events_for_client
 
-from collections import OrderedDict
-
-import logging
-import math
-import string
+from ._base import BaseHandler
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/handlers/room_list.py b/synapse/handlers/room_list.py
index fc507cef36..1abd45297b 100644
--- a/synapse/handlers/room_list.py
+++ b/synapse/handlers/room_list.py
@@ -13,26 +13,24 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from twisted.internet import defer
+import logging
+from collections import namedtuple
 
 from six import iteritems
 from six.moves import range
 
-from ._base import BaseHandler
+import msgpack
+from unpaddedbase64 import decode_base64, encode_base64
+
+from twisted.internet import defer
 
-from synapse.api.constants import (
-    EventTypes, JoinRules,
-)
+from synapse.api.constants import EventTypes, JoinRules
+from synapse.types import ThirdPartyInstanceID
 from synapse.util.async import concurrently_execute
 from synapse.util.caches.descriptors import cachedInlineCallbacks
 from synapse.util.caches.response_cache import ResponseCache
-from synapse.types import ThirdPartyInstanceID
-
-from collections import namedtuple
-from unpaddedbase64 import encode_base64, decode_base64
 
-import logging
-import msgpack
+from ._base import BaseHandler
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/handlers/room_member.py b/synapse/handlers/room_member.py
index f930e939e8..00f2e279bc 100644
--- a/synapse/handlers/room_member.py
+++ b/synapse/handlers/room_member.py
@@ -21,19 +21,17 @@ from six.moves import http_client
 
 from signedjson.key import decode_verify_key_bytes
 from signedjson.sign import verify_signed_json
-from twisted.internet import defer
 from unpaddedbase64 import decode_base64
 
+from twisted.internet import defer
+
 import synapse.server
 import synapse.types
-from synapse.api.constants import (
-    EventTypes, Membership,
-)
-from synapse.api.errors import AuthError, SynapseError, Codes
-from synapse.types import UserID, RoomID
+from synapse.api.constants import EventTypes, Membership
+from synapse.api.errors import AuthError, Codes, SynapseError
+from synapse.types import RoomID, UserID
 from synapse.util.async import Linearizer
-from synapse.util.distributor import user_left_room, user_joined_room
-
+from synapse.util.distributor import user_joined_room, user_left_room
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/handlers/room_member_worker.py b/synapse/handlers/room_member_worker.py
index 493aec1e48..22d8b4b0d3 100644
--- a/synapse/handlers/room_member_worker.py
+++ b/synapse/handlers/room_member_worker.py
@@ -20,11 +20,12 @@ from twisted.internet import defer
 from synapse.api.errors import SynapseError
 from synapse.handlers.room_member import RoomMemberHandler
 from synapse.replication.http.membership import (
-    remote_join, remote_reject_invite, get_or_register_3pid_guest,
+    get_or_register_3pid_guest,
     notify_user_membership_change,
+    remote_join,
+    remote_reject_invite,
 )
 
-
 logger = logging.getLogger(__name__)
 
 
diff --git a/synapse/handlers/search.py b/synapse/handlers/search.py
index 2e3a77ca4b..69ae9731d5 100644
--- a/synapse/handlers/search.py
+++ b/synapse/handlers/search.py
@@ -13,21 +13,20 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from twisted.internet import defer
+import itertools
+import logging
 
-from ._base import BaseHandler
+from unpaddedbase64 import decode_base64, encode_base64
 
-from synapse.api.constants import Membership, EventTypes
-from synapse.api.filtering import Filter
+from twisted.internet import defer
+
+from synapse.api.constants import EventTypes, Membership
 from synapse.api.errors import SynapseError
+from synapse.api.filtering import Filter
 from synapse.events.utils import serialize_event
 from synapse.visibility import filter_events_for_client
 
-from unpaddedbase64 import decode_base64, encode_base64
-
-import itertools
-import logging
-
+from ._base import BaseHandler
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/handlers/set_password.py b/synapse/handlers/set_password.py
index e057ae54c9..7ecdede4dc 100644
--- a/synapse/handlers/set_password.py
+++ b/synapse/handlers/set_password.py
@@ -17,6 +17,7 @@ import logging
 from twisted.internet import defer
 
 from synapse.api.errors import Codes, StoreError, SynapseError
+
 from ._base import BaseHandler
 
 logger = logging.getLogger(__name__)
diff --git a/synapse/handlers/sync.py b/synapse/handlers/sync.py
index 7f486e48e5..c24e35362a 100644
--- a/synapse/handlers/sync.py
+++ b/synapse/handlers/sync.py
@@ -13,22 +13,22 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from synapse.api.constants import Membership, EventTypes
+import collections
+import itertools
+import logging
+
+from six import iteritems, itervalues
+
+from twisted.internet import defer
+
+from synapse.api.constants import EventTypes, Membership
+from synapse.push.clientformat import format_push_rules_for_user
+from synapse.types import RoomStreamToken
 from synapse.util.async import concurrently_execute
+from synapse.util.caches.response_cache import ResponseCache
 from synapse.util.logcontext import LoggingContext
 from synapse.util.metrics import Measure, measure_func
-from synapse.util.caches.response_cache import ResponseCache
-from synapse.push.clientformat import format_push_rules_for_user
 from synapse.visibility import filter_events_for_client
-from synapse.types import RoomStreamToken
-
-from twisted.internet import defer
-
-import collections
-import logging
-import itertools
-
-from six import itervalues, iteritems
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/handlers/typing.py b/synapse/handlers/typing.py
index 5d9736e88f..2d2d3d5a0d 100644
--- a/synapse/handlers/typing.py
+++ b/synapse/handlers/typing.py
@@ -13,17 +13,16 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import logging
+from collections import namedtuple
+
 from twisted.internet import defer
 
-from synapse.api.errors import SynapseError, AuthError
+from synapse.api.errors import AuthError, SynapseError
+from synapse.types import UserID, get_domain_from_id
 from synapse.util.logcontext import run_in_background
 from synapse.util.metrics import Measure
 from synapse.util.wheel_timer import WheelTimer
-from synapse.types import UserID, get_domain_from_id
-
-import logging
-
-from collections import namedtuple
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/handlers/user_directory.py b/synapse/handlers/user_directory.py
index 7e4a114d4f..37dda64587 100644
--- a/synapse/handlers/user_directory.py
+++ b/synapse/handlers/user_directory.py
@@ -14,14 +14,15 @@
 # limitations under the License.
 
 import logging
+
+from six import iteritems
+
 from twisted.internet import defer
 
 from synapse.api.constants import EventTypes, JoinRules, Membership
 from synapse.storage.roommember import ProfileInfo
-from synapse.util.metrics import Measure
 from synapse.types import get_localpart_from_id
-
-from six import iteritems
+from synapse.util.metrics import Measure
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/http/additional_resource.py b/synapse/http/additional_resource.py
index a797396ade..0e10e3f8f7 100644
--- a/synapse/http/additional_resource.py
+++ b/synapse/http/additional_resource.py
@@ -13,10 +13,11 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from synapse.http.server import wrap_json_request_handler
 from twisted.web.resource import Resource
 from twisted.web.server import NOT_DONE_YET
 
+from synapse.http.server import wrap_json_request_handler
+
 
 class AdditionalResource(Resource):
     """Resource wrapper for additional_resources
diff --git a/synapse/http/client.py b/synapse/http/client.py
index 5bdc484c15..d6a0d75b2b 100644
--- a/synapse/http/client.py
+++ b/synapse/http/client.py
@@ -13,39 +13,41 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-from OpenSSL import SSL
-from OpenSSL.SSL import VERIFY_NONE
+import logging
+import urllib
 
-from synapse.api.errors import (
-    CodeMessageException, MatrixCodeMessageException, SynapseError, Codes,
-)
-from synapse.http import cancelled_to_request_timed_out_error, redact_uri
-from synapse.util.async import add_timeout_to_deferred
-from synapse.util.caches import CACHE_SIZE_FACTOR
-from synapse.util.logcontext import make_deferred_yieldable
-from synapse.http.endpoint import SpiderEndpoint
+from six import StringIO
 
-from canonicaljson import encode_canonical_json
+from canonicaljson import encode_canonical_json, json
+from prometheus_client import Counter
 
-from twisted.internet import defer, reactor, ssl, protocol, task
+from OpenSSL import SSL
+from OpenSSL.SSL import VERIFY_NONE
+from twisted.internet import defer, protocol, reactor, ssl, task
 from twisted.internet.endpoints import HostnameEndpoint, wrapClientTLS
+from twisted.web._newclient import ResponseDone
+from twisted.web.client import Agent, BrowserLikeRedirectAgent, ContentDecoderAgent
+from twisted.web.client import FileBodyProducer as TwistedFileBodyProducer
 from twisted.web.client import (
-    BrowserLikeRedirectAgent, ContentDecoderAgent, GzipDecoder, Agent,
-    readBody, PartialDownloadError,
+    GzipDecoder,
     HTTPConnectionPool,
+    PartialDownloadError,
+    readBody,
 )
-from twisted.web.client import FileBodyProducer as TwistedFileBodyProducer
 from twisted.web.http import PotentialDataLoss
 from twisted.web.http_headers import Headers
-from twisted.web._newclient import ResponseDone
-
-from six import StringIO
-
-from prometheus_client import Counter
-from canonicaljson import json
-import logging
-import urllib
 
+from synapse.api.errors import (
+    CodeMessageException,
+    Codes,
+    MatrixCodeMessageException,
+    SynapseError,
+)
+from synapse.http import cancelled_to_request_timed_out_error, redact_uri
+from synapse.http.endpoint import SpiderEndpoint
+from synapse.util.async import add_timeout_to_deferred
+from synapse.util.caches import CACHE_SIZE_FACTOR
+from synapse.util.logcontext import make_deferred_yieldable
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/http/endpoint.py b/synapse/http/endpoint.py
index 1b1123b292..d65daa72bb 100644
--- a/synapse/http/endpoint.py
+++ b/synapse/http/endpoint.py
@@ -12,20 +12,18 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+import collections
+import logging
+import random
 import re
+import time
 
-from twisted.internet.endpoints import HostnameEndpoint, wrapClientTLS
 from twisted.internet import defer
+from twisted.internet.endpoints import HostnameEndpoint, wrapClientTLS
 from twisted.internet.error import ConnectError
 from twisted.names import client, dns
 from twisted.names.error import DNSNameError, DomainError
 
-import collections
-import logging
-import random
-import time
-
-
 logger = logging.getLogger(__name__)
 
 
diff --git a/synapse/http/matrixfederationclient.py b/synapse/http/matrixfederationclient.py
index 2cb9e3e231..bf1aa29502 100644
--- a/synapse/http/matrixfederationclient.py
+++ b/synapse/http/matrixfederationclient.py
@@ -13,38 +13,38 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-from twisted.internet import defer, reactor, protocol
-from twisted.internet.error import DNSLookupError
-from twisted.web.client import readBody, HTTPConnectionPool, Agent
-from twisted.web.http_headers import Headers
-from twisted.web._newclient import ResponseDone
-
-from synapse.http import cancelled_to_request_timed_out_error
-from synapse.http.endpoint import matrix_federation_endpoint
-import synapse.metrics
-from synapse.util.async import add_timeout_to_deferred
-from synapse.util import logcontext
-from synapse.util.logcontext import make_deferred_yieldable
-import synapse.util.retryutils
-
-from canonicaljson import encode_canonical_json, json
-
-from synapse.api.errors import (
-    SynapseError, Codes, HttpResponseException, FederationDeniedError,
-)
-
-from signedjson.sign import sign_json
-
 import cgi
 import logging
 import random
 import sys
 import urllib
-from six.moves.urllib import parse as urlparse
-from six import string_types
 
+from six import string_types
+from six.moves.urllib import parse as urlparse
 
+from canonicaljson import encode_canonical_json, json
 from prometheus_client import Counter
+from signedjson.sign import sign_json
+
+from twisted.internet import defer, protocol, reactor
+from twisted.internet.error import DNSLookupError
+from twisted.web._newclient import ResponseDone
+from twisted.web.client import Agent, HTTPConnectionPool, readBody
+from twisted.web.http_headers import Headers
+
+import synapse.metrics
+import synapse.util.retryutils
+from synapse.api.errors import (
+    Codes,
+    FederationDeniedError,
+    HttpResponseException,
+    SynapseError,
+)
+from synapse.http import cancelled_to_request_timed_out_error
+from synapse.http.endpoint import matrix_federation_endpoint
+from synapse.util import logcontext
+from synapse.util.async import add_timeout_to_deferred
+from synapse.util.logcontext import make_deferred_yieldable
 
 logger = logging.getLogger(__name__)
 outbound_logger = logging.getLogger("synapse.http.outbound")
diff --git a/synapse/http/request_metrics.py b/synapse/http/request_metrics.py
index 1b711ca2de..bcaa2a9ecc 100644
--- a/synapse/http/request_metrics.py
+++ b/synapse/http/request_metrics.py
@@ -17,8 +17,8 @@
 import logging
 
 from prometheus_client.core import Counter, Histogram
-from synapse.metrics import LaterGauge
 
+from synapse.metrics import LaterGauge
 from synapse.util.logcontext import LoggingContext
 
 logger = logging.getLogger(__name__)
diff --git a/synapse/http/server.py b/synapse/http/server.py
index 517aaf7b5a..c70fdbdfd2 100644
--- a/synapse/http/server.py
+++ b/synapse/http/server.py
@@ -14,33 +14,33 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 import cgi
-from six.moves import http_client
+import collections
+import logging
+import urllib
 
-from synapse.api.errors import (
-    cs_exception, SynapseError, CodeMessageException, UnrecognizedRequestError, Codes
-)
-from synapse.http.request_metrics import (
-    requests_counter,
-)
-from synapse.util.logcontext import LoggingContext, PreserveLoggingContext
-from synapse.util.caches import intern_dict
-from synapse.util.metrics import Measure
-import synapse.metrics
-import synapse.events
+from six.moves import http_client
 
-from canonicaljson import (
-    encode_canonical_json, encode_pretty_printed_json, json
-)
+from canonicaljson import encode_canonical_json, encode_pretty_printed_json, json
 
 from twisted.internet import defer
 from twisted.python import failure
-from twisted.web import server, resource
+from twisted.web import resource, server
 from twisted.web.server import NOT_DONE_YET
 from twisted.web.util import redirectTo
 
-import collections
-import logging
-import urllib
+import synapse.events
+import synapse.metrics
+from synapse.api.errors import (
+    CodeMessageException,
+    Codes,
+    SynapseError,
+    UnrecognizedRequestError,
+    cs_exception,
+)
+from synapse.http.request_metrics import requests_counter
+from synapse.util.caches import intern_dict
+from synapse.util.logcontext import LoggingContext, PreserveLoggingContext
+from synapse.util.metrics import Measure
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/http/servlet.py b/synapse/http/servlet.py
index ef3a01ddc7..cf6723563a 100644
--- a/synapse/http/servlet.py
+++ b/synapse/http/servlet.py
@@ -15,12 +15,11 @@
 
 """ This module contains base REST classes for constructing REST servlets. """
 
-from synapse.api.errors import SynapseError, Codes
-
 import logging
 
 from canonicaljson import json
 
+from synapse.api.errors import Codes, SynapseError
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/http/site.py b/synapse/http/site.py
index fe93643b1e..fc954e343c 100644
--- a/synapse/http/site.py
+++ b/synapse/http/site.py
@@ -16,7 +16,7 @@ import contextlib
 import logging
 import time
 
-from twisted.web.server import Site, Request
+from twisted.web.server import Request, Site
 
 from synapse.http import redact_uri
 from synapse.http.request_metrics import RequestMetrics
diff --git a/synapse/metrics/__init__.py b/synapse/metrics/__init__.py
index 2d2397caae..a9158fc066 100644
--- a/synapse/metrics/__init__.py
+++ b/synapse/metrics/__init__.py
@@ -13,20 +13,19 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import logging
 import functools
-import time
 import gc
+import logging
 import os
 import platform
-import attr
+import time
 
-from prometheus_client import Gauge, Histogram, Counter
-from prometheus_client.core import GaugeMetricFamily, REGISTRY
+import attr
+from prometheus_client import Counter, Gauge, Histogram
+from prometheus_client.core import REGISTRY, GaugeMetricFamily
 
 from twisted.internet import reactor
 
-
 logger = logging.getLogger(__name__)
 
 running_on_pypy = platform.python_implementation() == "PyPy"
diff --git a/synapse/notifier.py b/synapse/notifier.py
index 3c0622a294..51cbd66f06 100644
--- a/synapse/notifier.py
+++ b/synapse/notifier.py
@@ -13,28 +13,27 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import logging
+from collections import namedtuple
+
+from prometheus_client import Counter
+
 from twisted.internet import defer
 
 from synapse.api.constants import EventTypes, Membership
 from synapse.api.errors import AuthError
 from synapse.handlers.presence import format_user_presence_state
-
-from synapse.util.logutils import log_function
+from synapse.metrics import LaterGauge
+from synapse.types import StreamToken
 from synapse.util.async import (
-    ObservableDeferred, add_timeout_to_deferred,
     DeferredTimeoutError,
+    ObservableDeferred,
+    add_timeout_to_deferred,
 )
 from synapse.util.logcontext import PreserveLoggingContext, run_in_background
+from synapse.util.logutils import log_function
 from synapse.util.metrics import Measure
-from synapse.types import StreamToken
 from synapse.visibility import filter_events_for_client
-from synapse.metrics import LaterGauge
-
-from collections import namedtuple
-from prometheus_client import Counter
-
-import logging
-
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/push/action_generator.py b/synapse/push/action_generator.py
index 8f619a7a1b..a5de75c48a 100644
--- a/synapse/push/action_generator.py
+++ b/synapse/push/action_generator.py
@@ -13,13 +13,13 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from twisted.internet import defer
+import logging
 
-from .bulk_push_rule_evaluator import BulkPushRuleEvaluator
+from twisted.internet import defer
 
 from synapse.util.metrics import Measure
 
-import logging
+from .bulk_push_rule_evaluator import BulkPushRuleEvaluator
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/push/baserules.py b/synapse/push/baserules.py
index a8ae7bcd6c..8f0682c948 100644
--- a/synapse/push/baserules.py
+++ b/synapse/push/baserules.py
@@ -13,9 +13,10 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from synapse.push.rulekinds import PRIORITY_CLASS_MAP, PRIORITY_CLASS_INVERSE_MAP
 import copy
 
+from synapse.push.rulekinds import PRIORITY_CLASS_INVERSE_MAP, PRIORITY_CLASS_MAP
+
 
 def list_with_base_rules(rawrules):
     """Combine the list of rules set by the user with the default push rules
diff --git a/synapse/push/bulk_push_rule_evaluator.py b/synapse/push/bulk_push_rule_evaluator.py
index a5cab1f043..bb181d94ee 100644
--- a/synapse/push/bulk_push_rule_evaluator.py
+++ b/synapse/push/bulk_push_rule_evaluator.py
@@ -15,21 +15,22 @@
 # limitations under the License.
 
 import logging
+from collections import namedtuple
 
-from twisted.internet import defer
+from six import iteritems, itervalues
 
-from .push_rule_evaluator import PushRuleEvaluatorForEvent
+from prometheus_client import Counter
+
+from twisted.internet import defer
 
-from synapse.event_auth import get_user_power_level
 from synapse.api.constants import EventTypes, Membership
+from synapse.event_auth import get_user_power_level
+from synapse.state import POWER_KEY
+from synapse.util.async import Linearizer
 from synapse.util.caches import register_cache
 from synapse.util.caches.descriptors import cached
-from synapse.util.async import Linearizer
-from synapse.state import POWER_KEY
 
-from collections import namedtuple
-from prometheus_client import Counter
-from six import itervalues, iteritems
+from .push_rule_evaluator import PushRuleEvaluatorForEvent
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/push/clientformat.py b/synapse/push/clientformat.py
index e0331b2d2d..ecbf364a5e 100644
--- a/synapse/push/clientformat.py
+++ b/synapse/push/clientformat.py
@@ -13,12 +13,10 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from synapse.push.rulekinds import (
-    PRIORITY_CLASS_MAP, PRIORITY_CLASS_INVERSE_MAP
-)
-
 import copy
 
+from synapse.push.rulekinds import PRIORITY_CLASS_INVERSE_MAP, PRIORITY_CLASS_MAP
+
 
 def format_push_rules_for_user(user, ruleslist):
     """Converts a list of rawrules and a enabled map into nested dictionaries
diff --git a/synapse/push/emailpusher.py b/synapse/push/emailpusher.py
index 52d4f087ee..d746371420 100644
--- a/synapse/push/emailpusher.py
+++ b/synapse/push/emailpusher.py
@@ -13,14 +13,13 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import logging
+
 from twisted.internet import defer
 from twisted.internet.error import AlreadyCalled, AlreadyCancelled
 
-import logging
-
-from synapse.util.metrics import Measure
 from synapse.util.logcontext import LoggingContext
-
+from synapse.util.metrics import Measure
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/push/httppusher.py b/synapse/push/httppusher.py
index 7a481b5a1e..81e18bcf7d 100644
--- a/synapse/push/httppusher.py
+++ b/synapse/push/httppusher.py
@@ -15,16 +15,16 @@
 # limitations under the License.
 import logging
 
+from prometheus_client import Counter
+
 from twisted.internet import defer
 from twisted.internet.error import AlreadyCalled, AlreadyCancelled
 
-from . import push_rule_evaluator
-from . import push_tools
 from synapse.push import PusherConfigException
 from synapse.util.logcontext import LoggingContext
 from synapse.util.metrics import Measure
 
-from prometheus_client import Counter
+from . import push_rule_evaluator, push_tools
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/push/mailer.py b/synapse/push/mailer.py
index d4be800e5e..9d601208fd 100644
--- a/synapse/push/mailer.py
+++ b/synapse/push/mailer.py
@@ -13,30 +13,31 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from twisted.internet import defer
-from twisted.mail.smtp import sendmail
-
-import email.utils
 import email.mime.multipart
-from email.mime.text import MIMEText
+import email.utils
+import logging
+import time
+import urllib
 from email.mime.multipart import MIMEMultipart
+from email.mime.text import MIMEText
 
-from synapse.util.async import concurrently_execute
+import bleach
+import jinja2
+
+from twisted.internet import defer
+from twisted.mail.smtp import sendmail
+
+from synapse.api.constants import EventTypes
+from synapse.api.errors import StoreError
 from synapse.push.presentable_names import (
-    calculate_room_name, name_from_member_event, descriptor_from_member_events
+    calculate_room_name,
+    descriptor_from_member_events,
+    name_from_member_event,
 )
 from synapse.types import UserID
-from synapse.api.errors import StoreError
-from synapse.api.constants import EventTypes
+from synapse.util.async import concurrently_execute
 from synapse.visibility import filter_events_for_client
 
-import jinja2
-import bleach
-
-import time
-import urllib
-
-import logging
 logger = logging.getLogger(__name__)
 
 
diff --git a/synapse/push/presentable_names.py b/synapse/push/presentable_names.py
index 43f0c74ff3..eef6e18c2e 100644
--- a/synapse/push/presentable_names.py
+++ b/synapse/push/presentable_names.py
@@ -13,10 +13,10 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from twisted.internet import defer
-
-import re
 import logging
+import re
+
+from twisted.internet import defer
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/push/push_rule_evaluator.py b/synapse/push/push_rule_evaluator.py
index cf735f7468..2bd321d530 100644
--- a/synapse/push/push_rule_evaluator.py
+++ b/synapse/push/push_rule_evaluator.py
@@ -17,12 +17,12 @@
 import logging
 import re
 
+from six import string_types
+
 from synapse.types import UserID
 from synapse.util.caches import CACHE_SIZE_FACTOR, register_cache
 from synapse.util.caches.lrucache import LruCache
 
-from six import string_types
-
 logger = logging.getLogger(__name__)
 
 
diff --git a/synapse/push/push_tools.py b/synapse/push/push_tools.py
index 6835f54e97..8049c298c2 100644
--- a/synapse/push/push_tools.py
+++ b/synapse/push/push_tools.py
@@ -14,9 +14,8 @@
 # limitations under the License.
 
 from twisted.internet import defer
-from synapse.push.presentable_names import (
-    calculate_room_name, name_from_member_event
-)
+
+from synapse.push.presentable_names import calculate_room_name, name_from_member_event
 
 
 @defer.inlineCallbacks
diff --git a/synapse/push/pusher.py b/synapse/push/pusher.py
index 5aa6667e91..fcee6d9d7e 100644
--- a/synapse/push/pusher.py
+++ b/synapse/push/pusher.py
@@ -13,9 +13,10 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import logging
+
 from .httppusher import HttpPusher
 
-import logging
 logger = logging.getLogger(__name__)
 
 # We try importing this if we can (it will fail if we don't
diff --git a/synapse/replication/http/__init__.py b/synapse/replication/http/__init__.py
index 1d7a607529..589ee94c66 100644
--- a/synapse/replication/http/__init__.py
+++ b/synapse/replication/http/__init__.py
@@ -16,7 +16,6 @@
 from synapse.http.server import JsonResource
 from synapse.replication.http import membership, send_event
 
-
 REPLICATION_PREFIX = "/_synapse/replication"
 
 
diff --git a/synapse/replication/http/membership.py b/synapse/replication/http/membership.py
index e66c4e881f..6bfc8a5b89 100644
--- a/synapse/replication/http/membership.py
+++ b/synapse/replication/http/membership.py
@@ -18,10 +18,10 @@ import re
 
 from twisted.internet import defer
 
-from synapse.api.errors import SynapseError, MatrixCodeMessageException
+from synapse.api.errors import MatrixCodeMessageException, SynapseError
 from synapse.http.servlet import RestServlet, parse_json_object_from_request
 from synapse.types import Requester, UserID
-from synapse.util.distributor import user_left_room, user_joined_room
+from synapse.util.distributor import user_joined_room, user_left_room
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/replication/http/send_event.py b/synapse/replication/http/send_event.py
index f080f96cc1..2eede54792 100644
--- a/synapse/replication/http/send_event.py
+++ b/synapse/replication/http/send_event.py
@@ -13,20 +13,22 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import logging
+import re
+
 from twisted.internet import defer
 
 from synapse.api.errors import (
-    SynapseError, MatrixCodeMessageException, CodeMessageException,
+    CodeMessageException,
+    MatrixCodeMessageException,
+    SynapseError,
 )
 from synapse.events import FrozenEvent
 from synapse.events.snapshot import EventContext
 from synapse.http.servlet import RestServlet, parse_json_object_from_request
+from synapse.types import Requester, UserID
 from synapse.util.caches.response_cache import ResponseCache
 from synapse.util.metrics import Measure
-from synapse.types import Requester, UserID
-
-import logging
-import re
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/replication/slave/storage/_base.py b/synapse/replication/slave/storage/_base.py
index 61f5590c53..3f7be74e02 100644
--- a/synapse/replication/slave/storage/_base.py
+++ b/synapse/replication/slave/storage/_base.py
@@ -13,13 +13,13 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import logging
+
 from synapse.storage._base import SQLBaseStore
 from synapse.storage.engines import PostgresEngine
 
 from ._slaved_id_tracker import SlavedIdTracker
 
-import logging
-
 logger = logging.getLogger(__name__)
 
 
diff --git a/synapse/replication/slave/storage/appservice.py b/synapse/replication/slave/storage/appservice.py
index 8cae3076f4..b53a4c6bd1 100644
--- a/synapse/replication/slave/storage/appservice.py
+++ b/synapse/replication/slave/storage/appservice.py
@@ -15,7 +15,8 @@
 # limitations under the License.
 
 from synapse.storage.appservice import (
-    ApplicationServiceWorkerStore, ApplicationServiceTransactionWorkerStore,
+    ApplicationServiceTransactionWorkerStore,
+    ApplicationServiceWorkerStore,
 )
 
 
diff --git a/synapse/replication/slave/storage/client_ips.py b/synapse/replication/slave/storage/client_ips.py
index 352c9a2aa8..60641f1a49 100644
--- a/synapse/replication/slave/storage/client_ips.py
+++ b/synapse/replication/slave/storage/client_ips.py
@@ -13,11 +13,12 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from ._base import BaseSlavedStore
 from synapse.storage.client_ips import LAST_SEEN_GRANULARITY
 from synapse.util.caches import CACHE_SIZE_FACTOR
 from synapse.util.caches.descriptors import Cache
 
+from ._base import BaseSlavedStore
+
 
 class SlavedClientIpStore(BaseSlavedStore):
     def __init__(self, db_conn, hs):
diff --git a/synapse/replication/slave/storage/deviceinbox.py b/synapse/replication/slave/storage/deviceinbox.py
index 6f3fb64770..87eaa53004 100644
--- a/synapse/replication/slave/storage/deviceinbox.py
+++ b/synapse/replication/slave/storage/deviceinbox.py
@@ -13,11 +13,12 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from ._base import BaseSlavedStore
-from ._slaved_id_tracker import SlavedIdTracker
 from synapse.storage import DataStore
-from synapse.util.caches.stream_change_cache import StreamChangeCache
 from synapse.util.caches.expiringcache import ExpiringCache
+from synapse.util.caches.stream_change_cache import StreamChangeCache
+
+from ._base import BaseSlavedStore
+from ._slaved_id_tracker import SlavedIdTracker
 
 
 class SlavedDeviceInboxStore(BaseSlavedStore):
diff --git a/synapse/replication/slave/storage/devices.py b/synapse/replication/slave/storage/devices.py
index 7687867aee..8206a988f7 100644
--- a/synapse/replication/slave/storage/devices.py
+++ b/synapse/replication/slave/storage/devices.py
@@ -13,12 +13,13 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from ._base import BaseSlavedStore
-from ._slaved_id_tracker import SlavedIdTracker
 from synapse.storage import DataStore
 from synapse.storage.end_to_end_keys import EndToEndKeyStore
 from synapse.util.caches.stream_change_cache import StreamChangeCache
 
+from ._base import BaseSlavedStore
+from ._slaved_id_tracker import SlavedIdTracker
+
 
 class SlavedDeviceStore(BaseSlavedStore):
     def __init__(self, db_conn, hs):
diff --git a/synapse/replication/slave/storage/directory.py b/synapse/replication/slave/storage/directory.py
index 6deecd3963..1d1d48709a 100644
--- a/synapse/replication/slave/storage/directory.py
+++ b/synapse/replication/slave/storage/directory.py
@@ -13,9 +13,10 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from ._base import BaseSlavedStore
 from synapse.storage.directory import DirectoryWorkerStore
 
+from ._base import BaseSlavedStore
+
 
 class DirectoryStore(DirectoryWorkerStore, BaseSlavedStore):
     pass
diff --git a/synapse/replication/slave/storage/events.py b/synapse/replication/slave/storage/events.py
index 97d3196633..bdb5eee4af 100644
--- a/synapse/replication/slave/storage/events.py
+++ b/synapse/replication/slave/storage/events.py
@@ -20,10 +20,11 @@ from synapse.storage.event_federation import EventFederationWorkerStore
 from synapse.storage.event_push_actions import EventPushActionsWorkerStore
 from synapse.storage.events_worker import EventsWorkerStore
 from synapse.storage.roommember import RoomMemberWorkerStore
+from synapse.storage.signatures import SignatureWorkerStore
 from synapse.storage.state import StateGroupWorkerStore
 from synapse.storage.stream import StreamWorkerStore
-from synapse.storage.signatures import SignatureWorkerStore
 from synapse.storage.user_erasure_store import UserErasureWorkerStore
+
 from ._base import BaseSlavedStore
 from ._slaved_id_tracker import SlavedIdTracker
 
diff --git a/synapse/replication/slave/storage/filtering.py b/synapse/replication/slave/storage/filtering.py
index 819ed62881..456a14cd5c 100644
--- a/synapse/replication/slave/storage/filtering.py
+++ b/synapse/replication/slave/storage/filtering.py
@@ -13,9 +13,10 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from ._base import BaseSlavedStore
 from synapse.storage.filtering import FilteringStore
 
+from ._base import BaseSlavedStore
+
 
 class SlavedFilteringStore(BaseSlavedStore):
     def __init__(self, db_conn, hs):
diff --git a/synapse/replication/slave/storage/groups.py b/synapse/replication/slave/storage/groups.py
index 0bc4bce5b0..5777f07c8d 100644
--- a/synapse/replication/slave/storage/groups.py
+++ b/synapse/replication/slave/storage/groups.py
@@ -13,11 +13,12 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from ._base import BaseSlavedStore
-from ._slaved_id_tracker import SlavedIdTracker
 from synapse.storage import DataStore
 from synapse.util.caches.stream_change_cache import StreamChangeCache
 
+from ._base import BaseSlavedStore
+from ._slaved_id_tracker import SlavedIdTracker
+
 
 class SlavedGroupServerStore(BaseSlavedStore):
     def __init__(self, db_conn, hs):
diff --git a/synapse/replication/slave/storage/keys.py b/synapse/replication/slave/storage/keys.py
index dd2ae49e48..05ed168463 100644
--- a/synapse/replication/slave/storage/keys.py
+++ b/synapse/replication/slave/storage/keys.py
@@ -13,10 +13,11 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from ._base import BaseSlavedStore
 from synapse.storage import DataStore
 from synapse.storage.keys import KeyStore
 
+from ._base import BaseSlavedStore
+
 
 class SlavedKeyStore(BaseSlavedStore):
     _get_server_verify_key = KeyStore.__dict__[
diff --git a/synapse/replication/slave/storage/presence.py b/synapse/replication/slave/storage/presence.py
index cfb9280181..80b744082a 100644
--- a/synapse/replication/slave/storage/presence.py
+++ b/synapse/replication/slave/storage/presence.py
@@ -13,12 +13,12 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from ._base import BaseSlavedStore
-from ._slaved_id_tracker import SlavedIdTracker
-
-from synapse.util.caches.stream_change_cache import StreamChangeCache
 from synapse.storage import DataStore
 from synapse.storage.presence import PresenceStore
+from synapse.util.caches.stream_change_cache import StreamChangeCache
+
+from ._base import BaseSlavedStore
+from ._slaved_id_tracker import SlavedIdTracker
 
 
 class SlavedPresenceStore(BaseSlavedStore):
diff --git a/synapse/replication/slave/storage/push_rule.py b/synapse/replication/slave/storage/push_rule.py
index bb2c40b6e3..f0200c1e98 100644
--- a/synapse/replication/slave/storage/push_rule.py
+++ b/synapse/replication/slave/storage/push_rule.py
@@ -14,10 +14,11 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from .events import SlavedEventStore
-from ._slaved_id_tracker import SlavedIdTracker
 from synapse.storage.push_rule import PushRulesWorkerStore
 
+from ._slaved_id_tracker import SlavedIdTracker
+from .events import SlavedEventStore
+
 
 class SlavedPushRuleStore(PushRulesWorkerStore, SlavedEventStore):
     def __init__(self, db_conn, hs):
diff --git a/synapse/replication/slave/storage/pushers.py b/synapse/replication/slave/storage/pushers.py
index a7cd5a7291..3b2213c0d4 100644
--- a/synapse/replication/slave/storage/pushers.py
+++ b/synapse/replication/slave/storage/pushers.py
@@ -14,11 +14,11 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from synapse.storage.pusher import PusherWorkerStore
+
 from ._base import BaseSlavedStore
 from ._slaved_id_tracker import SlavedIdTracker
 
-from synapse.storage.pusher import PusherWorkerStore
-
 
 class SlavedPusherStore(PusherWorkerStore, BaseSlavedStore):
 
diff --git a/synapse/replication/slave/storage/receipts.py b/synapse/replication/slave/storage/receipts.py
index 1647072f65..7ab12b850f 100644
--- a/synapse/replication/slave/storage/receipts.py
+++ b/synapse/replication/slave/storage/receipts.py
@@ -14,11 +14,11 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from synapse.storage.receipts import ReceiptsWorkerStore
+
 from ._base import BaseSlavedStore
 from ._slaved_id_tracker import SlavedIdTracker
 
-from synapse.storage.receipts import ReceiptsWorkerStore
-
 # So, um, we want to borrow a load of functions intended for reading from
 # a DataStore, but we don't want to take functions that either write to the
 # DataStore or are cached and don't have cache invalidation logic.
diff --git a/synapse/replication/slave/storage/registration.py b/synapse/replication/slave/storage/registration.py
index 7323bf0f1e..408d91df1c 100644
--- a/synapse/replication/slave/storage/registration.py
+++ b/synapse/replication/slave/storage/registration.py
@@ -13,9 +13,10 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from ._base import BaseSlavedStore
 from synapse.storage.registration import RegistrationWorkerStore
 
+from ._base import BaseSlavedStore
+
 
 class SlavedRegistrationStore(RegistrationWorkerStore, BaseSlavedStore):
     pass
diff --git a/synapse/replication/slave/storage/room.py b/synapse/replication/slave/storage/room.py
index 5ae1670157..0cb474928c 100644
--- a/synapse/replication/slave/storage/room.py
+++ b/synapse/replication/slave/storage/room.py
@@ -13,8 +13,9 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from ._base import BaseSlavedStore
 from synapse.storage.room import RoomWorkerStore
+
+from ._base import BaseSlavedStore
 from ._slaved_id_tracker import SlavedIdTracker
 
 
diff --git a/synapse/replication/slave/storage/transactions.py b/synapse/replication/slave/storage/transactions.py
index fbb58f35da..9c9a5eadd9 100644
--- a/synapse/replication/slave/storage/transactions.py
+++ b/synapse/replication/slave/storage/transactions.py
@@ -13,10 +13,11 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from ._base import BaseSlavedStore
 from synapse.storage import DataStore
 from synapse.storage.transactions import TransactionStore
 
+from ._base import BaseSlavedStore
+
 
 class TransactionStore(BaseSlavedStore):
     get_destination_retry_timings = TransactionStore.__dict__[
diff --git a/synapse/replication/tcp/client.py b/synapse/replication/tcp/client.py
index bb852b00af..e592ab57bf 100644
--- a/synapse/replication/tcp/client.py
+++ b/synapse/replication/tcp/client.py
@@ -15,17 +15,20 @@
 """A replication client for use by synapse workers.
 """
 
+import logging
+
 from twisted.internet import defer
 from twisted.internet.protocol import ReconnectingClientFactory
 
 from .commands import (
-    FederationAckCommand, UserSyncCommand, RemovePusherCommand, InvalidateCacheCommand,
+    FederationAckCommand,
+    InvalidateCacheCommand,
+    RemovePusherCommand,
     UserIpCommand,
+    UserSyncCommand,
 )
 from .protocol import ClientReplicationStreamProtocol
 
-import logging
-
 logger = logging.getLogger(__name__)
 
 
diff --git a/synapse/replication/tcp/protocol.py b/synapse/replication/tcp/protocol.py
index 171a698e14..dec5ac0913 100644
--- a/synapse/replication/tcp/protocol.py
+++ b/synapse/replication/tcp/protocol.py
@@ -49,29 +49,37 @@ indicate which side is sending, these are *not* included on the wire::
     * connection closed by server *
 """
 
+import fcntl
+import logging
+import struct
+from collections import defaultdict
+
+from six import iteritems, iterkeys
+
+from prometheus_client import Counter
+
 from twisted.internet import defer
 from twisted.protocols.basic import LineOnlyReceiver
 from twisted.python.failure import Failure
 
-from .commands import (
-    COMMAND_MAP, VALID_CLIENT_COMMANDS, VALID_SERVER_COMMANDS,
-    ErrorCommand, ServerCommand, RdataCommand, PositionCommand, PingCommand,
-    NameCommand, ReplicateCommand, UserSyncCommand, SyncCommand,
-)
-from .streams import STREAMS_MAP
-
 from synapse.metrics import LaterGauge
 from synapse.util.stringutils import random_string
 
-from prometheus_client import Counter
-
-from collections import defaultdict
-
-from six import iterkeys, iteritems
-
-import logging
-import struct
-import fcntl
+from .commands import (
+    COMMAND_MAP,
+    VALID_CLIENT_COMMANDS,
+    VALID_SERVER_COMMANDS,
+    ErrorCommand,
+    NameCommand,
+    PingCommand,
+    PositionCommand,
+    RdataCommand,
+    ReplicateCommand,
+    ServerCommand,
+    SyncCommand,
+    UserSyncCommand,
+)
+from .streams import STREAMS_MAP
 
 connection_close_counter = Counter(
     "synapse_replication_tcp_protocol_close_reason", "", ["reason_type"])
diff --git a/synapse/replication/tcp/resource.py b/synapse/replication/tcp/resource.py
index 95ad8c1b4c..611fb66e1d 100644
--- a/synapse/replication/tcp/resource.py
+++ b/synapse/replication/tcp/resource.py
@@ -15,19 +15,20 @@
 """The server side of the replication stream.
 """
 
+import logging
+
+from six import itervalues
+
+from prometheus_client import Counter
+
 from twisted.internet import defer
 from twisted.internet.protocol import Factory
 
-from .streams import STREAMS_MAP, FederationStream
-from .protocol import ServerReplicationStreamProtocol
-
-from synapse.util.metrics import Measure, measure_func
 from synapse.metrics import LaterGauge
+from synapse.util.metrics import Measure, measure_func
 
-import logging
-
-from prometheus_client import Counter
-from six import itervalues
+from .protocol import ServerReplicationStreamProtocol
+from .streams import STREAMS_MAP, FederationStream
 
 stream_updates_counter = Counter("synapse_replication_tcp_resource_stream_updates",
                                  "", ["stream_name"])
diff --git a/synapse/replication/tcp/streams.py b/synapse/replication/tcp/streams.py
index 4c60bf79f9..55fe701c5c 100644
--- a/synapse/replication/tcp/streams.py
+++ b/synapse/replication/tcp/streams.py
@@ -24,11 +24,10 @@ Each stream is defined by the following information:
     update_function:    The function that returns a list of updates between two tokens
 """
 
-from twisted.internet import defer
-from collections import namedtuple
-
 import logging
+from collections import namedtuple
 
+from twisted.internet import defer
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/rest/__init__.py b/synapse/rest/__init__.py
index 16f5a73b95..75c2a4ec8e 100644
--- a/synapse/rest/__init__.py
+++ b/synapse/rest/__init__.py
@@ -13,50 +13,35 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from synapse.rest.client import (
-    versions,
-)
-
-from synapse.rest.client.v1 import (
-    room,
-    events,
-    profile,
-    presence,
-    initial_sync,
-    directory,
-    voip,
-    admin,
-    pusher,
-    push_rule,
-    register as v1_register,
-    login as v1_login,
-    logout,
-)
-
+from synapse.http.server import JsonResource
+from synapse.rest.client import versions
+from synapse.rest.client.v1 import admin, directory, events, initial_sync
+from synapse.rest.client.v1 import login as v1_login
+from synapse.rest.client.v1 import logout, presence, profile, push_rule, pusher
+from synapse.rest.client.v1 import register as v1_register
+from synapse.rest.client.v1 import room, voip
 from synapse.rest.client.v2_alpha import (
-    sync,
-    filter,
     account,
-    register,
+    account_data,
     auth,
-    receipts,
-    read_marker,
+    devices,
+    filter,
+    groups,
     keys,
-    tokenrefresh,
-    tags,
-    account_data,
-    report_event,
-    openid,
     notifications,
-    devices,
-    thirdparty,
+    openid,
+    read_marker,
+    receipts,
+    register,
+    report_event,
     sendtodevice,
+    sync,
+    tags,
+    thirdparty,
+    tokenrefresh,
     user_directory,
-    groups,
 )
 
-from synapse.http.server import JsonResource
-
 
 class ClientRestResource(JsonResource):
     """A resource for version 1 of the matrix client API."""
diff --git a/synapse/rest/client/v1/admin.py b/synapse/rest/client/v1/admin.py
index 8fb08dc526..2b091d61a5 100644
--- a/synapse/rest/client/v1/admin.py
+++ b/synapse/rest/client/v1/admin.py
@@ -14,19 +14,19 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from twisted.internet import defer
+import logging
 
 from six.moves import http_client
 
+from twisted.internet import defer
+
 from synapse.api.constants import Membership
-from synapse.api.errors import AuthError, SynapseError, Codes, NotFoundError
-from synapse.types import UserID, create_requester
+from synapse.api.errors import AuthError, Codes, NotFoundError, SynapseError
 from synapse.http.servlet import parse_json_object_from_request
+from synapse.types import UserID, create_requester
 
 from .base import ClientV1RestServlet, client_path_patterns
 
-import logging
-
 logger = logging.getLogger(__name__)
 
 
diff --git a/synapse/rest/client/v1/base.py b/synapse/rest/client/v1/base.py
index 197335d7aa..dde02328c3 100644
--- a/synapse/rest/client/v1/base.py
+++ b/synapse/rest/client/v1/base.py
@@ -16,14 +16,12 @@
 """This module contains base REST classes for constructing client v1 servlets.
 """
 
-from synapse.http.servlet import RestServlet
-from synapse.api.urls import CLIENT_PREFIX
-from synapse.rest.client.transactions import HttpTransactionCache
-
-import re
-
 import logging
+import re
 
+from synapse.api.urls import CLIENT_PREFIX
+from synapse.http.servlet import RestServlet
+from synapse.rest.client.transactions import HttpTransactionCache
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/rest/client/v1/directory.py b/synapse/rest/client/v1/directory.py
index 1c3933380f..4fdbb83815 100644
--- a/synapse/rest/client/v1/directory.py
+++ b/synapse/rest/client/v1/directory.py
@@ -14,17 +14,16 @@
 # limitations under the License.
 
 
+import logging
+
 from twisted.internet import defer
 
-from synapse.api.errors import AuthError, SynapseError, Codes
-from synapse.types import RoomAlias
+from synapse.api.errors import AuthError, Codes, SynapseError
 from synapse.http.servlet import parse_json_object_from_request
+from synapse.types import RoomAlias
 
 from .base import ClientV1RestServlet, client_path_patterns
 
-import logging
-
-
 logger = logging.getLogger(__name__)
 
 
diff --git a/synapse/rest/client/v1/events.py b/synapse/rest/client/v1/events.py
index 701b6f549b..b70c9c2806 100644
--- a/synapse/rest/client/v1/events.py
+++ b/synapse/rest/client/v1/events.py
@@ -14,15 +14,15 @@
 # limitations under the License.
 
 """This module contains REST servlets to do with event streaming, /events."""
+import logging
+
 from twisted.internet import defer
 
 from synapse.api.errors import SynapseError
-from synapse.streams.config import PaginationConfig
-from .base import ClientV1RestServlet, client_path_patterns
 from synapse.events.utils import serialize_event
+from synapse.streams.config import PaginationConfig
 
-import logging
-
+from .base import ClientV1RestServlet, client_path_patterns
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/rest/client/v1/initial_sync.py b/synapse/rest/client/v1/initial_sync.py
index 478e21eea8..fbe8cb2023 100644
--- a/synapse/rest/client/v1/initial_sync.py
+++ b/synapse/rest/client/v1/initial_sync.py
@@ -16,6 +16,7 @@
 from twisted.internet import defer
 
 from synapse.streams.config import PaginationConfig
+
 from .base import ClientV1RestServlet, client_path_patterns
 
 
diff --git a/synapse/rest/client/v1/login.py b/synapse/rest/client/v1/login.py
index 88ca5184cd..cb85fa1436 100644
--- a/synapse/rest/client/v1/login.py
+++ b/synapse/rest/client/v1/login.py
@@ -13,30 +13,26 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from twisted.internet import defer
-
-from synapse.api.errors import SynapseError, LoginError, Codes
-from synapse.types import UserID
-from synapse.http.server import finish_request
-from synapse.http.servlet import parse_json_object_from_request
-from synapse.util.msisdn import phone_number_to_msisdn
-
-from .base import ClientV1RestServlet, client_path_patterns
-
-from canonicaljson import json
-
+import logging
 import urllib
+import xml.etree.ElementTree as ET
+
 from six.moves.urllib import parse as urlparse
 
-import logging
-from saml2 import BINDING_HTTP_POST
-from saml2 import config
+from canonicaljson import json
+from saml2 import BINDING_HTTP_POST, config
 from saml2.client import Saml2Client
 
-import xml.etree.ElementTree as ET
-
+from twisted.internet import defer
 from twisted.web.client import PartialDownloadError
 
+from synapse.api.errors import Codes, LoginError, SynapseError
+from synapse.http.server import finish_request
+from synapse.http.servlet import parse_json_object_from_request
+from synapse.types import UserID
+from synapse.util.msisdn import phone_number_to_msisdn
+
+from .base import ClientV1RestServlet, client_path_patterns
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/rest/client/v1/logout.py b/synapse/rest/client/v1/logout.py
index e092158cb7..05a8ecfcd8 100644
--- a/synapse/rest/client/v1/logout.py
+++ b/synapse/rest/client/v1/logout.py
@@ -13,6 +13,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import logging
+
 from twisted.internet import defer
 
 from synapse.api.auth import get_access_token_from_request
@@ -20,9 +22,6 @@ from synapse.api.errors import AuthError
 
 from .base import ClientV1RestServlet, client_path_patterns
 
-import logging
-
-
 logger = logging.getLogger(__name__)
 
 
diff --git a/synapse/rest/client/v1/presence.py b/synapse/rest/client/v1/presence.py
index 647994bd53..a14f0c807e 100644
--- a/synapse/rest/client/v1/presence.py
+++ b/synapse/rest/client/v1/presence.py
@@ -15,17 +15,18 @@
 
 """ This module contains REST servlets to do with presence: /presence/<paths>
 """
+import logging
+
+from six import string_types
+
 from twisted.internet import defer
 
-from synapse.api.errors import SynapseError, AuthError
-from synapse.types import UserID
+from synapse.api.errors import AuthError, SynapseError
 from synapse.handlers.presence import format_user_presence_state
 from synapse.http.servlet import parse_json_object_from_request
-from .base import ClientV1RestServlet, client_path_patterns
-
-from six import string_types
+from synapse.types import UserID
 
-import logging
+from .base import ClientV1RestServlet, client_path_patterns
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/rest/client/v1/profile.py b/synapse/rest/client/v1/profile.py
index e4e3611a14..a23edd8fe5 100644
--- a/synapse/rest/client/v1/profile.py
+++ b/synapse/rest/client/v1/profile.py
@@ -16,9 +16,10 @@
 """ This module contains REST servlets to do with profile: /profile/<paths> """
 from twisted.internet import defer
 
-from .base import ClientV1RestServlet, client_path_patterns
-from synapse.types import UserID
 from synapse.http.servlet import parse_json_object_from_request
+from synapse.types import UserID
+
+from .base import ClientV1RestServlet, client_path_patterns
 
 
 class ProfileDisplaynameRestServlet(ClientV1RestServlet):
diff --git a/synapse/rest/client/v1/push_rule.py b/synapse/rest/client/v1/push_rule.py
index 6bb4821ec6..0df7ce570f 100644
--- a/synapse/rest/client/v1/push_rule.py
+++ b/synapse/rest/client/v1/push_rule.py
@@ -16,16 +16,18 @@
 from twisted.internet import defer
 
 from synapse.api.errors import (
-    SynapseError, UnrecognizedRequestError, NotFoundError, StoreError
+    NotFoundError,
+    StoreError,
+    SynapseError,
+    UnrecognizedRequestError,
 )
-from .base import ClientV1RestServlet, client_path_patterns
-from synapse.storage.push_rule import (
-    InconsistentRuleException, RuleNotFoundException
-)
-from synapse.push.clientformat import format_push_rules_for_user
+from synapse.http.servlet import parse_json_value_from_request
 from synapse.push.baserules import BASE_RULE_IDS
+from synapse.push.clientformat import format_push_rules_for_user
 from synapse.push.rulekinds import PRIORITY_CLASS_MAP
-from synapse.http.servlet import parse_json_value_from_request
+from synapse.storage.push_rule import InconsistentRuleException, RuleNotFoundException
+
+from .base import ClientV1RestServlet, client_path_patterns
 
 
 class PushRuleRestServlet(ClientV1RestServlet):
diff --git a/synapse/rest/client/v1/pusher.py b/synapse/rest/client/v1/pusher.py
index 40e523cc5f..1581f88db5 100644
--- a/synapse/rest/client/v1/pusher.py
+++ b/synapse/rest/client/v1/pusher.py
@@ -13,20 +13,21 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import logging
+
 from twisted.internet import defer
 
-from synapse.api.errors import SynapseError, Codes
-from synapse.push import PusherConfigException
+from synapse.api.errors import Codes, StoreError, SynapseError
+from synapse.http.server import finish_request
 from synapse.http.servlet import (
-    parse_json_object_from_request, parse_string, RestServlet
+    RestServlet,
+    parse_json_object_from_request,
+    parse_string,
 )
-from synapse.http.server import finish_request
-from synapse.api.errors import StoreError
+from synapse.push import PusherConfigException
 
 from .base import ClientV1RestServlet, client_path_patterns
 
-import logging
-
 logger = logging.getLogger(__name__)
 
 
diff --git a/synapse/rest/client/v1/register.py b/synapse/rest/client/v1/register.py
index c10320dedf..3ce5f8b726 100644
--- a/synapse/rest/client/v1/register.py
+++ b/synapse/rest/client/v1/register.py
@@ -14,21 +14,22 @@
 # limitations under the License.
 
 """This module contains REST servlets to do with registration: /register"""
+import hmac
+import logging
+from hashlib import sha1
+
+from six import string_types
+
 from twisted.internet import defer
 
-from synapse.api.errors import SynapseError, Codes
-from synapse.api.constants import LoginType
-from synapse.api.auth import get_access_token_from_request
-from .base import ClientV1RestServlet, client_path_patterns
 import synapse.util.stringutils as stringutils
+from synapse.api.auth import get_access_token_from_request
+from synapse.api.constants import LoginType
+from synapse.api.errors import Codes, SynapseError
 from synapse.http.servlet import parse_json_object_from_request
 from synapse.types import create_requester
 
-from hashlib import sha1
-import hmac
-import logging
-
-from six import string_types
+from .base import ClientV1RestServlet, client_path_patterns
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/rest/client/v1/room.py b/synapse/rest/client/v1/room.py
index e6ae5db79b..2470db52ba 100644
--- a/synapse/rest/client/v1/room.py
+++ b/synapse/rest/client/v1/room.py
@@ -15,23 +15,27 @@
 # limitations under the License.
 
 """ This module contains REST servlets to do with rooms: /rooms/<paths> """
+import logging
+
+from six.moves.urllib import parse as urlparse
+
+from canonicaljson import json
+
 from twisted.internet import defer
 
-from .base import ClientV1RestServlet, client_path_patterns
-from synapse.api.errors import SynapseError, Codes, AuthError
-from synapse.streams.config import PaginationConfig
 from synapse.api.constants import EventTypes, Membership
+from synapse.api.errors import AuthError, Codes, SynapseError
 from synapse.api.filtering import Filter
-from synapse.types import UserID, RoomID, RoomAlias, ThirdPartyInstanceID
-from synapse.events.utils import serialize_event, format_event_for_client_v2
+from synapse.events.utils import format_event_for_client_v2, serialize_event
 from synapse.http.servlet import (
-    parse_json_object_from_request, parse_string, parse_integer
+    parse_integer,
+    parse_json_object_from_request,
+    parse_string,
 )
+from synapse.streams.config import PaginationConfig
+from synapse.types import RoomAlias, RoomID, ThirdPartyInstanceID, UserID
 
-from six.moves.urllib import parse as urlparse
-
-import logging
-from canonicaljson import json
+from .base import ClientV1RestServlet, client_path_patterns
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/rest/client/v1/voip.py b/synapse/rest/client/v1/voip.py
index c43b30b73a..62f4c3d93e 100644
--- a/synapse/rest/client/v1/voip.py
+++ b/synapse/rest/client/v1/voip.py
@@ -13,16 +13,15 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import base64
+import hashlib
+import hmac
+
 from twisted.internet import defer
 
 from .base import ClientV1RestServlet, client_path_patterns
 
 
-import hmac
-import hashlib
-import base64
-
-
 class VoipRestServlet(ClientV1RestServlet):
     PATTERNS = client_path_patterns("/voip/turnServer$")
 
diff --git a/synapse/rest/client/v2_alpha/account.py b/synapse/rest/client/v2_alpha/account.py
index 80dbc3c92e..528c1f43f9 100644
--- a/synapse/rest/client/v2_alpha/account.py
+++ b/synapse/rest/client/v2_alpha/account.py
@@ -17,17 +17,20 @@
 import logging
 
 from six.moves import http_client
+
 from twisted.internet import defer
 
 from synapse.api.auth import has_access_token
 from synapse.api.constants import LoginType
 from synapse.api.errors import Codes, SynapseError
 from synapse.http.servlet import (
-    RestServlet, assert_params_in_request,
+    RestServlet,
+    assert_params_in_request,
     parse_json_object_from_request,
 )
 from synapse.util.msisdn import phone_number_to_msisdn
 from synapse.util.threepids import check_3pid_allowed
+
 from ._base import client_v2_patterns, interactive_auth_handler
 
 logger = logging.getLogger(__name__)
diff --git a/synapse/rest/client/v2_alpha/account_data.py b/synapse/rest/client/v2_alpha/account_data.py
index 0e0a187efd..371e9aa354 100644
--- a/synapse/rest/client/v2_alpha/account_data.py
+++ b/synapse/rest/client/v2_alpha/account_data.py
@@ -13,14 +13,14 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from ._base import client_v2_patterns
-
-from synapse.http.servlet import RestServlet, parse_json_object_from_request
-from synapse.api.errors import AuthError, SynapseError
+import logging
 
 from twisted.internet import defer
 
-import logging
+from synapse.api.errors import AuthError, SynapseError
+from synapse.http.servlet import RestServlet, parse_json_object_from_request
+
+from ._base import client_v2_patterns
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/rest/client/v2_alpha/auth.py b/synapse/rest/client/v2_alpha/auth.py
index d6f3a19648..bd8b5f4afa 100644
--- a/synapse/rest/client/v2_alpha/auth.py
+++ b/synapse/rest/client/v2_alpha/auth.py
@@ -13,6 +13,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import logging
+
 from twisted.internet import defer
 
 from synapse.api.constants import LoginType
@@ -23,9 +25,6 @@ from synapse.http.servlet import RestServlet
 
 from ._base import client_v2_patterns
 
-import logging
-
-
 logger = logging.getLogger(__name__)
 
 RECAPTCHA_TEMPLATE = """
diff --git a/synapse/rest/client/v2_alpha/devices.py b/synapse/rest/client/v2_alpha/devices.py
index 35d58b367a..09f6a8efe3 100644
--- a/synapse/rest/client/v2_alpha/devices.py
+++ b/synapse/rest/client/v2_alpha/devices.py
@@ -19,6 +19,7 @@ from twisted.internet import defer
 
 from synapse.api import errors
 from synapse.http import servlet
+
 from ._base import client_v2_patterns, interactive_auth_handler
 
 logger = logging.getLogger(__name__)
diff --git a/synapse/rest/client/v2_alpha/filter.py b/synapse/rest/client/v2_alpha/filter.py
index 1b9dc4528d..ae86728879 100644
--- a/synapse/rest/client/v2_alpha/filter.py
+++ b/synapse/rest/client/v2_alpha/filter.py
@@ -13,17 +13,15 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import logging
+
 from twisted.internet import defer
 
-from synapse.api.errors import AuthError, SynapseError, StoreError, Codes
+from synapse.api.errors import AuthError, Codes, StoreError, SynapseError
 from synapse.http.servlet import RestServlet, parse_json_object_from_request
 from synapse.types import UserID
 
-from ._base import client_v2_patterns
-from ._base import set_timeline_upper_limit
-
-import logging
-
+from ._base import client_v2_patterns, set_timeline_upper_limit
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/rest/client/v2_alpha/groups.py b/synapse/rest/client/v2_alpha/groups.py
index 3bb1ec2af6..21e02c07c0 100644
--- a/synapse/rest/client/v2_alpha/groups.py
+++ b/synapse/rest/client/v2_alpha/groups.py
@@ -14,6 +14,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import logging
+
 from twisted.internet import defer
 
 from synapse.http.servlet import RestServlet, parse_json_object_from_request
@@ -21,8 +23,6 @@ from synapse.types import GroupID
 
 from ._base import client_v2_patterns
 
-import logging
-
 logger = logging.getLogger(__name__)
 
 
diff --git a/synapse/rest/client/v2_alpha/keys.py b/synapse/rest/client/v2_alpha/keys.py
index 3cc87ea63f..8486086b51 100644
--- a/synapse/rest/client/v2_alpha/keys.py
+++ b/synapse/rest/client/v2_alpha/keys.py
@@ -19,10 +19,13 @@ from twisted.internet import defer
 
 from synapse.api.errors import SynapseError
 from synapse.http.servlet import (
-    RestServlet, parse_json_object_from_request, parse_integer
+    RestServlet,
+    parse_integer,
+    parse_json_object_from_request,
+    parse_string,
 )
-from synapse.http.servlet import parse_string
 from synapse.types import StreamToken
+
 from ._base import client_v2_patterns
 
 logger = logging.getLogger(__name__)
diff --git a/synapse/rest/client/v2_alpha/notifications.py b/synapse/rest/client/v2_alpha/notifications.py
index 66583d6778..2a6ea3df5f 100644
--- a/synapse/rest/client/v2_alpha/notifications.py
+++ b/synapse/rest/client/v2_alpha/notifications.py
@@ -13,19 +13,18 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import logging
+
 from twisted.internet import defer
 
-from synapse.http.servlet import (
-    RestServlet, parse_string, parse_integer
-)
 from synapse.events.utils import (
-    serialize_event, format_event_for_client_v2_without_room_id,
+    format_event_for_client_v2_without_room_id,
+    serialize_event,
 )
+from synapse.http.servlet import RestServlet, parse_integer, parse_string
 
 from ._base import client_v2_patterns
 
-import logging
-
 logger = logging.getLogger(__name__)
 
 
diff --git a/synapse/rest/client/v2_alpha/openid.py b/synapse/rest/client/v2_alpha/openid.py
index aa1cae8e1e..01c90aa2a3 100644
--- a/synapse/rest/client/v2_alpha/openid.py
+++ b/synapse/rest/client/v2_alpha/openid.py
@@ -14,15 +14,15 @@
 # limitations under the License.
 
 
-from ._base import client_v2_patterns
+import logging
+
+from twisted.internet import defer
 
-from synapse.http.servlet import RestServlet, parse_json_object_from_request
 from synapse.api.errors import AuthError
+from synapse.http.servlet import RestServlet, parse_json_object_from_request
 from synapse.util.stringutils import random_string
 
-from twisted.internet import defer
-
-import logging
+from ._base import client_v2_patterns
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/rest/client/v2_alpha/read_marker.py b/synapse/rest/client/v2_alpha/read_marker.py
index 2f8784fe06..a6e582a5ae 100644
--- a/synapse/rest/client/v2_alpha/read_marker.py
+++ b/synapse/rest/client/v2_alpha/read_marker.py
@@ -13,13 +13,13 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import logging
+
 from twisted.internet import defer
 
 from synapse.http.servlet import RestServlet, parse_json_object_from_request
-from ._base import client_v2_patterns
-
-import logging
 
+from ._base import client_v2_patterns
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/rest/client/v2_alpha/receipts.py b/synapse/rest/client/v2_alpha/receipts.py
index 1fbff2edd8..de370cac45 100644
--- a/synapse/rest/client/v2_alpha/receipts.py
+++ b/synapse/rest/client/v2_alpha/receipts.py
@@ -13,14 +13,14 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import logging
+
 from twisted.internet import defer
 
 from synapse.api.errors import SynapseError
 from synapse.http.servlet import RestServlet
-from ._base import client_v2_patterns
-
-import logging
 
+from ._base import client_v2_patterns
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/rest/client/v2_alpha/register.py b/synapse/rest/client/v2_alpha/register.py
index 97e7c0f7c6..896650d5a5 100644
--- a/synapse/rest/client/v2_alpha/register.py
+++ b/synapse/rest/client/v2_alpha/register.py
@@ -14,29 +14,31 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import hmac
+import logging
+from hashlib import sha1
+
+from six import string_types
+
 from twisted.internet import defer
 
 import synapse
 import synapse.types
 from synapse.api.auth import get_access_token_from_request, has_access_token
 from synapse.api.constants import LoginType
-from synapse.api.errors import SynapseError, Codes, UnrecognizedRequestError
+from synapse.api.errors import Codes, SynapseError, UnrecognizedRequestError
 from synapse.http.servlet import (
-    RestServlet, parse_json_object_from_request, assert_params_in_request, parse_string
+    RestServlet,
+    assert_params_in_request,
+    parse_json_object_from_request,
+    parse_string,
 )
 from synapse.util.msisdn import phone_number_to_msisdn
+from synapse.util.ratelimitutils import FederationRateLimiter
 from synapse.util.threepids import check_3pid_allowed
 
 from ._base import client_v2_patterns, interactive_auth_handler
 
-import logging
-import hmac
-from hashlib import sha1
-from synapse.util.ratelimitutils import FederationRateLimiter
-
-from six import string_types
-
-
 # We ought to be using hmac.compare_digest() but on older pythons it doesn't
 # exist. It's a _really minor_ security flaw to use plain string comparison
 # because the timing attack is so obscured by all the other code here it's
diff --git a/synapse/rest/client/v2_alpha/report_event.py b/synapse/rest/client/v2_alpha/report_event.py
index 8903e12405..08bb8e04fd 100644
--- a/synapse/rest/client/v2_alpha/report_event.py
+++ b/synapse/rest/client/v2_alpha/report_event.py
@@ -13,13 +13,13 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import logging
+
 from twisted.internet import defer
 
 from synapse.http.servlet import RestServlet, parse_json_object_from_request
-from ._base import client_v2_patterns
-
-import logging
 
+from ._base import client_v2_patterns
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/rest/client/v2_alpha/sync.py b/synapse/rest/client/v2_alpha/sync.py
index d2aa47b326..8aa06faf23 100644
--- a/synapse/rest/client/v2_alpha/sync.py
+++ b/synapse/rest/client/v2_alpha/sync.py
@@ -13,27 +13,26 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import itertools
+import logging
+
+from canonicaljson import json
+
 from twisted.internet import defer
 
-from synapse.http.servlet import (
-    RestServlet, parse_string, parse_integer, parse_boolean
+from synapse.api.constants import PresenceState
+from synapse.api.errors import SynapseError
+from synapse.api.filtering import DEFAULT_FILTER_COLLECTION, FilterCollection
+from synapse.events.utils import (
+    format_event_for_client_v2_without_room_id,
+    serialize_event,
 )
 from synapse.handlers.presence import format_user_presence_state
 from synapse.handlers.sync import SyncConfig
+from synapse.http.servlet import RestServlet, parse_boolean, parse_integer, parse_string
 from synapse.types import StreamToken
-from synapse.events.utils import (
-    serialize_event, format_event_for_client_v2_without_room_id,
-)
-from synapse.api.filtering import FilterCollection, DEFAULT_FILTER_COLLECTION
-from synapse.api.errors import SynapseError
-from synapse.api.constants import PresenceState
-from ._base import client_v2_patterns
-from ._base import set_timeline_upper_limit
 
-import itertools
-import logging
-
-from canonicaljson import json
+from ._base import client_v2_patterns, set_timeline_upper_limit
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/rest/client/v2_alpha/tags.py b/synapse/rest/client/v2_alpha/tags.py
index dac8603b07..4fea614e95 100644
--- a/synapse/rest/client/v2_alpha/tags.py
+++ b/synapse/rest/client/v2_alpha/tags.py
@@ -13,14 +13,14 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from ._base import client_v2_patterns
-
-from synapse.http.servlet import RestServlet, parse_json_object_from_request
-from synapse.api.errors import AuthError
+import logging
 
 from twisted.internet import defer
 
-import logging
+from synapse.api.errors import AuthError
+from synapse.http.servlet import RestServlet, parse_json_object_from_request
+
+from ._base import client_v2_patterns
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/rest/client/v2_alpha/thirdparty.py b/synapse/rest/client/v2_alpha/thirdparty.py
index 6773b9ba60..d9d379182e 100644
--- a/synapse/rest/client/v2_alpha/thirdparty.py
+++ b/synapse/rest/client/v2_alpha/thirdparty.py
@@ -20,6 +20,7 @@ from twisted.internet import defer
 
 from synapse.api.constants import ThirdPartyEntityKind
 from synapse.http.servlet import RestServlet
+
 from ._base import client_v2_patterns
 
 logger = logging.getLogger(__name__)
diff --git a/synapse/rest/client/v2_alpha/user_directory.py b/synapse/rest/client/v2_alpha/user_directory.py
index 2d4a43c353..cac0624ba7 100644
--- a/synapse/rest/client/v2_alpha/user_directory.py
+++ b/synapse/rest/client/v2_alpha/user_directory.py
@@ -19,6 +19,7 @@ from twisted.internet import defer
 
 from synapse.api.errors import SynapseError
 from synapse.http.servlet import RestServlet, parse_json_object_from_request
+
 from ._base import client_v2_patterns
 
 logger = logging.getLogger(__name__)
diff --git a/synapse/rest/client/versions.py b/synapse/rest/client/versions.py
index 2ecb15deee..6ac2987b98 100644
--- a/synapse/rest/client/versions.py
+++ b/synapse/rest/client/versions.py
@@ -13,11 +13,11 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from synapse.http.servlet import RestServlet
-
 import logging
 import re
 
+from synapse.http.servlet import RestServlet
+
 logger = logging.getLogger(__name__)
 
 
diff --git a/synapse/rest/consent/consent_resource.py b/synapse/rest/consent/consent_resource.py
index 724911d1e6..147ff7d79b 100644
--- a/synapse/rest/consent/consent_resource.py
+++ b/synapse/rest/consent/consent_resource.py
@@ -13,28 +13,26 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from hashlib import sha256
 import hmac
 import logging
+from hashlib import sha256
 from os import path
+
 from six.moves import http_client
 
 import jinja2
 from jinja2 import TemplateNotFound
+
 from twisted.internet import defer
 from twisted.web.resource import Resource
 from twisted.web.server import NOT_DONE_YET
 
-from synapse.api.errors import NotFoundError, SynapseError, StoreError
+from synapse.api.errors import NotFoundError, StoreError, SynapseError
 from synapse.config import ConfigError
-from synapse.http.server import (
-    finish_request,
-    wrap_html_request_handler,
-)
+from synapse.http.server import finish_request, wrap_html_request_handler
 from synapse.http.servlet import parse_string
 from synapse.types import UserID
 
-
 # language to use for the templates. TODO: figure this out from Accept-Language
 TEMPLATE_LANGUAGE = "en"
 
diff --git a/synapse/rest/key/v1/server_key_resource.py b/synapse/rest/key/v1/server_key_resource.py
index 1498d188c1..b9ee6e1c13 100644
--- a/synapse/rest/key/v1/server_key_resource.py
+++ b/synapse/rest/key/v1/server_key_resource.py
@@ -14,14 +14,16 @@
 # limitations under the License.
 
 
-from twisted.web.resource import Resource
-from synapse.http.server import respond_with_json_bytes
+import logging
+
+from canonicaljson import encode_canonical_json
 from signedjson.sign import sign_json
 from unpaddedbase64 import encode_base64
-from canonicaljson import encode_canonical_json
+
 from OpenSSL import crypto
-import logging
+from twisted.web.resource import Resource
 
+from synapse.http.server import respond_with_json_bytes
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/rest/key/v2/__init__.py b/synapse/rest/key/v2/__init__.py
index a07224148c..3491fd2118 100644
--- a/synapse/rest/key/v2/__init__.py
+++ b/synapse/rest/key/v2/__init__.py
@@ -14,6 +14,7 @@
 # limitations under the License.
 
 from twisted.web.resource import Resource
+
 from .local_key_resource import LocalKey
 from .remote_key_resource import RemoteKey
 
diff --git a/synapse/rest/key/v2/local_key_resource.py b/synapse/rest/key/v2/local_key_resource.py
index 04775b3c45..ec0ec7b431 100644
--- a/synapse/rest/key/v2/local_key_resource.py
+++ b/synapse/rest/key/v2/local_key_resource.py
@@ -14,13 +14,15 @@
 # limitations under the License.
 
 
-from twisted.web.resource import Resource
-from synapse.http.server import respond_with_json_bytes
+import logging
+
+from canonicaljson import encode_canonical_json
 from signedjson.sign import sign_json
 from unpaddedbase64 import encode_base64
-from canonicaljson import encode_canonical_json
-import logging
 
+from twisted.web.resource import Resource
+
+from synapse.http.server import respond_with_json_bytes
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/rest/key/v2/remote_key_resource.py b/synapse/rest/key/v2/remote_key_resource.py
index 21b4c1175e..7d67e4b064 100644
--- a/synapse/rest/key/v2/remote_key_resource.py
+++ b/synapse/rest/key/v2/remote_key_resource.py
@@ -12,20 +12,18 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from synapse.http.server import (
-    respond_with_json_bytes, wrap_json_request_handler,
-)
-from synapse.http.servlet import parse_integer, parse_json_object_from_request
-from synapse.api.errors import SynapseError, Codes
-from synapse.crypto.keyring import KeyLookupError
+import logging
+from io import BytesIO
 
+from twisted.internet import defer
 from twisted.web.resource import Resource
 from twisted.web.server import NOT_DONE_YET
-from twisted.internet import defer
 
+from synapse.api.errors import Codes, SynapseError
+from synapse.crypto.keyring import KeyLookupError
+from synapse.http.server import respond_with_json_bytes, wrap_json_request_handler
+from synapse.http.servlet import parse_integer, parse_json_object_from_request
 
-from io import BytesIO
-import logging
 logger = logging.getLogger(__name__)
 
 
diff --git a/synapse/rest/media/v0/content_repository.py b/synapse/rest/media/v0/content_repository.py
index e44d4276d2..f255f2883f 100644
--- a/synapse/rest/media/v0/content_repository.py
+++ b/synapse/rest/media/v0/content_repository.py
@@ -13,22 +13,19 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from synapse.http.server import respond_with_json_bytes, finish_request
-
-from synapse.api.errors import (
-    Codes, cs_error
-)
-
-from twisted.protocols.basic import FileSender
-from twisted.web import server, resource
-
-from canonicaljson import json
-
 import base64
 import logging
 import os
 import re
 
+from canonicaljson import json
+
+from twisted.protocols.basic import FileSender
+from twisted.web import resource, server
+
+from synapse.api.errors import Codes, cs_error
+from synapse.http.server import finish_request, respond_with_json_bytes
+
 logger = logging.getLogger(__name__)
 
 
diff --git a/synapse/rest/media/v1/_base.py b/synapse/rest/media/v1/_base.py
index c0d2f06855..65f4bd2910 100644
--- a/synapse/rest/media/v1/_base.py
+++ b/synapse/rest/media/v1/_base.py
@@ -13,23 +13,20 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from synapse.http.server import respond_with_json, finish_request
-from synapse.api.errors import (
-    cs_error, Codes, SynapseError
-)
-from synapse.util import logcontext
+import logging
+import os
+import urllib
+
+from six.moves.urllib import parse as urlparse
 
 from twisted.internet import defer
 from twisted.protocols.basic import FileSender
 
+from synapse.api.errors import Codes, SynapseError, cs_error
+from synapse.http.server import finish_request, respond_with_json
+from synapse.util import logcontext
 from synapse.util.stringutils import is_ascii
 
-import os
-
-import logging
-import urllib
-from six.moves.urllib import parse as urlparse
-
 logger = logging.getLogger(__name__)
 
 
diff --git a/synapse/rest/media/v1/download_resource.py b/synapse/rest/media/v1/download_resource.py
index 8cf8820c31..fbfa85f74f 100644
--- a/synapse/rest/media/v1/download_resource.py
+++ b/synapse/rest/media/v1/download_resource.py
@@ -18,11 +18,9 @@ from twisted.internet import defer
 from twisted.web.resource import Resource
 from twisted.web.server import NOT_DONE_YET
 
-from synapse.http.server import (
-    set_cors_headers,
-    wrap_json_request_handler,
-)
 import synapse.http.servlet
+from synapse.http.server import set_cors_headers, wrap_json_request_handler
+
 from ._base import parse_media_id, respond_404
 
 logger = logging.getLogger(__name__)
diff --git a/synapse/rest/media/v1/filepath.py b/synapse/rest/media/v1/filepath.py
index d5164e47e0..c8586fa280 100644
--- a/synapse/rest/media/v1/filepath.py
+++ b/synapse/rest/media/v1/filepath.py
@@ -13,9 +13,9 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import functools
 import os
 import re
-import functools
 
 NEW_FORMAT_ID_RE = re.compile(r"^\d\d\d\d-\d\d-\d\d")
 
diff --git a/synapse/rest/media/v1/identicon_resource.py b/synapse/rest/media/v1/identicon_resource.py
index 66f2b6bd30..a2e391415f 100644
--- a/synapse/rest/media/v1/identicon_resource.py
+++ b/synapse/rest/media/v1/identicon_resource.py
@@ -13,6 +13,7 @@
 # limitations under the License.
 
 from pydenticon import Generator
+
 from twisted.web.resource import Resource
 
 FOREGROUND = [
diff --git a/synapse/rest/media/v1/media_repository.py b/synapse/rest/media/v1/media_repository.py
index 218ba7a083..30242c525a 100644
--- a/synapse/rest/media/v1/media_repository.py
+++ b/synapse/rest/media/v1/media_repository.py
@@ -14,41 +14,42 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from twisted.internet import defer, threads
+import cgi
+import errno
+import logging
+import os
+import shutil
+
+from six import iteritems
+from six.moves.urllib import parse as urlparse
+
 import twisted.internet.error
 import twisted.web.http
+from twisted.internet import defer, threads
 from twisted.web.resource import Resource
 
-from ._base import respond_404, FileInfo, respond_with_responder
-from .upload_resource import UploadResource
-from .download_resource import DownloadResource
-from .thumbnail_resource import ThumbnailResource
-from .identicon_resource import IdenticonResource
-from .preview_url_resource import PreviewUrlResource
-from .filepath import MediaFilePaths
-from .thumbnailer import Thumbnailer
-from .storage_provider import StorageProviderWrapper
-from .media_storage import MediaStorage
-
-from synapse.http.matrixfederationclient import MatrixFederationHttpClient
-from synapse.util.stringutils import random_string
 from synapse.api.errors import (
-    SynapseError, HttpResponseException, NotFoundError, FederationDeniedError,
+    FederationDeniedError,
+    HttpResponseException,
+    NotFoundError,
+    SynapseError,
 )
-
+from synapse.http.matrixfederationclient import MatrixFederationHttpClient
 from synapse.util.async import Linearizer
-from synapse.util.stringutils import is_ascii
 from synapse.util.logcontext import make_deferred_yieldable
 from synapse.util.retryutils import NotRetryingDestination
+from synapse.util.stringutils import is_ascii, random_string
 
-import os
-import errno
-import shutil
-
-import cgi
-import logging
-from six.moves.urllib import parse as urlparse
-from six import iteritems
+from ._base import FileInfo, respond_404, respond_with_responder
+from .download_resource import DownloadResource
+from .filepath import MediaFilePaths
+from .identicon_resource import IdenticonResource
+from .media_storage import MediaStorage
+from .preview_url_resource import PreviewUrlResource
+from .storage_provider import StorageProviderWrapper
+from .thumbnail_resource import ThumbnailResource
+from .thumbnailer import Thumbnailer
+from .upload_resource import UploadResource
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/rest/media/v1/media_storage.py b/synapse/rest/media/v1/media_storage.py
index d6b8ebbedb..b25993fcb5 100644
--- a/synapse/rest/media/v1/media_storage.py
+++ b/synapse/rest/media/v1/media_storage.py
@@ -13,22 +13,21 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from twisted.internet import defer, threads
-from twisted.protocols.basic import FileSender
+import contextlib
+import logging
+import os
+import shutil
+import sys
 
 import six
 
-from ._base import Responder
+from twisted.internet import defer, threads
+from twisted.protocols.basic import FileSender
 
 from synapse.util.file_consumer import BackgroundFileConsumer
 from synapse.util.logcontext import make_deferred_yieldable
 
-import contextlib
-import os
-import logging
-import shutil
-import sys
-
+from ._base import Responder
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/rest/media/v1/preview_url_resource.py b/synapse/rest/media/v1/preview_url_resource.py
index adca490640..4e3a18ce08 100644
--- a/synapse/rest/media/v1/preview_url_resource.py
+++ b/synapse/rest/media/v1/preview_url_resource.py
@@ -24,31 +24,28 @@ import shutil
 import sys
 import traceback
 
-from canonicaljson import json
-
-from six.moves import urllib_parse as urlparse
 from six import string_types
+from six.moves import urllib_parse as urlparse
+
+from canonicaljson import json
 
-from twisted.web.server import NOT_DONE_YET
 from twisted.internet import defer
 from twisted.web.resource import Resource
+from twisted.web.server import NOT_DONE_YET
 
-from ._base import FileInfo
-
-from synapse.api.errors import (
-    SynapseError, Codes,
-)
-from synapse.util.logcontext import make_deferred_yieldable, run_in_background
-from synapse.util.stringutils import random_string
-from synapse.util.caches.expiringcache import ExpiringCache
+from synapse.api.errors import Codes, SynapseError
 from synapse.http.client import SpiderHttpClient
 from synapse.http.server import (
-    respond_with_json_bytes,
     respond_with_json,
+    respond_with_json_bytes,
     wrap_json_request_handler,
 )
 from synapse.util.async import ObservableDeferred
-from synapse.util.stringutils import is_ascii
+from synapse.util.caches.expiringcache import ExpiringCache
+from synapse.util.logcontext import make_deferred_yieldable, run_in_background
+from synapse.util.stringutils import is_ascii, random_string
+
+from ._base import FileInfo
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/rest/media/v1/storage_provider.py b/synapse/rest/media/v1/storage_provider.py
index 0252afd9d3..7b9f8b4d79 100644
--- a/synapse/rest/media/v1/storage_provider.py
+++ b/synapse/rest/media/v1/storage_provider.py
@@ -13,17 +13,16 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from twisted.internet import defer, threads
+import logging
+import os
+import shutil
 
-from .media_storage import FileResponder
+from twisted.internet import defer, threads
 
 from synapse.config._base import Config
 from synapse.util.logcontext import run_in_background
 
-import logging
-import os
-import shutil
-
+from .media_storage import FileResponder
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/rest/media/v1/thumbnail_resource.py b/synapse/rest/media/v1/thumbnail_resource.py
index aae6e464e8..5305e9175f 100644
--- a/synapse/rest/media/v1/thumbnail_resource.py
+++ b/synapse/rest/media/v1/thumbnail_resource.py
@@ -20,13 +20,14 @@ from twisted.internet import defer
 from twisted.web.resource import Resource
 from twisted.web.server import NOT_DONE_YET
 
-from synapse.http.server import (
-    set_cors_headers,
-    wrap_json_request_handler,
-)
+from synapse.http.server import set_cors_headers, wrap_json_request_handler
 from synapse.http.servlet import parse_integer, parse_string
+
 from ._base import (
-    FileInfo, parse_media_id, respond_404, respond_with_file,
+    FileInfo,
+    parse_media_id,
+    respond_404,
+    respond_with_file,
     respond_with_responder,
 )
 
diff --git a/synapse/rest/media/v1/thumbnailer.py b/synapse/rest/media/v1/thumbnailer.py
index e1ee535b9a..a4b26c2587 100644
--- a/synapse/rest/media/v1/thumbnailer.py
+++ b/synapse/rest/media/v1/thumbnailer.py
@@ -13,10 +13,10 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import PIL.Image as Image
+import logging
 from io import BytesIO
 
-import logging
+import PIL.Image as Image
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/rest/media/v1/upload_resource.py b/synapse/rest/media/v1/upload_resource.py
index 7567476fce..1a98120e1d 100644
--- a/synapse/rest/media/v1/upload_resource.py
+++ b/synapse/rest/media/v1/upload_resource.py
@@ -20,10 +20,7 @@ from twisted.web.resource import Resource
 from twisted.web.server import NOT_DONE_YET
 
 from synapse.api.errors import SynapseError
-from synapse.http.server import (
-    respond_with_json,
-    wrap_json_request_handler,
-)
+from synapse.http.server import respond_with_json, wrap_json_request_handler
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/server.py b/synapse/server.py
index c29c19289a..92bea96c5c 100644
--- a/synapse/server.py
+++ b/synapse/server.py
@@ -33,19 +33,30 @@ from synapse.crypto.keyring import Keyring
 from synapse.events.builder import EventBuilderFactory
 from synapse.events.spamcheck import SpamChecker
 from synapse.federation.federation_client import FederationClient
-from synapse.federation.federation_server import FederationServer
+from synapse.federation.federation_server import (
+    FederationHandlerRegistry,
+    FederationServer,
+)
 from synapse.federation.send_queue import FederationRemoteSendQueue
-from synapse.federation.federation_server import FederationHandlerRegistry
-from synapse.federation.transport.client import TransportLayerClient
 from synapse.federation.transaction_queue import TransactionQueue
+from synapse.federation.transport.client import TransportLayerClient
+from synapse.groups.attestations import GroupAttestationSigning, GroupAttestionRenewer
+from synapse.groups.groups_server import GroupsServerHandler
 from synapse.handlers import Handlers
 from synapse.handlers.appservice import ApplicationServicesHandler
 from synapse.handlers.auth import AuthHandler, MacaroonGenerator
 from synapse.handlers.deactivate_account import DeactivateAccountHandler
-from synapse.handlers.devicemessage import DeviceMessageHandler
 from synapse.handlers.device import DeviceHandler
+from synapse.handlers.devicemessage import DeviceMessageHandler
 from synapse.handlers.e2e_keys import E2eKeysHandler
+from synapse.handlers.events import EventHandler, EventStreamHandler
+from synapse.handlers.groups_local import GroupsLocalHandler
+from synapse.handlers.initial_sync import InitialSyncHandler
+from synapse.handlers.message import EventCreationHandler
 from synapse.handlers.presence import PresenceHandler
+from synapse.handlers.profile import ProfileHandler
+from synapse.handlers.read_marker import ReadMarkerHandler
+from synapse.handlers.receipts import ReceiptsHandler
 from synapse.handlers.room import RoomCreationHandler
 from synapse.handlers.room_list import RoomListHandler
 from synapse.handlers.room_member import RoomMemberMasterHandler
@@ -53,17 +64,8 @@ from synapse.handlers.room_member_worker import RoomMemberWorkerHandler
 from synapse.handlers.set_password import SetPasswordHandler
 from synapse.handlers.sync import SyncHandler
 from synapse.handlers.typing import TypingHandler
-from synapse.handlers.events import EventHandler, EventStreamHandler
-from synapse.handlers.initial_sync import InitialSyncHandler
-from synapse.handlers.receipts import ReceiptsHandler
-from synapse.handlers.read_marker import ReadMarkerHandler
 from synapse.handlers.user_directory import UserDirectoryHandler
-from synapse.handlers.groups_local import GroupsLocalHandler
-from synapse.handlers.profile import ProfileHandler
-from synapse.handlers.message import EventCreationHandler
-from synapse.groups.groups_server import GroupsServerHandler
-from synapse.groups.attestations import GroupAttestionRenewer, GroupAttestationSigning
-from synapse.http.client import SimpleHttpClient, InsecureInterceptableContextFactory
+from synapse.http.client import InsecureInterceptableContextFactory, SimpleHttpClient
 from synapse.http.matrixfederationclient import MatrixFederationHttpClient
 from synapse.notifier import Notifier
 from synapse.push.action_generator import ActionGenerator
@@ -74,9 +76,7 @@ from synapse.rest.media.v1.media_repository import (
 )
 from synapse.server_notices.server_notices_manager import ServerNoticesManager
 from synapse.server_notices.server_notices_sender import ServerNoticesSender
-from synapse.server_notices.worker_server_notices_sender import (
-    WorkerServerNoticesSender,
-)
+from synapse.server_notices.worker_server_notices_sender import WorkerServerNoticesSender
 from synapse.state import StateHandler, StateResolutionHandler
 from synapse.storage import DataStore
 from synapse.streams.events import EventSources
diff --git a/synapse/server_notices/consent_server_notices.py b/synapse/server_notices/consent_server_notices.py
index bb74af1af5..5e3044d164 100644
--- a/synapse/server_notices/consent_server_notices.py
+++ b/synapse/server_notices/consent_server_notices.py
@@ -14,7 +14,8 @@
 # limitations under the License.
 import logging
 
-from six import (iteritems, string_types)
+from six import iteritems, string_types
+
 from twisted.internet import defer
 
 from synapse.api.errors import SynapseError
diff --git a/synapse/state.py b/synapse/state.py
index 8098db94b4..15a593d41c 100644
--- a/synapse/state.py
+++ b/synapse/state.py
@@ -14,25 +14,25 @@
 # limitations under the License.
 
 
+import hashlib
+import logging
+from collections import namedtuple
+
+from six import iteritems, itervalues
+
+from frozendict import frozendict
+
 from twisted.internet import defer
 
 from synapse import event_auth
-from synapse.util.logutils import log_function
-from synapse.util.caches.expiringcache import ExpiringCache
-from synapse.util.metrics import Measure
 from synapse.api.constants import EventTypes
 from synapse.api.errors import AuthError
 from synapse.events.snapshot import EventContext
 from synapse.util.async import Linearizer
 from synapse.util.caches import CACHE_SIZE_FACTOR
-
-from collections import namedtuple
-from frozendict import frozendict
-
-import logging
-import hashlib
-
-from six import iteritems, itervalues
+from synapse.util.caches.expiringcache import ExpiringCache
+from synapse.util.logutils import log_function
+from synapse.util.metrics import Measure
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/storage/__init__.py b/synapse/storage/__init__.py
index e843b702b9..ba88a54979 100644
--- a/synapse/storage/__init__.py
+++ b/synapse/storage/__init__.py
@@ -15,51 +15,48 @@
 # limitations under the License.
 
 import datetime
-from dateutil import tz
-import time
 import logging
+import time
 
+from dateutil import tz
+
+from synapse.api.constants import PresenceState
 from synapse.storage.devices import DeviceStore
 from synapse.storage.user_erasure_store import UserErasureStore
-from .appservice import (
-    ApplicationServiceStore, ApplicationServiceTransactionStore
-)
+from synapse.util.caches.stream_change_cache import StreamChangeCache
+
+from .account_data import AccountDataStore
+from .appservice import ApplicationServiceStore, ApplicationServiceTransactionStore
+from .client_ips import ClientIpStore
+from .deviceinbox import DeviceInboxStore
 from .directory import DirectoryStore
+from .end_to_end_keys import EndToEndKeyStore
+from .engines import PostgresEngine
+from .event_federation import EventFederationStore
+from .event_push_actions import EventPushActionsStore
 from .events import EventsStore
+from .filtering import FilteringStore
+from .group_server import GroupServerStore
+from .keys import KeyStore
+from .media_repository import MediaRepositoryStore
+from .openid import OpenIdStore
 from .presence import PresenceStore, UserPresenceState
 from .profile import ProfileStore
+from .push_rule import PushRuleStore
+from .pusher import PusherStore
+from .receipts import ReceiptsStore
 from .registration import RegistrationStore
+from .rejections import RejectionsStore
 from .room import RoomStore
 from .roommember import RoomMemberStore
-from .stream import StreamStore
-from .transactions import TransactionStore
-from .keys import KeyStore
-from .event_federation import EventFederationStore
-from .pusher import PusherStore
-from .push_rule import PushRuleStore
-from .media_repository import MediaRepositoryStore
-from .rejections import RejectionsStore
-from .event_push_actions import EventPushActionsStore
-from .deviceinbox import DeviceInboxStore
-from .group_server import GroupServerStore
-from .state import StateStore
-from .signatures import SignatureStore
-from .filtering import FilteringStore
-from .end_to_end_keys import EndToEndKeyStore
-
-from .receipts import ReceiptsStore
 from .search import SearchStore
+from .signatures import SignatureStore
+from .state import StateStore
+from .stream import StreamStore
 from .tags import TagsStore
-from .account_data import AccountDataStore
-from .openid import OpenIdStore
-from .client_ips import ClientIpStore
+from .transactions import TransactionStore
 from .user_directory import UserDirectoryStore
-
-from .util.id_generators import IdGenerator, StreamIdGenerator, ChainedIdGenerator
-from .engines import PostgresEngine
-
-from synapse.api.constants import PresenceState
-from synapse.util.caches.stream_change_cache import StreamChangeCache
+from .util.id_generators import ChainedIdGenerator, IdGenerator, StreamIdGenerator
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/storage/_base.py b/synapse/storage/_base.py
index 22d6257a9f..1fd5d8f162 100644
--- a/synapse/storage/_base.py
+++ b/synapse/storage/_base.py
@@ -13,22 +13,21 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 import logging
+import sys
+import threading
+import time
 
-from synapse.api.errors import StoreError
-from synapse.util.logcontext import LoggingContext, PreserveLoggingContext
-from synapse.util.caches.descriptors import Cache
-from synapse.storage.engines import PostgresEngine
+from six import iteritems, iterkeys, itervalues
+from six.moves import intern, range
 
 from prometheus_client import Histogram
 
 from twisted.internet import defer
 
-import sys
-import time
-import threading
-
-from six import itervalues, iterkeys, iteritems
-from six.moves import intern, range
+from synapse.api.errors import StoreError
+from synapse.storage.engines import PostgresEngine
+from synapse.util.caches.descriptors import Cache
+from synapse.util.logcontext import LoggingContext, PreserveLoggingContext
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/storage/account_data.py b/synapse/storage/account_data.py
index 7034a61399..bbc3355c73 100644
--- a/synapse/storage/account_data.py
+++ b/synapse/storage/account_data.py
@@ -14,18 +14,17 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import abc
+import logging
+
+from canonicaljson import json
+
 from twisted.internet import defer
 
 from synapse.storage._base import SQLBaseStore
 from synapse.storage.util.id_generators import StreamIdGenerator
-
-from synapse.util.caches.stream_change_cache import StreamChangeCache
 from synapse.util.caches.descriptors import cached, cachedInlineCallbacks
-
-from canonicaljson import json
-
-import abc
-import logging
+from synapse.util.caches.stream_change_cache import StreamChangeCache
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/storage/appservice.py b/synapse/storage/appservice.py
index 4d32d0bdf6..9f12b360bc 100644
--- a/synapse/storage/appservice.py
+++ b/synapse/storage/appservice.py
@@ -15,14 +15,16 @@
 # limitations under the License.
 import logging
 import re
-from twisted.internet import defer
+
 from canonicaljson import json
 
+from twisted.internet import defer
+
 from synapse.appservice import AppServiceTransaction
 from synapse.config.appservice import load_appservices
 from synapse.storage.events import EventsWorkerStore
-from ._base import SQLBaseStore
 
+from ._base import SQLBaseStore
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/storage/background_updates.py b/synapse/storage/background_updates.py
index af18964510..dc9eca7d15 100644
--- a/synapse/storage/background_updates.py
+++ b/synapse/storage/background_updates.py
@@ -13,14 +13,14 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from ._base import SQLBaseStore
-from . import engines
-
-from twisted.internet import defer
+import logging
 
 from canonicaljson import json
 
-import logging
+from twisted.internet import defer
+
+from . import engines
+from ._base import SQLBaseStore
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/storage/client_ips.py b/synapse/storage/client_ips.py
index 968d2fed22..b78eda3413 100644
--- a/synapse/storage/client_ips.py
+++ b/synapse/storage/client_ips.py
@@ -15,15 +15,14 @@
 
 import logging
 
-from twisted.internet import defer
+from six import iteritems
 
-from ._base import Cache
-from . import background_updates
+from twisted.internet import defer
 
 from synapse.util.caches import CACHE_SIZE_FACTOR
 
-from six import iteritems
-
+from . import background_updates
+from ._base import Cache
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/storage/deviceinbox.py b/synapse/storage/deviceinbox.py
index 38addbf9c0..73646da025 100644
--- a/synapse/storage/deviceinbox.py
+++ b/synapse/storage/deviceinbox.py
@@ -19,10 +19,9 @@ from canonicaljson import json
 
 from twisted.internet import defer
 
-from .background_updates import BackgroundUpdateStore
-
 from synapse.util.caches.expiringcache import ExpiringCache
 
+from .background_updates import BackgroundUpdateStore
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/storage/devices.py b/synapse/storage/devices.py
index 2ed9ada783..ec68e39f1e 100644
--- a/synapse/storage/devices.py
+++ b/synapse/storage/devices.py
@@ -14,15 +14,16 @@
 # limitations under the License.
 import logging
 
+from six import iteritems, itervalues
+
+from canonicaljson import json
+
 from twisted.internet import defer
 
 from synapse.api.errors import StoreError
-from ._base import SQLBaseStore, Cache
-from synapse.util.caches.descriptors import cached, cachedList, cachedInlineCallbacks
-
-from canonicaljson import json
+from synapse.util.caches.descriptors import cached, cachedInlineCallbacks, cachedList
 
-from six import itervalues, iteritems
+from ._base import Cache, SQLBaseStore
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/storage/directory.py b/synapse/storage/directory.py
index d0c0059757..808194236a 100644
--- a/synapse/storage/directory.py
+++ b/synapse/storage/directory.py
@@ -13,15 +13,14 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from ._base import SQLBaseStore
-from synapse.util.caches.descriptors import cached
-
-from synapse.api.errors import SynapseError
+from collections import namedtuple
 
 from twisted.internet import defer
 
-from collections import namedtuple
+from synapse.api.errors import SynapseError
+from synapse.util.caches.descriptors import cached
 
+from ._base import SQLBaseStore
 
 RoomAliasMapping = namedtuple(
     "RoomAliasMapping",
diff --git a/synapse/storage/end_to_end_keys.py b/synapse/storage/end_to_end_keys.py
index 181047c8b7..7ae5c65482 100644
--- a/synapse/storage/end_to_end_keys.py
+++ b/synapse/storage/end_to_end_keys.py
@@ -12,16 +12,16 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+from six import iteritems
+
+from canonicaljson import encode_canonical_json, json
+
 from twisted.internet import defer
 
 from synapse.util.caches.descriptors import cached
 
-from canonicaljson import encode_canonical_json, json
-
 from ._base import SQLBaseStore
 
-from six import iteritems
-
 
 class EndToEndKeyStore(SQLBaseStore):
     def set_e2e_device_keys(self, user_id, device_id, time_now, device_keys):
diff --git a/synapse/storage/engines/__init__.py b/synapse/storage/engines/__init__.py
index 8c868ece75..e2f9de8451 100644
--- a/synapse/storage/engines/__init__.py
+++ b/synapse/storage/engines/__init__.py
@@ -13,13 +13,12 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from ._base import IncorrectDatabaseSetup
-from .postgres import PostgresEngine
-from .sqlite3 import Sqlite3Engine
-
 import importlib
 import platform
 
+from ._base import IncorrectDatabaseSetup
+from .postgres import PostgresEngine
+from .sqlite3 import Sqlite3Engine
 
 SUPPORTED_MODULE = {
     "sqlite3": Sqlite3Engine,
diff --git a/synapse/storage/engines/sqlite3.py b/synapse/storage/engines/sqlite3.py
index 60f0fa7fb3..19949fc474 100644
--- a/synapse/storage/engines/sqlite3.py
+++ b/synapse/storage/engines/sqlite3.py
@@ -13,11 +13,11 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from synapse.storage.prepare_database import prepare_database
-
 import struct
 import threading
 
+from synapse.storage.prepare_database import prepare_database
+
 
 class Sqlite3Engine(object):
     single_threaded = True
diff --git a/synapse/storage/event_federation.py b/synapse/storage/event_federation.py
index 8fbf7ffba7..8d366d1b91 100644
--- a/synapse/storage/event_federation.py
+++ b/synapse/storage/event_federation.py
@@ -12,23 +12,21 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+import logging
 import random
 
+from six.moves import range
+from six.moves.queue import Empty, PriorityQueue
+
+from unpaddedbase64 import encode_base64
+
 from twisted.internet import defer
 
+from synapse.api.errors import StoreError
 from synapse.storage._base import SQLBaseStore
 from synapse.storage.events import EventsWorkerStore
 from synapse.storage.signatures import SignatureWorkerStore
-
-from synapse.api.errors import StoreError
 from synapse.util.caches.descriptors import cached
-from unpaddedbase64 import encode_base64
-
-import logging
-from six.moves.queue import PriorityQueue, Empty
-
-from six.moves import range
-
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/storage/event_push_actions.py b/synapse/storage/event_push_actions.py
index 05cb3f61ce..29b511ae5e 100644
--- a/synapse/storage/event_push_actions.py
+++ b/synapse/storage/event_push_actions.py
@@ -14,15 +14,16 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from synapse.storage._base import SQLBaseStore, LoggingTransaction
-from twisted.internet import defer
-from synapse.util.caches.descriptors import cachedInlineCallbacks
-
 import logging
 
+from six import iteritems
+
 from canonicaljson import json
 
-from six import iteritems
+from twisted.internet import defer
+
+from synapse.storage._base import LoggingTransaction, SQLBaseStore
+from synapse.util.caches.descriptors import cachedInlineCallbacks
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/storage/events.py b/synapse/storage/events.py
index a54abb9edd..2aaab0d02c 100644
--- a/synapse/storage/events.py
+++ b/synapse/storage/events.py
@@ -14,37 +14,33 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from collections import OrderedDict, deque, namedtuple
-from functools import wraps
 import itertools
 import logging
+from collections import OrderedDict, deque, namedtuple
+from functools import wraps
+
+from six import iteritems, itervalues
+from six.moves import range
 
 from canonicaljson import json
+from prometheus_client import Counter
 
 from twisted.internet import defer
 
+import synapse.metrics
+from synapse.api.constants import EventTypes
+from synapse.api.errors import SynapseError
+# these are only included to make the type annotations work
+from synapse.events import EventBase  # noqa: F401
+from synapse.events.snapshot import EventContext  # noqa: F401
 from synapse.storage.events_worker import EventsWorkerStore
+from synapse.types import RoomStreamToken, get_domain_from_id
 from synapse.util.async import ObservableDeferred
+from synapse.util.caches.descriptors import cached, cachedInlineCallbacks
 from synapse.util.frozenutils import frozendict_json_encoder
-from synapse.util.logcontext import (
-    PreserveLoggingContext, make_deferred_yieldable,
-)
+from synapse.util.logcontext import PreserveLoggingContext, make_deferred_yieldable
 from synapse.util.logutils import log_function
 from synapse.util.metrics import Measure
-from synapse.api.constants import EventTypes
-from synapse.api.errors import SynapseError
-from synapse.util.caches.descriptors import cached, cachedInlineCallbacks
-from synapse.types import get_domain_from_id, RoomStreamToken
-import synapse.metrics
-
-# these are only included to make the type annotations work
-from synapse.events import EventBase    # noqa: F401
-from synapse.events.snapshot import EventContext   # noqa: F401
-
-from six.moves import range
-from six import itervalues, iteritems
-
-from prometheus_client import Counter
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/storage/events_worker.py b/synapse/storage/events_worker.py
index 896225aab9..5fe1fd13e5 100644
--- a/synapse/storage/events_worker.py
+++ b/synapse/storage/events_worker.py
@@ -12,29 +12,28 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-from ._base import SQLBaseStore
+import logging
+from collections import namedtuple
+
+from canonicaljson import json
 
 from twisted.internet import defer
 
+from synapse.api.errors import SynapseError
+# these are only included to make the type annotations work
+from synapse.events import EventBase  # noqa: F401
 from synapse.events import FrozenEvent
+from synapse.events.snapshot import EventContext  # noqa: F401
 from synapse.events.utils import prune_event
-
 from synapse.util.logcontext import (
-    PreserveLoggingContext, make_deferred_yieldable, run_in_background,
     LoggingContext,
+    PreserveLoggingContext,
+    make_deferred_yieldable,
+    run_in_background,
 )
 from synapse.util.metrics import Measure
-from synapse.api.errors import SynapseError
 
-from collections import namedtuple
-
-import logging
-
-from canonicaljson import json
-
-# these are only included to make the type annotations work
-from synapse.events import EventBase    # noqa: F401
-from synapse.events.snapshot import EventContext   # noqa: F401
+from ._base import SQLBaseStore
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/storage/filtering.py b/synapse/storage/filtering.py
index eae6027cee..2d5896c5b4 100644
--- a/synapse/storage/filtering.py
+++ b/synapse/storage/filtering.py
@@ -13,13 +13,14 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from canonicaljson import encode_canonical_json, json
+
 from twisted.internet import defer
 
-from ._base import SQLBaseStore
-from synapse.api.errors import SynapseError, Codes
+from synapse.api.errors import Codes, SynapseError
 from synapse.util.caches.descriptors import cachedInlineCallbacks
 
-from canonicaljson import encode_canonical_json, json
+from ._base import SQLBaseStore
 
 
 class FilteringStore(SQLBaseStore):
diff --git a/synapse/storage/group_server.py b/synapse/storage/group_server.py
index b77402d295..592d1b4c2a 100644
--- a/synapse/storage/group_server.py
+++ b/synapse/storage/group_server.py
@@ -14,15 +14,14 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from canonicaljson import json
+
 from twisted.internet import defer
 
 from synapse.api.errors import SynapseError
 
 from ._base import SQLBaseStore
 
-from canonicaljson import json
-
-
 # The category ID for the "default" category. We don't store as null in the
 # database to avoid the fun of null != null
 _DEFAULT_CATEGORY_ID = ""
diff --git a/synapse/storage/keys.py b/synapse/storage/keys.py
index 0f13b61da8..f547977600 100644
--- a/synapse/storage/keys.py
+++ b/synapse/storage/keys.py
@@ -13,17 +13,19 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from ._base import SQLBaseStore
-from synapse.util.caches.descriptors import cachedInlineCallbacks
+import hashlib
+import logging
 
-from twisted.internet import defer
 import six
 
-import OpenSSL
 from signedjson.key import decode_verify_key_bytes
-import hashlib
 
-import logging
+import OpenSSL
+from twisted.internet import defer
+
+from synapse.util.caches.descriptors import cachedInlineCallbacks
+
+from ._base import SQLBaseStore
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/storage/prepare_database.py b/synapse/storage/prepare_database.py
index cf2aae0468..b290f834b3 100644
--- a/synapse/storage/prepare_database.py
+++ b/synapse/storage/prepare_database.py
@@ -20,7 +20,6 @@ import logging
 import os
 import re
 
-
 logger = logging.getLogger(__name__)
 
 
diff --git a/synapse/storage/presence.py b/synapse/storage/presence.py
index f05d91cc58..a0c7a0dc87 100644
--- a/synapse/storage/presence.py
+++ b/synapse/storage/presence.py
@@ -13,13 +13,15 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from ._base import SQLBaseStore
+from collections import namedtuple
+
+from twisted.internet import defer
+
 from synapse.api.constants import PresenceState
-from synapse.util.caches.descriptors import cached, cachedInlineCallbacks, cachedList
 from synapse.util import batch_iter
+from synapse.util.caches.descriptors import cached, cachedInlineCallbacks, cachedList
 
-from collections import namedtuple
-from twisted.internet import defer
+from ._base import SQLBaseStore
 
 
 class UserPresenceState(namedtuple("UserPresenceState",
diff --git a/synapse/storage/profile.py b/synapse/storage/profile.py
index 8612bd5ecc..60295da254 100644
--- a/synapse/storage/profile.py
+++ b/synapse/storage/profile.py
@@ -15,8 +15,8 @@
 
 from twisted.internet import defer
 
-from synapse.storage.roommember import ProfileInfo
 from synapse.api.errors import StoreError
+from synapse.storage.roommember import ProfileInfo
 
 from ._base import SQLBaseStore
 
diff --git a/synapse/storage/push_rule.py b/synapse/storage/push_rule.py
index 9e52e992b3..be655d287b 100644
--- a/synapse/storage/push_rule.py
+++ b/synapse/storage/push_rule.py
@@ -14,21 +14,23 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from ._base import SQLBaseStore
+import abc
+import logging
+
+from canonicaljson import json
+
+from twisted.internet import defer
+
+from synapse.api.constants import EventTypes
+from synapse.push.baserules import list_with_base_rules
 from synapse.storage.appservice import ApplicationServiceWorkerStore
 from synapse.storage.pusher import PusherWorkerStore
 from synapse.storage.receipts import ReceiptsWorkerStore
 from synapse.storage.roommember import RoomMemberWorkerStore
 from synapse.util.caches.descriptors import cachedInlineCallbacks, cachedList
 from synapse.util.caches.stream_change_cache import StreamChangeCache
-from synapse.push.baserules import list_with_base_rules
-from synapse.api.constants import EventTypes
-from twisted.internet import defer
 
-from canonicaljson import json
-
-import abc
-import logging
+from ._base import SQLBaseStore
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/storage/pusher.py b/synapse/storage/pusher.py
index c6def861cf..cc273a57b2 100644
--- a/synapse/storage/pusher.py
+++ b/synapse/storage/pusher.py
@@ -14,15 +14,16 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from ._base import SQLBaseStore
-from twisted.internet import defer
+import logging
+import types
 
 from canonicaljson import encode_canonical_json, json
 
+from twisted.internet import defer
+
 from synapse.util.caches.descriptors import cachedInlineCallbacks, cachedList
 
-import logging
-import types
+from ._base import SQLBaseStore
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/storage/receipts.py b/synapse/storage/receipts.py
index f230a3bab7..3738901ea4 100644
--- a/synapse/storage/receipts.py
+++ b/synapse/storage/receipts.py
@@ -14,18 +14,18 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from ._base import SQLBaseStore
-from .util.id_generators import StreamIdGenerator
-from synapse.util.caches.descriptors import cachedInlineCallbacks, cachedList, cached
-from synapse.util.caches.stream_change_cache import StreamChangeCache
-
-from twisted.internet import defer
+import abc
+import logging
 
 from canonicaljson import json
 
-import abc
-import logging
+from twisted.internet import defer
 
+from synapse.util.caches.descriptors import cached, cachedInlineCallbacks, cachedList
+from synapse.util.caches.stream_change_cache import StreamChangeCache
+
+from ._base import SQLBaseStore
+from .util.id_generators import StreamIdGenerator
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/storage/registration.py b/synapse/storage/registration.py
index 0d18f6d869..07333f777d 100644
--- a/synapse/storage/registration.py
+++ b/synapse/storage/registration.py
@@ -15,15 +15,15 @@
 
 import re
 
+from six.moves import range
+
 from twisted.internet import defer
 
-from synapse.api.errors import StoreError, Codes
+from synapse.api.errors import Codes, StoreError
 from synapse.storage import background_updates
 from synapse.storage._base import SQLBaseStore
 from synapse.util.caches.descriptors import cached, cachedInlineCallbacks
 
-from six.moves import range
-
 
 class RegistrationWorkerStore(SQLBaseStore):
     @cached()
diff --git a/synapse/storage/rejections.py b/synapse/storage/rejections.py
index 40acb5c4ed..880f047adb 100644
--- a/synapse/storage/rejections.py
+++ b/synapse/storage/rejections.py
@@ -13,10 +13,10 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from ._base import SQLBaseStore
-
 import logging
 
+from ._base import SQLBaseStore
+
 logger = logging.getLogger(__name__)
 
 
diff --git a/synapse/storage/room.py b/synapse/storage/room.py
index ca0eb187e5..3147fb6827 100644
--- a/synapse/storage/room.py
+++ b/synapse/storage/room.py
@@ -13,6 +13,12 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import collections
+import logging
+import re
+
+from canonicaljson import json
+
 from twisted.internet import defer
 
 from synapse.api.errors import StoreError
@@ -20,12 +26,6 @@ from synapse.storage._base import SQLBaseStore
 from synapse.storage.search import SearchStore
 from synapse.util.caches.descriptors import cached, cachedInlineCallbacks
 
-from canonicaljson import json
-
-import collections
-import logging
-import re
-
 logger = logging.getLogger(__name__)
 
 
diff --git a/synapse/storage/roommember.py b/synapse/storage/roommember.py
index 8fc9549a75..02a802bed9 100644
--- a/synapse/storage/roommember.py
+++ b/synapse/storage/roommember.py
@@ -14,24 +14,23 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from twisted.internet import defer
-
+import logging
 from collections import namedtuple
 
+from six import iteritems, itervalues
+
+from canonicaljson import json
+
+from twisted.internet import defer
+
+from synapse.api.constants import EventTypes, Membership
 from synapse.storage.events import EventsWorkerStore
+from synapse.types import get_domain_from_id
 from synapse.util.async import Linearizer
 from synapse.util.caches import intern_string
 from synapse.util.caches.descriptors import cached, cachedInlineCallbacks
 from synapse.util.stringutils import to_ascii
 
-from synapse.api.constants import Membership, EventTypes
-from synapse.types import get_domain_from_id
-
-import logging
-from canonicaljson import json
-
-from six import itervalues, iteritems
-
 logger = logging.getLogger(__name__)
 
 
diff --git a/synapse/storage/schema/delta/25/fts.py b/synapse/storage/schema/delta/25/fts.py
index e7351c3ae6..4b2ffd35fd 100644
--- a/synapse/storage/schema/delta/25/fts.py
+++ b/synapse/storage/schema/delta/25/fts.py
@@ -14,11 +14,11 @@
 
 import logging
 
-from synapse.storage.prepare_database import get_statements
-from synapse.storage.engines import PostgresEngine, Sqlite3Engine
-
 import simplejson
 
+from synapse.storage.engines import PostgresEngine, Sqlite3Engine
+from synapse.storage.prepare_database import get_statements
+
 logger = logging.getLogger(__name__)
 
 
diff --git a/synapse/storage/schema/delta/27/ts.py b/synapse/storage/schema/delta/27/ts.py
index 6df57b5206..414f9f5aa0 100644
--- a/synapse/storage/schema/delta/27/ts.py
+++ b/synapse/storage/schema/delta/27/ts.py
@@ -14,10 +14,10 @@
 
 import logging
 
-from synapse.storage.prepare_database import get_statements
-
 import simplejson
 
+from synapse.storage.prepare_database import get_statements
+
 logger = logging.getLogger(__name__)
 
 
diff --git a/synapse/storage/schema/delta/30/as_users.py b/synapse/storage/schema/delta/30/as_users.py
index 85bd1a2006..ef7ec34346 100644
--- a/synapse/storage/schema/delta/30/as_users.py
+++ b/synapse/storage/schema/delta/30/as_users.py
@@ -12,10 +12,10 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 import logging
-from synapse.config.appservice import load_appservices
 
 from six.moves import range
 
+from synapse.config.appservice import load_appservices
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/storage/schema/delta/31/search_update.py b/synapse/storage/schema/delta/31/search_update.py
index fe6b7d196d..7d8ca5f93f 100644
--- a/synapse/storage/schema/delta/31/search_update.py
+++ b/synapse/storage/schema/delta/31/search_update.py
@@ -12,12 +12,13 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from synapse.storage.engines import PostgresEngine
-from synapse.storage.prepare_database import get_statements
-
 import logging
+
 import simplejson
 
+from synapse.storage.engines import PostgresEngine
+from synapse.storage.prepare_database import get_statements
+
 logger = logging.getLogger(__name__)
 
 
diff --git a/synapse/storage/schema/delta/33/event_fields.py b/synapse/storage/schema/delta/33/event_fields.py
index 1e002f9db2..bff1256a7b 100644
--- a/synapse/storage/schema/delta/33/event_fields.py
+++ b/synapse/storage/schema/delta/33/event_fields.py
@@ -12,11 +12,12 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from synapse.storage.prepare_database import get_statements
-
 import logging
+
 import simplejson
 
+from synapse.storage.prepare_database import get_statements
+
 logger = logging.getLogger(__name__)
 
 
diff --git a/synapse/storage/schema/delta/33/remote_media_ts.py b/synapse/storage/schema/delta/33/remote_media_ts.py
index 55ae43f395..9754d3ccfb 100644
--- a/synapse/storage/schema/delta/33/remote_media_ts.py
+++ b/synapse/storage/schema/delta/33/remote_media_ts.py
@@ -14,7 +14,6 @@
 
 import time
 
-
 ALTER_TABLE = "ALTER TABLE remote_media_cache ADD COLUMN last_access_ts BIGINT"
 
 
diff --git a/synapse/storage/schema/delta/34/cache_stream.py b/synapse/storage/schema/delta/34/cache_stream.py
index 3b63a1562d..cf09e43e2b 100644
--- a/synapse/storage/schema/delta/34/cache_stream.py
+++ b/synapse/storage/schema/delta/34/cache_stream.py
@@ -12,11 +12,11 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from synapse.storage.prepare_database import get_statements
-from synapse.storage.engines import PostgresEngine
-
 import logging
 
+from synapse.storage.engines import PostgresEngine
+from synapse.storage.prepare_database import get_statements
+
 logger = logging.getLogger(__name__)
 
 
diff --git a/synapse/storage/schema/delta/34/received_txn_purge.py b/synapse/storage/schema/delta/34/received_txn_purge.py
index 033144341c..67d505e68b 100644
--- a/synapse/storage/schema/delta/34/received_txn_purge.py
+++ b/synapse/storage/schema/delta/34/received_txn_purge.py
@@ -12,10 +12,10 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from synapse.storage.engines import PostgresEngine
-
 import logging
 
+from synapse.storage.engines import PostgresEngine
+
 logger = logging.getLogger(__name__)
 
 
diff --git a/synapse/storage/schema/delta/34/sent_txn_purge.py b/synapse/storage/schema/delta/34/sent_txn_purge.py
index 81948e3431..0ffab10b6f 100644
--- a/synapse/storage/schema/delta/34/sent_txn_purge.py
+++ b/synapse/storage/schema/delta/34/sent_txn_purge.py
@@ -12,10 +12,10 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from synapse.storage.engines import PostgresEngine
-
 import logging
 
+from synapse.storage.engines import PostgresEngine
+
 logger = logging.getLogger(__name__)
 
 
diff --git a/synapse/storage/schema/delta/37/remove_auth_idx.py b/synapse/storage/schema/delta/37/remove_auth_idx.py
index 20ad8bd5a6..a377884169 100644
--- a/synapse/storage/schema/delta/37/remove_auth_idx.py
+++ b/synapse/storage/schema/delta/37/remove_auth_idx.py
@@ -12,11 +12,11 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from synapse.storage.prepare_database import get_statements
-from synapse.storage.engines import PostgresEngine
-
 import logging
 
+from synapse.storage.engines import PostgresEngine
+from synapse.storage.prepare_database import get_statements
+
 logger = logging.getLogger(__name__)
 
 DROP_INDICES = """
diff --git a/synapse/storage/schema/delta/42/user_dir.py b/synapse/storage/schema/delta/42/user_dir.py
index ea6a18196d..506f326f4d 100644
--- a/synapse/storage/schema/delta/42/user_dir.py
+++ b/synapse/storage/schema/delta/42/user_dir.py
@@ -14,8 +14,8 @@
 
 import logging
 
-from synapse.storage.prepare_database import get_statements
 from synapse.storage.engines import PostgresEngine, Sqlite3Engine
+from synapse.storage.prepare_database import get_statements
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/storage/search.py b/synapse/storage/search.py
index 9b77c45318..d5b5df93e6 100644
--- a/synapse/storage/search.py
+++ b/synapse/storage/search.py
@@ -13,19 +13,21 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from collections import namedtuple
 import logging
 import re
-from canonicaljson import json
+from collections import namedtuple
 
 from six import string_types
 
+from canonicaljson import json
+
 from twisted.internet import defer
 
-from .background_updates import BackgroundUpdateStore
 from synapse.api.errors import SynapseError
 from synapse.storage.engines import PostgresEngine, Sqlite3Engine
 
+from .background_updates import BackgroundUpdateStore
+
 logger = logging.getLogger(__name__)
 
 SearchEntry = namedtuple('SearchEntry', [
diff --git a/synapse/storage/signatures.py b/synapse/storage/signatures.py
index 25922e5a9c..470212aa2a 100644
--- a/synapse/storage/signatures.py
+++ b/synapse/storage/signatures.py
@@ -13,15 +13,17 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from twisted.internet import defer
 import six
 
-from ._base import SQLBaseStore
-
 from unpaddedbase64 import encode_base64
+
+from twisted.internet import defer
+
 from synapse.crypto.event_signing import compute_event_reference_hash
 from synapse.util.caches.descriptors import cached, cachedList
 
+from ._base import SQLBaseStore
+
 # py2 sqlite has buffer hardcoded as only binary type, so we must use it,
 # despite being deprecated and removed in favor of memoryview
 if six.PY2:
diff --git a/synapse/storage/state.py b/synapse/storage/state.py
index cd9821c270..89a05c4618 100644
--- a/synapse/storage/state.py
+++ b/synapse/storage/state.py
@@ -13,8 +13,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from collections import namedtuple
 import logging
+from collections import namedtuple
 
 from six import iteritems, itervalues
 from six.moves import range
@@ -23,10 +23,11 @@ from twisted.internet import defer
 
 from synapse.storage.background_updates import BackgroundUpdateStore
 from synapse.storage.engines import PostgresEngine
-from synapse.util.caches import intern_string, get_cache_factor_for
+from synapse.util.caches import get_cache_factor_for, intern_string
 from synapse.util.caches.descriptors import cached, cachedList
 from synapse.util.caches.dictionary_cache import DictionaryCache
 from synapse.util.stringutils import to_ascii
+
 from ._base import SQLBaseStore
 
 logger = logging.getLogger(__name__)
diff --git a/synapse/storage/stream.py b/synapse/storage/stream.py
index fb463c525a..66856342f0 100644
--- a/synapse/storage/stream.py
+++ b/synapse/storage/stream.py
@@ -33,22 +33,20 @@ what sort order was used:
       and stream ordering columns respectively.
 """
 
+import abc
+import logging
+from collections import namedtuple
+
+from six.moves import range
+
 from twisted.internet import defer
 
 from synapse.storage._base import SQLBaseStore
+from synapse.storage.engines import PostgresEngine
 from synapse.storage.events import EventsWorkerStore
-
 from synapse.types import RoomStreamToken
 from synapse.util.caches.stream_change_cache import StreamChangeCache
 from synapse.util.logcontext import make_deferred_yieldable, run_in_background
-from synapse.storage.engines import PostgresEngine
-
-import abc
-import logging
-
-from six.moves import range
-from collections import namedtuple
-
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/storage/tags.py b/synapse/storage/tags.py
index 04d123ed95..0f657b2bd3 100644
--- a/synapse/storage/tags.py
+++ b/synapse/storage/tags.py
@@ -14,16 +14,16 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from synapse.storage.account_data import AccountDataWorkerStore
+import logging
 
-from synapse.util.caches.descriptors import cached
-from twisted.internet import defer
+from six.moves import range
 
 from canonicaljson import json
 
-import logging
+from twisted.internet import defer
 
-from six.moves import range
+from synapse.storage.account_data import AccountDataWorkerStore
+from synapse.util.caches.descriptors import cached
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/storage/transactions.py b/synapse/storage/transactions.py
index acbc03446e..c3bc94f56d 100644
--- a/synapse/storage/transactions.py
+++ b/synapse/storage/transactions.py
@@ -13,17 +13,18 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from ._base import SQLBaseStore
-from synapse.util.caches.descriptors import cached
+import logging
+from collections import namedtuple
 
-from twisted.internet import defer
 import six
 
 from canonicaljson import encode_canonical_json, json
 
-from collections import namedtuple
+from twisted.internet import defer
 
-import logging
+from synapse.util.caches.descriptors import cached
+
+from ._base import SQLBaseStore
 
 # py2 sqlite has buffer hardcoded as only binary type, so we must use it,
 # despite being deprecated and removed in favor of memoryview
diff --git a/synapse/storage/user_directory.py b/synapse/storage/user_directory.py
index 275c299998..ce59e70d0e 100644
--- a/synapse/storage/user_directory.py
+++ b/synapse/storage/user_directory.py
@@ -13,19 +13,19 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from twisted.internet import defer
+import logging
+import re
 
-from ._base import SQLBaseStore
+from six import iteritems
+
+from twisted.internet import defer
 
-from synapse.util.caches.descriptors import cached, cachedInlineCallbacks
 from synapse.api.constants import EventTypes, JoinRules
 from synapse.storage.engines import PostgresEngine, Sqlite3Engine
 from synapse.types import get_domain_from_id, get_localpart_from_id
+from synapse.util.caches.descriptors import cached, cachedInlineCallbacks
 
-from six import iteritems
-
-import re
-import logging
+from ._base import SQLBaseStore
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/storage/user_erasure_store.py b/synapse/storage/user_erasure_store.py
index 47bfc01e84..be013f4427 100644
--- a/synapse/storage/user_erasure_store.py
+++ b/synapse/storage/user_erasure_store.py
@@ -17,7 +17,7 @@ import operator
 from twisted.internet import defer
 
 from synapse.storage._base import SQLBaseStore
-from synapse.util.caches.descriptors import cachedList, cached
+from synapse.util.caches.descriptors import cached, cachedList
 
 
 class UserErasureWorkerStore(SQLBaseStore):
diff --git a/synapse/storage/util/id_generators.py b/synapse/storage/util/id_generators.py
index 95031dc9ec..d6160d5e4d 100644
--- a/synapse/storage/util/id_generators.py
+++ b/synapse/storage/util/id_generators.py
@@ -13,9 +13,9 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from collections import deque
 import contextlib
 import threading
+from collections import deque
 
 
 class IdGenerator(object):
diff --git a/synapse/streams/config.py b/synapse/streams/config.py
index ca78e551cb..46ccbbda7d 100644
--- a/synapse/streams/config.py
+++ b/synapse/streams/config.py
@@ -13,11 +13,10 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from synapse.api.errors import SynapseError
-from synapse.types import StreamToken
-
 import logging
 
+from synapse.api.errors import SynapseError
+from synapse.types import StreamToken
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/streams/events.py b/synapse/streams/events.py
index f03ad99118..e5220132a3 100644
--- a/synapse/streams/events.py
+++ b/synapse/streams/events.py
@@ -15,13 +15,12 @@
 
 from twisted.internet import defer
 
-from synapse.types import StreamToken
-
+from synapse.handlers.account_data import AccountDataEventSource
 from synapse.handlers.presence import PresenceEventSource
+from synapse.handlers.receipts import ReceiptEventSource
 from synapse.handlers.room import RoomEventSource
 from synapse.handlers.typing import TypingNotificationEventSource
-from synapse.handlers.receipts import ReceiptEventSource
-from synapse.handlers.account_data import AccountDataEventSource
+from synapse.types import StreamToken
 
 
 class EventSources(object):
diff --git a/synapse/types.py b/synapse/types.py
index cc7c182a78..08f058f714 100644
--- a/synapse/types.py
+++ b/synapse/types.py
@@ -13,11 +13,10 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 import string
+from collections import namedtuple
 
 from synapse.api.errors import SynapseError
 
-from collections import namedtuple
-
 
 class Requester(namedtuple("Requester", [
     "user", "access_token_id", "is_guest", "device_id", "app_service",
diff --git a/synapse/util/__init__.py b/synapse/util/__init__.py
index e9886ef299..680ea928c7 100644
--- a/synapse/util/__init__.py
+++ b/synapse/util/__init__.py
@@ -17,6 +17,7 @@ import logging
 from itertools import islice
 
 import attr
+
 from twisted.internet import defer, task
 
 from synapse.util.logcontext import PreserveLoggingContext
diff --git a/synapse/util/async.py b/synapse/util/async.py
index 1668df4ce6..5d0fb39130 100644
--- a/synapse/util/async.py
+++ b/synapse/util/async.py
@@ -13,20 +13,22 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import logging
+from contextlib import contextmanager
+
+from six.moves import range
+
 from twisted.internet import defer
 from twisted.internet.defer import CancelledError
 from twisted.python import failure
 
+from synapse.util import Clock, logcontext, unwrapFirstError
+
 from .logcontext import (
-    PreserveLoggingContext, make_deferred_yieldable, run_in_background
+    PreserveLoggingContext,
+    make_deferred_yieldable,
+    run_in_background,
 )
-from synapse.util import logcontext, unwrapFirstError, Clock
-
-from contextlib import contextmanager
-
-import logging
-
-from six.moves import range
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/util/caches/__init__.py b/synapse/util/caches/__init__.py
index 900575eb3c..7b065b195e 100644
--- a/synapse/util/caches/__init__.py
+++ b/synapse/util/caches/__init__.py
@@ -13,12 +13,12 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from prometheus_client.core import Gauge, REGISTRY, GaugeMetricFamily
-
 import os
 
-from six.moves import intern
 import six
+from six.moves import intern
+
+from prometheus_client.core import REGISTRY, Gauge, GaugeMetricFamily
 
 CACHE_SIZE_FACTOR = float(os.environ.get("SYNAPSE_CACHE_FACTOR", 0.5))
 
diff --git a/synapse/util/caches/descriptors.py b/synapse/util/caches/descriptors.py
index 65a1042de1..f8a07df6b8 100644
--- a/synapse/util/caches/descriptors.py
+++ b/synapse/util/caches/descriptors.py
@@ -13,10 +13,19 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+import functools
+import inspect
 import logging
+import threading
+from collections import namedtuple
 
+import six
+from six import itervalues, string_types
+
+from twisted.internet import defer
+
+from synapse.util import logcontext, unwrapFirstError
 from synapse.util.async import ObservableDeferred
-from synapse.util import unwrapFirstError, logcontext
 from synapse.util.caches import get_cache_factor_for
 from synapse.util.caches.lrucache import LruCache
 from synapse.util.caches.treecache import TreeCache, iterate_tree_cache_entry
@@ -24,17 +33,6 @@ from synapse.util.stringutils import to_ascii
 
 from . import register_cache
 
-from twisted.internet import defer
-from collections import namedtuple
-
-import functools
-import inspect
-import threading
-
-from six import string_types, itervalues
-import six
-
-
 logger = logging.getLogger(__name__)
 
 
diff --git a/synapse/util/caches/dictionary_cache.py b/synapse/util/caches/dictionary_cache.py
index 95793d466d..6c0b5a4094 100644
--- a/synapse/util/caches/dictionary_cache.py
+++ b/synapse/util/caches/dictionary_cache.py
@@ -13,12 +13,13 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from synapse.util.caches.lrucache import LruCache
-from collections import namedtuple
-from . import register_cache
-import threading
 import logging
+import threading
+from collections import namedtuple
+
+from synapse.util.caches.lrucache import LruCache
 
+from . import register_cache
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/util/caches/expiringcache.py b/synapse/util/caches/expiringcache.py
index ff04c91955..4abca91f6d 100644
--- a/synapse/util/caches/expiringcache.py
+++ b/synapse/util/caches/expiringcache.py
@@ -13,11 +13,10 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from synapse.util.caches import register_cache
-
-from collections import OrderedDict
 import logging
+from collections import OrderedDict
 
+from synapse.util.caches import register_cache
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/util/caches/lrucache.py b/synapse/util/caches/lrucache.py
index 1c5a982094..b684f24e7b 100644
--- a/synapse/util/caches/lrucache.py
+++ b/synapse/util/caches/lrucache.py
@@ -14,8 +14,8 @@
 # limitations under the License.
 
 
-from functools import wraps
 import threading
+from functools import wraps
 
 from synapse.util.caches.treecache import TreeCache
 
diff --git a/synapse/util/caches/stream_change_cache.py b/synapse/util/caches/stream_change_cache.py
index 0fb8620001..8637867c6d 100644
--- a/synapse/util/caches/stream_change_cache.py
+++ b/synapse/util/caches/stream_change_cache.py
@@ -13,12 +13,11 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from synapse.util import caches
-
+import logging
 
 from sortedcontainers import SortedDict
-import logging
 
+from synapse.util import caches
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/util/file_consumer.py b/synapse/util/file_consumer.py
index c78801015b..629ed44149 100644
--- a/synapse/util/file_consumer.py
+++ b/synapse/util/file_consumer.py
@@ -13,12 +13,12 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from six.moves import queue
+
 from twisted.internet import threads
 
 from synapse.util.logcontext import make_deferred_yieldable, run_in_background
 
-from six.moves import queue
-
 
 class BackgroundFileConsumer(object):
     """A consumer that writes to a file like object. Supports both push
diff --git a/synapse/util/frozenutils.py b/synapse/util/frozenutils.py
index 535e7d0e7a..581c6052ac 100644
--- a/synapse/util/frozenutils.py
+++ b/synapse/util/frozenutils.py
@@ -13,11 +13,11 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from frozendict import frozendict
-from canonicaljson import json
-
 from six import string_types
 
+from canonicaljson import json
+from frozendict import frozendict
+
 
 def freeze(o):
     if isinstance(o, dict):
diff --git a/synapse/util/httpresourcetree.py b/synapse/util/httpresourcetree.py
index e9f0f292ee..2d7ddc1cbe 100644
--- a/synapse/util/httpresourcetree.py
+++ b/synapse/util/httpresourcetree.py
@@ -12,10 +12,10 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from twisted.web.resource import NoResource
-
 import logging
 
+from twisted.web.resource import NoResource
+
 logger = logging.getLogger(__name__)
 
 
diff --git a/synapse/util/logcontext.py b/synapse/util/logcontext.py
index df2b71b791..fe9288b031 100644
--- a/synapse/util/logcontext.py
+++ b/synapse/util/logcontext.py
@@ -22,10 +22,10 @@ them.
 See doc/log_contexts.rst for details on how this works.
 """
 
-from twisted.internet import defer
-
-import threading
 import logging
+import threading
+
+from twisted.internet import defer
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/util/logformatter.py b/synapse/util/logformatter.py
index 3e42868ea9..a46bc47ce3 100644
--- a/synapse/util/logformatter.py
+++ b/synapse/util/logformatter.py
@@ -14,10 +14,11 @@
 # limitations under the License.
 
 
-from six import StringIO
 import logging
 import traceback
 
+from six import StringIO
+
 
 class LogFormatter(logging.Formatter):
     """Log formatter which gives more detail for exceptions
diff --git a/synapse/util/logutils.py b/synapse/util/logutils.py
index 03249c5dc8..62a00189cc 100644
--- a/synapse/util/logutils.py
+++ b/synapse/util/logutils.py
@@ -14,13 +14,11 @@
 # limitations under the License.
 
 
-from inspect import getcallargs
-from functools import wraps
-
-import logging
 import inspect
+import logging
 import time
-
+from functools import wraps
+from inspect import getcallargs
 
 _TIME_FUNC_ID = 0
 
diff --git a/synapse/util/manhole.py b/synapse/util/manhole.py
index 97e0f00b67..14be3c7396 100644
--- a/synapse/util/manhole.py
+++ b/synapse/util/manhole.py
@@ -12,11 +12,11 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from twisted.conch.manhole import ColoredManhole
-from twisted.conch.insults import insults
 from twisted.conch import manhole_ssh
-from twisted.cred import checkers, portal
+from twisted.conch.insults import insults
+from twisted.conch.manhole import ColoredManhole
 from twisted.conch.ssh.keys import Key
+from twisted.cred import checkers, portal
 
 PUBLIC_KEY = (
     "ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAGEArzJx8OYOnJmzf4tfBEvLi8DVPrJ3/c9k2I/Az"
diff --git a/synapse/util/metrics.py b/synapse/util/metrics.py
index 1ba7d65c7c..63bc64c642 100644
--- a/synapse/util/metrics.py
+++ b/synapse/util/metrics.py
@@ -13,14 +13,14 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from twisted.internet import defer
+import logging
+from functools import wraps
 
 from prometheus_client import Counter
-from synapse.util.logcontext import LoggingContext
 
-from functools import wraps
-import logging
+from twisted.internet import defer
 
+from synapse.util.logcontext import LoggingContext
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/util/msisdn.py b/synapse/util/msisdn.py
index 607161e7f0..a6c30e5265 100644
--- a/synapse/util/msisdn.py
+++ b/synapse/util/msisdn.py
@@ -14,6 +14,7 @@
 # limitations under the License.
 
 import phonenumbers
+
 from synapse.api.errors import SynapseError
 
 
diff --git a/synapse/util/ratelimitutils.py b/synapse/util/ratelimitutils.py
index c5a45cef7c..5ac33b2132 100644
--- a/synapse/util/ratelimitutils.py
+++ b/synapse/util/ratelimitutils.py
@@ -13,20 +13,19 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import collections
+import contextlib
+import logging
+
 from twisted.internet import defer
 
 from synapse.api.errors import LimitExceededError
-
 from synapse.util.logcontext import (
-    run_in_background, make_deferred_yieldable,
     PreserveLoggingContext,
+    make_deferred_yieldable,
+    run_in_background,
 )
 
-import collections
-import contextlib
-import logging
-
-
 logger = logging.getLogger(__name__)
 
 
diff --git a/synapse/util/retryutils.py b/synapse/util/retryutils.py
index 4e93f69d3a..8a3a06fd74 100644
--- a/synapse/util/retryutils.py
+++ b/synapse/util/retryutils.py
@@ -12,14 +12,13 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-import synapse.util.logcontext
-from twisted.internet import defer
-
-from synapse.api.errors import CodeMessageException
-
 import logging
 import random
 
+from twisted.internet import defer
+
+import synapse.util.logcontext
+from synapse.api.errors import CodeMessageException
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/util/rlimit.py b/synapse/util/rlimit.py
index f4a9abf83f..6c0f2bb0cf 100644
--- a/synapse/util/rlimit.py
+++ b/synapse/util/rlimit.py
@@ -13,9 +13,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import resource
 import logging
-
+import resource
 
 logger = logging.getLogger("synapse.app.homeserver")
 
diff --git a/synapse/util/stringutils.py b/synapse/util/stringutils.py
index b98b9dc6e4..43d9db67ec 100644
--- a/synapse/util/stringutils.py
+++ b/synapse/util/stringutils.py
@@ -15,6 +15,7 @@
 
 import random
 import string
+
 from six.moves import range
 
 _string_with_symbols = (
diff --git a/synapse/util/versionstring.py b/synapse/util/versionstring.py
index 52086df465..1fbcd41115 100644
--- a/synapse/util/versionstring.py
+++ b/synapse/util/versionstring.py
@@ -14,9 +14,9 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import subprocess
-import os
 import logging
+import os
+import subprocess
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/visibility.py b/synapse/visibility.py
index 65d79cf0d0..015c2bab37 100644
--- a/synapse/visibility.py
+++ b/synapse/visibility.py
@@ -20,9 +20,7 @@ from twisted.internet import defer
 
 from synapse.api.constants import EventTypes, Membership
 from synapse.events.utils import prune_event
-from synapse.util.logcontext import (
-    make_deferred_yieldable, preserve_fn,
-)
+from synapse.util.logcontext import make_deferred_yieldable, preserve_fn
 
 logger = logging.getLogger(__name__)
 
diff --git a/tests/__init__.py b/tests/__init__.py
index aab20e8e02..24006c949e 100644
--- a/tests/__init__.py
+++ b/tests/__init__.py
@@ -14,4 +14,5 @@
 # limitations under the License.
 
 from twisted.trial import util
+
 util.DEFAULT_TIMEOUT_DURATION = 10
diff --git a/tests/api/test_auth.py b/tests/api/test_auth.py
index aec3b62897..5f158ec4b9 100644
--- a/tests/api/test_auth.py
+++ b/tests/api/test_auth.py
@@ -13,16 +13,19 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import pymacaroons
 from mock import Mock
+
+import pymacaroons
+
 from twisted.internet import defer
 
 import synapse.handlers.auth
 from synapse.api.auth import Auth
 from synapse.api.errors import AuthError
 from synapse.types import UserID
+
 from tests import unittest
-from tests.utils import setup_test_homeserver, mock_getRawHeaders
+from tests.utils import mock_getRawHeaders, setup_test_homeserver
 
 
 class TestHandlers(object):
diff --git a/tests/api/test_filtering.py b/tests/api/test_filtering.py
index dcceca7f3e..836a23fb54 100644
--- a/tests/api/test_filtering.py
+++ b/tests/api/test_filtering.py
@@ -13,19 +13,18 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from tests import unittest
-from twisted.internet import defer
-
 from mock import Mock
-from tests.utils import (
-    MockHttpResource, DeferredMockCallable, setup_test_homeserver
-)
 
+import jsonschema
+
+from twisted.internet import defer
+
+from synapse.api.errors import SynapseError
 from synapse.api.filtering import Filter
 from synapse.events import FrozenEvent
-from synapse.api.errors import SynapseError
 
-import jsonschema
+from tests import unittest
+from tests.utils import DeferredMockCallable, MockHttpResource, setup_test_homeserver
 
 user_localpart = "test_user"
 
diff --git a/tests/appservice/test_appservice.py b/tests/appservice/test_appservice.py
index 5b2b95860a..891e0cc973 100644
--- a/tests/appservice/test_appservice.py
+++ b/tests/appservice/test_appservice.py
@@ -12,14 +12,15 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-from synapse.appservice import ApplicationService
+import re
+
+from mock import Mock
 
 from twisted.internet import defer
 
-from mock import Mock
-from tests import unittest
+from synapse.appservice import ApplicationService
 
-import re
+from tests import unittest
 
 
 def _regex(regex, exclusive=True):
diff --git a/tests/appservice/test_scheduler.py b/tests/appservice/test_scheduler.py
index 9181692771..b9f4863e9a 100644
--- a/tests/appservice/test_scheduler.py
+++ b/tests/appservice/test_scheduler.py
@@ -12,17 +12,22 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+from mock import Mock
+
+from twisted.internet import defer
+
 from synapse.appservice import ApplicationServiceState
 from synapse.appservice.scheduler import (
-    _ServiceQueuer, _TransactionController, _Recoverer
+    _Recoverer,
+    _ServiceQueuer,
+    _TransactionController,
 )
-from twisted.internet import defer
-
 from synapse.util.logcontext import make_deferred_yieldable
-from ..utils import MockClock
-from mock import Mock
+
 from tests import unittest
 
+from ..utils import MockClock
+
 
 class ApplicationServiceSchedulerTransactionCtrlTestCase(unittest.TestCase):
 
diff --git a/tests/config/test_generate.py b/tests/config/test_generate.py
index 879159ccea..eb7f0ab12a 100644
--- a/tests/config/test_generate.py
+++ b/tests/config/test_generate.py
@@ -19,6 +19,7 @@ import shutil
 import tempfile
 
 from synapse.config.homeserver import HomeServerConfig
+
 from tests import unittest
 
 
diff --git a/tests/config/test_load.py b/tests/config/test_load.py
index 772afd2cf9..5c422eff38 100644
--- a/tests/config/test_load.py
+++ b/tests/config/test_load.py
@@ -15,8 +15,11 @@
 import os.path
 import shutil
 import tempfile
+
 import yaml
+
 from synapse.config.homeserver import HomeServerConfig
+
 from tests import unittest
 
 
diff --git a/tests/crypto/test_event_signing.py b/tests/crypto/test_event_signing.py
index 47cb328a01..cd11871b80 100644
--- a/tests/crypto/test_event_signing.py
+++ b/tests/crypto/test_event_signing.py
@@ -14,15 +14,13 @@
 # limitations under the License.
 
 
-from tests import unittest
-
-from synapse.events.builder import EventBuilder
-from synapse.crypto.event_signing import add_hashes_and_signatures
-
+import nacl.signing
 from unpaddedbase64 import decode_base64
 
-import nacl.signing
+from synapse.crypto.event_signing import add_hashes_and_signatures
+from synapse.events.builder import EventBuilder
 
+from tests import unittest
 
 # Perform these tests using given secret key so we get entirely deterministic
 # signatures output that we can test against.
diff --git a/tests/crypto/test_keyring.py b/tests/crypto/test_keyring.py
index cc1c862ba4..a9d37fe084 100644
--- a/tests/crypto/test_keyring.py
+++ b/tests/crypto/test_keyring.py
@@ -14,15 +14,19 @@
 # limitations under the License.
 import time
 
+from mock import Mock
+
 import signedjson.key
 import signedjson.sign
-from mock import Mock
+
+from twisted.internet import defer, reactor
+
 from synapse.api.errors import SynapseError
 from synapse.crypto import keyring
-from synapse.util import logcontext, Clock
+from synapse.util import Clock, logcontext
 from synapse.util.logcontext import LoggingContext
+
 from tests import unittest, utils
-from twisted.internet import defer, reactor
 
 
 class MockPerspectiveServer(object):
diff --git a/tests/events/test_utils.py b/tests/events/test_utils.py
index dfc870066e..f51d99419e 100644
--- a/tests/events/test_utils.py
+++ b/tests/events/test_utils.py
@@ -14,11 +14,11 @@
 # limitations under the License.
 
 
-from .. import unittest
-
 from synapse.events import FrozenEvent
 from synapse.events.utils import prune_event, serialize_event
 
+from .. import unittest
+
 
 def MockEvent(**kwargs):
     if "event_id" not in kwargs:
diff --git a/tests/federation/test_federation_server.py b/tests/federation/test_federation_server.py
index 4e8dc8fea0..c91e25f54f 100644
--- a/tests/federation/test_federation_server.py
+++ b/tests/federation/test_federation_server.py
@@ -16,6 +16,7 @@ import logging
 
 from synapse.events import FrozenEvent
 from synapse.federation.federation_server import server_matches_acl_event
+
 from tests import unittest
 
 
diff --git a/tests/handlers/test_appservice.py b/tests/handlers/test_appservice.py
index b753455943..57c0771cf3 100644
--- a/tests/handlers/test_appservice.py
+++ b/tests/handlers/test_appservice.py
@@ -13,13 +13,15 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from mock import Mock
+
 from twisted.internet import defer
-from .. import unittest
-from tests.utils import MockClock
 
 from synapse.handlers.appservice import ApplicationServicesHandler
 
-from mock import Mock
+from tests.utils import MockClock
+
+from .. import unittest
 
 
 class AppServiceHandlerTestCase(unittest.TestCase):
diff --git a/tests/handlers/test_auth.py b/tests/handlers/test_auth.py
index 1822dcf1e0..2e5e8e4dec 100644
--- a/tests/handlers/test_auth.py
+++ b/tests/handlers/test_auth.py
@@ -14,11 +14,13 @@
 # limitations under the License.
 
 import pymacaroons
+
 from twisted.internet import defer
 
 import synapse
 import synapse.api.errors
 from synapse.handlers.auth import AuthHandler
+
 from tests import unittest
 from tests.utils import setup_test_homeserver
 
diff --git a/tests/handlers/test_device.py b/tests/handlers/test_device.py
index 778ff2f6e9..633a0b7f36 100644
--- a/tests/handlers/test_device.py
+++ b/tests/handlers/test_device.py
@@ -17,8 +17,8 @@ from twisted.internet import defer
 
 import synapse.api.errors
 import synapse.handlers.device
-
 import synapse.storage
+
 from tests import unittest, utils
 
 user1 = "@boris:aaa"
diff --git a/tests/handlers/test_directory.py b/tests/handlers/test_directory.py
index 7e5332e272..a353070316 100644
--- a/tests/handlers/test_directory.py
+++ b/tests/handlers/test_directory.py
@@ -14,14 +14,14 @@
 # limitations under the License.
 
 
-from tests import unittest
-from twisted.internet import defer
-
 from mock import Mock
 
+from twisted.internet import defer
+
 from synapse.handlers.directory import DirectoryHandler
 from synapse.types import RoomAlias
 
+from tests import unittest
 from tests.utils import setup_test_homeserver
 
 
diff --git a/tests/handlers/test_e2e_keys.py b/tests/handlers/test_e2e_keys.py
index d1bd87b898..ca1542236d 100644
--- a/tests/handlers/test_e2e_keys.py
+++ b/tests/handlers/test_e2e_keys.py
@@ -14,13 +14,14 @@
 # limitations under the License.
 
 import mock
-from synapse.api import errors
+
 from twisted.internet import defer
 
 import synapse.api.errors
 import synapse.handlers.e2e_keys
-
 import synapse.storage
+from synapse.api import errors
+
 from tests import unittest, utils
 
 
diff --git a/tests/handlers/test_presence.py b/tests/handlers/test_presence.py
index de06a6ad30..121ce78634 100644
--- a/tests/handlers/test_presence.py
+++ b/tests/handlers/test_presence.py
@@ -14,18 +14,22 @@
 # limitations under the License.
 
 
-from tests import unittest
-
 from mock import Mock, call
 
 from synapse.api.constants import PresenceState
 from synapse.handlers.presence import (
-    handle_update, handle_timeout,
-    IDLE_TIMER, SYNC_ONLINE_TIMEOUT, LAST_ACTIVE_GRANULARITY, FEDERATION_TIMEOUT,
     FEDERATION_PING_INTERVAL,
+    FEDERATION_TIMEOUT,
+    IDLE_TIMER,
+    LAST_ACTIVE_GRANULARITY,
+    SYNC_ONLINE_TIMEOUT,
+    handle_timeout,
+    handle_update,
 )
 from synapse.storage.presence import UserPresenceState
 
+from tests import unittest
+
 
 class PresenceUpdateTestCase(unittest.TestCase):
     def test_offline_to_online(self):
diff --git a/tests/handlers/test_profile.py b/tests/handlers/test_profile.py
index 458296ee4c..dc17918a3d 100644
--- a/tests/handlers/test_profile.py
+++ b/tests/handlers/test_profile.py
@@ -14,16 +14,16 @@
 # limitations under the License.
 
 
-from tests import unittest
-from twisted.internet import defer
-
 from mock import Mock, NonCallableMock
 
+from twisted.internet import defer
+
 import synapse.types
 from synapse.api.errors import AuthError
 from synapse.handlers.profile import ProfileHandler
 from synapse.types import UserID
 
+from tests import unittest
 from tests.utils import setup_test_homeserver
 
 
diff --git a/tests/handlers/test_register.py b/tests/handlers/test_register.py
index e990e45220..025fa1be81 100644
--- a/tests/handlers/test_register.py
+++ b/tests/handlers/test_register.py
@@ -13,15 +13,16 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from mock import Mock
+
 from twisted.internet import defer
-from .. import unittest
 
 from synapse.handlers.register import RegistrationHandler
 from synapse.types import UserID, create_requester
 
 from tests.utils import setup_test_homeserver
 
-from mock import Mock
+from .. import unittest
 
 
 class RegistrationHandlers(object):
diff --git a/tests/handlers/test_typing.py b/tests/handlers/test_typing.py
index a433bbfa8a..b08856f763 100644
--- a/tests/handlers/test_typing.py
+++ b/tests/handlers/test_typing.py
@@ -14,19 +14,24 @@
 # limitations under the License.
 
 
-from tests import unittest
-from twisted.internet import defer
-
-from mock import Mock, call, ANY
 import json
 
-from ..utils import (
-    MockHttpResource, MockClock, DeferredMockCallable, setup_test_homeserver
-)
+from mock import ANY, Mock, call
+
+from twisted.internet import defer
 
 from synapse.api.errors import AuthError
 from synapse.types import UserID
 
+from tests import unittest
+
+from ..utils import (
+    DeferredMockCallable,
+    MockClock,
+    MockHttpResource,
+    setup_test_homeserver,
+)
+
 
 def _expect_edu(destination, edu_type, content, origin="test"):
     return {
diff --git a/tests/http/test_endpoint.py b/tests/http/test_endpoint.py
index b8a48d20a4..60e6a75953 100644
--- a/tests/http/test_endpoint.py
+++ b/tests/http/test_endpoint.py
@@ -12,10 +12,8 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-from synapse.http.endpoint import (
-    parse_server_name,
-    parse_and_validate_server_name,
-)
+from synapse.http.endpoint import parse_and_validate_server_name, parse_server_name
+
 from tests import unittest
 
 
diff --git a/tests/replication/slave/storage/_base.py b/tests/replication/slave/storage/_base.py
index 64e07a8c93..8708c8a196 100644
--- a/tests/replication/slave/storage/_base.py
+++ b/tests/replication/slave/storage/_base.py
@@ -12,17 +12,20 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from twisted.internet import defer, reactor
-from tests import unittest
-
 import tempfile
 
 from mock import Mock, NonCallableMock
-from tests.utils import setup_test_homeserver
-from synapse.replication.tcp.resource import ReplicationStreamProtocolFactory
+
+from twisted.internet import defer, reactor
+
 from synapse.replication.tcp.client import (
-    ReplicationClientHandler, ReplicationClientFactory,
+    ReplicationClientFactory,
+    ReplicationClientHandler,
 )
+from synapse.replication.tcp.resource import ReplicationStreamProtocolFactory
+
+from tests import unittest
+from tests.utils import setup_test_homeserver
 
 
 class BaseSlavedStoreTestCase(unittest.TestCase):
diff --git a/tests/replication/slave/storage/test_account_data.py b/tests/replication/slave/storage/test_account_data.py
index f47a42e45d..adf226404e 100644
--- a/tests/replication/slave/storage/test_account_data.py
+++ b/tests/replication/slave/storage/test_account_data.py
@@ -13,11 +13,11 @@
 # limitations under the License.
 
 
-from ._base import BaseSlavedStoreTestCase
+from twisted.internet import defer
 
 from synapse.replication.slave.storage.account_data import SlavedAccountDataStore
 
-from twisted.internet import defer
+from ._base import BaseSlavedStoreTestCase
 
 USER_ID = "@feeling:blue"
 TYPE = "my.type"
diff --git a/tests/replication/slave/storage/test_events.py b/tests/replication/slave/storage/test_events.py
index cb058d3142..cea01d93eb 100644
--- a/tests/replication/slave/storage/test_events.py
+++ b/tests/replication/slave/storage/test_events.py
@@ -12,15 +12,14 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from ._base import BaseSlavedStoreTestCase
+from twisted.internet import defer
 
 from synapse.events import FrozenEvent, _EventInternalMetadata
 from synapse.events.snapshot import EventContext
 from synapse.replication.slave.storage.events import SlavedEventStore
 from synapse.storage.roommember import RoomsForUser
 
-from twisted.internet import defer
-
+from ._base import BaseSlavedStoreTestCase
 
 USER_ID = "@feeling:blue"
 USER_ID_2 = "@bright:blue"
diff --git a/tests/replication/slave/storage/test_receipts.py b/tests/replication/slave/storage/test_receipts.py
index 6624fe4eea..e6d670cc1f 100644
--- a/tests/replication/slave/storage/test_receipts.py
+++ b/tests/replication/slave/storage/test_receipts.py
@@ -12,11 +12,11 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from ._base import BaseSlavedStoreTestCase
+from twisted.internet import defer
 
 from synapse.replication.slave.storage.receipts import SlavedReceiptsStore
 
-from twisted.internet import defer
+from ._base import BaseSlavedStoreTestCase
 
 USER_ID = "@feeling:blue"
 ROOM_ID = "!room:blue"
diff --git a/tests/rest/client/test_transactions.py b/tests/rest/client/test_transactions.py
index 6a757289db..eee99ca2e0 100644
--- a/tests/rest/client/test_transactions.py
+++ b/tests/rest/client/test_transactions.py
@@ -1,10 +1,11 @@
-from synapse.rest.client.transactions import HttpTransactionCache
-from synapse.rest.client.transactions import CLEANUP_PERIOD_MS
-from twisted.internet import defer, reactor
 from mock import Mock, call
 
+from twisted.internet import defer, reactor
+
+from synapse.rest.client.transactions import CLEANUP_PERIOD_MS, HttpTransactionCache
 from synapse.util import Clock
 from synapse.util.logcontext import LoggingContext
+
 from tests import unittest
 from tests.utils import MockClock
 
diff --git a/tests/rest/client/v1/test_events.py b/tests/rest/client/v1/test_events.py
index f5a7258e68..a5af36a99c 100644
--- a/tests/rest/client/v1/test_events.py
+++ b/tests/rest/client/v1/test_events.py
@@ -14,7 +14,7 @@
 # limitations under the License.
 
 """ Tests REST events for /events paths."""
-from tests import unittest
+from mock import Mock, NonCallableMock
 
 # twisted imports
 from twisted.internet import defer
@@ -23,13 +23,11 @@ import synapse.rest.client.v1.events
 import synapse.rest.client.v1.register
 import synapse.rest.client.v1.room
 
+from tests import unittest
 
 from ....utils import MockHttpResource, setup_test_homeserver
 from .utils import RestTestCase
 
-from mock import Mock, NonCallableMock
-
-
 PATH_PREFIX = "/_matrix/client/api/v1"
 
 
diff --git a/tests/rest/client/v1/test_profile.py b/tests/rest/client/v1/test_profile.py
index dc94b8bd19..d71cc8e0db 100644
--- a/tests/rest/client/v1/test_profile.py
+++ b/tests/rest/client/v1/test_profile.py
@@ -15,12 +15,15 @@
 
 """Tests REST events for /profile paths."""
 from mock import Mock
+
 from twisted.internet import defer
 
 import synapse.types
-from synapse.api.errors import SynapseError, AuthError
+from synapse.api.errors import AuthError, SynapseError
 from synapse.rest.client.v1 import profile
+
 from tests import unittest
+
 from ....utils import MockHttpResource, setup_test_homeserver
 
 myid = "@1234ABCD:test"
diff --git a/tests/rest/client/v1/test_register.py b/tests/rest/client/v1/test_register.py
index a6a4e2ffe0..f596acb85f 100644
--- a/tests/rest/client/v1/test_register.py
+++ b/tests/rest/client/v1/test_register.py
@@ -13,12 +13,16 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from synapse.rest.client.v1.register import CreateUserRestServlet
-from twisted.internet import defer
+import json
+
 from mock import Mock
+
+from twisted.internet import defer
+
+from synapse.rest.client.v1.register import CreateUserRestServlet
+
 from tests import unittest
 from tests.utils import mock_getRawHeaders
-import json
 
 
 class CreateUserServletTestCase(unittest.TestCase):
diff --git a/tests/rest/client/v1/test_rooms.py b/tests/rest/client/v1/test_rooms.py
index 61d737725b..895dffa095 100644
--- a/tests/rest/client/v1/test_rooms.py
+++ b/tests/rest/client/v1/test_rooms.py
@@ -15,22 +15,21 @@
 
 """Tests REST events for /rooms paths."""
 
+import json
+
+from mock import Mock, NonCallableMock
+from six.moves.urllib import parse as urlparse
+
 # twisted imports
 from twisted.internet import defer
 
 import synapse.rest.client.v1.room
 from synapse.api.constants import Membership
-
 from synapse.types import UserID
 
-import json
-from six.moves.urllib import parse as urlparse
-
 from ....utils import MockHttpResource, setup_test_homeserver
 from .utils import RestTestCase
 
-from mock import Mock, NonCallableMock
-
 PATH_PREFIX = "/_matrix/client/api/v1"
 
 
diff --git a/tests/rest/client/v1/test_typing.py b/tests/rest/client/v1/test_typing.py
index fe161ee5cb..bddb3302e4 100644
--- a/tests/rest/client/v1/test_typing.py
+++ b/tests/rest/client/v1/test_typing.py
@@ -15,18 +15,17 @@
 
 """Tests REST events for /rooms paths."""
 
+from mock import Mock, NonCallableMock
+
 # twisted imports
 from twisted.internet import defer
 
 import synapse.rest.client.v1.room
 from synapse.types import UserID
 
-from ....utils import MockHttpResource, MockClock, setup_test_homeserver
+from ....utils import MockClock, MockHttpResource, setup_test_homeserver
 from .utils import RestTestCase
 
-from mock import Mock, NonCallableMock
-
-
 PATH_PREFIX = "/_matrix/client/api/v1"
 
 
diff --git a/tests/rest/client/v1/utils.py b/tests/rest/client/v1/utils.py
index 3bb1dd003a..54d7ba380d 100644
--- a/tests/rest/client/v1/utils.py
+++ b/tests/rest/client/v1/utils.py
@@ -13,16 +13,16 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import json
+import time
+
 # twisted imports
 from twisted.internet import defer
 
-# trial imports
-from tests import unittest
-
 from synapse.api.constants import Membership
 
-import json
-import time
+# trial imports
+from tests import unittest
 
 
 class RestTestCase(unittest.TestCase):
diff --git a/tests/rest/client/v2_alpha/__init__.py b/tests/rest/client/v2_alpha/__init__.py
index 5170217d9e..f18a8a6027 100644
--- a/tests/rest/client/v2_alpha/__init__.py
+++ b/tests/rest/client/v2_alpha/__init__.py
@@ -13,16 +13,15 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from tests import unittest
-
 from mock import Mock
 
-from ....utils import MockHttpResource, setup_test_homeserver
+from twisted.internet import defer
 
 from synapse.types import UserID
 
-from twisted.internet import defer
+from tests import unittest
 
+from ....utils import MockHttpResource, setup_test_homeserver
 
 PATH_PREFIX = "/_matrix/client/v2_alpha"
 
diff --git a/tests/rest/client/v2_alpha/test_filter.py b/tests/rest/client/v2_alpha/test_filter.py
index 76b833e119..bb0b2f94ea 100644
--- a/tests/rest/client/v2_alpha/test_filter.py
+++ b/tests/rest/client/v2_alpha/test_filter.py
@@ -15,16 +15,13 @@
 
 from twisted.internet import defer
 
-from tests import unittest
-
-from synapse.rest.client.v2_alpha import filter
-
-from synapse.api.errors import Codes
-
 import synapse.types
-
+from synapse.api.errors import Codes
+from synapse.rest.client.v2_alpha import filter
 from synapse.types import UserID
 
+from tests import unittest
+
 from ....utils import MockHttpResource, setup_test_homeserver
 
 PATH_PREFIX = "/_matrix/client/v2_alpha"
diff --git a/tests/rest/client/v2_alpha/test_register.py b/tests/rest/client/v2_alpha/test_register.py
index 8aba456510..9b57a56070 100644
--- a/tests/rest/client/v2_alpha/test_register.py
+++ b/tests/rest/client/v2_alpha/test_register.py
@@ -1,12 +1,15 @@
+import json
+
+from mock import Mock
+
+from twisted.internet import defer
 from twisted.python import failure
 
+from synapse.api.errors import InteractiveAuthIncompleteError, SynapseError
 from synapse.rest.client.v2_alpha.register import RegisterRestServlet
-from synapse.api.errors import SynapseError, InteractiveAuthIncompleteError
-from twisted.internet import defer
-from mock import Mock
+
 from tests import unittest
 from tests.utils import mock_getRawHeaders
-import json
 
 
 class RegisterRestServletTestCase(unittest.TestCase):
diff --git a/tests/rest/media/v1/test_media_storage.py b/tests/rest/media/v1/test_media_storage.py
index c5e2f5549a..bf254a260d 100644
--- a/tests/rest/media/v1/test_media_storage.py
+++ b/tests/rest/media/v1/test_media_storage.py
@@ -14,21 +14,21 @@
 # limitations under the License.
 
 
+import os
+import shutil
+import tempfile
+
+from mock import Mock
+
 from twisted.internet import defer, reactor
 
 from synapse.rest.media.v1._base import FileInfo
-from synapse.rest.media.v1.media_storage import MediaStorage
 from synapse.rest.media.v1.filepath import MediaFilePaths
+from synapse.rest.media.v1.media_storage import MediaStorage
 from synapse.rest.media.v1.storage_provider import FileStorageProviderBackend
 
-from mock import Mock
-
 from tests import unittest
 
-import os
-import shutil
-import tempfile
-
 
 class MediaStorageTests(unittest.TestCase):
     def setUp(self):
diff --git a/tests/server.py b/tests/server.py
index 73069dff52..46223ccf05 100644
--- a/tests/server.py
+++ b/tests/server.py
@@ -1,15 +1,17 @@
+import json
 from io import BytesIO
 
-import attr
-import json
 from six import text_type
 
-from twisted.python.failure import Failure
+import attr
+
+from twisted.internet import threads
 from twisted.internet.defer import Deferred
+from twisted.python.failure import Failure
 from twisted.test.proto_helpers import MemoryReactorClock
 
 from synapse.http.site import SynapseRequest
-from twisted.internet import threads
+
 from tests.utils import setup_test_homeserver as _sth
 
 
diff --git a/tests/storage/test__base.py b/tests/storage/test__base.py
index 3cfa21c9f8..6d6f00c5c5 100644
--- a/tests/storage/test__base.py
+++ b/tests/storage/test__base.py
@@ -14,15 +14,15 @@
 # limitations under the License.
 
 
-from tests import unittest
-from twisted.internet import defer
-
 from mock import Mock
 
-from synapse.util.async import ObservableDeferred
+from twisted.internet import defer
 
+from synapse.util.async import ObservableDeferred
 from synapse.util.caches.descriptors import Cache, cached
 
+from tests import unittest
+
 
 class CacheTestCase(unittest.TestCase):
 
diff --git a/tests/storage/test_appservice.py b/tests/storage/test_appservice.py
index 00825498b1..099861b27c 100644
--- a/tests/storage/test_appservice.py
+++ b/tests/storage/test_appservice.py
@@ -12,21 +12,25 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+import json
+import os
 import tempfile
-from synapse.config._base import ConfigError
-from tests import unittest
+
+from mock import Mock
+
+import yaml
+
 from twisted.internet import defer
 
-from tests.utils import setup_test_homeserver
 from synapse.appservice import ApplicationService, ApplicationServiceState
+from synapse.config._base import ConfigError
 from synapse.storage.appservice import (
-    ApplicationServiceStore, ApplicationServiceTransactionStore
+    ApplicationServiceStore,
+    ApplicationServiceTransactionStore,
 )
 
-import json
-import os
-import yaml
-from mock import Mock
+from tests import unittest
+from tests.utils import setup_test_homeserver
 
 
 class ApplicationServiceStoreTestCase(unittest.TestCase):
diff --git a/tests/storage/test_background_update.py b/tests/storage/test_background_update.py
index 1286b4ce2d..ab1f310572 100644
--- a/tests/storage/test_background_update.py
+++ b/tests/storage/test_background_update.py
@@ -1,10 +1,10 @@
-from tests import unittest
+from mock import Mock
+
 from twisted.internet import defer
 
+from tests import unittest
 from tests.utils import setup_test_homeserver
 
-from mock import Mock
-
 
 class BackgroundUpdateTestCase(unittest.TestCase):
 
diff --git a/tests/storage/test_base.py b/tests/storage/test_base.py
index 0ac910e76f..1d1234ee39 100644
--- a/tests/storage/test_base.py
+++ b/tests/storage/test_base.py
@@ -14,18 +14,18 @@
 # limitations under the License.
 
 
-from tests import unittest
-from twisted.internet import defer
+from collections import OrderedDict
 
 from mock import Mock
 
-from collections import OrderedDict
+from twisted.internet import defer
 
 from synapse.server import HomeServer
-
 from synapse.storage._base import SQLBaseStore
 from synapse.storage.engines import create_engine
 
+from tests import unittest
+
 
 class SQLBaseStoreTestCase(unittest.TestCase):
     """ Test the "simple" SQL generating methods in SQLBaseStore. """
diff --git a/tests/storage/test_devices.py b/tests/storage/test_devices.py
index f8725acea0..a54cc6bc32 100644
--- a/tests/storage/test_devices.py
+++ b/tests/storage/test_devices.py
@@ -16,6 +16,7 @@
 from twisted.internet import defer
 
 import synapse.api.errors
+
 import tests.unittest
 import tests.utils
 
diff --git a/tests/storage/test_directory.py b/tests/storage/test_directory.py
index 95709cd50a..129ebaf343 100644
--- a/tests/storage/test_directory.py
+++ b/tests/storage/test_directory.py
@@ -14,12 +14,12 @@
 # limitations under the License.
 
 
-from tests import unittest
 from twisted.internet import defer
 
 from synapse.storage.directory import DirectoryStore
-from synapse.types import RoomID, RoomAlias
+from synapse.types import RoomAlias, RoomID
 
+from tests import unittest
 from tests.utils import setup_test_homeserver
 
 
diff --git a/tests/storage/test_event_push_actions.py b/tests/storage/test_event_push_actions.py
index 3cbf9a78b1..8430fc7ba6 100644
--- a/tests/storage/test_event_push_actions.py
+++ b/tests/storage/test_event_push_actions.py
@@ -13,11 +13,12 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from mock import Mock
+
 from twisted.internet import defer
 
 import tests.unittest
 import tests.utils
-from mock import Mock
 
 USER_ID = "@user:example.com"
 
diff --git a/tests/storage/test_keys.py b/tests/storage/test_keys.py
index 0be790d8f8..3a3d002782 100644
--- a/tests/storage/test_keys.py
+++ b/tests/storage/test_keys.py
@@ -14,6 +14,7 @@
 # limitations under the License.
 
 import signedjson.key
+
 from twisted.internet import defer
 
 import tests.unittest
diff --git a/tests/storage/test_presence.py b/tests/storage/test_presence.py
index f5fcb611d4..3276b39504 100644
--- a/tests/storage/test_presence.py
+++ b/tests/storage/test_presence.py
@@ -14,13 +14,13 @@
 # limitations under the License.
 
 
-from tests import unittest
 from twisted.internet import defer
 
 from synapse.storage.presence import PresenceStore
 from synapse.types import UserID
 
-from tests.utils import setup_test_homeserver, MockClock
+from tests import unittest
+from tests.utils import MockClock, setup_test_homeserver
 
 
 class PresenceStoreTestCase(unittest.TestCase):
diff --git a/tests/storage/test_profile.py b/tests/storage/test_profile.py
index 423710c9c1..2c95e5e95a 100644
--- a/tests/storage/test_profile.py
+++ b/tests/storage/test_profile.py
@@ -14,12 +14,12 @@
 # limitations under the License.
 
 
-from tests import unittest
 from twisted.internet import defer
 
 from synapse.storage.profile import ProfileStore
 from synapse.types import UserID
 
+from tests import unittest
 from tests.utils import setup_test_homeserver
 
 
diff --git a/tests/storage/test_redaction.py b/tests/storage/test_redaction.py
index 888ddfaddd..475ec900c4 100644
--- a/tests/storage/test_redaction.py
+++ b/tests/storage/test_redaction.py
@@ -14,16 +14,16 @@
 # limitations under the License.
 
 
-from tests import unittest
+from mock import Mock
+
 from twisted.internet import defer
 
 from synapse.api.constants import EventTypes, Membership
-from synapse.types import UserID, RoomID
+from synapse.types import RoomID, UserID
 
+from tests import unittest
 from tests.utils import setup_test_homeserver
 
-from mock import Mock
-
 
 class RedactionTestCase(unittest.TestCase):
 
diff --git a/tests/storage/test_registration.py b/tests/storage/test_registration.py
index f863b75846..7821ea3fa3 100644
--- a/tests/storage/test_registration.py
+++ b/tests/storage/test_registration.py
@@ -14,9 +14,9 @@
 # limitations under the License.
 
 
-from tests import unittest
 from twisted.internet import defer
 
+from tests import unittest
 from tests.utils import setup_test_homeserver
 
 
diff --git a/tests/storage/test_room.py b/tests/storage/test_room.py
index ef8a4d234f..ae8ae94b6d 100644
--- a/tests/storage/test_room.py
+++ b/tests/storage/test_room.py
@@ -14,12 +14,12 @@
 # limitations under the License.
 
 
-from tests import unittest
 from twisted.internet import defer
 
 from synapse.api.constants import EventTypes
-from synapse.types import UserID, RoomID, RoomAlias
+from synapse.types import RoomAlias, RoomID, UserID
 
+from tests import unittest
 from tests.utils import setup_test_homeserver
 
 
diff --git a/tests/storage/test_roommember.py b/tests/storage/test_roommember.py
index 657b279e5d..c5fd54f67e 100644
--- a/tests/storage/test_roommember.py
+++ b/tests/storage/test_roommember.py
@@ -14,16 +14,16 @@
 # limitations under the License.
 
 
-from tests import unittest
+from mock import Mock
+
 from twisted.internet import defer
 
 from synapse.api.constants import EventTypes, Membership
-from synapse.types import UserID, RoomID
+from synapse.types import RoomID, UserID
 
+from tests import unittest
 from tests.utils import setup_test_homeserver
 
-from mock import Mock
-
 
 class RoomMemberStoreTestCase(unittest.TestCase):
 
diff --git a/tests/storage/test_user_directory.py b/tests/storage/test_user_directory.py
index 0891308f25..23fad12bca 100644
--- a/tests/storage/test_user_directory.py
+++ b/tests/storage/test_user_directory.py
@@ -17,6 +17,7 @@ from twisted.internet import defer
 
 from synapse.storage import UserDirectoryStore
 from synapse.storage.roommember import ProfileInfo
+
 from tests import unittest
 from tests.utils import setup_test_homeserver
 
diff --git a/tests/test_distributor.py b/tests/test_distributor.py
index c066381698..04a88056f1 100644
--- a/tests/test_distributor.py
+++ b/tests/test_distributor.py
@@ -13,13 +13,14 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from . import unittest
-from twisted.internet import defer
-
 from mock import Mock, patch
 
+from twisted.internet import defer
+
 from synapse.util.distributor import Distributor
 
+from . import unittest
+
 
 class DistributorTestCase(unittest.TestCase):
 
diff --git a/tests/test_dns.py b/tests/test_dns.py
index 3b360a0fc7..b647d92697 100644
--- a/tests/test_dns.py
+++ b/tests/test_dns.py
@@ -13,16 +13,17 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from . import unittest
+from mock import Mock
+
 from twisted.internet import defer
 from twisted.names import dns, error
 
-from mock import Mock
-
 from synapse.http.endpoint import resolve_service
 
 from tests.utils import MockClock
 
+from . import unittest
+
 
 @unittest.DEBUG
 class DnsTestCase(unittest.TestCase):
diff --git a/tests/test_event_auth.py b/tests/test_event_auth.py
index d08e19c53a..06112430e5 100644
--- a/tests/test_event_auth.py
+++ b/tests/test_event_auth.py
@@ -13,10 +13,11 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import unittest
+
 from synapse import event_auth
 from synapse.api.errors import AuthError
 from synapse.events import FrozenEvent
-import unittest
 
 
 class EventAuthTestCase(unittest.TestCase):
diff --git a/tests/test_federation.py b/tests/test_federation.py
index fc80a69369..159a136971 100644
--- a/tests/test_federation.py
+++ b/tests/test_federation.py
@@ -1,14 +1,14 @@
 
-from twisted.internet.defer import succeed, maybeDeferred
+from mock import Mock
+
+from twisted.internet.defer import maybeDeferred, succeed
 
-from synapse.util import Clock
 from synapse.events import FrozenEvent
 from synapse.types import Requester, UserID
+from synapse.util import Clock
 
 from tests import unittest
-from tests.server import setup_test_homeserver, ThreadedMemoryReactorClock
-
-from mock import Mock
+from tests.server import ThreadedMemoryReactorClock, setup_test_homeserver
 
 
 class MessageAcceptTests(unittest.TestCase):
diff --git a/tests/test_preview.py b/tests/test_preview.py
index 5bd36c74aa..446843367e 100644
--- a/tests/test_preview.py
+++ b/tests/test_preview.py
@@ -13,12 +13,13 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from . import unittest
-
 from synapse.rest.media.v1.preview_url_resource import (
-    summarize_paragraphs, decode_and_calc_og
+    decode_and_calc_og,
+    summarize_paragraphs,
 )
 
+from . import unittest
+
 
 class PreviewTestCase(unittest.TestCase):
 
diff --git a/tests/test_server.py b/tests/test_server.py
index 8ad822c43b..4192013f6d 100644
--- a/tests/test_server.py
+++ b/tests/test_server.py
@@ -4,9 +4,10 @@ import re
 from twisted.internet.defer import Deferred
 from twisted.test.proto_helpers import MemoryReactorClock
 
-from synapse.util import Clock
 from synapse.api.errors import Codes, SynapseError
 from synapse.http.server import JsonResource
+from synapse.util import Clock
+
 from tests import unittest
 from tests.server import make_request, setup_test_homeserver
 
diff --git a/tests/test_state.py b/tests/test_state.py
index 71c412faf4..c0f2d1152d 100644
--- a/tests/test_state.py
+++ b/tests/test_state.py
@@ -13,18 +13,18 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from tests import unittest
+from mock import Mock
+
 from twisted.internet import defer
 
-from synapse.events import FrozenEvent
 from synapse.api.auth import Auth
 from synapse.api.constants import EventTypes, Membership
+from synapse.events import FrozenEvent
 from synapse.state import StateHandler, StateResolutionHandler
 
-from .utils import MockClock
-
-from mock import Mock
+from tests import unittest
 
+from .utils import MockClock
 
 _next_event_id = 1000
 
diff --git a/tests/test_test_utils.py b/tests/test_test_utils.py
index d28bb726bb..bc97c12245 100644
--- a/tests/test_test_utils.py
+++ b/tests/test_test_utils.py
@@ -14,7 +14,6 @@
 # limitations under the License.
 
 from tests import unittest
-
 from tests.utils import MockClock
 
 
diff --git a/tests/test_types.py b/tests/test_types.py
index 115def2287..729bd676c1 100644
--- a/tests/test_types.py
+++ b/tests/test_types.py
@@ -13,11 +13,11 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from tests import unittest
-
 from synapse.api.errors import SynapseError
 from synapse.server import HomeServer
-from synapse.types import UserID, RoomAlias, GroupID
+from synapse.types import GroupID, RoomAlias, UserID
+
+from tests import unittest
 
 mock_homeserver = HomeServer(hostname="my.domain")
 
diff --git a/tests/util/caches/test_descriptors.py b/tests/util/caches/test_descriptors.py
index a94d566c96..8176a7dabd 100644
--- a/tests/util/caches/test_descriptors.py
+++ b/tests/util/caches/test_descriptors.py
@@ -13,14 +13,17 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-from functools import partial
 import logging
+from functools import partial
 
 import mock
+
+from twisted.internet import defer, reactor
+
 from synapse.api.errors import SynapseError
 from synapse.util import logcontext
-from twisted.internet import defer, reactor
 from synapse.util.caches import descriptors
+
 from tests import unittest
 
 logger = logging.getLogger(__name__)
diff --git a/tests/util/test_dict_cache.py b/tests/util/test_dict_cache.py
index 543ac5bed9..26f2fa5800 100644
--- a/tests/util/test_dict_cache.py
+++ b/tests/util/test_dict_cache.py
@@ -14,10 +14,10 @@
 # limitations under the License.
 
 
-from tests import unittest
-
 from synapse.util.caches.dictionary_cache import DictionaryCache
 
+from tests import unittest
+
 
 class DictCacheTestCase(unittest.TestCase):
 
diff --git a/tests/util/test_expiring_cache.py b/tests/util/test_expiring_cache.py
index 31d24adb8b..d12b5e838b 100644
--- a/tests/util/test_expiring_cache.py
+++ b/tests/util/test_expiring_cache.py
@@ -14,12 +14,12 @@
 # limitations under the License.
 
 
-from .. import unittest
-
 from synapse.util.caches.expiringcache import ExpiringCache
 
 from tests.utils import MockClock
 
+from .. import unittest
+
 
 class ExpiringCacheTestCase(unittest.TestCase):
 
diff --git a/tests/util/test_file_consumer.py b/tests/util/test_file_consumer.py
index c2aae8f54c..7ce5f8c258 100644
--- a/tests/util/test_file_consumer.py
+++ b/tests/util/test_file_consumer.py
@@ -14,15 +14,16 @@
 # limitations under the License.
 
 
-from twisted.internet import defer, reactor
+import threading
+
 from mock import NonCallableMock
+from six import StringIO
+
+from twisted.internet import defer, reactor
 
 from synapse.util.file_consumer import BackgroundFileConsumer
 
 from tests import unittest
-from six import StringIO
-
-import threading
 
 
 class FileConsumerTests(unittest.TestCase):
diff --git a/tests/util/test_limiter.py b/tests/util/test_limiter.py
index 9c795d9fdb..a5a767b1ff 100644
--- a/tests/util/test_limiter.py
+++ b/tests/util/test_limiter.py
@@ -14,12 +14,12 @@
 # limitations under the License.
 
 
-from tests import unittest
-
 from twisted.internet import defer
 
 from synapse.util.async import Limiter
 
+from tests import unittest
+
 
 class LimiterTestCase(unittest.TestCase):
 
diff --git a/tests/util/test_linearizer.py b/tests/util/test_linearizer.py
index bf7e3aa885..c95907b32c 100644
--- a/tests/util/test_linearizer.py
+++ b/tests/util/test_linearizer.py
@@ -13,13 +13,14 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from synapse.util import logcontext, Clock
-from tests import unittest
+from six.moves import range
 
 from twisted.internet import defer, reactor
 
+from synapse.util import Clock, logcontext
 from synapse.util.async import Linearizer
-from six.moves import range
+
+from tests import unittest
 
 
 class LinearizerTestCase(unittest.TestCase):
diff --git a/tests/util/test_logcontext.py b/tests/util/test_logcontext.py
index 9cf90fcfc4..c54001f7a4 100644
--- a/tests/util/test_logcontext.py
+++ b/tests/util/test_logcontext.py
@@ -1,11 +1,11 @@
 import twisted.python.failure
-from twisted.internet import defer
-from twisted.internet import reactor
-from .. import unittest
+from twisted.internet import defer, reactor
 
-from synapse.util import logcontext, Clock
+from synapse.util import Clock, logcontext
 from synapse.util.logcontext import LoggingContext
 
+from .. import unittest
+
 
 class LoggingContextTestCase(unittest.TestCase):
 
diff --git a/tests/util/test_logformatter.py b/tests/util/test_logformatter.py
index 1a1a8412f2..297aebbfbe 100644
--- a/tests/util/test_logformatter.py
+++ b/tests/util/test_logformatter.py
@@ -15,6 +15,7 @@
 import sys
 
 from synapse.util.logformatter import LogFormatter
+
 from tests import unittest
 
 
diff --git a/tests/util/test_lrucache.py b/tests/util/test_lrucache.py
index dfb78cb8bd..9b36ef4482 100644
--- a/tests/util/test_lrucache.py
+++ b/tests/util/test_lrucache.py
@@ -14,12 +14,12 @@
 # limitations under the License.
 
 
-from .. import unittest
+from mock import Mock
 
 from synapse.util.caches.lrucache import LruCache
 from synapse.util.caches.treecache import TreeCache
 
-from mock import Mock
+from .. import unittest
 
 
 class LruCacheTestCase(unittest.TestCase):
diff --git a/tests/util/test_rwlock.py b/tests/util/test_rwlock.py
index 1d745ae1a7..24194e3b25 100644
--- a/tests/util/test_rwlock.py
+++ b/tests/util/test_rwlock.py
@@ -14,10 +14,10 @@
 # limitations under the License.
 
 
-from tests import unittest
-
 from synapse.util.async import ReadWriteLock
 
+from tests import unittest
+
 
 class ReadWriteLockTestCase(unittest.TestCase):
 
diff --git a/tests/util/test_snapshot_cache.py b/tests/util/test_snapshot_cache.py
index d3a8630c2f..0f5b32fcc0 100644
--- a/tests/util/test_snapshot_cache.py
+++ b/tests/util/test_snapshot_cache.py
@@ -14,10 +14,11 @@
 # limitations under the License.
 
 
-from .. import unittest
+from twisted.internet.defer import Deferred
 
 from synapse.util.caches.snapshot_cache import SnapshotCache
-from twisted.internet.defer import Deferred
+
+from .. import unittest
 
 
 class SnapshotCacheTestCase(unittest.TestCase):
diff --git a/tests/util/test_stream_change_cache.py b/tests/util/test_stream_change_cache.py
index 67ece166c7..e3897c0d19 100644
--- a/tests/util/test_stream_change_cache.py
+++ b/tests/util/test_stream_change_cache.py
@@ -1,8 +1,9 @@
-from tests import unittest
 from mock import patch
 
 from synapse.util.caches.stream_change_cache import StreamChangeCache
 
+from tests import unittest
+
 
 class StreamChangeCacheTests(unittest.TestCase):
     """
diff --git a/tests/util/test_treecache.py b/tests/util/test_treecache.py
index 7ab578a185..a5f2261208 100644
--- a/tests/util/test_treecache.py
+++ b/tests/util/test_treecache.py
@@ -14,10 +14,10 @@
 # limitations under the License.
 
 
-from .. import unittest
-
 from synapse.util.caches.treecache import TreeCache
 
+from .. import unittest
+
 
 class TreeCacheTestCase(unittest.TestCase):
     def test_get_set_onelevel(self):
diff --git a/tests/util/test_wheel_timer.py b/tests/util/test_wheel_timer.py
index fdb24a48b0..03201a4d9b 100644
--- a/tests/util/test_wheel_timer.py
+++ b/tests/util/test_wheel_timer.py
@@ -13,10 +13,10 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from .. import unittest
-
 from synapse.util.wheel_timer import WheelTimer
 
+from .. import unittest
+
 
 class WheelTimerTestCase(unittest.TestCase):
     def test_single_insert_fetch(self):
diff --git a/tests/utils.py b/tests/utils.py
index 189fd2711c..6adbdbfca1 100644
--- a/tests/utils.py
+++ b/tests/utils.py
@@ -15,9 +15,10 @@
 
 import hashlib
 from inspect import getcallargs
-from six.moves.urllib import parse as urlparse
 
 from mock import Mock, patch
+from six.moves.urllib import parse as urlparse
+
 from twisted.internet import defer, reactor
 
 from synapse.api.errors import CodeMessageException, cs_error
-- 
cgit 1.5.1