Pass around the reactor explicitly (#3385)

25 files changed, 141 insertions, 93 deletions

diff --git a/synapse/handlers/auth.py b/synapse/handlers/auth.py
index dabc744890..a131b7f73f 100644
--- a/synapse/handlers/auth.py
+++ b/synapse/handlers/auth.py
@@ -33,6 +33,7 @@ import logging
 import bcrypt
 import pymacaroons
 import simplejson
+import attr
 
 import synapse.util.stringutils as stringutils
 
@@ -854,7 +855,11 @@ class AuthHandler(BaseHandler):
             return bcrypt.hashpw(password.encode('utf8') + self.hs.config.password_pepper,
                                  bcrypt.gensalt(self.bcrypt_rounds))
 
-        return make_deferred_yieldable(threads.deferToThread(_do_hash))
+        return make_deferred_yieldable(
+            threads.deferToThreadPool(
+                self.hs.get_reactor(), self.hs.get_reactor().getThreadPool(), _do_hash
+            ),
+        )
 
     def validate_hash(self, password, stored_hash):
         """Validates that self.hash(password) == stored_hash.
@@ -874,16 +879,21 @@ class AuthHandler(BaseHandler):
             )
 
         if stored_hash:
-            return make_deferred_yieldable(threads.deferToThread(_do_validate_hash))
+            return make_deferred_yieldable(
+                threads.deferToThreadPool(
+                    self.hs.get_reactor(),
+                    self.hs.get_reactor().getThreadPool(),
+                    _do_validate_hash,
+                ),
+            )
         else:
             return defer.succeed(False)
 
 
-class MacaroonGeneartor(object):
-    def __init__(self, hs):
-        self.clock = hs.get_clock()
-        self.server_name = hs.config.server_name
-        self.macaroon_secret_key = hs.config.macaroon_secret_key
+@attr.s
+class MacaroonGenerator(object):
+
+    hs = attr.ib()
 
     def generate_access_token(self, user_id, extra_caveats=None):
         extra_caveats = extra_caveats or []
@@ -901,7 +911,7 @@ class MacaroonGeneartor(object):
     def generate_short_term_login_token(self, user_id, duration_in_ms=(2 * 60 * 1000)):
         macaroon = self._generate_base_macaroon(user_id)
         macaroon.add_first_party_caveat("type = login")
-        now = self.clock.time_msec()
+        now = self.hs.get_clock().time_msec()
         expiry = now + duration_in_ms
         macaroon.add_first_party_caveat("time < %d" % (expiry,))
         return macaroon.serialize()
@@ -913,9 +923,9 @@ class MacaroonGeneartor(object):
 
     def _generate_base_macaroon(self, user_id):
         macaroon = pymacaroons.Macaroon(
-            location=self.server_name,
+            location=self.hs.config.server_name,
             identifier="key",
-            key=self.macaroon_secret_key)
+            key=self.hs.config.macaroon_secret_key)
         macaroon.add_first_party_caveat("gen = 1")
         macaroon.add_first_party_caveat("user_id = %s" % (user_id,))
         return macaroon
diff --git a/synapse/handlers/message.py b/synapse/handlers/message.py
index 18dcc6d196..7b9946ab91 100644
--- a/synapse/handlers/message.py
+++ b/synapse/handlers/message.py
@@ -806,6 +806,7 @@ class EventCreationHandler(object):
             # If we're a worker we need to hit out to the master.
             if self.config.worker_app:
                 yield send_event_to_master(
+                    self.hs.get_clock(),
                     self.http_client,
                     host=self.config.worker_replication_host,
                     port=self.config.worker_replication_http_port,
diff --git a/synapse/handlers/user_directory.py b/synapse/handlers/user_directory.py
index a39f0f7343..7e4a114d4f 100644
--- a/synapse/handlers/user_directory.py
+++ b/synapse/handlers/user_directory.py
@@ -19,7 +19,6 @@ 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.util.async import sleep
 from synapse.types import get_localpart_from_id
 
 from six import iteritems
@@ -174,7 +173,7 @@ class UserDirectoryHandler(object):
             logger.info("Handling room %d/%d", num_processed_rooms + 1, len(room_ids))
             yield self._handle_initial_room(room_id)
             num_processed_rooms += 1
-            yield sleep(self.INITIAL_ROOM_SLEEP_MS / 1000.)
+            yield self.clock.sleep(self.INITIAL_ROOM_SLEEP_MS / 1000.)
 
         logger.info("Processed all rooms.")
 
@@ -188,7 +187,7 @@ class UserDirectoryHandler(object):
                 logger.info("Handling user %d/%d", num_processed_users + 1, len(user_ids))
                 yield self._handle_local_user(user_id)
                 num_processed_users += 1
-                yield sleep(self.INITIAL_USER_SLEEP_MS / 1000.)
+                yield self.clock.sleep(self.INITIAL_USER_SLEEP_MS / 1000.)
 
             logger.info("Processed all users")
 
@@ -236,7 +235,7 @@ class UserDirectoryHandler(object):
         count = 0
         for user_id in user_ids:
             if count % self.INITIAL_ROOM_SLEEP_COUNT == 0:
-                yield sleep(self.INITIAL_ROOM_SLEEP_MS / 1000.)
+                yield self.clock.sleep(self.INITIAL_ROOM_SLEEP_MS / 1000.)
 
             if not self.is_mine_id(user_id):
                 count += 1
@@ -251,7 +250,7 @@ class UserDirectoryHandler(object):
                     continue
 
                 if count % self.INITIAL_ROOM_SLEEP_COUNT == 0:
-                    yield sleep(self.INITIAL_ROOM_SLEEP_MS / 1000.)
+                    yield self.clock.sleep(self.INITIAL_ROOM_SLEEP_MS / 1000.)
                 count += 1
 
                 user_set = (user_id, other_user_id)
diff --git a/synapse/http/client.py b/synapse/http/client.py
index 8064a84c5c..46ffb41de1 100644
--- a/synapse/http/client.py
+++ b/synapse/http/client.py
@@ -98,8 +98,8 @@ class SimpleHttpClient(object):
                 method, uri, *args, **kwargs
             )
             add_timeout_to_deferred(
-                request_deferred,
-                60, cancelled_to_request_timed_out_error,
+                request_deferred, 60, self.hs.get_reactor(),
+                cancelled_to_request_timed_out_error,
             )
             response = yield make_deferred_yieldable(request_deferred)
 
@@ -115,7 +115,7 @@ class SimpleHttpClient(object):
                 "Error sending request to  %s %s: %s %s",
                 method, redact_uri(uri), type(e).__name__, e.message
             )
-            raise e
+            raise
 
     @defer.inlineCallbacks
     def post_urlencoded_get_json(self, uri, args={}, headers=None):
diff --git a/synapse/http/matrixfederationclient.py b/synapse/http/matrixfederationclient.py
index 993dc06e02..4e0399e762 100644
--- a/synapse/http/matrixfederationclient.py
+++ b/synapse/http/matrixfederationclient.py
@@ -22,7 +22,7 @@ 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 sleep, add_timeout_to_deferred
+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
@@ -193,6 +193,7 @@ class MatrixFederationHttpClient(object):
                         add_timeout_to_deferred(
                             request_deferred,
                             timeout / 1000. if timeout else 60,
+                            self.hs.get_reactor(),
                             cancelled_to_request_timed_out_error,
                         )
                         response = yield make_deferred_yieldable(
@@ -234,7 +235,7 @@ class MatrixFederationHttpClient(object):
                                 delay = min(delay, 2)
                                 delay *= random.uniform(0.8, 1.4)
 
-                            yield sleep(delay)
+                            yield self.clock.sleep(delay)
                             retries_left -= 1
                         else:
                             raise
diff --git a/synapse/notifier.py b/synapse/notifier.py
index 6dce20a284..3c0622a294 100644
--- a/synapse/notifier.py
+++ b/synapse/notifier.py
@@ -161,6 +161,7 @@ class Notifier(object):
         self.user_to_user_stream = {}
         self.room_to_user_streams = {}
 
+        self.hs = hs
         self.event_sources = hs.get_event_sources()
         self.store = hs.get_datastore()
         self.pending_new_room_events = []
@@ -340,6 +341,7 @@ class Notifier(object):
                     add_timeout_to_deferred(
                         listener.deferred,
                         (end_time - now) / 1000.,
+                        self.hs.get_reactor(),
                     )
                     with PreserveLoggingContext():
                         yield listener.deferred
@@ -561,6 +563,7 @@ class Notifier(object):
             add_timeout_to_deferred(
                 listener.deferred.addTimeout,
                 (end_time - now) / 1000.,
+                self.hs.get_reactor(),
             )
             try:
                 with PreserveLoggingContext():
diff --git a/synapse/replication/http/send_event.py b/synapse/replication/http/send_event.py
index a9baa2c1c3..f080f96cc1 100644
--- a/synapse/replication/http/send_event.py
+++ b/synapse/replication/http/send_event.py
@@ -21,7 +21,6 @@ from synapse.api.errors import (
 from synapse.events import FrozenEvent
 from synapse.events.snapshot import EventContext
 from synapse.http.servlet import RestServlet, parse_json_object_from_request
-from synapse.util.async import sleep
 from synapse.util.caches.response_cache import ResponseCache
 from synapse.util.metrics import Measure
 from synapse.types import Requester, UserID
@@ -33,11 +32,12 @@ logger = logging.getLogger(__name__)
 
 
 @defer.inlineCallbacks
-def send_event_to_master(client, host, port, requester, event, context,
+def send_event_to_master(clock, client, host, port, requester, event, context,
                          ratelimit, extra_users):
     """Send event to be handled on the master
 
     Args:
+        clock (synapse.util.Clock)
         client (SimpleHttpClient)
         host (str): host of master
         port (int): port on master listening for HTTP replication
@@ -77,7 +77,7 @@ def send_event_to_master(client, host, port, requester, event, context,
 
             # If we timed out we probably don't need to worry about backing
             # off too much, but lets just wait a little anyway.
-            yield sleep(1)
+            yield clock.sleep(1)
     except MatrixCodeMessageException as e:
         # We convert to SynapseError as we know that it was a SynapseError
         # on the master process that we should send to the client. (And
diff --git a/synapse/rest/media/v1/media_repository.py b/synapse/rest/media/v1/media_repository.py
index 2ac767d2dc..218ba7a083 100644
--- a/synapse/rest/media/v1/media_repository.py
+++ b/synapse/rest/media/v1/media_repository.py
@@ -58,6 +58,7 @@ UPDATE_RECENTLY_ACCESSED_TS = 60 * 1000
 
 class MediaRepository(object):
     def __init__(self, hs):
+        self.hs = hs
         self.auth = hs.get_auth()
         self.client = MatrixFederationHttpClient(hs)
         self.clock = hs.get_clock()
@@ -94,7 +95,7 @@ class MediaRepository(object):
             storage_providers.append(provider)
 
         self.media_storage = MediaStorage(
-            self.primary_base_path, self.filepaths, storage_providers,
+            self.hs, self.primary_base_path, self.filepaths, storage_providers,
         )
 
         self.clock.looping_call(
diff --git a/synapse/rest/media/v1/media_storage.py b/synapse/rest/media/v1/media_storage.py
index d23fe10b07..d6b8ebbedb 100644
--- a/synapse/rest/media/v1/media_storage.py
+++ b/synapse/rest/media/v1/media_storage.py
@@ -37,13 +37,15 @@ class MediaStorage(object):
     """Responsible for storing/fetching files from local sources.
 
     Args:
+        hs (synapse.server.Homeserver)
         local_media_directory (str): Base path where we store media on disk
         filepaths (MediaFilePaths)
         storage_providers ([StorageProvider]): List of StorageProvider that are
             used to fetch and store files.
     """
 
-    def __init__(self, local_media_directory, filepaths, storage_providers):
+    def __init__(self, hs, local_media_directory, filepaths, storage_providers):
+        self.hs = hs
         self.local_media_directory = local_media_directory
         self.filepaths = filepaths
         self.storage_providers = storage_providers
@@ -175,7 +177,8 @@ class MediaStorage(object):
             res = yield provider.fetch(path, file_info)
             if res:
                 with res:
-                    consumer = BackgroundFileConsumer(open(local_path, "w"))
+                    consumer = BackgroundFileConsumer(
+                        open(local_path, "w"), self.hs.get_reactor())
                     yield res.write_to_consumer(consumer)
                     yield consumer.wait()
                 defer.returnValue(local_path)
diff --git a/synapse/server.py b/synapse/server.py
index 58dbf78437..c29c19289a 100644
--- a/synapse/server.py
+++ b/synapse/server.py
@@ -40,7 +40,7 @@ from synapse.federation.transport.client import TransportLayerClient
 from synapse.federation.transaction_queue import TransactionQueue
 from synapse.handlers import Handlers
 from synapse.handlers.appservice import ApplicationServicesHandler
-from synapse.handlers.auth import AuthHandler, MacaroonGeneartor
+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
@@ -165,15 +165,19 @@ class HomeServer(object):
         'server_notices_sender',
     ]
 
-    def __init__(self, hostname, **kwargs):
+    def __init__(self, hostname, reactor=None, **kwargs):
         """
         Args:
             hostname : The hostname for the server.
         """
+        if not reactor:
+            from twisted.internet import reactor
+
+        self._reactor = reactor
         self.hostname = hostname
         self._building = {}
 
-        self.clock = Clock()
+        self.clock = Clock(reactor)
         self.distributor = Distributor()
         self.ratelimiter = Ratelimiter()
 
@@ -186,6 +190,12 @@ class HomeServer(object):
         self.datastore = DataStore(self.get_db_conn(), self)
         logger.info("Finished setting up.")
 
+    def get_reactor(self):
+        """
+        Fetch the Twisted reactor in use by this HomeServer.
+        """
+        return self._reactor
+
     def get_ip_from_request(self, request):
         # X-Forwarded-For is handled by our custom request type.
         return request.getClientIP()
@@ -261,7 +271,7 @@ class HomeServer(object):
         return AuthHandler(self)
 
     def build_macaroon_generator(self):
-        return MacaroonGeneartor(self)
+        return MacaroonGenerator(self)
 
     def build_device_handler(self):
         return DeviceHandler(self)
@@ -328,6 +338,7 @@ class HomeServer(object):
 
         return adbapi.ConnectionPool(
             name,
+            cp_reactor=self.get_reactor(),
             **self.db_config.get("args", {})
         )
 
diff --git a/synapse/storage/background_updates.py b/synapse/storage/background_updates.py
index 8af325a9f5..b7e9c716c8 100644
--- a/synapse/storage/background_updates.py
+++ b/synapse/storage/background_updates.py
@@ -12,7 +12,6 @@
 # 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.async
 
 from ._base import SQLBaseStore
 from . import engines
@@ -92,7 +91,7 @@ class BackgroundUpdateStore(SQLBaseStore):
         logger.info("Starting background schema updates")
 
         while True:
-            yield synapse.util.async.sleep(
+            yield self.hs.get_clock().sleep(
                 self.BACKGROUND_UPDATE_INTERVAL_MS / 1000.)
 
             try:
diff --git a/synapse/storage/client_ips.py b/synapse/storage/client_ips.py
index ce338514e8..968d2fed22 100644
--- a/synapse/storage/client_ips.py
+++ b/synapse/storage/client_ips.py
@@ -15,7 +15,7 @@
 
 import logging
 
-from twisted.internet import defer, reactor
+from twisted.internet import defer
 
 from ._base import Cache
 from . import background_updates
@@ -70,7 +70,9 @@ class ClientIpStore(background_updates.BackgroundUpdateStore):
         self._client_ip_looper = self._clock.looping_call(
             self._update_client_ips_batch, 5 * 1000
         )
-        reactor.addSystemEventTrigger("before", "shutdown", self._update_client_ips_batch)
+        self.hs.get_reactor().addSystemEventTrigger(
+            "before", "shutdown", self._update_client_ips_batch
+        )
 
     def insert_client_ip(self, user_id, access_token, ip, user_agent, device_id,
                          now=None):
diff --git a/synapse/storage/event_push_actions.py b/synapse/storage/event_push_actions.py
index d0350ee5fe..c4a0208ce4 100644
--- a/synapse/storage/event_push_actions.py
+++ b/synapse/storage/event_push_actions.py
@@ -16,7 +16,6 @@
 
 from synapse.storage._base import SQLBaseStore, LoggingTransaction
 from twisted.internet import defer
-from synapse.util.async import sleep
 from synapse.util.caches.descriptors import cachedInlineCallbacks
 
 import logging
@@ -800,7 +799,7 @@ class EventPushActionsStore(EventPushActionsWorkerStore):
                 )
                 if caught_up:
                     break
-                yield sleep(5)
+                yield self.hs.get_clock().sleep(5)
         finally:
             self._doing_notif_rotation = False
 
diff --git a/synapse/storage/events_worker.py b/synapse/storage/events_worker.py
index 32d9d00ffb..38fcf7d444 100644
--- a/synapse/storage/events_worker.py
+++ b/synapse/storage/events_worker.py
@@ -14,7 +14,7 @@
 # limitations under the License.
 from ._base import SQLBaseStore
 
-from twisted.internet import defer, reactor
+from twisted.internet import defer
 
 from synapse.events import FrozenEvent
 from synapse.events.utils import prune_event
@@ -265,7 +265,7 @@ class EventsWorkerStore(SQLBaseStore):
                             except Exception:
                                 logger.exception("Failed to callback")
                 with PreserveLoggingContext():
-                    reactor.callFromThread(fire, event_list, row_dict)
+                    self.hs.get_reactor().callFromThread(fire, event_list, row_dict)
             except Exception as e:
                 logger.exception("do_fetch")
 
@@ -278,7 +278,7 @@ class EventsWorkerStore(SQLBaseStore):
 
                 if event_list:
                     with PreserveLoggingContext():
-                        reactor.callFromThread(fire, event_list)
+                        self.hs.get_reactor().callFromThread(fire, event_list)
 
     @defer.inlineCallbacks
     def _enqueue_events(self, events, check_redacted=True, allow_rejected=False):
diff --git a/synapse/util/__init__.py b/synapse/util/__init__.py
index fc11e26623..2a3df7c71d 100644
--- a/synapse/util/__init__.py
+++ b/synapse/util/__init__.py
@@ -13,15 +13,14 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from synapse.util.logcontext import PreserveLoggingContext
-
-from twisted.internet import defer, reactor, task
-
-import time
 import logging
-
 from itertools import islice
 
+import attr
+from twisted.internet import defer, task
+
+from synapse.util.logcontext import PreserveLoggingContext
+
 logger = logging.getLogger(__name__)
 
 
@@ -31,16 +30,24 @@ def unwrapFirstError(failure):
     return failure.value.subFailure
 
 
+@attr.s
 class Clock(object):
-    """A small utility that obtains current time-of-day so that time may be
-    mocked during unit-tests.
-
-    TODO(paul): Also move the sleep() functionality into it
     """
+    A Clock wraps a Twisted reactor and provides utilities on top of it.
+    """
+    _reactor = attr.ib()
+
+    @defer.inlineCallbacks
+    def sleep(self, seconds):
+        d = defer.Deferred()
+        with PreserveLoggingContext():
+            self._reactor.callLater(seconds, d.callback, seconds)
+            res = yield d
+        defer.returnValue(res)
 
     def time(self):
         """Returns the current system time in seconds since epoch."""
-        return time.time()
+        return self._reactor.seconds()
 
     def time_msec(self):
         """Returns the current system time in miliseconds since epoch."""
@@ -56,6 +63,7 @@ class Clock(object):
             msec(float): How long to wait between calls in milliseconds.
         """
         call = task.LoopingCall(f)
+        call.clock = self._reactor
         call.start(msec / 1000.0, now=False)
         return call
 
@@ -73,7 +81,7 @@ class Clock(object):
                 callback(*args, **kwargs)
 
         with PreserveLoggingContext():
-            return reactor.callLater(delay, wrapped_callback, *args, **kwargs)
+            return self._reactor.callLater(delay, wrapped_callback, *args, **kwargs)
 
     def cancel_call_later(self, timer, ignore_errs=False):
         try:
diff --git a/synapse/util/async.py b/synapse/util/async.py
index b8e57efc54..1668df4ce6 100644
--- a/synapse/util/async.py
+++ b/synapse/util/async.py
@@ -13,14 +13,14 @@
 # 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.defer import CancelledError
 from twisted.python import failure
 
 from .logcontext import (
     PreserveLoggingContext, make_deferred_yieldable, run_in_background
 )
-from synapse.util import logcontext, unwrapFirstError
+from synapse.util import logcontext, unwrapFirstError, Clock
 
 from contextlib import contextmanager
 
@@ -31,15 +31,6 @@ from six.moves import range
 logger = logging.getLogger(__name__)
 
 
-@defer.inlineCallbacks
-def sleep(seconds):
-    d = defer.Deferred()
-    with PreserveLoggingContext():
-        reactor.callLater(seconds, d.callback, seconds)
-        res = yield d
-    defer.returnValue(res)
-
-
 class ObservableDeferred(object):
     """Wraps a deferred object so that we can add observer deferreds. These
     observer deferreds do not affect the callback chain of the original
@@ -172,13 +163,18 @@ class Linearizer(object):
             # do some work.
 
     """
-    def __init__(self, name=None):
+    def __init__(self, name=None, clock=None):
         if name is None:
             self.name = id(self)
         else:
             self.name = name
         self.key_to_defer = {}
 
+        if not clock:
+            from twisted.internet import reactor
+            clock = Clock(reactor)
+        self._clock = clock
+
     @defer.inlineCallbacks
     def queue(self, key):
         # If there is already a deferred in the queue, we pull it out so that
@@ -219,7 +215,7 @@ class Linearizer(object):
             # the context manager, but it needs to happen while we hold the
             # lock, and the context manager's exit code must be synchronous,
             # so actually this is the only sensible place.
-            yield sleep(0)
+            yield self._clock.sleep(0)
 
         else:
             logger.info("Acquired uncontended linearizer lock %r for key %r",
@@ -396,7 +392,7 @@ class DeferredTimeoutError(Exception):
     """
 
 
-def add_timeout_to_deferred(deferred, timeout, on_timeout_cancel=None):
+def add_timeout_to_deferred(deferred, timeout, reactor, on_timeout_cancel=None):
     """
     Add a timeout to a deferred by scheduling it to be cancelled after
     timeout seconds.
@@ -411,6 +407,7 @@ def add_timeout_to_deferred(deferred, timeout, on_timeout_cancel=None):
     Args:
         deferred (defer.Deferred): deferred to be timed out
         timeout (Number): seconds to time out after
+        reactor (twisted.internet.reactor): the Twisted reactor to use
 
         on_timeout_cancel (callable): A callable which is called immediately
             after the deferred times out, and not if this deferred is
diff --git a/synapse/util/file_consumer.py b/synapse/util/file_consumer.py
index 3380970e4e..c78801015b 100644
--- a/synapse/util/file_consumer.py
+++ b/synapse/util/file_consumer.py
@@ -13,7 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from twisted.internet import threads, reactor
+from twisted.internet import threads
 
 from synapse.util.logcontext import make_deferred_yieldable, run_in_background
 
@@ -27,6 +27,7 @@ class BackgroundFileConsumer(object):
     Args:
         file_obj (file): The file like object to write to. Closed when
             finished.
+        reactor (twisted.internet.reactor): the Twisted reactor to use
     """
 
     # For PushProducers pause if we have this many unwritten slices
@@ -34,9 +35,11 @@ class BackgroundFileConsumer(object):
     # And resume once the size of the queue is less than this
     _RESUME_ON_QUEUE_SIZE = 2
 
-    def __init__(self, file_obj):
+    def __init__(self, file_obj, reactor):
         self._file_obj = file_obj
 
+        self._reactor = reactor
+
         # Producer we're registered with
         self._producer = None
 
@@ -71,7 +74,10 @@ class BackgroundFileConsumer(object):
         self._producer = producer
         self.streaming = streaming
         self._finished_deferred = run_in_background(
-            threads.deferToThread, self._writer
+            threads.deferToThreadPool,
+            self._reactor,
+            self._reactor.getThreadPool(),
+            self._writer,
         )
         if not streaming:
             self._producer.resumeProducing()
@@ -109,7 +115,7 @@ class BackgroundFileConsumer(object):
                 # producer.
                 if self._producer and self._paused_producer:
                     if self._bytes_queue.qsize() <= self._RESUME_ON_QUEUE_SIZE:
-                        reactor.callFromThread(self._resume_paused_producer)
+                        self._reactor.callFromThread(self._resume_paused_producer)
 
                 bytes = self._bytes_queue.get()
 
@@ -121,7 +127,7 @@ class BackgroundFileConsumer(object):
                 # If its a pull producer then we need to explicitly ask for
                 # more stuff.
                 if not self.streaming and self._producer:
-                    reactor.callFromThread(self._producer.resumeProducing)
+                    self._reactor.callFromThread(self._producer.resumeProducing)
         except Exception as e:
             self._write_exception = e
             raise
diff --git a/synapse/util/ratelimitutils.py b/synapse/util/ratelimitutils.py
index 0ab63c3d7d..c5a45cef7c 100644
--- a/synapse/util/ratelimitutils.py
+++ b/synapse/util/ratelimitutils.py
@@ -17,7 +17,6 @@ from twisted.internet import defer
 
 from synapse.api.errors import LimitExceededError
 
-from synapse.util.async import sleep
 from synapse.util.logcontext import (
     run_in_background, make_deferred_yieldable,
     PreserveLoggingContext,
@@ -153,7 +152,7 @@ class _PerHostRatelimiter(object):
                 "Ratelimit [%s]: sleeping req",
                 id(request_id),
             )
-            ret_defer = run_in_background(sleep, self.sleep_msec / 1000.0)
+            ret_defer = run_in_background(self.clock.sleep, self.sleep_msec / 1000.0)
 
             self.sleeping_requests.add(request_id)
 
diff --git a/tests/crypto/test_keyring.py b/tests/crypto/test_keyring.py
index 149e443022..cc1c862ba4 100644
--- a/tests/crypto/test_keyring.py
+++ b/tests/crypto/test_keyring.py
@@ -19,10 +19,10 @@ import signedjson.sign
 from mock import Mock
 from synapse.api.errors import SynapseError
 from synapse.crypto import keyring
-from synapse.util import async, logcontext
+from synapse.util import logcontext, Clock
 from synapse.util.logcontext import LoggingContext
 from tests import unittest, utils
-from twisted.internet import defer
+from twisted.internet import defer, reactor
 
 
 class MockPerspectiveServer(object):
@@ -118,6 +118,7 @@ class KeyringTestCase(unittest.TestCase):
 
     @defer.inlineCallbacks
     def test_verify_json_objects_for_server_awaits_previous_requests(self):
+        clock = Clock(reactor)
         key1 = signedjson.key.generate_signing_key(1)
 
         kr = keyring.Keyring(self.hs)
@@ -167,7 +168,7 @@ class KeyringTestCase(unittest.TestCase):
 
             # wait a tick for it to send the request to the perspectives server
             # (it first tries the datastore)
-            yield async.sleep(1)   # XXX find out why this takes so long!
+            yield clock.sleep(1)   # XXX find out why this takes so long!
             self.http_client.post_json.assert_called_once()
 
             self.assertIs(LoggingContext.current_context(), context_11)
@@ -183,7 +184,7 @@ class KeyringTestCase(unittest.TestCase):
                 res_deferreds_2 = kr.verify_json_objects_for_server(
                     [("server10", json1)],
                 )
-                yield async.sleep(1)
+                yield clock.sleep(1)
                 self.http_client.post_json.assert_not_called()
                 res_deferreds_2[0].addBoth(self.check_context, None)
 
diff --git a/tests/rest/client/test_transactions.py b/tests/rest/client/test_transactions.py
index b5bc2fa255..6a757289db 100644
--- a/tests/rest/client/test_transactions.py
+++ b/tests/rest/client/test_transactions.py
@@ -1,9 +1,9 @@
 from synapse.rest.client.transactions import HttpTransactionCache
 from synapse.rest.client.transactions import CLEANUP_PERIOD_MS
-from twisted.internet import defer
+from twisted.internet import defer, reactor
 from mock import Mock, call
 
-from synapse.util import async
+from synapse.util import Clock
 from synapse.util.logcontext import LoggingContext
 from tests import unittest
 from tests.utils import MockClock
@@ -46,7 +46,7 @@ class HttpTransactionCacheTestCase(unittest.TestCase):
     def test_logcontexts_with_async_result(self):
         @defer.inlineCallbacks
         def cb():
-            yield async.sleep(0)
+            yield Clock(reactor).sleep(0)
             defer.returnValue("yay")
 
         @defer.inlineCallbacks
diff --git a/tests/rest/media/v1/test_media_storage.py b/tests/rest/media/v1/test_media_storage.py
index eef38b6781..c5e2f5549a 100644
--- a/tests/rest/media/v1/test_media_storage.py
+++ b/tests/rest/media/v1/test_media_storage.py
@@ -14,7 +14,7 @@
 # limitations under the License.
 
 
-from twisted.internet import defer
+from twisted.internet import defer, reactor
 
 from synapse.rest.media.v1._base import FileInfo
 from synapse.rest.media.v1.media_storage import MediaStorage
@@ -38,6 +38,7 @@ class MediaStorageTests(unittest.TestCase):
         self.secondary_base_path = os.path.join(self.test_dir, "secondary")
 
         hs = Mock()
+        hs.get_reactor = Mock(return_value=reactor)
         hs.config.media_store_path = self.primary_base_path
 
         storage_providers = [FileStorageProviderBackend(
@@ -46,7 +47,7 @@ class MediaStorageTests(unittest.TestCase):
 
         self.filepaths = MediaFilePaths(self.primary_base_path)
         self.media_storage = MediaStorage(
-            self.primary_base_path, self.filepaths, storage_providers,
+            hs, self.primary_base_path, self.filepaths, storage_providers,
         )
 
     def tearDown(self):
diff --git a/tests/util/test_file_consumer.py b/tests/util/test_file_consumer.py
index d6e1082779..c2aae8f54c 100644
--- a/tests/util/test_file_consumer.py
+++ b/tests/util/test_file_consumer.py
@@ -30,7 +30,7 @@ class FileConsumerTests(unittest.TestCase):
     @defer.inlineCallbacks
     def test_pull_consumer(self):
         string_file = StringIO()
-        consumer = BackgroundFileConsumer(string_file)
+        consumer = BackgroundFileConsumer(string_file, reactor=reactor)
 
         try:
             producer = DummyPullProducer()
@@ -54,7 +54,7 @@ class FileConsumerTests(unittest.TestCase):
     @defer.inlineCallbacks
     def test_push_consumer(self):
         string_file = BlockingStringWrite()
-        consumer = BackgroundFileConsumer(string_file)
+        consumer = BackgroundFileConsumer(string_file, reactor=reactor)
 
         try:
             producer = NonCallableMock(spec_set=[])
@@ -80,7 +80,7 @@ class FileConsumerTests(unittest.TestCase):
     @defer.inlineCallbacks
     def test_push_producer_feedback(self):
         string_file = BlockingStringWrite()
-        consumer = BackgroundFileConsumer(string_file)
+        consumer = BackgroundFileConsumer(string_file, reactor=reactor)
 
         try:
             producer = NonCallableMock(spec_set=["pauseProducing", "resumeProducing"])
diff --git a/tests/util/test_linearizer.py b/tests/util/test_linearizer.py
index 4865eb4bc6..bf7e3aa885 100644
--- a/tests/util/test_linearizer.py
+++ b/tests/util/test_linearizer.py
@@ -12,10 +12,11 @@
 # 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 async, logcontext
+
+from synapse.util import logcontext, Clock
 from tests import unittest
 
-from twisted.internet import defer
+from twisted.internet import defer, reactor
 
 from synapse.util.async import Linearizer
 from six.moves import range
@@ -53,7 +54,7 @@ class LinearizerTestCase(unittest.TestCase):
                     self.assertEqual(
                         logcontext.LoggingContext.current_context(), lc)
                     if sleep:
-                        yield async.sleep(0)
+                        yield Clock(reactor).sleep(0)
 
                 self.assertEqual(
                     logcontext.LoggingContext.current_context(), lc)
diff --git a/tests/util/test_logcontext.py b/tests/util/test_logcontext.py
index ad78d884e0..9cf90fcfc4 100644
--- a/tests/util/test_logcontext.py
+++ b/tests/util/test_logcontext.py
@@ -3,8 +3,7 @@ from twisted.internet import defer
 from twisted.internet import reactor
 from .. import unittest
 
-from synapse.util.async import sleep
-from synapse.util import logcontext
+from synapse.util import logcontext, Clock
 from synapse.util.logcontext import LoggingContext
 
 
@@ -22,18 +21,20 @@ class LoggingContextTestCase(unittest.TestCase):
 
     @defer.inlineCallbacks
     def test_sleep(self):
+        clock = Clock(reactor)
+
         @defer.inlineCallbacks
         def competing_callback():
             with LoggingContext() as competing_context:
                 competing_context.request = "competing"
-                yield sleep(0)
+                yield clock.sleep(0)
                 self._check_test_key("competing")
 
         reactor.callLater(0, competing_callback)
 
         with LoggingContext() as context_one:
             context_one.request = "one"
-            yield sleep(0)
+            yield clock.sleep(0)
             self._check_test_key("one")
 
     def _test_run_in_background(self, function):
@@ -87,7 +88,7 @@ class LoggingContextTestCase(unittest.TestCase):
     def test_run_in_background_with_blocking_fn(self):
         @defer.inlineCallbacks
         def blocking_function():
-            yield sleep(0)
+            yield Clock(reactor).sleep(0)
 
         return self._test_run_in_background(blocking_function)
 
diff --git a/tests/utils.py b/tests/utils.py
index 262c4a5714..189fd2711c 100644
--- a/tests/utils.py
+++ b/tests/utils.py
@@ -37,11 +37,15 @@ USE_POSTGRES_FOR_TESTS = False
 
 
 @defer.inlineCallbacks
-def setup_test_homeserver(name="test", datastore=None, config=None, **kargs):
+def setup_test_homeserver(name="test", datastore=None, config=None, reactor=None,
+                          **kargs):
     """Setup a homeserver suitable for running tests against. Keyword arguments
     are passed to the Homeserver constructor. If no datastore is supplied a
     datastore backed by an in-memory sqlite db will be given to the HS.
     """
+    if reactor is None:
+        from twisted.internet import reactor
+
     if config is None:
         config = Mock()
         config.signing_key = [MockKey()]
@@ -110,6 +114,7 @@ def setup_test_homeserver(name="test", datastore=None, config=None, **kargs):
             database_engine=db_engine,
             room_list_handler=object(),
             tls_server_context_factory=Mock(),
+            reactor=reactor,
             **kargs
         )
         db_conn = hs.get_db_conn()