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-rw-r--r--synapse/api/auth.py13
-rw-r--r--synapse/api/errors.py23
-rw-r--r--synapse/app/_base.py6
-rw-r--r--synapse/app/frontend_proxy.py39
-rwxr-xr-xsynapse/app/homeserver.py1
-rw-r--r--synapse/app/synchrotron.py16
-rw-r--r--synapse/config/server.py33
-rw-r--r--synapse/federation/transaction_queue.py4
-rw-r--r--synapse/handlers/initial_sync.py4
-rw-r--r--synapse/handlers/message.py6
-rw-r--r--synapse/handlers/presence.py26
-rw-r--r--synapse/handlers/room.py4
-rw-r--r--synapse/handlers/sync.py3
-rw-r--r--synapse/http/server.py87
-rw-r--r--synapse/http/site.py201
-rw-r--r--synapse/rest/client/v1/presence.py3
-rw-r--r--synapse/rest/client/v1_only/register.py54
-rw-r--r--synapse/storage/monthly_active_users.py5
18 files changed, 352 insertions, 176 deletions
diff --git a/synapse/api/auth.py b/synapse/api/auth.py
index 3b2a2ab77a..022211e34e 100644
--- a/synapse/api/auth.py
+++ b/synapse/api/auth.py
@@ -25,7 +25,7 @@ from twisted.internet import defer
 import synapse.types
 from synapse import event_auth
 from synapse.api.constants import EventTypes, JoinRules, Membership
-from synapse.api.errors import AuthError, Codes
+from synapse.api.errors import AuthError, Codes, ResourceLimitError
 from synapse.types import UserID
 from synapse.util.caches import CACHE_SIZE_FACTOR, register_cache
 from synapse.util.caches.lrucache import LruCache
@@ -784,10 +784,11 @@ class Auth(object):
             MAU cohort
         """
         if self.hs.config.hs_disabled:
-            raise AuthError(
+            raise ResourceLimitError(
                 403, self.hs.config.hs_disabled_message,
                 errcode=Codes.RESOURCE_LIMIT_EXCEED,
                 admin_uri=self.hs.config.admin_uri,
+                limit_type=self.hs.config.hs_disabled_limit_type
             )
         if self.hs.config.limit_usage_by_mau is True:
             # If the user is already part of the MAU cohort
@@ -798,8 +799,10 @@ class Auth(object):
             # Else if there is no room in the MAU bucket, bail
             current_mau = yield self.store.get_monthly_active_count()
             if current_mau >= self.hs.config.max_mau_value:
-                raise AuthError(
-                    403, "Monthly Active User Limits AU Limit Exceeded",
+                raise ResourceLimitError(
+                    403, "Monthly Active User Limit Exceeded",
+
                     admin_uri=self.hs.config.admin_uri,
-                    errcode=Codes.RESOURCE_LIMIT_EXCEED
+                    errcode=Codes.RESOURCE_LIMIT_EXCEED,
+                    limit_type="monthly_active_user"
                 )
diff --git a/synapse/api/errors.py b/synapse/api/errors.py
index 08f0cb5554..e26001ab12 100644
--- a/synapse/api/errors.py
+++ b/synapse/api/errors.py
@@ -224,15 +224,34 @@ class NotFoundError(SynapseError):
 
 class AuthError(SynapseError):
     """An error raised when there was a problem authorising an event."""
-    def __init__(self, code, msg, errcode=Codes.FORBIDDEN, admin_uri=None):
+
+    def __init__(self, *args, **kwargs):
+        if "errcode" not in kwargs:
+            kwargs["errcode"] = Codes.FORBIDDEN
+        super(AuthError, self).__init__(*args, **kwargs)
+
+
+class ResourceLimitError(SynapseError):
+    """
+    Any error raised when there is a problem with resource usage.
+    For instance, the monthly active user limit for the server has been exceeded
+    """
+    def __init__(
+        self, code, msg,
+        errcode=Codes.RESOURCE_LIMIT_EXCEED,
+        admin_uri=None,
+        limit_type=None,
+    ):
         self.admin_uri = admin_uri
-        super(AuthError, self).__init__(code, msg, errcode=errcode)
+        self.limit_type = limit_type
+        super(ResourceLimitError, self).__init__(code, msg, errcode=errcode)
 
     def error_dict(self):
         return cs_error(
             self.msg,
             self.errcode,
             admin_uri=self.admin_uri,
+            limit_type=self.limit_type
         )
 
 
diff --git a/synapse/app/_base.py b/synapse/app/_base.py
index 391bd14c5c..7c866e246a 100644
--- a/synapse/app/_base.py
+++ b/synapse/app/_base.py
@@ -140,7 +140,7 @@ def listen_metrics(bind_addresses, port):
         logger.info("Metrics now reporting on %s:%d", host, port)
 
 
-def listen_tcp(bind_addresses, port, factory, backlog=50):
+def listen_tcp(bind_addresses, port, factory, reactor=reactor, backlog=50):
     """
     Create a TCP socket for a port and several addresses
     """
@@ -156,7 +156,9 @@ def listen_tcp(bind_addresses, port, factory, backlog=50):
             check_bind_error(e, address, bind_addresses)
 
 
-def listen_ssl(bind_addresses, port, factory, context_factory, backlog=50):
+def listen_ssl(
+    bind_addresses, port, factory, context_factory, reactor=reactor, backlog=50
+):
     """
     Create an SSL socket for a port and several addresses
     """
diff --git a/synapse/app/frontend_proxy.py b/synapse/app/frontend_proxy.py
index 671fbbcb2a..8d484c1cd4 100644
--- a/synapse/app/frontend_proxy.py
+++ b/synapse/app/frontend_proxy.py
@@ -38,6 +38,7 @@ from synapse.replication.slave.storage.client_ips import SlavedClientIpStore
 from synapse.replication.slave.storage.devices import SlavedDeviceStore
 from synapse.replication.slave.storage.registration import SlavedRegistrationStore
 from synapse.replication.tcp.client import ReplicationClientHandler
+from synapse.rest.client.v1.base import ClientV1RestServlet, client_path_patterns
 from synapse.rest.client.v2_alpha._base import client_v2_patterns
 from synapse.server import HomeServer
 from synapse.storage.engines import create_engine
@@ -49,6 +50,35 @@ from synapse.util.versionstring import get_version_string
 logger = logging.getLogger("synapse.app.frontend_proxy")
 
 
+class PresenceStatusStubServlet(ClientV1RestServlet):
+    PATTERNS = client_path_patterns("/presence/(?P<user_id>[^/]*)/status")
+
+    def __init__(self, hs):
+        super(PresenceStatusStubServlet, self).__init__(hs)
+        self.http_client = hs.get_simple_http_client()
+        self.auth = hs.get_auth()
+        self.main_uri = hs.config.worker_main_http_uri
+
+    @defer.inlineCallbacks
+    def on_GET(self, request, user_id):
+        # Pass through the auth headers, if any, in case the access token
+        # is there.
+        auth_headers = request.requestHeaders.getRawHeaders("Authorization", [])
+        headers = {
+            "Authorization": auth_headers,
+        }
+        result = yield self.http_client.get_json(
+            self.main_uri + request.uri,
+            headers=headers,
+        )
+        defer.returnValue((200, result))
+
+    @defer.inlineCallbacks
+    def on_PUT(self, request, user_id):
+        yield self.auth.get_user_by_req(request)
+        defer.returnValue((200, {}))
+
+
 class KeyUploadServlet(RestServlet):
     PATTERNS = client_v2_patterns("/keys/upload(/(?P<device_id>[^/]+))?$")
 
@@ -135,6 +165,12 @@ class FrontendProxyServer(HomeServer):
                 elif name == "client":
                     resource = JsonResource(self, canonical_json=False)
                     KeyUploadServlet(self).register(resource)
+
+                    # If presence is disabled, use the stub servlet that does
+                    # not allow sending presence
+                    if not self.config.use_presence:
+                        PresenceStatusStubServlet(self).register(resource)
+
                     resources.update({
                         "/_matrix/client/r0": resource,
                         "/_matrix/client/unstable": resource,
@@ -153,7 +189,8 @@ class FrontendProxyServer(HomeServer):
                 listener_config,
                 root_resource,
                 self.version_string,
-            )
+            ),
+            reactor=self.get_reactor()
         )
 
         logger.info("Synapse client reader now listening on port %d", port)
diff --git a/synapse/app/homeserver.py b/synapse/app/homeserver.py
index a98bb506e5..005921dcf7 100755
--- a/synapse/app/homeserver.py
+++ b/synapse/app/homeserver.py
@@ -525,6 +525,7 @@ def run(hs):
     clock.looping_call(
         hs.get_datastore().reap_monthly_active_users, 1000 * 60 * 60
     )
+    hs.get_datastore().reap_monthly_active_users()
 
     @defer.inlineCallbacks
     def generate_monthly_active_users():
diff --git a/synapse/app/synchrotron.py b/synapse/app/synchrotron.py
index e201f18efd..cade09d60e 100644
--- a/synapse/app/synchrotron.py
+++ b/synapse/app/synchrotron.py
@@ -114,7 +114,10 @@ class SynchrotronPresence(object):
         logger.info("Presence process_id is %r", self.process_id)
 
     def send_user_sync(self, user_id, is_syncing, last_sync_ms):
-        self.hs.get_tcp_replication().send_user_sync(user_id, is_syncing, last_sync_ms)
+        if self.hs.config.use_presence:
+            self.hs.get_tcp_replication().send_user_sync(
+                user_id, is_syncing, last_sync_ms
+            )
 
     def mark_as_coming_online(self, user_id):
         """A user has started syncing. Send a UserSync to the master, unless they
@@ -211,10 +214,13 @@ class SynchrotronPresence(object):
         yield self.notify_from_replication(states, stream_id)
 
     def get_currently_syncing_users(self):
-        return [
-            user_id for user_id, count in iteritems(self.user_to_num_current_syncs)
-            if count > 0
-        ]
+        if self.hs.config.use_presence:
+            return [
+                user_id for user_id, count in iteritems(self.user_to_num_current_syncs)
+                if count > 0
+            ]
+        else:
+            return set()
 
 
 class SynchrotronTyping(object):
diff --git a/synapse/config/server.py b/synapse/config/server.py
index 2190f3210a..68a612e594 100644
--- a/synapse/config/server.py
+++ b/synapse/config/server.py
@@ -49,6 +49,9 @@ class ServerConfig(Config):
         # "disable" federation
         self.send_federation = config.get("send_federation", True)
 
+        # Whether to enable user presence.
+        self.use_presence = config.get("use_presence", True)
+
         # Whether to update the user directory or not. This should be set to
         # false only if we are updating the user directory in a worker
         self.update_user_directory = config.get("update_user_directory", True)
@@ -81,6 +84,7 @@ class ServerConfig(Config):
         # Options to disable HS
         self.hs_disabled = config.get("hs_disabled", False)
         self.hs_disabled_message = config.get("hs_disabled_message", "")
+        self.hs_disabled_limit_type = config.get("hs_disabled_limit_type", "")
 
         # Admin uri to direct users at should their instance become blocked
         # due to resource constraints
@@ -249,6 +253,9 @@ class ServerConfig(Config):
         # hard limit.
         soft_file_limit: 0
 
+        # Set to false to disable presence tracking on this homeserver.
+        use_presence: true
+
         # The GC threshold parameters to pass to `gc.set_threshold`, if defined
         # gc_thresholds: [700, 10, 10]
 
@@ -340,6 +347,32 @@ class ServerConfig(Config):
           # - port: 9000
           #   bind_addresses: ['::1', '127.0.0.1']
           #   type: manhole
+
+
+          # Homeserver blocking
+          #
+          # How to reach the server admin, used in ResourceLimitError
+          # admin_uri: 'mailto:admin@server.com'
+          #
+          # Global block config
+          #
+          # hs_disabled: False
+          # hs_disabled_message: 'Human readable reason for why the HS is blocked'
+          # hs_disabled_limit_type: 'error code(str), to help clients decode reason'
+          #
+          # Monthly Active User Blocking
+          #
+          # Enables monthly active user checking
+          # limit_usage_by_mau: False
+          # max_mau_value: 50
+          #
+          # Sometimes the server admin will want to ensure certain accounts are
+          # never blocked by mau checking. These accounts are specified here.
+          #
+          # mau_limit_reserved_threepids:
+          # - medium: 'email'
+          #   address: 'reserved_user@example.com'
+
         """ % locals()
 
     def read_arguments(self, args):
diff --git a/synapse/federation/transaction_queue.py b/synapse/federation/transaction_queue.py
index f603c8a368..94d7423d01 100644
--- a/synapse/federation/transaction_queue.py
+++ b/synapse/federation/transaction_queue.py
@@ -58,6 +58,7 @@ class TransactionQueue(object):
     """
 
     def __init__(self, hs):
+        self.hs = hs
         self.server_name = hs.hostname
 
         self.store = hs.get_datastore()
@@ -308,6 +309,9 @@ class TransactionQueue(object):
         Args:
             states (list(UserPresenceState))
         """
+        if not self.hs.config.use_presence:
+            # No-op if presence is disabled.
+            return
 
         # First we queue up the new presence by user ID, so multiple presence
         # updates in quick successtion are correctly handled
diff --git a/synapse/handlers/initial_sync.py b/synapse/handlers/initial_sync.py
index 1fb17fd9a5..e009395207 100644
--- a/synapse/handlers/initial_sync.py
+++ b/synapse/handlers/initial_sync.py
@@ -372,6 +372,10 @@ class InitialSyncHandler(BaseHandler):
 
         @defer.inlineCallbacks
         def get_presence():
+            # If presence is disabled, return an empty list
+            if not self.hs.config.use_presence:
+                defer.returnValue([])
+
             states = yield presence_handler.get_states(
                 [m.user_id for m in room_members],
                 as_event=True,
diff --git a/synapse/handlers/message.py b/synapse/handlers/message.py
index f21d740968..e484061cc0 100644
--- a/synapse/handlers/message.py
+++ b/synapse/handlers/message.py
@@ -276,10 +276,14 @@ class EventCreationHandler(object):
                 where *hashes* is a map from algorithm to hash.
 
                 If None, they will be requested from the database.
-
+        Raises:
+            ResourceLimitError if server is blocked to some resource being
+            exceeded
         Returns:
             Tuple of created event (FrozenEvent), Context
         """
+        yield self.auth.check_auth_blocking(requester.user.to_string())
+
         builder = self.event_builder_factory.new(event_dict)
 
         self.validator.validate_new(builder)
diff --git a/synapse/handlers/presence.py b/synapse/handlers/presence.py
index 3671d24f60..ba3856674d 100644
--- a/synapse/handlers/presence.py
+++ b/synapse/handlers/presence.py
@@ -395,6 +395,10 @@ class PresenceHandler(object):
         """We've seen the user do something that indicates they're interacting
         with the app.
         """
+        # If presence is disabled, no-op
+        if not self.hs.config.use_presence:
+            return
+
         user_id = user.to_string()
 
         bump_active_time_counter.inc()
@@ -424,6 +428,11 @@ class PresenceHandler(object):
                 Useful for streams that are not associated with an actual
                 client that is being used by a user.
         """
+        # Override if it should affect the user's presence, if presence is
+        # disabled.
+        if not self.hs.config.use_presence:
+            affect_presence = False
+
         if affect_presence:
             curr_sync = self.user_to_num_current_syncs.get(user_id, 0)
             self.user_to_num_current_syncs[user_id] = curr_sync + 1
@@ -469,13 +478,16 @@ class PresenceHandler(object):
         Returns:
             set(str): A set of user_id strings.
         """
-        syncing_user_ids = {
-            user_id for user_id, count in self.user_to_num_current_syncs.items()
-            if count
-        }
-        for user_ids in self.external_process_to_current_syncs.values():
-            syncing_user_ids.update(user_ids)
-        return syncing_user_ids
+        if self.hs.config.use_presence:
+            syncing_user_ids = {
+                user_id for user_id, count in self.user_to_num_current_syncs.items()
+                if count
+            }
+            for user_ids in self.external_process_to_current_syncs.values():
+                syncing_user_ids.update(user_ids)
+            return syncing_user_ids
+        else:
+            return set()
 
     @defer.inlineCallbacks
     def update_external_syncs_row(self, process_id, user_id, is_syncing, sync_time_msec):
diff --git a/synapse/handlers/room.py b/synapse/handlers/room.py
index 6a17c42238..c3f820b975 100644
--- a/synapse/handlers/room.py
+++ b/synapse/handlers/room.py
@@ -98,9 +98,13 @@ class RoomCreationHandler(BaseHandler):
         Raises:
             SynapseError if the room ID couldn't be stored, or something went
             horribly wrong.
+            ResourceLimitError if server is blocked to some resource being
+            exceeded
         """
         user_id = requester.user.to_string()
 
+        self.auth.check_auth_blocking(user_id)
+
         if not self.spam_checker.user_may_create_room(user_id):
             raise SynapseError(403, "You are not permitted to create rooms")
 
diff --git a/synapse/handlers/sync.py b/synapse/handlers/sync.py
index ac3edf0cc9..648debc8aa 100644
--- a/synapse/handlers/sync.py
+++ b/synapse/handlers/sync.py
@@ -185,6 +185,7 @@ class SyncResult(collections.namedtuple("SyncResult", [
 class SyncHandler(object):
 
     def __init__(self, hs):
+        self.hs_config = hs.config
         self.store = hs.get_datastore()
         self.notifier = hs.get_notifier()
         self.presence_handler = hs.get_presence_handler()
@@ -860,7 +861,7 @@ class SyncHandler(object):
             since_token is None and
             sync_config.filter_collection.blocks_all_presence()
         )
-        if not block_all_presence_data:
+        if self.hs_config.use_presence and not block_all_presence_data:
             yield self._generate_sync_entry_for_presence(
                 sync_result_builder, newly_joined_rooms, newly_joined_users
             )
diff --git a/synapse/http/server.py b/synapse/http/server.py
index 6dacb31037..2d5c23e673 100644
--- a/synapse/http/server.py
+++ b/synapse/http/server.py
@@ -25,8 +25,9 @@ from canonicaljson import encode_canonical_json, encode_pretty_printed_json, jso
 
 from twisted.internet import defer
 from twisted.python import failure
-from twisted.web import resource, server
+from twisted.web import resource
 from twisted.web.server import NOT_DONE_YET
+from twisted.web.static import NoRangeStaticProducer
 from twisted.web.util import redirectTo
 
 import synapse.events
@@ -37,10 +38,13 @@ from synapse.api.errors import (
     SynapseError,
     UnrecognizedRequestError,
 )
-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
+from synapse.util.logcontext import preserve_fn
+
+if PY3:
+    from io import BytesIO
+else:
+    from cStringIO import StringIO as BytesIO
 
 logger = logging.getLogger(__name__)
 
@@ -60,11 +64,10 @@ HTML_ERROR_TEMPLATE = """<!DOCTYPE html>
 def wrap_json_request_handler(h):
     """Wraps a request handler method with exception handling.
 
-    Also adds logging as per wrap_request_handler_with_logging.
+    Also does the wrapping with request.processing as per wrap_async_request_handler.
 
     The handler method must have a signature of "handle_foo(self, request)",
-    where "self" must have a "clock" attribute (and "request" must be a
-    SynapseRequest).
+    where "request" must be a SynapseRequest.
 
     The handler must return a deferred. If the deferred succeeds we assume that
     a response has been sent. If the deferred fails with a SynapseError we use
@@ -108,24 +111,23 @@ def wrap_json_request_handler(h):
                 pretty_print=_request_user_agent_is_curl(request),
             )
 
-    return wrap_request_handler_with_logging(wrapped_request_handler)
+    return wrap_async_request_handler(wrapped_request_handler)
 
 
 def wrap_html_request_handler(h):
     """Wraps a request handler method with exception handling.
 
-    Also adds logging as per wrap_request_handler_with_logging.
+    Also does the wrapping with request.processing as per wrap_async_request_handler.
 
     The handler method must have a signature of "handle_foo(self, request)",
-    where "self" must have a "clock" attribute (and "request" must be a
-    SynapseRequest).
+    where "request" must be a SynapseRequest.
     """
     def wrapped_request_handler(self, request):
         d = defer.maybeDeferred(h, self, request)
         d.addErrback(_return_html_error, request)
         return d
 
-    return wrap_request_handler_with_logging(wrapped_request_handler)
+    return wrap_async_request_handler(wrapped_request_handler)
 
 
 def _return_html_error(f, request):
@@ -170,46 +172,26 @@ def _return_html_error(f, request):
     finish_request(request)
 
 
-def wrap_request_handler_with_logging(h):
-    """Wraps a request handler to provide logging and metrics
+def wrap_async_request_handler(h):
+    """Wraps an async request handler so that it calls request.processing.
+
+    This helps ensure that work done by the request handler after the request is completed
+    is correctly recorded against the request metrics/logs.
 
     The handler method must have a signature of "handle_foo(self, request)",
-    where "self" must have a "clock" attribute (and "request" must be a
-    SynapseRequest).
+    where "request" must be a SynapseRequest.
 
-    As well as calling `request.processing` (which will log the response and
-    duration for this request), the wrapped request handler will insert the
-    request id into the logging context.
+    The handler may return a deferred, in which case the completion of the request isn't
+    logged until the deferred completes.
     """
     @defer.inlineCallbacks
-    def wrapped_request_handler(self, request):
-        """
-        Args:
-            self:
-            request (synapse.http.site.SynapseRequest):
-        """
+    def wrapped_async_request_handler(self, request):
+        with request.processing():
+            yield h(self, request)
 
-        request_id = request.get_request_id()
-        with LoggingContext(request_id) as request_context:
-            request_context.request = request_id
-            with Measure(self.clock, "wrapped_request_handler"):
-                # we start the request metrics timer here with an initial stab
-                # at the servlet name. For most requests that name will be
-                # JsonResource (or a subclass), and JsonResource._async_render
-                # will update it once it picks a servlet.
-                servlet_name = self.__class__.__name__
-                with request.processing(servlet_name):
-                    with PreserveLoggingContext(request_context):
-                        d = defer.maybeDeferred(h, self, request)
-
-                        # record the arrival of the request *after*
-                        # dispatching to the handler, so that the handler
-                        # can update the servlet name in the request
-                        # metrics
-                        requests_counter.labels(request.method,
-                                                request.request_metrics.name).inc()
-                        yield d
-    return wrapped_request_handler
+    # we need to preserve_fn here, because the synchronous render method won't yield for
+    # us (obviously)
+    return preserve_fn(wrapped_async_request_handler)
 
 
 class HttpServer(object):
@@ -272,7 +254,7 @@ class JsonResource(HttpServer, resource.Resource):
         """ This gets called by twisted every time someone sends us a request.
         """
         self._async_render(request)
-        return server.NOT_DONE_YET
+        return NOT_DONE_YET
 
     @wrap_json_request_handler
     @defer.inlineCallbacks
@@ -413,8 +395,7 @@ def respond_with_json(request, code, json_object, send_cors=False,
         return
 
     if pretty_print:
-        json_bytes = (encode_pretty_printed_json(json_object) + "\n"
-                      ).encode("utf-8")
+        json_bytes = encode_pretty_printed_json(json_object) + b"\n"
     else:
         if canonical_json or synapse.events.USE_FROZEN_DICTS:
             # canonicaljson already encodes to bytes
@@ -450,8 +431,12 @@ def respond_with_json_bytes(request, code, json_bytes, send_cors=False,
     if send_cors:
         set_cors_headers(request)
 
-    request.write(json_bytes)
-    finish_request(request)
+    # todo: we can almost certainly avoid this copy and encode the json straight into
+    # the bytesIO, but it would involve faffing around with string->bytes wrappers.
+    bytes_io = BytesIO(json_bytes)
+
+    producer = NoRangeStaticProducer(request, bytes_io)
+    producer.start()
     return NOT_DONE_YET
 
 
diff --git a/synapse/http/site.py b/synapse/http/site.py
index 5fd30a4c2c..f5a8f78406 100644
--- a/synapse/http/site.py
+++ b/synapse/http/site.py
@@ -11,7 +11,6 @@
 # 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 contextlib
 import logging
 import time
@@ -19,8 +18,8 @@ import time
 from twisted.web.server import Request, Site
 
 from synapse.http import redact_uri
-from synapse.http.request_metrics import RequestMetrics
-from synapse.util.logcontext import ContextResourceUsage, LoggingContext
+from synapse.http.request_metrics import RequestMetrics, requests_counter
+from synapse.util.logcontext import LoggingContext, PreserveLoggingContext
 
 logger = logging.getLogger(__name__)
 
@@ -34,25 +33,43 @@ class SynapseRequest(Request):
 
     It extends twisted's twisted.web.server.Request, and adds:
      * Unique request ID
+     * A log context associated with the request
      * Redaction of access_token query-params in __repr__
      * Logging at start and end
      * Metrics to record CPU, wallclock and DB time by endpoint.
 
-    It provides a method `processing` which should be called by the Resource
-    which is handling the request, and returns a context manager.
+    It also provides a method `processing`, which returns a context manager. If this
+    method is called, the request won't be logged until the context manager is closed;
+    this is useful for asynchronous request handlers which may go on processing the
+    request even after the client has disconnected.
 
+    Attributes:
+        logcontext(LoggingContext) : the log context for this request
     """
     def __init__(self, site, channel, *args, **kw):
         Request.__init__(self, channel, *args, **kw)
         self.site = site
-        self._channel = channel
+        self._channel = channel     # this is used by the tests
         self.authenticated_entity = None
         self.start_time = 0
 
+        # we can't yet create the logcontext, as we don't know the method.
+        self.logcontext = None
+
         global _next_request_seq
         self.request_seq = _next_request_seq
         _next_request_seq += 1
 
+        # whether an asynchronous request handler has called processing()
+        self._is_processing = False
+
+        # the time when the asynchronous request handler completed its processing
+        self._processing_finished_time = None
+
+        # what time we finished sending the response to the client (or the connection
+        # dropped)
+        self.finish_time = None
+
     def __repr__(self):
         # We overwrite this so that we don't log ``access_token``
         return '<%s at 0x%x method=%r uri=%r clientproto=%r site=%r>' % (
@@ -74,11 +91,116 @@ class SynapseRequest(Request):
         return self.requestHeaders.getRawHeaders(b"User-Agent", [None])[-1]
 
     def render(self, resrc):
+        # this is called once a Resource has been found to serve the request; in our
+        # case the Resource in question will normally be a JsonResource.
+
+        # create a LogContext for this request
+        request_id = self.get_request_id()
+        logcontext = self.logcontext = LoggingContext(request_id)
+        logcontext.request = request_id
+
         # override the Server header which is set by twisted
         self.setHeader("Server", self.site.server_version_string)
-        return Request.render(self, resrc)
+
+        with PreserveLoggingContext(self.logcontext):
+            # we start the request metrics timer here with an initial stab
+            # at the servlet name. For most requests that name will be
+            # JsonResource (or a subclass), and JsonResource._async_render
+            # will update it once it picks a servlet.
+            servlet_name = resrc.__class__.__name__
+            self._started_processing(servlet_name)
+
+            Request.render(self, resrc)
+
+            # record the arrival of the request *after*
+            # dispatching to the handler, so that the handler
+            # can update the servlet name in the request
+            # metrics
+            requests_counter.labels(self.method,
+                                    self.request_metrics.name).inc()
+
+    @contextlib.contextmanager
+    def processing(self):
+        """Record the fact that we are processing this request.
+
+        Returns a context manager; the correct way to use this is:
+
+        @defer.inlineCallbacks
+        def handle_request(request):
+            with request.processing("FooServlet"):
+                yield really_handle_the_request()
+
+        Once the context manager is closed, the completion of the request will be logged,
+        and the various metrics will be updated.
+        """
+        if self._is_processing:
+            raise RuntimeError("Request is already processing")
+        self._is_processing = True
+
+        try:
+            yield
+        except Exception:
+            # this should already have been caught, and sent back to the client as a 500.
+            logger.exception("Asynchronous messge handler raised an uncaught exception")
+        finally:
+            # the request handler has finished its work and either sent the whole response
+            # back, or handed over responsibility to a Producer.
+
+            self._processing_finished_time = time.time()
+            self._is_processing = False
+
+            # if we've already sent the response, log it now; otherwise, we wait for the
+            # response to be sent.
+            if self.finish_time is not None:
+                self._finished_processing()
+
+    def finish(self):
+        """Called when all response data has been written to this Request.
+
+        Overrides twisted.web.server.Request.finish to record the finish time and do
+        logging.
+        """
+        self.finish_time = time.time()
+        Request.finish(self)
+        if not self._is_processing:
+            with PreserveLoggingContext(self.logcontext):
+                self._finished_processing()
+
+    def connectionLost(self, reason):
+        """Called when the client connection is closed before the response is written.
+
+        Overrides twisted.web.server.Request.connectionLost to record the finish time and
+        do logging.
+        """
+        self.finish_time = time.time()
+        Request.connectionLost(self, reason)
+
+        # we only get here if the connection to the client drops before we send
+        # the response.
+        #
+        # It's useful to log it here so that we can get an idea of when
+        # the client disconnects.
+        with PreserveLoggingContext(self.logcontext):
+            logger.warn(
+                "Error processing request: %s %s", reason.type, reason.value,
+            )
+
+            if not self._is_processing:
+                self._finished_processing()
 
     def _started_processing(self, servlet_name):
+        """Record the fact that we are processing this request.
+
+        This will log the request's arrival. Once the request completes,
+        be sure to call finished_processing.
+
+        Args:
+            servlet_name (str): the name of the servlet which will be
+                processing this request. This is used in the metrics.
+
+                It is possible to update this afterwards by updating
+                self.request_metrics.name.
+        """
         self.start_time = time.time()
         self.request_metrics = RequestMetrics()
         self.request_metrics.start(
@@ -94,13 +216,21 @@ class SynapseRequest(Request):
         )
 
     def _finished_processing(self):
-        try:
-            context = LoggingContext.current_context()
-            usage = context.get_resource_usage()
-        except Exception:
-            usage = ContextResourceUsage()
+        """Log the completion of this request and update the metrics
+        """
+
+        usage = self.logcontext.get_resource_usage()
+
+        if self._processing_finished_time is None:
+            # we completed the request without anything calling processing()
+            self._processing_finished_time = time.time()
 
-        end_time = time.time()
+        # the time between receiving the request and the request handler finishing
+        processing_time = self._processing_finished_time - self.start_time
+
+        # the time between the request handler finishing and the response being sent
+        # to the client (nb may be negative)
+        response_send_time = self.finish_time - self._processing_finished_time
 
         # need to decode as it could be raw utf-8 bytes
         # from a IDN servname in an auth header
@@ -116,22 +246,31 @@ class SynapseRequest(Request):
         user_agent = self.get_user_agent()
         if user_agent is not None:
             user_agent = user_agent.decode("utf-8", "replace")
+        else:
+            user_agent = "-"
+
+        code = str(self.code)
+        if not self.finished:
+            # we didn't send the full response before we gave up (presumably because
+            # the connection dropped)
+            code += "!"
 
         self.site.access_logger.info(
             "%s - %s - {%s}"
-            " Processed request: %.3fsec (%.3fsec, %.3fsec) (%.3fsec/%.3fsec/%d)"
+            " Processed request: %.3fsec/%.3fsec (%.3fsec, %.3fsec) (%.3fsec/%.3fsec/%d)"
             " %sB %s \"%s %s %s\" \"%s\" [%d dbevts]",
             self.getClientIP(),
             self.site.site_tag,
             authenticated_entity,
-            end_time - self.start_time,
+            processing_time,
+            response_send_time,
             usage.ru_utime,
             usage.ru_stime,
             usage.db_sched_duration_sec,
             usage.db_txn_duration_sec,
             int(usage.db_txn_count),
             self.sentLength,
-            self.code,
+            code,
             self.method,
             self.get_redacted_uri(),
             self.clientproto,
@@ -140,38 +279,10 @@ class SynapseRequest(Request):
         )
 
         try:
-            self.request_metrics.stop(end_time, self)
+            self.request_metrics.stop(self.finish_time, self)
         except Exception as e:
             logger.warn("Failed to stop metrics: %r", e)
 
-    @contextlib.contextmanager
-    def processing(self, servlet_name):
-        """Record the fact that we are processing this request.
-
-        Returns a context manager; the correct way to use this is:
-
-        @defer.inlineCallbacks
-        def handle_request(request):
-            with request.processing("FooServlet"):
-                yield really_handle_the_request()
-
-        This will log the request's arrival. Once the context manager is
-        closed, the completion of the request will be logged, and the various
-        metrics will be updated.
-
-        Args:
-            servlet_name (str): the name of the servlet which will be
-                processing this request. This is used in the metrics.
-
-                It is possible to update this afterwards by updating
-                self.request_metrics.servlet_name.
-        """
-        # TODO: we should probably just move this into render() and finish(),
-        # to save having to call a separate method.
-        self._started_processing(servlet_name)
-        yield
-        self._finished_processing()
-
 
 class XForwardedForRequest(SynapseRequest):
     def __init__(self, *args, **kw):
diff --git a/synapse/rest/client/v1/presence.py b/synapse/rest/client/v1/presence.py
index a14f0c807e..b5a6d6aebf 100644
--- a/synapse/rest/client/v1/presence.py
+++ b/synapse/rest/client/v1/presence.py
@@ -84,7 +84,8 @@ class PresenceStatusRestServlet(ClientV1RestServlet):
         except Exception:
             raise SynapseError(400, "Unable to parse state")
 
-        yield self.presence_handler.set_state(user, state)
+        if self.hs.config.use_presence:
+            yield self.presence_handler.set_state(user, state)
 
         defer.returnValue((200, {}))
 
diff --git a/synapse/rest/client/v1_only/register.py b/synapse/rest/client/v1_only/register.py
index 3439c3c6d4..5e99cffbcb 100644
--- a/synapse/rest/client/v1_only/register.py
+++ b/synapse/rest/client/v1_only/register.py
@@ -129,12 +129,9 @@ class RegisterRestServlet(ClientV1RestServlet):
             login_type = register_json["type"]
 
             is_application_server = login_type == LoginType.APPLICATION_SERVICE
-            is_using_shared_secret = login_type == LoginType.SHARED_SECRET
-
             can_register = (
                 self.enable_registration
                 or is_application_server
-                or is_using_shared_secret
             )
             if not can_register:
                 raise SynapseError(403, "Registration has been disabled")
@@ -144,7 +141,6 @@ class RegisterRestServlet(ClientV1RestServlet):
                 LoginType.PASSWORD: self._do_password,
                 LoginType.EMAIL_IDENTITY: self._do_email_identity,
                 LoginType.APPLICATION_SERVICE: self._do_app_service,
-                LoginType.SHARED_SECRET: self._do_shared_secret,
             }
 
             session_info = self._get_session_info(request, session)
@@ -325,56 +321,6 @@ class RegisterRestServlet(ClientV1RestServlet):
             "home_server": self.hs.hostname,
         })
 
-    @defer.inlineCallbacks
-    def _do_shared_secret(self, request, register_json, session):
-        assert_params_in_dict(register_json, ["mac", "user", "password"])
-
-        if not self.hs.config.registration_shared_secret:
-            raise SynapseError(400, "Shared secret registration is not enabled")
-
-        user = register_json["user"].encode("utf-8")
-        password = register_json["password"].encode("utf-8")
-        admin = register_json.get("admin", None)
-
-        # Its important to check as we use null bytes as HMAC field separators
-        if b"\x00" in user:
-            raise SynapseError(400, "Invalid user")
-        if b"\x00" in password:
-            raise SynapseError(400, "Invalid password")
-
-        # str() because otherwise hmac complains that 'unicode' does not
-        # have the buffer interface
-        got_mac = str(register_json["mac"])
-
-        want_mac = hmac.new(
-            key=self.hs.config.registration_shared_secret.encode(),
-            digestmod=sha1,
-        )
-        want_mac.update(user)
-        want_mac.update(b"\x00")
-        want_mac.update(password)
-        want_mac.update(b"\x00")
-        want_mac.update(b"admin" if admin else b"notadmin")
-        want_mac = want_mac.hexdigest()
-
-        if compare_digest(want_mac, got_mac):
-            handler = self.handlers.registration_handler
-            user_id, token = yield handler.register(
-                localpart=user.lower(),
-                password=password,
-                admin=bool(admin),
-            )
-            self._remove_session(session)
-            defer.returnValue({
-                "user_id": user_id,
-                "access_token": token,
-                "home_server": self.hs.hostname,
-            })
-        else:
-            raise SynapseError(
-                403, "HMAC incorrect",
-            )
-
 
 class CreateUserRestServlet(ClientV1RestServlet):
     """Handles user creation via a server-to-server interface
diff --git a/synapse/storage/monthly_active_users.py b/synapse/storage/monthly_active_users.py
index 7e417f811e..06f9a75a97 100644
--- a/synapse/storage/monthly_active_users.py
+++ b/synapse/storage/monthly_active_users.py
@@ -96,7 +96,10 @@ class MonthlyActiveUsersStore(SQLBaseStore):
             # While Postgres does not require 'LIMIT', but also does not support
             # negative LIMIT values. So there is no way to write it that both can
             # support
-            query_args = [self.hs.config.max_mau_value]
+            safe_guard = self.hs.config.max_mau_value - len(self.reserved_users)
+            # Must be greater than zero for postgres
+            safe_guard = safe_guard if safe_guard > 0 else 0
+            query_args = [safe_guard]
 
             base_sql = """
                 DELETE FROM monthly_active_users