From d1ae1015ecb7dcb36d7cb39d5d41733e1ced2a52 Mon Sep 17 00:00:00 2001
From: Brendan Abolivier <babolivier@matrix.org>
Date: Thu, 21 May 2020 17:41:12 +0200
Subject: [PATCH 01/16] Retry to sync out of sync device lists (#7453)

When a call to `user_device_resync` fails, we don't currently mark the remote user's device list as out of sync, nor do we retry to sync it.

https://github.com/matrix-org/synapse/pull/6776 introduced some code infrastructure to mark device lists as stale/out of sync.

This commit uses that code infrastructure to mark device lists as out of sync if processing an incoming device list update makes the device handler realise that the device list is out of sync, but we can't resync right now.

It also adds a looping call to retry all failed resync every 30s. This shouldn't cause too much spam in the logs as this commit also removes the "Failed to handle device list update for..." warning logs when catching `NotRetryingDestination`.

Fixes #7418
---
 changelog.d/7453.bugfix                     |  1 +
 synapse/handlers/device.py                  | 80 +++++++++++++++++++--
 synapse/storage/data_stores/main/devices.py | 34 +++++----
 tests/test_federation.py                    | 63 +++++++++++++++-
 4 files changed, 158 insertions(+), 20 deletions(-)
 create mode 100644 changelog.d/7453.bugfix

diff --git a/changelog.d/7453.bugfix b/changelog.d/7453.bugfix
new file mode 100644
index 0000000000..629a3d61e2
--- /dev/null
+++ b/changelog.d/7453.bugfix
@@ -0,0 +1 @@
+Fix a bug that would cause Synapse not to resync out-of-sync device lists.
diff --git a/synapse/handlers/device.py b/synapse/handlers/device.py
index 9bd941b5a0..29a19b4572 100644
--- a/synapse/handlers/device.py
+++ b/synapse/handlers/device.py
@@ -29,6 +29,7 @@ from synapse.api.errors import (
     SynapseError,
 )
 from synapse.logging.opentracing import log_kv, set_tag, trace
+from synapse.metrics.background_process_metrics import run_as_background_process
 from synapse.types import RoomStreamToken, get_domain_from_id
 from synapse.util import stringutils
 from synapse.util.async_helpers import Linearizer
@@ -535,6 +536,15 @@ class DeviceListUpdater(object):
             iterable=True,
         )
 
+        # Attempt to resync out of sync device lists every 30s.
+        self._resync_retry_in_progress = False
+        self.clock.looping_call(
+            run_as_background_process,
+            30 * 1000,
+            func=self._maybe_retry_device_resync,
+            desc="_maybe_retry_device_resync",
+        )
+
     @trace
     @defer.inlineCallbacks
     def incoming_device_list_update(self, origin, edu_content):
@@ -679,11 +689,50 @@ class DeviceListUpdater(object):
         return False
 
     @defer.inlineCallbacks
-    def user_device_resync(self, user_id):
+    def _maybe_retry_device_resync(self):
+        """Retry to resync device lists that are out of sync, except if another retry is
+        in progress.
+        """
+        if self._resync_retry_in_progress:
+            return
+
+        try:
+            # Prevent another call of this function to retry resyncing device lists so
+            # we don't send too many requests.
+            self._resync_retry_in_progress = True
+            # Get all of the users that need resyncing.
+            need_resync = yield self.store.get_user_ids_requiring_device_list_resync()
+            # Iterate over the set of user IDs.
+            for user_id in need_resync:
+                # Try to resync the current user's devices list. Exception handling
+                # isn't necessary here, since user_device_resync catches all instances
+                # of "Exception" that might be raised from the federation request. This
+                # means that if an exception is raised by this function, it must be
+                # because of a database issue, which means _maybe_retry_device_resync
+                # probably won't be able to go much further anyway.
+                result = yield self.user_device_resync(
+                    user_id=user_id, mark_failed_as_stale=False,
+                )
+                # user_device_resync only returns a result if it managed to successfully
+                # resync and update the database. Updating the table of users requiring
+                # resync isn't necessary here as user_device_resync already does it
+                # (through self.store.update_remote_device_list_cache).
+                if result:
+                    logger.debug(
+                        "Successfully resynced the device list for %s" % user_id,
+                    )
+        finally:
+            # Allow future calls to retry resyncinc out of sync device lists.
+            self._resync_retry_in_progress = False
+
+    @defer.inlineCallbacks
+    def user_device_resync(self, user_id, mark_failed_as_stale=True):
         """Fetches all devices for a user and updates the device cache with them.
 
         Args:
             user_id (str): The user's id whose device_list will be updated.
+            mark_failed_as_stale (bool): Whether to mark the user's device list as stale
+                if the attempt to resync failed.
         Returns:
             Deferred[dict]: a dict with device info as under the "devices" in the result of this
             request:
@@ -694,10 +743,23 @@ class DeviceListUpdater(object):
         origin = get_domain_from_id(user_id)
         try:
             result = yield self.federation.query_user_devices(origin, user_id)
-        except (NotRetryingDestination, RequestSendFailed, HttpResponseException):
-            # TODO: Remember that we are now out of sync and try again
-            # later
-            logger.warning("Failed to handle device list update for %s", user_id)
+        except NotRetryingDestination:
+            if mark_failed_as_stale:
+                # Mark the remote user's device list as stale so we know we need to retry
+                # it later.
+                yield self.store.mark_remote_user_device_cache_as_stale(user_id)
+
+            return
+        except (RequestSendFailed, HttpResponseException) as e:
+            logger.warning(
+                "Failed to handle device list update for %s: %s", user_id, e,
+            )
+
+            if mark_failed_as_stale:
+                # Mark the remote user's device list as stale so we know we need to retry
+                # it later.
+                yield self.store.mark_remote_user_device_cache_as_stale(user_id)
+
             # We abort on exceptions rather than accepting the update
             # as otherwise synapse will 'forget' that its device list
             # is out of date. If we bail then we will retry the resync
@@ -711,13 +773,17 @@ class DeviceListUpdater(object):
             logger.info(e)
             return
         except Exception as e:
-            # TODO: Remember that we are now out of sync and try again
-            # later
             set_tag("error", True)
             log_kv(
                 {"message": "Exception raised by federation request", "exception": e}
             )
             logger.exception("Failed to handle device list update for %s", user_id)
+
+            if mark_failed_as_stale:
+                # Mark the remote user's device list as stale so we know we need to retry
+                # it later.
+                yield self.store.mark_remote_user_device_cache_as_stale(user_id)
+
             return
         log_kv({"result": result})
         stream_id = result["stream_id"]
diff --git a/synapse/storage/data_stores/main/devices.py b/synapse/storage/data_stores/main/devices.py
index fe6d6ecfe0..0e8378714a 100644
--- a/synapse/storage/data_stores/main/devices.py
+++ b/synapse/storage/data_stores/main/devices.py
@@ -15,7 +15,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 import logging
-from typing import List, Tuple
+from typing import List, Optional, Set, Tuple
 
 from six import iteritems
 
@@ -649,21 +649,31 @@ class DeviceWorkerStore(SQLBaseStore):
         return results
 
     @defer.inlineCallbacks
-    def get_user_ids_requiring_device_list_resync(self, user_ids: Collection[str]):
+    def get_user_ids_requiring_device_list_resync(
+        self, user_ids: Optional[Collection[str]] = None,
+    ) -> Set[str]:
         """Given a list of remote users return the list of users that we
-        should resync the device lists for.
+        should resync the device lists for. If None is given instead of a list,
+        return every user that we should resync the device lists for.
 
         Returns:
-            Deferred[Set[str]]
+            The IDs of users whose device lists need resync.
         """
-
-        rows = yield self.db.simple_select_many_batch(
-            table="device_lists_remote_resync",
-            column="user_id",
-            iterable=user_ids,
-            retcols=("user_id",),
-            desc="get_user_ids_requiring_device_list_resync",
-        )
+        if user_ids:
+            rows = yield self.db.simple_select_many_batch(
+                table="device_lists_remote_resync",
+                column="user_id",
+                iterable=user_ids,
+                retcols=("user_id",),
+                desc="get_user_ids_requiring_device_list_resync_with_iterable",
+            )
+        else:
+            rows = yield self.db.simple_select_list(
+                table="device_lists_remote_resync",
+                keyvalues=None,
+                retcols=("user_id",),
+                desc="get_user_ids_requiring_device_list_resync",
+            )
 
         return {row["user_id"] for row in rows}
 
diff --git a/tests/test_federation.py b/tests/test_federation.py
index f297de95f1..13ff14863e 100644
--- a/tests/test_federation.py
+++ b/tests/test_federation.py
@@ -6,12 +6,13 @@ from synapse.events import make_event_from_dict
 from synapse.logging.context import LoggingContext
 from synapse.types import Requester, UserID
 from synapse.util import Clock
+from synapse.util.retryutils import NotRetryingDestination
 
 from tests import unittest
 from tests.server import ThreadedMemoryReactorClock, setup_test_homeserver
 
 
-class MessageAcceptTests(unittest.TestCase):
+class MessageAcceptTests(unittest.HomeserverTestCase):
     def setUp(self):
 
         self.http_client = Mock()
@@ -145,3 +146,63 @@ class MessageAcceptTests(unittest.TestCase):
         # Make sure the invalid event isn't there
         extrem = maybeDeferred(self.store.get_latest_event_ids_in_room, self.room_id)
         self.assertEqual(self.successResultOf(extrem)[0], "$join:test.serv")
+
+    def test_retry_device_list_resync(self):
+        """Tests that device lists are marked as stale if they couldn't be synced, and
+        that stale device lists are retried periodically.
+        """
+        remote_user_id = "@john:test_remote"
+        remote_origin = "test_remote"
+
+        # Track the number of attempts to resync the user's device list.
+        self.resync_attempts = 0
+
+        # When this function is called, increment the number of resync attempts (only if
+        # we're querying devices for the right user ID), then raise a
+        # NotRetryingDestination error to fail the resync gracefully.
+        def query_user_devices(destination, user_id):
+            if user_id == remote_user_id:
+                self.resync_attempts += 1
+
+            raise NotRetryingDestination(0, 0, destination)
+
+        # Register the mock on the federation client.
+        federation_client = self.homeserver.get_federation_client()
+        federation_client.query_user_devices = Mock(side_effect=query_user_devices)
+
+        # Register a mock on the store so that the incoming update doesn't fail because
+        # we don't share a room with the user.
+        store = self.homeserver.get_datastore()
+        store.get_rooms_for_user = Mock(return_value=["!someroom:test"])
+
+        # Manually inject a fake device list update. We need this update to include at
+        # least one prev_id so that the user's device list will need to be retried.
+        device_list_updater = self.homeserver.get_device_handler().device_list_updater
+        self.get_success(
+            device_list_updater.incoming_device_list_update(
+                origin=remote_origin,
+                edu_content={
+                    "deleted": False,
+                    "device_display_name": "Mobile",
+                    "device_id": "QBUAZIFURK",
+                    "prev_id": [5],
+                    "stream_id": 6,
+                    "user_id": remote_user_id,
+                },
+            )
+        )
+
+        # Check that there was one resync attempt.
+        self.assertEqual(self.resync_attempts, 1)
+
+        # Check that the resync attempt failed and caused the user's device list to be
+        # marked as stale.
+        need_resync = self.get_success(
+            store.get_user_ids_requiring_device_list_resync()
+        )
+        self.assertIn(remote_user_id, need_resync)
+
+        # Check that waiting for 30 seconds caused Synapse to retry resyncing the device
+        # list.
+        self.reactor.advance(30)
+        self.assertEqual(self.resync_attempts, 2)

From 66a564c859c035c273c8feb25c624473055f1d78 Mon Sep 17 00:00:00 2001
From: Richard van der Hoff <1389908+richvdh@users.noreply.github.com>
Date: Fri, 22 May 2020 10:11:50 +0100
Subject: [PATCH 02/16] Fix some DETECTED VIOLATIONS in the config file (#7550)

consistency ftw
---
 changelog.d/7550.misc          |  1 +
 docs/sample_config.yaml        | 61 +++++++++++++++++++---------------
 synapse/config/captcha.py      | 17 ++++++----
 synapse/config/emailconfig.py  |  4 +--
 synapse/config/key.py          |  4 +--
 synapse/config/metrics.py      |  3 +-
 synapse/config/registration.py |  4 +--
 synapse/config/server.py       | 33 ++++++++++--------
 8 files changed, 72 insertions(+), 55 deletions(-)
 create mode 100644 changelog.d/7550.misc

diff --git a/changelog.d/7550.misc b/changelog.d/7550.misc
new file mode 100644
index 0000000000..79e119e977
--- /dev/null
+++ b/changelog.d/7550.misc
@@ -0,0 +1 @@
+Fix some indentation inconsistencies in the sample config.
diff --git a/docs/sample_config.yaml b/docs/sample_config.yaml
index 8a8415b9a2..0e1be153c7 100644
--- a/docs/sample_config.yaml
+++ b/docs/sample_config.yaml
@@ -322,22 +322,27 @@ listeners:
 # Used by phonehome stats to group together related servers.
 #server_context: context
 
-# Resource-constrained homeserver Settings
+# Resource-constrained homeserver settings
 #
-# If limit_remote_rooms.enabled is True, the room complexity will be
-# checked before a user joins a new remote room. If it is above
-# limit_remote_rooms.complexity, it will disallow joining or
-# instantly leave.
+# When this is enabled, the room "complexity" will be checked before a user
+# joins a new remote room. If it is above the complexity limit, the server will
+# disallow joining, or will instantly leave.
 #
-# limit_remote_rooms.complexity_error can be set to customise the text
-# displayed to the user when a room above the complexity threshold has
-# its join cancelled.
+# Room complexity is an arbitrary measure based on factors such as the number of
+# users in the room.
 #
-# Uncomment the below lines to enable:
-#limit_remote_rooms:
-#  enabled: true
-#  complexity: 1.0
-#  complexity_error: "This room is too complex."
+limit_remote_rooms:
+  # Uncomment to enable room complexity checking.
+  #
+  #enabled: true
+
+  # the limit above which rooms cannot be joined. The default is 1.0.
+  #
+  #complexity: 0.5
+
+  # override the error which is returned when the room is too complex.
+  #
+  #complexity_error: "This room is too complex."
 
 # Whether to require a user to be in the room to add an alias to it.
 # Defaults to 'true'.
@@ -942,25 +947,28 @@ url_preview_accept_language:
 
 
 ## Captcha ##
-# See docs/CAPTCHA_SETUP for full details of configuring this.
+# See docs/CAPTCHA_SETUP.md for full details of configuring this.
 
-# This homeserver's ReCAPTCHA public key.
+# This homeserver's ReCAPTCHA public key. Must be specified if
+# enable_registration_captcha is enabled.
 #
 #recaptcha_public_key: "YOUR_PUBLIC_KEY"
 
-# This homeserver's ReCAPTCHA private key.
+# This homeserver's ReCAPTCHA private key. Must be specified if
+# enable_registration_captcha is enabled.
 #
 #recaptcha_private_key: "YOUR_PRIVATE_KEY"
 
-# Enables ReCaptcha checks when registering, preventing signup
+# Uncomment to enable ReCaptcha checks when registering, preventing signup
 # unless a captcha is answered. Requires a valid ReCaptcha
-# public/private key.
+# public/private key. Defaults to 'false'.
 #
-#enable_registration_captcha: false
+#enable_registration_captcha: true
 
 # The API endpoint to use for verifying m.login.recaptcha responses.
+# Defaults to "https://www.recaptcha.net/recaptcha/api/siteverify".
 #
-#recaptcha_siteverify_api: "https://www.recaptcha.net/recaptcha/api/siteverify"
+#recaptcha_siteverify_api: "https://my.recaptcha.site"
 
 
 ## TURN ##
@@ -1104,7 +1112,7 @@ account_validity:
 # If set, allows registration of standard or admin accounts by anyone who
 # has the shared secret, even if registration is otherwise disabled.
 #
-# registration_shared_secret: <PRIVATE STRING>
+#registration_shared_secret: <PRIVATE STRING>
 
 # Set the number of bcrypt rounds used to generate password hash.
 # Larger numbers increase the work factor needed to generate the hash.
@@ -1237,7 +1245,8 @@ metrics_flags:
     #known_servers: true
 
 # Whether or not to report anonymized homeserver usage statistics.
-# report_stats: true|false
+#
+#report_stats: true|false
 
 # The endpoint to report the anonymized homeserver usage statistics to.
 # Defaults to https://matrix.org/report-usage-stats/push
@@ -1273,13 +1282,13 @@ metrics_flags:
 # the registration_shared_secret is used, if one is given; otherwise,
 # a secret key is derived from the signing key.
 #
-# macaroon_secret_key: <PRIVATE STRING>
+#macaroon_secret_key: <PRIVATE STRING>
 
 # a secret which is used to calculate HMACs for form values, to stop
 # falsification of values. Must be specified for the User Consent
 # forms to work.
 #
-# form_secret: <PRIVATE STRING>
+#form_secret: <PRIVATE STRING>
 
 ## Signing Keys ##
 
@@ -1764,8 +1773,8 @@ email:
   # Username/password for authentication to the SMTP server. By default, no
   # authentication is attempted.
   #
-  # smtp_user: "exampleusername"
-  # smtp_pass: "examplepassword"
+  #smtp_user: "exampleusername"
+  #smtp_pass: "examplepassword"
 
   # Uncomment the following to require TLS transport security for SMTP.
   # By default, Synapse will connect over plain text, and will then switch to
diff --git a/synapse/config/captcha.py b/synapse/config/captcha.py
index 56c87fa296..82f04d7966 100644
--- a/synapse/config/captcha.py
+++ b/synapse/config/captcha.py
@@ -32,23 +32,26 @@ class CaptchaConfig(Config):
     def generate_config_section(self, **kwargs):
         return """\
         ## Captcha ##
-        # See docs/CAPTCHA_SETUP for full details of configuring this.
+        # See docs/CAPTCHA_SETUP.md for full details of configuring this.
 
-        # This homeserver's ReCAPTCHA public key.
+        # This homeserver's ReCAPTCHA public key. Must be specified if
+        # enable_registration_captcha is enabled.
         #
         #recaptcha_public_key: "YOUR_PUBLIC_KEY"
 
-        # This homeserver's ReCAPTCHA private key.
+        # This homeserver's ReCAPTCHA private key. Must be specified if
+        # enable_registration_captcha is enabled.
         #
         #recaptcha_private_key: "YOUR_PRIVATE_KEY"
 
-        # Enables ReCaptcha checks when registering, preventing signup
+        # Uncomment to enable ReCaptcha checks when registering, preventing signup
         # unless a captcha is answered. Requires a valid ReCaptcha
-        # public/private key.
+        # public/private key. Defaults to 'false'.
         #
-        #enable_registration_captcha: false
+        #enable_registration_captcha: true
 
         # The API endpoint to use for verifying m.login.recaptcha responses.
+        # Defaults to "https://www.recaptcha.net/recaptcha/api/siteverify".
         #
-        #recaptcha_siteverify_api: "https://www.recaptcha.net/recaptcha/api/siteverify"
+        #recaptcha_siteverify_api: "https://my.recaptcha.site"
         """
diff --git a/synapse/config/emailconfig.py b/synapse/config/emailconfig.py
index 76b8957ea5..ca61214454 100644
--- a/synapse/config/emailconfig.py
+++ b/synapse/config/emailconfig.py
@@ -311,8 +311,8 @@ class EmailConfig(Config):
           # Username/password for authentication to the SMTP server. By default, no
           # authentication is attempted.
           #
-          # smtp_user: "exampleusername"
-          # smtp_pass: "examplepassword"
+          #smtp_user: "exampleusername"
+          #smtp_pass: "examplepassword"
 
           # Uncomment the following to require TLS transport security for SMTP.
           # By default, Synapse will connect over plain text, and will then switch to
diff --git a/synapse/config/key.py b/synapse/config/key.py
index 066e7838c3..b529ea5da0 100644
--- a/synapse/config/key.py
+++ b/synapse/config/key.py
@@ -175,8 +175,8 @@ class KeyConfig(Config):
             )
             form_secret = 'form_secret: "%s"' % random_string_with_symbols(50)
         else:
-            macaroon_secret_key = "# macaroon_secret_key: <PRIVATE STRING>"
-            form_secret = "# form_secret: <PRIVATE STRING>"
+            macaroon_secret_key = "#macaroon_secret_key: <PRIVATE STRING>"
+            form_secret = "#form_secret: <PRIVATE STRING>"
 
         return (
             """\
diff --git a/synapse/config/metrics.py b/synapse/config/metrics.py
index 6f517a71d0..6aad0d37c0 100644
--- a/synapse/config/metrics.py
+++ b/synapse/config/metrics.py
@@ -93,10 +93,11 @@ class MetricsConfig(Config):
             #known_servers: true
 
         # Whether or not to report anonymized homeserver usage statistics.
+        #
         """
 
         if report_stats is None:
-            res += "# report_stats: true|false\n"
+            res += "#report_stats: true|false\n"
         else:
             res += "report_stats: %s\n" % ("true" if report_stats else "false")
 
diff --git a/synapse/config/registration.py b/synapse/config/registration.py
index e7ea3a01cb..a9aa8c3737 100644
--- a/synapse/config/registration.py
+++ b/synapse/config/registration.py
@@ -148,9 +148,7 @@ class RegistrationConfig(Config):
                 random_string_with_symbols(50),
             )
         else:
-            registration_shared_secret = (
-                "# registration_shared_secret: <PRIVATE STRING>"
-            )
+            registration_shared_secret = "#registration_shared_secret: <PRIVATE STRING>"
 
         return (
             """\
diff --git a/synapse/config/server.py b/synapse/config/server.py
index ed28da3deb..f57eefc99c 100644
--- a/synapse/config/server.py
+++ b/synapse/config/server.py
@@ -434,7 +434,7 @@ class ServerConfig(Config):
             )
 
         self.limit_remote_rooms = LimitRemoteRoomsConfig(
-            **config.get("limit_remote_rooms", {})
+            **(config.get("limit_remote_rooms") or {})
         )
 
         bind_port = config.get("bind_port")
@@ -895,22 +895,27 @@ class ServerConfig(Config):
         # Used by phonehome stats to group together related servers.
         #server_context: context
 
-        # Resource-constrained homeserver Settings
+        # Resource-constrained homeserver settings
         #
-        # If limit_remote_rooms.enabled is True, the room complexity will be
-        # checked before a user joins a new remote room. If it is above
-        # limit_remote_rooms.complexity, it will disallow joining or
-        # instantly leave.
+        # When this is enabled, the room "complexity" will be checked before a user
+        # joins a new remote room. If it is above the complexity limit, the server will
+        # disallow joining, or will instantly leave.
         #
-        # limit_remote_rooms.complexity_error can be set to customise the text
-        # displayed to the user when a room above the complexity threshold has
-        # its join cancelled.
+        # Room complexity is an arbitrary measure based on factors such as the number of
+        # users in the room.
         #
-        # Uncomment the below lines to enable:
-        #limit_remote_rooms:
-        #  enabled: true
-        #  complexity: 1.0
-        #  complexity_error: "This room is too complex."
+        limit_remote_rooms:
+          # Uncomment to enable room complexity checking.
+          #
+          #enabled: true
+
+          # the limit above which rooms cannot be joined. The default is 1.0.
+          #
+          #complexity: 0.5
+
+          # override the error which is returned when the room is too complex.
+          #
+          #complexity_error: "This room is too complex."
 
         # Whether to require a user to be in the room to add an alias to it.
         # Defaults to 'true'.

From d84bdfe599aa47617d59c8e6eea5071463382c1c Mon Sep 17 00:00:00 2001
From: Richard van der Hoff <1389908+richvdh@users.noreply.github.com>
Date: Fri, 22 May 2020 10:12:17 +0100
Subject: [PATCH 03/16] mypy for synapse.http.site (#7553)

---
 changelog.d/7553.misc | 1 +
 synapse/http/site.py  | 9 ++++++---
 tox.ini               | 1 +
 3 files changed, 8 insertions(+), 3 deletions(-)
 create mode 100644 changelog.d/7553.misc

diff --git a/changelog.d/7553.misc b/changelog.d/7553.misc
new file mode 100644
index 0000000000..90b9e8693a
--- /dev/null
+++ b/changelog.d/7553.misc
@@ -0,0 +1 @@
+Include `synapse.http.site` in type checking.
diff --git a/synapse/http/site.py b/synapse/http/site.py
index 514f2f1402..167293c46d 100644
--- a/synapse/http/site.py
+++ b/synapse/http/site.py
@@ -14,6 +14,7 @@
 import contextlib
 import logging
 import time
+from typing import Optional
 
 from twisted.python.failure import Failure
 from twisted.web.server import Request, Site
@@ -45,7 +46,7 @@ class SynapseRequest(Request):
     request even after the client has disconnected.
 
     Attributes:
-        logcontext(LoggingContext) : the log context for this request
+        logcontext: the log context for this request
     """
 
     def __init__(self, channel, *args, **kw):
@@ -53,10 +54,10 @@ class SynapseRequest(Request):
         self.site = channel.site
         self._channel = channel  # this is used by the tests
         self.authenticated_entity = None
-        self.start_time = 0
+        self.start_time = 0.0
 
         # we can't yet create the logcontext, as we don't know the method.
-        self.logcontext = None
+        self.logcontext = None  # type: Optional[LoggingContext]
 
         global _next_request_seq
         self.request_seq = _next_request_seq
@@ -182,6 +183,7 @@ class SynapseRequest(Request):
         self.finish_time = time.time()
         Request.finish(self)
         if not self._is_processing:
+            assert self.logcontext is not None
             with PreserveLoggingContext(self.logcontext):
                 self._finished_processing()
 
@@ -249,6 +251,7 @@ class SynapseRequest(Request):
     def _finished_processing(self):
         """Log the completion of this request and update the metrics
         """
+        assert self.logcontext is not None
         usage = self.logcontext.get_resource_usage()
 
         if self._processing_finished_time is None:
diff --git a/tox.ini b/tox.ini
index 3bb4d45e2a..9fefcb72b5 100644
--- a/tox.ini
+++ b/tox.ini
@@ -193,6 +193,7 @@ commands = mypy \
             synapse/handlers/saml_handler.py \
             synapse/handlers/sync.py \
             synapse/handlers/ui_auth \
+            synapse/http/site.py \
             synapse/logging/ \
             synapse/metrics \
             synapse/module_api \

From a0f99f81b35b0e2ff600d7c72a0d71f15bf94f4c Mon Sep 17 00:00:00 2001
From: Richard van der Hoff <1389908+richvdh@users.noreply.github.com>
Date: Fri, 22 May 2020 10:17:36 +0100
Subject: [PATCH 04/16] Fix stacktrace mangling in `patch_inline_callbacks`
 (#7554)

`Failure()` is more cunning than `Failure(e)`.
---
 changelog.d/7554.misc                  | 1 +
 synapse/util/patch_inline_callbacks.py | 9 +++++++--
 2 files changed, 8 insertions(+), 2 deletions(-)
 create mode 100644 changelog.d/7554.misc

diff --git a/changelog.d/7554.misc b/changelog.d/7554.misc
new file mode 100644
index 0000000000..7c35c46aa6
--- /dev/null
+++ b/changelog.d/7554.misc
@@ -0,0 +1 @@
+Fix some test code to not mangle stacktraces, to make it easier to debug errors.
diff --git a/synapse/util/patch_inline_callbacks.py b/synapse/util/patch_inline_callbacks.py
index fdff195771..2605f3c65b 100644
--- a/synapse/util/patch_inline_callbacks.py
+++ b/synapse/util/patch_inline_callbacks.py
@@ -186,10 +186,15 @@ def _check_yield_points(f: Callable, changes: List[str]):
                     )
                     raise Exception(err)
 
+            # the wrapped function yielded a Deferred: yield it back up to the parent
+            # inlineCallbacks().
             try:
                 result = yield d
-            except Exception as e:
-                result = Failure(e)
+            except Exception:
+                # this will fish an earlier Failure out of the stack where possible, and
+                # thus is preferable to passing in an exeception to the Failure
+                # constructor, since it results in less stack-mangling.
+                result = Failure()
 
             if current_context() != expected_context:
 

From 8c75da916c7be82e6e6ad6a83f48aa8416d806f8 Mon Sep 17 00:00:00 2001
From: Richard van der Hoff <1389908+richvdh@users.noreply.github.com>
Date: Fri, 22 May 2020 10:17:47 +0100
Subject: [PATCH 05/16] Refresh apt cache when building dh_virtualenv docker
 image (#7555)

When we tried to build debs for 1.13.0, the build failed because docker used a
base docker image which had a stale apt cache.

Fixes: #7540
---
 changelog.d/7555.misc          | 1 +
 docker/Dockerfile-dhvirtualenv | 6 ++++--
 2 files changed, 5 insertions(+), 2 deletions(-)
 create mode 100644 changelog.d/7555.misc

diff --git a/changelog.d/7555.misc b/changelog.d/7555.misc
new file mode 100644
index 0000000000..75a3176133
--- /dev/null
+++ b/changelog.d/7555.misc
@@ -0,0 +1 @@
+Refresh apt cache when building dh_virtualenv docker image.
diff --git a/docker/Dockerfile-dhvirtualenv b/docker/Dockerfile-dhvirtualenv
index 579724685c..bf6af74104 100644
--- a/docker/Dockerfile-dhvirtualenv
+++ b/docker/Dockerfile-dhvirtualenv
@@ -31,8 +31,10 @@ RUN mkdir /dh-virtualenv
 RUN wget -q -O /dh-virtualenv.tar.gz https://github.com/matrix-org/dh-virtualenv/archive/matrixorg-20200519.tar.gz
 RUN tar -xv --strip-components=1 -C /dh-virtualenv -f /dh-virtualenv.tar.gz
 
-# install its build deps
-RUN cd /dh-virtualenv \
+# install its build deps. We do another apt-cache-update here, because we might
+# be using a stale cache from docker build.
+RUN apt-get update -qq -o Acquire::Languages=none \
+    && cd /dh-virtualenv \
     && env DEBIAN_FRONTEND=noninteractive mk-build-deps -ri -t "apt-get -y --no-install-recommends"
 
 # build it

From ac481a738eac021e07e591d8de0fa5f741574103 Mon Sep 17 00:00:00 2001
From: Ivan Shapovalov <intelfx@intelfx.name>
Date: Fri, 22 May 2020 13:08:41 +0300
Subject: [PATCH 06/16] synapse.metrics: implement detailed memory usage
 reporting on PyPy (#7536)

PyPy's gc.get_stats() returns an object containing detailed allocator statistics
which could be beneficial to collect as metrics.

Signed-off-by: Ivan Shapovalov <intelfx@intelfx.name>
---
 changelog.d/7536.misc       |  1 +
 synapse/metrics/__init__.py | 79 ++++++++++++++++++++++++++++++++++++-
 2 files changed, 79 insertions(+), 1 deletion(-)
 create mode 100644 changelog.d/7536.misc

diff --git a/changelog.d/7536.misc b/changelog.d/7536.misc
new file mode 100644
index 0000000000..c1211167fc
--- /dev/null
+++ b/changelog.d/7536.misc
@@ -0,0 +1 @@
+Synapse now exports [detailed allocator statistics](https://doc.pypy.org/en/latest/gc_info.html#gc-get-stats) and basic GC timings as Prometheus metrics (`pypy_gc_time_seconds_total` and `pypy_memory_bytes`) when run under PyPy. Contributed by Ivan Shapovalov.
diff --git a/synapse/metrics/__init__.py b/synapse/metrics/__init__.py
index d2fd29acb4..9cf31f96b3 100644
--- a/synapse/metrics/__init__.py
+++ b/synapse/metrics/__init__.py
@@ -26,7 +26,12 @@ import six
 
 import attr
 from prometheus_client import Counter, Gauge, Histogram
-from prometheus_client.core import REGISTRY, GaugeMetricFamily, HistogramMetricFamily
+from prometheus_client.core import (
+    REGISTRY,
+    CounterMetricFamily,
+    GaugeMetricFamily,
+    HistogramMetricFamily,
+)
 
 from twisted.internet import reactor
 
@@ -338,6 +343,78 @@ class GCCounts(object):
 if not running_on_pypy:
     REGISTRY.register(GCCounts())
 
+
+#
+# PyPy GC / memory metrics
+#
+
+
+class PyPyGCStats(object):
+    def collect(self):
+
+        # @stats is a pretty-printer object with __str__() returning a nice table,
+        # plus some fields that contain data from that table.
+        # unfortunately, fields are pretty-printed themselves (i. e. '4.5MB').
+        stats = gc.get_stats(memory_pressure=False)  # type: ignore
+        # @s contains same fields as @stats, but as actual integers.
+        s = stats._s  # type: ignore
+
+        # also note that field naming is completely braindead
+        # and only vaguely correlates with the pretty-printed table.
+        # >>>> gc.get_stats(False)
+        # Total memory consumed:
+        #     GC used:            8.7MB (peak: 39.0MB)        # s.total_gc_memory, s.peak_memory
+        #        in arenas:            3.0MB                  # s.total_arena_memory
+        #        rawmalloced:          1.7MB                  # s.total_rawmalloced_memory
+        #        nursery:              4.0MB                  # s.nursery_size
+        #     raw assembler used: 31.0kB                      # s.jit_backend_used
+        #     -----------------------------
+        #     Total:              8.8MB                       # stats.memory_used_sum
+        #
+        #     Total memory allocated:
+        #     GC allocated:            38.7MB (peak: 41.1MB)  # s.total_allocated_memory, s.peak_allocated_memory
+        #        in arenas:            30.9MB                 # s.peak_arena_memory
+        #        rawmalloced:          4.1MB                  # s.peak_rawmalloced_memory
+        #        nursery:              4.0MB                  # s.nursery_size
+        #     raw assembler allocated: 1.0MB                  # s.jit_backend_allocated
+        #     -----------------------------
+        #     Total:                   39.7MB                 # stats.memory_allocated_sum
+        #
+        #     Total time spent in GC:  0.073                  # s.total_gc_time
+
+        pypy_gc_time = CounterMetricFamily(
+            "pypy_gc_time_seconds_total", "Total time spent in PyPy GC", labels=[],
+        )
+        pypy_gc_time.add_metric([], s.total_gc_time / 1000)
+        yield pypy_gc_time
+
+        pypy_mem = GaugeMetricFamily(
+            "pypy_memory_bytes",
+            "Memory tracked by PyPy allocator",
+            labels=["state", "class", "kind"],
+        )
+        # memory used by JIT assembler
+        pypy_mem.add_metric(["used", "", "jit"], s.jit_backend_used)
+        pypy_mem.add_metric(["allocated", "", "jit"], s.jit_backend_allocated)
+        # memory used by GCed objects
+        pypy_mem.add_metric(["used", "", "arenas"], s.total_arena_memory)
+        pypy_mem.add_metric(["allocated", "", "arenas"], s.peak_arena_memory)
+        pypy_mem.add_metric(["used", "", "rawmalloced"], s.total_rawmalloced_memory)
+        pypy_mem.add_metric(["allocated", "", "rawmalloced"], s.peak_rawmalloced_memory)
+        pypy_mem.add_metric(["used", "", "nursery"], s.nursery_size)
+        pypy_mem.add_metric(["allocated", "", "nursery"], s.nursery_size)
+        # totals
+        pypy_mem.add_metric(["used", "totals", "gc"], s.total_gc_memory)
+        pypy_mem.add_metric(["allocated", "totals", "gc"], s.total_allocated_memory)
+        pypy_mem.add_metric(["used", "totals", "gc_peak"], s.peak_memory)
+        pypy_mem.add_metric(["allocated", "totals", "gc_peak"], s.peak_allocated_memory)
+        yield pypy_mem
+
+
+if running_on_pypy:
+    REGISTRY.register(PyPyGCStats())
+
+
 #
 # Twisted reactor metrics
 #

From 547e4dd83e7d70c30ce8b40578d0750fc10373fa Mon Sep 17 00:00:00 2001
From: Erik Johnston <erik@matrix.org>
Date: Fri, 22 May 2020 11:39:20 +0100
Subject: [PATCH 07/16] Fix exception reporting due to HTTP request errors.
 (#7556)

These are business as usual errors, rather than stuff we want to log at
error.
---
 changelog.d/7556.misc                  |  1 +
 synapse/app/generic_worker.py          | 13 +++++++++----
 synapse/handlers/federation.py         |  7 +++++++
 synapse/http/matrixfederationclient.py |  7 +++++++
 4 files changed, 24 insertions(+), 4 deletions(-)
 create mode 100644 changelog.d/7556.misc

diff --git a/changelog.d/7556.misc b/changelog.d/7556.misc
new file mode 100644
index 0000000000..ed271f9de8
--- /dev/null
+++ b/changelog.d/7556.misc
@@ -0,0 +1 @@
+Stop logging some expected HTTP request errors as exceptions.
diff --git a/synapse/app/generic_worker.py b/synapse/app/generic_worker.py
index d751c9772b..a45c876213 100644
--- a/synapse/app/generic_worker.py
+++ b/synapse/app/generic_worker.py
@@ -26,7 +26,7 @@ from twisted.web.resource import NoResource
 
 import synapse
 import synapse.events
-from synapse.api.errors import SynapseError
+from synapse.api.errors import HttpResponseException, RequestSendFailed, SynapseError
 from synapse.api.urls import (
     CLIENT_API_PREFIX,
     FEDERATION_PREFIX,
@@ -202,9 +202,14 @@ class KeyUploadServlet(RestServlet):
             # is there.
             auth_headers = request.requestHeaders.getRawHeaders(b"Authorization", [])
             headers = {"Authorization": auth_headers}
-            result = await self.http_client.post_json_get_json(
-                self.main_uri + request.uri.decode("ascii"), body, headers=headers
-            )
+            try:
+                result = await self.http_client.post_json_get_json(
+                    self.main_uri + request.uri.decode("ascii"), body, headers=headers
+                )
+            except HttpResponseException as e:
+                raise e.to_synapse() from e
+            except RequestSendFailed as e:
+                raise SynapseError(502, "Failed to talk to master") from e
 
             return 200, result
         else:
diff --git a/synapse/handlers/federation.py b/synapse/handlers/federation.py
index 81d859f807..bb03cc9add 100644
--- a/synapse/handlers/federation.py
+++ b/synapse/handlers/federation.py
@@ -40,6 +40,7 @@ from synapse.api.errors import (
     Codes,
     FederationDeniedError,
     FederationError,
+    HttpResponseException,
     RequestSendFailed,
     SynapseError,
 )
@@ -1036,6 +1037,12 @@ class FederationHandler(BaseHandler):
                     # TODO: We can probably do something more intelligent here.
                     return True
                 except SynapseError as e:
+                    logger.info("Failed to backfill from %s because %s", dom, e)
+                    continue
+                except HttpResponseException as e:
+                    if 400 <= e.code < 500:
+                        raise e.to_synapse_error()
+
                     logger.info("Failed to backfill from %s because %s", dom, e)
                     continue
                 except CodeMessageException as e:
diff --git a/synapse/http/matrixfederationclient.py b/synapse/http/matrixfederationclient.py
index 44077f5349..2d47b9ea00 100644
--- a/synapse/http/matrixfederationclient.py
+++ b/synapse/http/matrixfederationclient.py
@@ -144,6 +144,11 @@ def _handle_json_response(reactor, timeout_sec, request, response):
         d = timeout_deferred(d, timeout=timeout_sec, reactor=reactor)
 
         body = yield make_deferred_yieldable(d)
+    except TimeoutError as e:
+        logger.warning(
+            "{%s} [%s] Timed out reading response", request.txn_id, request.destination,
+        )
+        raise RequestSendFailed(e, can_retry=True) from e
     except Exception as e:
         logger.warning(
             "{%s} [%s] Error reading response: %s",
@@ -424,6 +429,8 @@ class MatrixFederationHttpClient(object):
                             )
 
                             response = yield request_deferred
+                    except TimeoutError as e:
+                        raise RequestSendFailed(e, can_retry=True) from e
                     except DNSLookupError as e:
                         raise_from(RequestSendFailed(e, can_retry=retry_on_dns_fail), e)
                     except Exception as e:

From 710d958c646dcdebea9d0ec254f1bc80fb0e82f5 Mon Sep 17 00:00:00 2001
From: Erik Johnston <erik@matrix.org>
Date: Fri, 22 May 2020 11:41:41 +0100
Subject: [PATCH 08/16] On upgrade room only send canonical alias once. (#7547)

Instead of doing a complicated dance of deleting and moving aliases one
by one, which sends a canonical alias update into the old room for each
one, lets do it all in one go.

This also changes the function to move *all* local alias events to the new
room, however that happens later on anyway.
---
 changelog.d/7547.misc    |   1 +
 synapse/handlers/room.py | 113 ++++++++++++++++++++-------------------
 2 files changed, 60 insertions(+), 54 deletions(-)
 create mode 100644 changelog.d/7547.misc

diff --git a/changelog.d/7547.misc b/changelog.d/7547.misc
new file mode 100644
index 0000000000..2cb8f9bd5b
--- /dev/null
+++ b/changelog.d/7547.misc
@@ -0,0 +1 @@
+On upgrade room only send canonical alias once. 
diff --git a/synapse/handlers/room.py b/synapse/handlers/room.py
index 73f9eeb399..13850ba672 100644
--- a/synapse/handlers/room.py
+++ b/synapse/handlers/room.py
@@ -439,73 +439,78 @@ class RoomCreationHandler(BaseHandler):
         new_room_id: str,
         old_room_state: StateMap[str],
     ):
-        directory_handler = self.hs.get_handlers().directory_handler
-
-        aliases = await self.store.get_aliases_for_room(old_room_id)
-
         # check to see if we have a canonical alias.
         canonical_alias_event = None
         canonical_alias_event_id = old_room_state.get((EventTypes.CanonicalAlias, ""))
         if canonical_alias_event_id:
             canonical_alias_event = await self.store.get_event(canonical_alias_event_id)
 
-        # first we try to remove the aliases from the old room (we suppress sending
-        # the room_aliases event until the end).
-        #
-        # Note that we'll only be able to remove aliases that (a) aren't owned by an AS,
-        # and (b) unless the user is a server admin, which the user created.
-        #
-        # This is probably correct - given we don't allow such aliases to be deleted
-        # normally, it would be odd to allow it in the case of doing a room upgrade -
-        # but it makes the upgrade less effective, and you have to wonder why a room
-        # admin can't remove aliases that point to that room anyway.
-        # (cf https://github.com/matrix-org/synapse/issues/2360)
-        #
-        removed_aliases = []
-        for alias_str in aliases:
-            alias = RoomAlias.from_string(alias_str)
-            try:
-                await directory_handler.delete_association(requester, alias)
-                removed_aliases.append(alias_str)
-            except SynapseError as e:
-                logger.warning("Unable to remove alias %s from old room: %s", alias, e)
+        await self.store.update_aliases_for_room(old_room_id, new_room_id)
 
-        # if we didn't find any aliases, or couldn't remove anyway, we can skip the rest
-        # of this.
-        if not removed_aliases:
+        if not canonical_alias_event:
             return
 
-        # we can now add any aliases we successfully removed to the new room.
-        for alias in removed_aliases:
-            try:
-                await directory_handler.create_association(
-                    requester,
-                    RoomAlias.from_string(alias),
-                    new_room_id,
-                    servers=(self.hs.hostname,),
-                    check_membership=False,
-                )
-                logger.info("Moved alias %s to new room", alias)
-            except SynapseError as e:
-                # I'm not really expecting this to happen, but it could if the spam
-                # checking module decides it shouldn't, or similar.
-                logger.error("Error adding alias %s to new room: %s", alias, e)
+        # If there is a canonical alias we need to update the one in the old
+        # room and set one in the new one.
+        old_canonical_alias_content = dict(canonical_alias_event.content)
+        new_canonical_alias_content = {}
+
+        canonical = canonical_alias_event.content.get("alias")
+        if canonical and self.hs.is_mine_id(canonical):
+            new_canonical_alias_content["alias"] = canonical
+            old_canonical_alias_content.pop("alias", None)
+
+        # We convert to a list as it will be a Tuple.
+        old_alt_aliases = list(old_canonical_alias_content.get("alt_aliases", []))
+        if old_alt_aliases:
+            old_canonical_alias_content["alt_aliases"] = old_alt_aliases
+            new_alt_aliases = new_canonical_alias_content.setdefault("alt_aliases", [])
+            for alias in canonical_alias_event.content.get("alt_aliases", []):
+                try:
+                    if self.hs.is_mine_id(alias):
+                        new_alt_aliases.append(alias)
+                        old_alt_aliases.remove(alias)
+                except Exception:
+                    logger.info(
+                        "Invalid alias %s in canonical alias event %s",
+                        alias,
+                        canonical_alias_event_id,
+                    )
+
+            if not old_alt_aliases:
+                old_canonical_alias_content.pop("alt_aliases")
 
         # If a canonical alias event existed for the old room, fire a canonical
         # alias event for the new room with a copy of the information.
         try:
-            if canonical_alias_event:
-                await self.event_creation_handler.create_and_send_nonmember_event(
-                    requester,
-                    {
-                        "type": EventTypes.CanonicalAlias,
-                        "state_key": "",
-                        "room_id": new_room_id,
-                        "sender": requester.user.to_string(),
-                        "content": canonical_alias_event.content,
-                    },
-                    ratelimit=False,
-                )
+            await self.event_creation_handler.create_and_send_nonmember_event(
+                requester,
+                {
+                    "type": EventTypes.CanonicalAlias,
+                    "state_key": "",
+                    "room_id": old_room_id,
+                    "sender": requester.user.to_string(),
+                    "content": old_canonical_alias_content,
+                },
+                ratelimit=False,
+            )
+        except SynapseError as e:
+            # again I'm not really expecting this to fail, but if it does, I'd rather
+            # we returned the new room to the client at this point.
+            logger.error("Unable to send updated alias events in old room: %s", e)
+
+        try:
+            await self.event_creation_handler.create_and_send_nonmember_event(
+                requester,
+                {
+                    "type": EventTypes.CanonicalAlias,
+                    "state_key": "",
+                    "room_id": new_room_id,
+                    "sender": requester.user.to_string(),
+                    "content": new_canonical_alias_content,
+                },
+                ratelimit=False,
+            )
         except SynapseError as e:
             # again I'm not really expecting this to fail, but if it does, I'd rather
             # we returned the new room to the client at this point.

From 66f2ebc22fec01b4673fabae22f2c94dfeac58e3 Mon Sep 17 00:00:00 2001
From: Patrick Cloke <clokep@users.noreply.github.com>
Date: Fri, 22 May 2020 07:17:30 -0400
Subject: [PATCH 09/16] Use a non-empty RelayState for user interactive auth
 with SAML. (#7552)

---
 changelog.d/7552.bugfix              | 1 +
 synapse/rest/client/v2_alpha/auth.py | 5 ++++-
 2 files changed, 5 insertions(+), 1 deletion(-)
 create mode 100644 changelog.d/7552.bugfix

diff --git a/changelog.d/7552.bugfix b/changelog.d/7552.bugfix
new file mode 100644
index 0000000000..60b31d6d31
--- /dev/null
+++ b/changelog.d/7552.bugfix
@@ -0,0 +1 @@
+Fix "Missing RelayState parameter" error when using user interactive authentication with SAML for some SAML providers.
diff --git a/synapse/rest/client/v2_alpha/auth.py b/synapse/rest/client/v2_alpha/auth.py
index 7bca1326d5..75590ebaeb 100644
--- a/synapse/rest/client/v2_alpha/auth.py
+++ b/synapse/rest/client/v2_alpha/auth.py
@@ -177,7 +177,10 @@ class AuthRestServlet(RestServlet):
                 )
 
             elif self._saml_enabled:
-                client_redirect_url = b""
+                # Some SAML identity providers (e.g. Google) require a
+                # RelayState parameter on requests. It is not necessary here, so
+                # pass in a dummy redirect URL (which will never get used).
+                client_redirect_url = b"unused"
                 sso_redirect_url = self._saml_handler.handle_redirect_request(
                     client_redirect_url, session
                 )

From 06a02bc1ce9ef23a6dff28dbfd30f910ae330b1d Mon Sep 17 00:00:00 2001
From: Erik Johnston <erik@matrix.org>
Date: Fri, 22 May 2020 13:41:11 +0100
Subject: [PATCH 10/16] Convert sending mail to async/await. (#7557)

Mainly because sometimes the email push code raises exceptions where the
stack traces have gotten lost, which is hopefully fixed by this.
---
 changelog.d/7557.misc                      |  1 +
 synapse/handlers/identity.py               |  9 ++-
 synapse/push/emailpusher.py                | 38 +++++-----
 synapse/push/mailer.py                     | 84 ++++++++++------------
 tests/rest/client/v2_alpha/test_account.py |  4 +-
 5 files changed, 60 insertions(+), 76 deletions(-)
 create mode 100644 changelog.d/7557.misc

diff --git a/changelog.d/7557.misc b/changelog.d/7557.misc
new file mode 100644
index 0000000000..c850a2bc0c
--- /dev/null
+++ b/changelog.d/7557.misc
@@ -0,0 +1 @@
+Convert sending mail to async/await.
diff --git a/synapse/handlers/identity.py b/synapse/handlers/identity.py
index 0f0e632b62..9ed0d23b0f 100644
--- a/synapse/handlers/identity.py
+++ b/synapse/handlers/identity.py
@@ -290,8 +290,7 @@ class IdentityHandler(BaseHandler):
 
         return changed
 
-    @defer.inlineCallbacks
-    def send_threepid_validation(
+    async def send_threepid_validation(
         self,
         email_address,
         client_secret,
@@ -319,7 +318,7 @@ class IdentityHandler(BaseHandler):
         """
         # Check that this email/client_secret/send_attempt combo is new or
         # greater than what we've seen previously
-        session = yield self.store.get_threepid_validation_session(
+        session = await self.store.get_threepid_validation_session(
             "email", client_secret, address=email_address, validated=False
         )
 
@@ -353,7 +352,7 @@ class IdentityHandler(BaseHandler):
         # Send the mail with the link containing the token, client_secret
         # and session_id
         try:
-            yield send_email_func(email_address, token, client_secret, session_id)
+            await send_email_func(email_address, token, client_secret, session_id)
         except Exception:
             logger.exception(
                 "Error sending threepid validation email to %s", email_address
@@ -364,7 +363,7 @@ class IdentityHandler(BaseHandler):
             self.hs.clock.time_msec() + self.hs.config.email_validation_token_lifetime
         )
 
-        yield self.store.start_or_continue_validation_session(
+        await self.store.start_or_continue_validation_session(
             "email",
             email_address,
             session_id,
diff --git a/synapse/push/emailpusher.py b/synapse/push/emailpusher.py
index ba4551d619..568c13eaea 100644
--- a/synapse/push/emailpusher.py
+++ b/synapse/push/emailpusher.py
@@ -15,7 +15,6 @@
 
 import logging
 
-from twisted.internet import defer
 from twisted.internet.error import AlreadyCalled, AlreadyCancelled
 
 from synapse.metrics.background_process_metrics import run_as_background_process
@@ -132,8 +131,7 @@ class EmailPusher(object):
         self._is_processing = False
         self._start_processing()
 
-    @defer.inlineCallbacks
-    def _process(self):
+    async def _process(self):
         # we should never get here if we are already processing
         assert not self._is_processing
 
@@ -142,7 +140,7 @@ class EmailPusher(object):
 
             if self.throttle_params is None:
                 # this is our first loop: load up the throttle params
-                self.throttle_params = yield self.store.get_throttle_params_by_room(
+                self.throttle_params = await self.store.get_throttle_params_by_room(
                     self.pusher_id
                 )
 
@@ -151,7 +149,7 @@ class EmailPusher(object):
             while True:
                 starting_max_ordering = self.max_stream_ordering
                 try:
-                    yield self._unsafe_process()
+                    await self._unsafe_process()
                 except Exception:
                     logger.exception("Exception processing notifs")
                 if self.max_stream_ordering == starting_max_ordering:
@@ -159,8 +157,7 @@ class EmailPusher(object):
         finally:
             self._is_processing = False
 
-    @defer.inlineCallbacks
-    def _unsafe_process(self):
+    async def _unsafe_process(self):
         """
         Main logic of the push loop without the wrapper function that sets
         up logging, measures and guards against multiple instances of it
@@ -168,12 +165,12 @@ class EmailPusher(object):
         """
         start = 0 if INCLUDE_ALL_UNREAD_NOTIFS else self.last_stream_ordering
         fn = self.store.get_unread_push_actions_for_user_in_range_for_email
-        unprocessed = yield fn(self.user_id, start, self.max_stream_ordering)
+        unprocessed = await fn(self.user_id, start, self.max_stream_ordering)
 
         soonest_due_at = None
 
         if not unprocessed:
-            yield self.save_last_stream_ordering_and_success(self.max_stream_ordering)
+            await self.save_last_stream_ordering_and_success(self.max_stream_ordering)
             return
 
         for push_action in unprocessed:
@@ -201,15 +198,15 @@ class EmailPusher(object):
                     "throttle_ms": self.get_room_throttle_ms(push_action["room_id"]),
                 }
 
-                yield self.send_notification(unprocessed, reason)
+                await self.send_notification(unprocessed, reason)
 
-                yield self.save_last_stream_ordering_and_success(
+                await self.save_last_stream_ordering_and_success(
                     max(ea["stream_ordering"] for ea in unprocessed)
                 )
 
                 # we update the throttle on all the possible unprocessed push actions
                 for ea in unprocessed:
-                    yield self.sent_notif_update_throttle(ea["room_id"], ea)
+                    await self.sent_notif_update_throttle(ea["room_id"], ea)
                 break
             else:
                 if soonest_due_at is None or should_notify_at < soonest_due_at:
@@ -227,14 +224,13 @@ class EmailPusher(object):
                 self.seconds_until(soonest_due_at), self.on_timer
             )
 
-    @defer.inlineCallbacks
-    def save_last_stream_ordering_and_success(self, last_stream_ordering):
+    async def save_last_stream_ordering_and_success(self, last_stream_ordering):
         if last_stream_ordering is None:
             # This happens if we haven't yet processed anything
             return
 
         self.last_stream_ordering = last_stream_ordering
-        pusher_still_exists = yield self.store.update_pusher_last_stream_ordering_and_success(
+        pusher_still_exists = await self.store.update_pusher_last_stream_ordering_and_success(
             self.app_id,
             self.email,
             self.user_id,
@@ -275,13 +271,12 @@ class EmailPusher(object):
         may_send_at = last_sent_ts + throttle_ms
         return may_send_at
 
-    @defer.inlineCallbacks
-    def sent_notif_update_throttle(self, room_id, notified_push_action):
+    async def sent_notif_update_throttle(self, room_id, notified_push_action):
         # We have sent a notification, so update the throttle accordingly.
         # If the event that triggered the notif happened more than
         # THROTTLE_RESET_AFTER_MS after the previous one that triggered a
         # notif, we release the throttle. Otherwise, the throttle is increased.
-        time_of_previous_notifs = yield self.store.get_time_of_last_push_action_before(
+        time_of_previous_notifs = await self.store.get_time_of_last_push_action_before(
             notified_push_action["stream_ordering"]
         )
 
@@ -310,14 +305,13 @@ class EmailPusher(object):
             "last_sent_ts": self.clock.time_msec(),
             "throttle_ms": new_throttle_ms,
         }
-        yield self.store.set_throttle_params(
+        await self.store.set_throttle_params(
             self.pusher_id, room_id, self.throttle_params[room_id]
         )
 
-    @defer.inlineCallbacks
-    def send_notification(self, push_actions, reason):
+    async def send_notification(self, push_actions, reason):
         logger.info("Sending notif email for user %r", self.user_id)
 
-        yield self.mailer.send_notification_mail(
+        await self.mailer.send_notification_mail(
             self.app_id, self.user_id, self.email, push_actions, reason
         )
diff --git a/synapse/push/mailer.py b/synapse/push/mailer.py
index ab33abbeed..d57a66a697 100644
--- a/synapse/push/mailer.py
+++ b/synapse/push/mailer.py
@@ -26,8 +26,6 @@ from six.moves import urllib
 import bleach
 import jinja2
 
-from twisted.internet import defer
-
 from synapse.api.constants import EventTypes
 from synapse.api.errors import StoreError
 from synapse.logging.context import make_deferred_yieldable
@@ -127,8 +125,7 @@ class Mailer(object):
 
         logger.info("Created Mailer for app_name %s" % app_name)
 
-    @defer.inlineCallbacks
-    def send_password_reset_mail(self, email_address, token, client_secret, sid):
+    async def send_password_reset_mail(self, email_address, token, client_secret, sid):
         """Send an email with a password reset link to a user
 
         Args:
@@ -149,14 +146,13 @@ class Mailer(object):
 
         template_vars = {"link": link}
 
-        yield self.send_email(
+        await self.send_email(
             email_address,
             "[%s] Password Reset" % self.hs.config.server_name,
             template_vars,
         )
 
-    @defer.inlineCallbacks
-    def send_registration_mail(self, email_address, token, client_secret, sid):
+    async def send_registration_mail(self, email_address, token, client_secret, sid):
         """Send an email with a registration confirmation link to a user
 
         Args:
@@ -177,14 +173,13 @@ class Mailer(object):
 
         template_vars = {"link": link}
 
-        yield self.send_email(
+        await self.send_email(
             email_address,
             "[%s] Register your Email Address" % self.hs.config.server_name,
             template_vars,
         )
 
-    @defer.inlineCallbacks
-    def send_add_threepid_mail(self, email_address, token, client_secret, sid):
+    async def send_add_threepid_mail(self, email_address, token, client_secret, sid):
         """Send an email with a validation link to a user for adding a 3pid to their account
 
         Args:
@@ -206,20 +201,19 @@ class Mailer(object):
 
         template_vars = {"link": link}
 
-        yield self.send_email(
+        await self.send_email(
             email_address,
             "[%s] Validate Your Email" % self.hs.config.server_name,
             template_vars,
         )
 
-    @defer.inlineCallbacks
-    def send_notification_mail(
+    async def send_notification_mail(
         self, app_id, user_id, email_address, push_actions, reason
     ):
         """Send email regarding a user's room notifications"""
         rooms_in_order = deduped_ordered_list([pa["room_id"] for pa in push_actions])
 
-        notif_events = yield self.store.get_events(
+        notif_events = await self.store.get_events(
             [pa["event_id"] for pa in push_actions]
         )
 
@@ -232,7 +226,7 @@ class Mailer(object):
         state_by_room = {}
 
         try:
-            user_display_name = yield self.store.get_profile_displayname(
+            user_display_name = await self.store.get_profile_displayname(
                 UserID.from_string(user_id).localpart
             )
             if user_display_name is None:
@@ -240,14 +234,13 @@ class Mailer(object):
         except StoreError:
             user_display_name = user_id
 
-        @defer.inlineCallbacks
-        def _fetch_room_state(room_id):
-            room_state = yield self.store.get_current_state_ids(room_id)
+        async def _fetch_room_state(room_id):
+            room_state = await self.store.get_current_state_ids(room_id)
             state_by_room[room_id] = room_state
 
         # Run at most 3 of these at once: sync does 10 at a time but email
         # notifs are much less realtime than sync so we can afford to wait a bit.
-        yield concurrently_execute(_fetch_room_state, rooms_in_order, 3)
+        await concurrently_execute(_fetch_room_state, rooms_in_order, 3)
 
         # actually sort our so-called rooms_in_order list, most recent room first
         rooms_in_order.sort(key=lambda r: -(notifs_by_room[r][-1]["received_ts"] or 0))
@@ -255,19 +248,19 @@ class Mailer(object):
         rooms = []
 
         for r in rooms_in_order:
-            roomvars = yield self.get_room_vars(
+            roomvars = await self.get_room_vars(
                 r, user_id, notifs_by_room[r], notif_events, state_by_room[r]
             )
             rooms.append(roomvars)
 
-        reason["room_name"] = yield calculate_room_name(
+        reason["room_name"] = await calculate_room_name(
             self.store,
             state_by_room[reason["room_id"]],
             user_id,
             fallback_to_members=True,
         )
 
-        summary_text = yield self.make_summary_text(
+        summary_text = await self.make_summary_text(
             notifs_by_room, state_by_room, notif_events, user_id, reason
         )
 
@@ -282,12 +275,11 @@ class Mailer(object):
             "reason": reason,
         }
 
-        yield self.send_email(
+        await self.send_email(
             email_address, "[%s] %s" % (self.app_name, summary_text), template_vars
         )
 
-    @defer.inlineCallbacks
-    def send_email(self, email_address, subject, template_vars):
+    async def send_email(self, email_address, subject, template_vars):
         """Send an email with the given information and template text"""
         try:
             from_string = self.hs.config.email_notif_from % {"app": self.app_name}
@@ -317,7 +309,7 @@ class Mailer(object):
 
         logger.info("Sending email to %s" % email_address)
 
-        yield make_deferred_yieldable(
+        await make_deferred_yieldable(
             self.sendmail(
                 self.hs.config.email_smtp_host,
                 raw_from,
@@ -332,13 +324,14 @@ class Mailer(object):
             )
         )
 
-    @defer.inlineCallbacks
-    def get_room_vars(self, room_id, user_id, notifs, notif_events, room_state_ids):
+    async def get_room_vars(
+        self, room_id, user_id, notifs, notif_events, room_state_ids
+    ):
         my_member_event_id = room_state_ids[("m.room.member", user_id)]
-        my_member_event = yield self.store.get_event(my_member_event_id)
+        my_member_event = await self.store.get_event(my_member_event_id)
         is_invite = my_member_event.content["membership"] == "invite"
 
-        room_name = yield calculate_room_name(self.store, room_state_ids, user_id)
+        room_name = await calculate_room_name(self.store, room_state_ids, user_id)
 
         room_vars = {
             "title": room_name,
@@ -350,7 +343,7 @@ class Mailer(object):
 
         if not is_invite:
             for n in notifs:
-                notifvars = yield self.get_notif_vars(
+                notifvars = await self.get_notif_vars(
                     n, user_id, notif_events[n["event_id"]], room_state_ids
                 )
 
@@ -377,9 +370,8 @@ class Mailer(object):
 
         return room_vars
 
-    @defer.inlineCallbacks
-    def get_notif_vars(self, notif, user_id, notif_event, room_state_ids):
-        results = yield self.store.get_events_around(
+    async def get_notif_vars(self, notif, user_id, notif_event, room_state_ids):
+        results = await self.store.get_events_around(
             notif["room_id"],
             notif["event_id"],
             before_limit=CONTEXT_BEFORE,
@@ -392,25 +384,24 @@ class Mailer(object):
             "messages": [],
         }
 
-        the_events = yield filter_events_for_client(
+        the_events = await filter_events_for_client(
             self.storage, user_id, results["events_before"]
         )
         the_events.append(notif_event)
 
         for event in the_events:
-            messagevars = yield self.get_message_vars(notif, event, room_state_ids)
+            messagevars = await self.get_message_vars(notif, event, room_state_ids)
             if messagevars is not None:
                 ret["messages"].append(messagevars)
 
         return ret
 
-    @defer.inlineCallbacks
-    def get_message_vars(self, notif, event, room_state_ids):
+    async def get_message_vars(self, notif, event, room_state_ids):
         if event.type != EventTypes.Message:
             return
 
         sender_state_event_id = room_state_ids[("m.room.member", event.sender)]
-        sender_state_event = yield self.store.get_event(sender_state_event_id)
+        sender_state_event = await self.store.get_event(sender_state_event_id)
         sender_name = name_from_member_event(sender_state_event)
         sender_avatar_url = sender_state_event.content.get("avatar_url")
 
@@ -460,8 +451,7 @@ class Mailer(object):
 
         return messagevars
 
-    @defer.inlineCallbacks
-    def make_summary_text(
+    async def make_summary_text(
         self, notifs_by_room, room_state_ids, notif_events, user_id, reason
     ):
         if len(notifs_by_room) == 1:
@@ -471,17 +461,17 @@ class Mailer(object):
             # If the room has some kind of name, use it, but we don't
             # want the generated-from-names one here otherwise we'll
             # end up with, "new message from Bob in the Bob room"
-            room_name = yield calculate_room_name(
+            room_name = await calculate_room_name(
                 self.store, room_state_ids[room_id], user_id, fallback_to_members=False
             )
 
             my_member_event_id = room_state_ids[room_id][("m.room.member", user_id)]
-            my_member_event = yield self.store.get_event(my_member_event_id)
+            my_member_event = await self.store.get_event(my_member_event_id)
             if my_member_event.content["membership"] == "invite":
                 inviter_member_event_id = room_state_ids[room_id][
                     ("m.room.member", my_member_event.sender)
                 ]
-                inviter_member_event = yield self.store.get_event(
+                inviter_member_event = await self.store.get_event(
                     inviter_member_event_id
                 )
                 inviter_name = name_from_member_event(inviter_member_event)
@@ -506,7 +496,7 @@ class Mailer(object):
                     state_event_id = room_state_ids[room_id][
                         ("m.room.member", event.sender)
                     ]
-                    state_event = yield self.store.get_event(state_event_id)
+                    state_event = await self.store.get_event(state_event_id)
                     sender_name = name_from_member_event(state_event)
 
                 if sender_name is not None and room_name is not None:
@@ -535,7 +525,7 @@ class Mailer(object):
                         }
                     )
 
-                    member_events = yield self.store.get_events(
+                    member_events = await self.store.get_events(
                         [
                             room_state_ids[room_id][("m.room.member", s)]
                             for s in sender_ids
@@ -567,7 +557,7 @@ class Mailer(object):
                     }
                 )
 
-                member_events = yield self.store.get_events(
+                member_events = await self.store.get_events(
                     [room_state_ids[room_id][("m.room.member", s)] for s in sender_ids]
                 )
 
diff --git a/tests/rest/client/v2_alpha/test_account.py b/tests/rest/client/v2_alpha/test_account.py
index 0d6936fd36..3ab611f618 100644
--- a/tests/rest/client/v2_alpha/test_account.py
+++ b/tests/rest/client/v2_alpha/test_account.py
@@ -46,7 +46,7 @@ class PasswordResetTestCase(unittest.HomeserverTestCase):
         # Email config.
         self.email_attempts = []
 
-        def sendmail(smtphost, from_addr, to_addrs, msg, **kwargs):
+        async def sendmail(smtphost, from_addr, to_addrs, msg, **kwargs):
             self.email_attempts.append(msg)
             return
 
@@ -358,7 +358,7 @@ class ThreepidEmailRestTestCase(unittest.HomeserverTestCase):
         # Email config.
         self.email_attempts = []
 
-        def sendmail(smtphost, from_addr, to_addrs, msg, **kwargs):
+        async def sendmail(smtphost, from_addr, to_addrs, msg, **kwargs):
             self.email_attempts.append(msg)
 
         config["email"] = {

From 1531b214fc57714c14046a8f66c7b5fe5ec5dcdd Mon Sep 17 00:00:00 2001
From: Erik Johnston <erik@matrix.org>
Date: Fri, 22 May 2020 14:21:54 +0100
Subject: [PATCH 11/16] Add ability to wait for replication streams (#7542)

The idea here is that if an instance persists an event via the replication HTTP API it can return before we receive that event over replication, which can lead to races where code assumes that persisting an event immediately updates various caches (e.g. current state of the room).

Most of Synapse doesn't hit such races, so we don't do the waiting automagically, instead we do so where necessary to avoid unnecessary delays. We may decide to change our minds here if it turns out there are a lot of subtle races going on.

People probably want to look at this commit by commit.
---
 changelog.d/7542.misc                         |  1 +
 synapse/handlers/federation.py                | 33 ++++---
 synapse/handlers/message.py                   | 36 +++++---
 synapse/handlers/room.py                      | 65 +++++++++-----
 synapse/handlers/room_member.py               | 65 +++++++++-----
 synapse/handlers/room_member_worker.py        | 11 +--
 synapse/replication/http/federation.py        | 13 ++-
 synapse/replication/http/membership.py        | 14 +--
 synapse/replication/http/send_event.py        |  4 +-
 synapse/replication/http/streams.py           |  5 +-
 synapse/replication/tcp/client.py             | 90 ++++++++++++++++++-
 synapse/rest/admin/rooms.py                   | 10 ++-
 synapse/rest/client/v1/room.py                | 20 +++--
 synapse/rest/client/v2_alpha/relations.py     |  2 +-
 synapse/server.py                             |  5 ++
 synapse/server.pyi                            |  5 ++
 .../server_notices/server_notices_manager.py  |  6 +-
 .../storage/data_stores/main/events_worker.py |  6 +-
 .../storage/data_stores/main/roommember.py    |  2 +
 tests/federation/test_complexity.py           |  8 +-
 tests/handlers/test_typing.py                 |  5 +-
 tests/storage/test_cleanup_extrems.py         |  4 +-
 tests/storage/test_event_metrics.py           |  2 +-
 tests/test_federation.py                      |  4 +-
 24 files changed, 304 insertions(+), 112 deletions(-)
 create mode 100644 changelog.d/7542.misc

diff --git a/changelog.d/7542.misc b/changelog.d/7542.misc
new file mode 100644
index 0000000000..7dd9b4823b
--- /dev/null
+++ b/changelog.d/7542.misc
@@ -0,0 +1 @@
+Add ability to wait for replication streams.
diff --git a/synapse/handlers/federation.py b/synapse/handlers/federation.py
index bb03cc9add..e354c803db 100644
--- a/synapse/handlers/federation.py
+++ b/synapse/handlers/federation.py
@@ -126,6 +126,7 @@ class FederationHandler(BaseHandler):
         self._server_notices_mxid = hs.config.server_notices_mxid
         self.config = hs.config
         self.http_client = hs.get_simple_http_client()
+        self._replication = hs.get_replication_data_handler()
 
         self._send_events_to_master = ReplicationFederationSendEventsRestServlet.make_client(
             hs
@@ -1221,7 +1222,7 @@ class FederationHandler(BaseHandler):
 
     async def do_invite_join(
         self, target_hosts: Iterable[str], room_id: str, joinee: str, content: JsonDict
-    ) -> None:
+    ) -> Tuple[str, int]:
         """ Attempts to join the `joinee` to the room `room_id` via the
         servers contained in `target_hosts`.
 
@@ -1304,15 +1305,23 @@ class FederationHandler(BaseHandler):
                 room_id=room_id, room_version=room_version_obj,
             )
 
-            await self._persist_auth_tree(
+            max_stream_id = await self._persist_auth_tree(
                 origin, auth_chain, state, event, room_version_obj
             )
 
+            # We wait here until this instance has seen the events come down
+            # replication (if we're using replication) as the below uses caches.
+            #
+            # TODO: Currently the events stream is written to from master
+            await self._replication.wait_for_stream_position(
+                "master", "events", max_stream_id
+            )
+
             # Check whether this room is the result of an upgrade of a room we already know
             # about. If so, migrate over user information
             predecessor = await self.store.get_room_predecessor(room_id)
             if not predecessor or not isinstance(predecessor.get("room_id"), str):
-                return
+                return event.event_id, max_stream_id
             old_room_id = predecessor["room_id"]
             logger.debug(
                 "Found predecessor for %s during remote join: %s", room_id, old_room_id
@@ -1325,6 +1334,7 @@ class FederationHandler(BaseHandler):
             )
 
             logger.debug("Finished joining %s to %s", joinee, room_id)
+            return event.event_id, max_stream_id
         finally:
             room_queue = self.room_queues[room_id]
             del self.room_queues[room_id]
@@ -1554,7 +1564,7 @@ class FederationHandler(BaseHandler):
 
     async def do_remotely_reject_invite(
         self, target_hosts: Iterable[str], room_id: str, user_id: str, content: JsonDict
-    ) -> EventBase:
+    ) -> Tuple[EventBase, int]:
         origin, event, room_version = await self._make_and_verify_event(
             target_hosts, room_id, user_id, "leave", content=content
         )
@@ -1574,9 +1584,9 @@ class FederationHandler(BaseHandler):
         await self.federation_client.send_leave(target_hosts, event)
 
         context = await self.state_handler.compute_event_context(event)
-        await self.persist_events_and_notify([(event, context)])
+        stream_id = await self.persist_events_and_notify([(event, context)])
 
-        return event
+        return event, stream_id
 
     async def _make_and_verify_event(
         self,
@@ -1888,7 +1898,7 @@ class FederationHandler(BaseHandler):
         state: List[EventBase],
         event: EventBase,
         room_version: RoomVersion,
-    ) -> None:
+    ) -> int:
         """Checks the auth chain is valid (and passes auth checks) for the
         state and event. Then persists the auth chain and state atomically.
         Persists the event separately. Notifies about the persisted events
@@ -1982,7 +1992,7 @@ class FederationHandler(BaseHandler):
             event, old_state=state
         )
 
-        await self.persist_events_and_notify([(event, new_event_context)])
+        return await self.persist_events_and_notify([(event, new_event_context)])
 
     async def _prep_event(
         self,
@@ -2835,7 +2845,7 @@ class FederationHandler(BaseHandler):
         self,
         event_and_contexts: Sequence[Tuple[EventBase, EventContext]],
         backfilled: bool = False,
-    ) -> None:
+    ) -> int:
         """Persists events and tells the notifier/pushers about them, if
         necessary.
 
@@ -2845,11 +2855,12 @@ class FederationHandler(BaseHandler):
                 backfilling or not
         """
         if self.config.worker_app:
-            await self._send_events_to_master(
+            result = await self._send_events_to_master(
                 store=self.store,
                 event_and_contexts=event_and_contexts,
                 backfilled=backfilled,
             )
+            return result["max_stream_id"]
         else:
             max_stream_id = await self.storage.persistence.persist_events(
                 event_and_contexts, backfilled=backfilled
@@ -2864,6 +2875,8 @@ class FederationHandler(BaseHandler):
                 for event, _ in event_and_contexts:
                     await self._notify_persisted_event(event, max_stream_id)
 
+            return max_stream_id
+
     async def _notify_persisted_event(
         self, event: EventBase, max_stream_id: int
     ) -> None:
diff --git a/synapse/handlers/message.py b/synapse/handlers/message.py
index 8f362896a2..f445e2aa2a 100644
--- a/synapse/handlers/message.py
+++ b/synapse/handlers/message.py
@@ -15,7 +15,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 import logging
-from typing import Optional
+from typing import Optional, Tuple
 
 from six import iteritems, itervalues, string_types
 
@@ -42,6 +42,7 @@ from synapse.api.errors import (
 )
 from synapse.api.room_versions import KNOWN_ROOM_VERSIONS, RoomVersions
 from synapse.api.urls import ConsentURIBuilder
+from synapse.events import EventBase
 from synapse.events.validator import EventValidator
 from synapse.logging.context import run_in_background
 from synapse.metrics.background_process_metrics import run_as_background_process
@@ -630,7 +631,9 @@ class EventCreationHandler(object):
         msg = self._block_events_without_consent_error % {"consent_uri": consent_uri}
         raise ConsentNotGivenError(msg=msg, consent_uri=consent_uri)
 
-    async def send_nonmember_event(self, requester, event, context, ratelimit=True):
+    async def send_nonmember_event(
+        self, requester, event, context, ratelimit=True
+    ) -> int:
         """
         Persists and notifies local clients and federation of an event.
 
@@ -639,6 +642,9 @@ class EventCreationHandler(object):
             context (Context) the context of the event.
             ratelimit (bool): Whether to rate limit this send.
             is_guest (bool): Whether the sender is a guest.
+
+        Return:
+            The stream_id of the persisted event.
         """
         if event.type == EventTypes.Member:
             raise SynapseError(
@@ -659,7 +665,7 @@ class EventCreationHandler(object):
                 )
                 return prev_state
 
-        await self.handle_new_client_event(
+        return await self.handle_new_client_event(
             requester=requester, event=event, context=context, ratelimit=ratelimit
         )
 
@@ -688,7 +694,7 @@ class EventCreationHandler(object):
 
     async def create_and_send_nonmember_event(
         self, requester, event_dict, ratelimit=True, txn_id=None
-    ):
+    ) -> Tuple[EventBase, int]:
         """
         Creates an event, then sends it.
 
@@ -711,10 +717,10 @@ class EventCreationHandler(object):
                     spam_error = "Spam is not permitted here"
                 raise SynapseError(403, spam_error, Codes.FORBIDDEN)
 
-            await self.send_nonmember_event(
+            stream_id = await self.send_nonmember_event(
                 requester, event, context, ratelimit=ratelimit
             )
-        return event
+        return event, stream_id
 
     @measure_func("create_new_client_event")
     @defer.inlineCallbacks
@@ -774,7 +780,7 @@ class EventCreationHandler(object):
     @measure_func("handle_new_client_event")
     async def handle_new_client_event(
         self, requester, event, context, ratelimit=True, extra_users=[]
-    ):
+    ) -> int:
         """Processes a new event. This includes checking auth, persisting it,
         notifying users, sending to remote servers, etc.
 
@@ -787,6 +793,9 @@ class EventCreationHandler(object):
             context (EventContext)
             ratelimit (bool)
             extra_users (list(UserID)): Any extra users to notify about event
+
+        Return:
+            The stream_id of the persisted event.
         """
 
         if event.is_state() and (event.type, event.state_key) == (
@@ -827,7 +836,7 @@ class EventCreationHandler(object):
         try:
             # If we're a worker we need to hit out to the master.
             if self.config.worker_app:
-                await self.send_event_to_master(
+                result = await self.send_event_to_master(
                     event_id=event.event_id,
                     store=self.store,
                     requester=requester,
@@ -836,14 +845,17 @@ class EventCreationHandler(object):
                     ratelimit=ratelimit,
                     extra_users=extra_users,
                 )
+                stream_id = result["stream_id"]
+                event.internal_metadata.stream_ordering = stream_id
                 success = True
-                return
+                return stream_id
 
-            await self.persist_and_notify_client_event(
+            stream_id = await self.persist_and_notify_client_event(
                 requester, event, context, ratelimit=ratelimit, extra_users=extra_users
             )
 
             success = True
+            return stream_id
         finally:
             if not success:
                 # Ensure that we actually remove the entries in the push actions
@@ -886,7 +898,7 @@ class EventCreationHandler(object):
 
     async def persist_and_notify_client_event(
         self, requester, event, context, ratelimit=True, extra_users=[]
-    ):
+    ) -> int:
         """Called when we have fully built the event, have already
         calculated the push actions for the event, and checked auth.
 
@@ -1076,6 +1088,8 @@ class EventCreationHandler(object):
             # matters as sometimes presence code can take a while.
             run_in_background(self._bump_active_time, requester.user)
 
+        return event_stream_id
+
     async def _bump_active_time(self, user):
         try:
             presence = self.hs.get_presence_handler()
diff --git a/synapse/handlers/room.py b/synapse/handlers/room.py
index 13850ba672..2698a129ca 100644
--- a/synapse/handlers/room.py
+++ b/synapse/handlers/room.py
@@ -22,6 +22,7 @@ import logging
 import math
 import string
 from collections import OrderedDict
+from typing import Tuple
 
 from six import iteritems, string_types
 
@@ -518,7 +519,7 @@ class RoomCreationHandler(BaseHandler):
 
     async def create_room(
         self, requester, config, ratelimit=True, creator_join_profile=None
-    ):
+    ) -> Tuple[dict, int]:
         """ Creates a new room.
 
         Args:
@@ -535,9 +536,9 @@ class RoomCreationHandler(BaseHandler):
                 `avatar_url` and/or `displayname`.
 
         Returns:
-            Deferred[dict]:
-                a dict containing the keys `room_id` and, if an alias was
-                requested, `room_alias`.
+                First, a dict containing the keys `room_id` and, if an alias
+                was, requested, `room_alias`. Secondly, the stream_id of the
+                last persisted event.
         Raises:
             SynapseError if the room ID couldn't be stored, or something went
             horribly wrong.
@@ -669,7 +670,7 @@ class RoomCreationHandler(BaseHandler):
         # override any attempt to set room versions via the creation_content
         creation_content["room_version"] = room_version.identifier
 
-        await self._send_events_for_new_room(
+        last_stream_id = await self._send_events_for_new_room(
             requester,
             room_id,
             preset_config=preset_config,
@@ -683,7 +684,10 @@ class RoomCreationHandler(BaseHandler):
 
         if "name" in config:
             name = config["name"]
-            await self.event_creation_handler.create_and_send_nonmember_event(
+            (
+                _,
+                last_stream_id,
+            ) = await self.event_creation_handler.create_and_send_nonmember_event(
                 requester,
                 {
                     "type": EventTypes.Name,
@@ -697,7 +701,10 @@ class RoomCreationHandler(BaseHandler):
 
         if "topic" in config:
             topic = config["topic"]
-            await self.event_creation_handler.create_and_send_nonmember_event(
+            (
+                _,
+                last_stream_id,
+            ) = await self.event_creation_handler.create_and_send_nonmember_event(
                 requester,
                 {
                     "type": EventTypes.Topic,
@@ -715,7 +722,7 @@ class RoomCreationHandler(BaseHandler):
             if is_direct:
                 content["is_direct"] = is_direct
 
-            await self.room_member_handler.update_membership(
+            _, last_stream_id = await self.room_member_handler.update_membership(
                 requester,
                 UserID.from_string(invitee),
                 room_id,
@@ -729,7 +736,7 @@ class RoomCreationHandler(BaseHandler):
             id_access_token = invite_3pid.get("id_access_token")  # optional
             address = invite_3pid["address"]
             medium = invite_3pid["medium"]
-            await self.hs.get_room_member_handler().do_3pid_invite(
+            last_stream_id = await self.hs.get_room_member_handler().do_3pid_invite(
                 room_id,
                 requester.user,
                 medium,
@@ -745,7 +752,7 @@ class RoomCreationHandler(BaseHandler):
         if room_alias:
             result["room_alias"] = room_alias.to_string()
 
-        return result
+        return result, last_stream_id
 
     async def _send_events_for_new_room(
         self,
@@ -758,7 +765,13 @@ class RoomCreationHandler(BaseHandler):
         room_alias=None,
         power_level_content_override=None,  # Doesn't apply when initial state has power level state event content
         creator_join_profile=None,
-    ):
+    ) -> int:
+        """Sends the initial events into a new room.
+
+        Returns:
+            The stream_id of the last event persisted.
+        """
+
         def create(etype, content, **kwargs):
             e = {"type": etype, "content": content}
 
@@ -767,12 +780,16 @@ class RoomCreationHandler(BaseHandler):
 
             return e
 
-        async def send(etype, content, **kwargs):
+        async def send(etype, content, **kwargs) -> int:
             event = create(etype, content, **kwargs)
             logger.debug("Sending %s in new room", etype)
-            await self.event_creation_handler.create_and_send_nonmember_event(
+            (
+                _,
+                last_stream_id,
+            ) = await self.event_creation_handler.create_and_send_nonmember_event(
                 creator, event, ratelimit=False
             )
+            return last_stream_id
 
         config = RoomCreationHandler.PRESETS_DICT[preset_config]
 
@@ -797,7 +814,9 @@ class RoomCreationHandler(BaseHandler):
         # of the first events that get sent into a room.
         pl_content = initial_state.pop((EventTypes.PowerLevels, ""), None)
         if pl_content is not None:
-            await send(etype=EventTypes.PowerLevels, content=pl_content)
+            last_sent_stream_id = await send(
+                etype=EventTypes.PowerLevels, content=pl_content
+            )
         else:
             power_level_content = {
                 "users": {creator_id: 100},
@@ -830,33 +849,39 @@ class RoomCreationHandler(BaseHandler):
             if power_level_content_override:
                 power_level_content.update(power_level_content_override)
 
-            await send(etype=EventTypes.PowerLevels, content=power_level_content)
+            last_sent_stream_id = await send(
+                etype=EventTypes.PowerLevels, content=power_level_content
+            )
 
         if room_alias and (EventTypes.CanonicalAlias, "") not in initial_state:
-            await send(
+            last_sent_stream_id = await send(
                 etype=EventTypes.CanonicalAlias,
                 content={"alias": room_alias.to_string()},
             )
 
         if (EventTypes.JoinRules, "") not in initial_state:
-            await send(
+            last_sent_stream_id = await send(
                 etype=EventTypes.JoinRules, content={"join_rule": config["join_rules"]}
             )
 
         if (EventTypes.RoomHistoryVisibility, "") not in initial_state:
-            await send(
+            last_sent_stream_id = await send(
                 etype=EventTypes.RoomHistoryVisibility,
                 content={"history_visibility": config["history_visibility"]},
             )
 
         if config["guest_can_join"]:
             if (EventTypes.GuestAccess, "") not in initial_state:
-                await send(
+                last_sent_stream_id = await send(
                     etype=EventTypes.GuestAccess, content={"guest_access": "can_join"}
                 )
 
         for (etype, state_key), content in initial_state.items():
-            await send(etype=etype, state_key=state_key, content=content)
+            last_sent_stream_id = await send(
+                etype=etype, state_key=state_key, content=content
+            )
+
+        return last_sent_stream_id
 
     async def _generate_room_id(
         self, creator_id: str, is_public: str, room_version: RoomVersion,
diff --git a/synapse/handlers/room_member.py b/synapse/handlers/room_member.py
index e51e1c32fe..691b6705b2 100644
--- a/synapse/handlers/room_member.py
+++ b/synapse/handlers/room_member.py
@@ -17,7 +17,7 @@
 
 import abc
 import logging
-from typing import Dict, Iterable, List, Optional, Tuple, Union
+from typing import Dict, Iterable, List, Optional, Tuple
 
 from six.moves import http_client
 
@@ -84,7 +84,7 @@ class RoomMemberHandler(object):
         room_id: str,
         user: UserID,
         content: dict,
-    ) -> Optional[dict]:
+    ) -> Tuple[str, int]:
         """Try and join a room that this server is not in
 
         Args:
@@ -104,7 +104,7 @@ class RoomMemberHandler(object):
         room_id: str,
         target: UserID,
         content: dict,
-    ) -> dict:
+    ) -> Tuple[Optional[str], int]:
         """Attempt to reject an invite for a room this server is not in. If we
         fail to do so we locally mark the invite as rejected.
 
@@ -154,7 +154,7 @@ class RoomMemberHandler(object):
         ratelimit: bool = True,
         content: Optional[dict] = None,
         require_consent: bool = True,
-    ) -> EventBase:
+    ) -> Tuple[str, int]:
         user_id = target.to_string()
 
         if content is None:
@@ -187,9 +187,10 @@ class RoomMemberHandler(object):
         )
         if duplicate is not None:
             # Discard the new event since this membership change is a no-op.
-            return duplicate
+            _, stream_id = await self.store.get_event_ordering(duplicate.event_id)
+            return duplicate.event_id, stream_id
 
-        await self.event_creation_handler.handle_new_client_event(
+        stream_id = await self.event_creation_handler.handle_new_client_event(
             requester, event, context, extra_users=[target], ratelimit=ratelimit
         )
 
@@ -213,7 +214,7 @@ class RoomMemberHandler(object):
                 if prev_member_event.membership == Membership.JOIN:
                     await self._user_left_room(target, room_id)
 
-        return event
+        return event.event_id, stream_id
 
     async def copy_room_tags_and_direct_to_room(
         self, old_room_id, new_room_id, user_id
@@ -263,7 +264,7 @@ class RoomMemberHandler(object):
         ratelimit: bool = True,
         content: Optional[dict] = None,
         require_consent: bool = True,
-    ) -> Union[EventBase, Optional[dict]]:
+    ) -> Tuple[Optional[str], int]:
         key = (room_id,)
 
         with (await self.member_linearizer.queue(key)):
@@ -294,7 +295,7 @@ class RoomMemberHandler(object):
         ratelimit: bool = True,
         content: Optional[dict] = None,
         require_consent: bool = True,
-    ) -> Union[EventBase, Optional[dict]]:
+    ) -> Tuple[Optional[str], int]:
         content_specified = bool(content)
         if content is None:
             content = {}
@@ -398,7 +399,13 @@ class RoomMemberHandler(object):
                 same_membership = old_membership == effective_membership_state
                 same_sender = requester.user.to_string() == old_state.sender
                 if same_sender and same_membership and same_content:
-                    return old_state
+                    _, stream_id = await self.store.get_event_ordering(
+                        old_state.event_id
+                    )
+                    return (
+                        old_state.event_id,
+                        stream_id,
+                    )
 
             if old_membership in ["ban", "leave"] and action == "kick":
                 raise AuthError(403, "The target user is not in the room")
@@ -705,7 +712,7 @@ class RoomMemberHandler(object):
         requester: Requester,
         txn_id: Optional[str],
         id_access_token: Optional[str] = None,
-    ) -> None:
+    ) -> int:
         if self.config.block_non_admin_invites:
             is_requester_admin = await self.auth.is_server_admin(requester.user)
             if not is_requester_admin:
@@ -737,11 +744,11 @@ class RoomMemberHandler(object):
         )
 
         if invitee:
-            await self.update_membership(
+            _, stream_id = await self.update_membership(
                 requester, UserID.from_string(invitee), room_id, "invite", txn_id=txn_id
             )
         else:
-            await self._make_and_store_3pid_invite(
+            stream_id = await self._make_and_store_3pid_invite(
                 requester,
                 id_server,
                 medium,
@@ -752,6 +759,8 @@ class RoomMemberHandler(object):
                 id_access_token=id_access_token,
             )
 
+        return stream_id
+
     async def _make_and_store_3pid_invite(
         self,
         requester: Requester,
@@ -762,7 +771,7 @@ class RoomMemberHandler(object):
         user: UserID,
         txn_id: Optional[str],
         id_access_token: Optional[str] = None,
-    ) -> None:
+    ) -> int:
         room_state = await self.state_handler.get_current_state(room_id)
 
         inviter_display_name = ""
@@ -817,7 +826,10 @@ class RoomMemberHandler(object):
             id_access_token=id_access_token,
         )
 
-        await self.event_creation_handler.create_and_send_nonmember_event(
+        (
+            event,
+            stream_id,
+        ) = await self.event_creation_handler.create_and_send_nonmember_event(
             requester,
             {
                 "type": EventTypes.ThirdPartyInvite,
@@ -835,6 +847,7 @@ class RoomMemberHandler(object):
             ratelimit=False,
             txn_id=txn_id,
         )
+        return stream_id
 
     async def _is_host_in_room(
         self, current_state_ids: Dict[Tuple[str, str], str]
@@ -916,7 +929,7 @@ class RoomMemberMasterHandler(RoomMemberHandler):
         room_id: str,
         user: UserID,
         content: dict,
-    ) -> None:
+    ) -> Tuple[str, int]:
         """Implements RoomMemberHandler._remote_join
         """
         # filter ourselves out of remote_room_hosts: do_invite_join ignores it
@@ -945,7 +958,7 @@ class RoomMemberMasterHandler(RoomMemberHandler):
         # join dance for now, since we're kinda implicitly checking
         # that we are allowed to join when we decide whether or not we
         # need to do the invite/join dance.
-        await self.federation_handler.do_invite_join(
+        event_id, stream_id = await self.federation_handler.do_invite_join(
             remote_room_hosts, room_id, user.to_string(), content
         )
         await self._user_joined_room(user, room_id)
@@ -955,14 +968,14 @@ class RoomMemberMasterHandler(RoomMemberHandler):
         if self.hs.config.limit_remote_rooms.enabled:
             if too_complex is False:
                 # We checked, and we're under the limit.
-                return
+                return event_id, stream_id
 
             # Check again, but with the local state events
             too_complex = await self._is_local_room_too_complex(room_id)
 
             if too_complex is False:
                 # We're under the limit.
-                return
+                return event_id, stream_id
 
             # The room is too large. Leave.
             requester = types.create_requester(user, None, False, None)
@@ -975,6 +988,8 @@ class RoomMemberMasterHandler(RoomMemberHandler):
                 errcode=Codes.RESOURCE_LIMIT_EXCEEDED,
             )
 
+        return event_id, stream_id
+
     async def _remote_reject_invite(
         self,
         requester: Requester,
@@ -982,15 +997,15 @@ class RoomMemberMasterHandler(RoomMemberHandler):
         room_id: str,
         target: UserID,
         content: dict,
-    ) -> dict:
+    ) -> Tuple[Optional[str], int]:
         """Implements RoomMemberHandler._remote_reject_invite
         """
         fed_handler = self.federation_handler
         try:
-            ret = await fed_handler.do_remotely_reject_invite(
+            event, stream_id = await fed_handler.do_remotely_reject_invite(
                 remote_room_hosts, room_id, target.to_string(), content=content,
             )
-            return ret
+            return event.event_id, stream_id
         except Exception as e:
             # if we were unable to reject the exception, just mark
             # it as rejected on our end and plough ahead.
@@ -1000,8 +1015,10 @@ class RoomMemberMasterHandler(RoomMemberHandler):
             #
             logger.warning("Failed to reject invite: %s", e)
 
-            await self.store.locally_reject_invite(target.to_string(), room_id)
-            return {}
+            stream_id = await self.store.locally_reject_invite(
+                target.to_string(), room_id
+            )
+            return None, stream_id
 
     async def _user_joined_room(self, target: UserID, room_id: str) -> None:
         """Implements RoomMemberHandler._user_joined_room
diff --git a/synapse/handlers/room_member_worker.py b/synapse/handlers/room_member_worker.py
index 5c776cc0be..02e0c4103d 100644
--- a/synapse/handlers/room_member_worker.py
+++ b/synapse/handlers/room_member_worker.py
@@ -14,7 +14,7 @@
 # limitations under the License.
 
 import logging
-from typing import List, Optional
+from typing import List, Optional, Tuple
 
 from synapse.api.errors import SynapseError
 from synapse.handlers.room_member import RoomMemberHandler
@@ -43,7 +43,7 @@ class RoomMemberWorkerHandler(RoomMemberHandler):
         room_id: str,
         user: UserID,
         content: dict,
-    ) -> Optional[dict]:
+    ) -> Tuple[str, int]:
         """Implements RoomMemberHandler._remote_join
         """
         if len(remote_room_hosts) == 0:
@@ -59,7 +59,7 @@ class RoomMemberWorkerHandler(RoomMemberHandler):
 
         await self._user_joined_room(user, room_id)
 
-        return ret
+        return ret["event_id"], ret["stream_id"]
 
     async def _remote_reject_invite(
         self,
@@ -68,16 +68,17 @@ class RoomMemberWorkerHandler(RoomMemberHandler):
         room_id: str,
         target: UserID,
         content: dict,
-    ) -> dict:
+    ) -> Tuple[Optional[str], int]:
         """Implements RoomMemberHandler._remote_reject_invite
         """
-        return await self._remote_reject_client(
+        ret = await self._remote_reject_client(
             requester=requester,
             remote_room_hosts=remote_room_hosts,
             room_id=room_id,
             user_id=target.to_string(),
             content=content,
         )
+        return ret["event_id"], ret["stream_id"]
 
     async def _user_joined_room(self, target: UserID, room_id: str) -> None:
         """Implements RoomMemberHandler._user_joined_room
diff --git a/synapse/replication/http/federation.py b/synapse/replication/http/federation.py
index 7e23b565b9..c287c4e269 100644
--- a/synapse/replication/http/federation.py
+++ b/synapse/replication/http/federation.py
@@ -29,7 +29,7 @@ logger = logging.getLogger(__name__)
 
 class ReplicationFederationSendEventsRestServlet(ReplicationEndpoint):
     """Handles events newly received from federation, including persisting and
-    notifying.
+    notifying. Returns the maximum stream ID of the persisted events.
 
     The API looks like:
 
@@ -46,6 +46,13 @@ class ReplicationFederationSendEventsRestServlet(ReplicationEndpoint):
                 "context": { .. serialized event context .. },
             }],
             "backfilled": false
+        }
+
+        200 OK
+
+        {
+            "max_stream_id": 32443,
+        }
     """
 
     NAME = "fed_send_events"
@@ -115,11 +122,11 @@ class ReplicationFederationSendEventsRestServlet(ReplicationEndpoint):
 
         logger.info("Got %d events from federation", len(event_and_contexts))
 
-        await self.federation_handler.persist_events_and_notify(
+        max_stream_id = await self.federation_handler.persist_events_and_notify(
             event_and_contexts, backfilled
         )
 
-        return 200, {}
+        return 200, {"max_stream_id": max_stream_id}
 
 
 class ReplicationFederationSendEduRestServlet(ReplicationEndpoint):
diff --git a/synapse/replication/http/membership.py b/synapse/replication/http/membership.py
index 3577611fd7..050fd34562 100644
--- a/synapse/replication/http/membership.py
+++ b/synapse/replication/http/membership.py
@@ -76,11 +76,11 @@ class ReplicationRemoteJoinRestServlet(ReplicationEndpoint):
 
         logger.info("remote_join: %s into room: %s", user_id, room_id)
 
-        await self.federation_handler.do_invite_join(
+        event_id, stream_id = await self.federation_handler.do_invite_join(
             remote_room_hosts, room_id, user_id, event_content
         )
 
-        return 200, {}
+        return 200, {"event_id": event_id, "stream_id": stream_id}
 
 
 class ReplicationRemoteRejectInviteRestServlet(ReplicationEndpoint):
@@ -136,10 +136,10 @@ class ReplicationRemoteRejectInviteRestServlet(ReplicationEndpoint):
         logger.info("remote_reject_invite: %s out of room: %s", user_id, room_id)
 
         try:
-            event = await self.federation_handler.do_remotely_reject_invite(
+            event, stream_id = await self.federation_handler.do_remotely_reject_invite(
                 remote_room_hosts, room_id, user_id, event_content,
             )
-            ret = event.get_pdu_json()
+            event_id = event.event_id
         except Exception as e:
             # if we were unable to reject the exception, just mark
             # it as rejected on our end and plough ahead.
@@ -149,10 +149,10 @@ class ReplicationRemoteRejectInviteRestServlet(ReplicationEndpoint):
             #
             logger.warning("Failed to reject invite: %s", e)
 
-            await self.store.locally_reject_invite(user_id, room_id)
-            ret = {}
+            stream_id = await self.store.locally_reject_invite(user_id, room_id)
+            event_id = None
 
-        return 200, ret
+        return 200, {"event_id": event_id, "stream_id": stream_id}
 
 
 class ReplicationUserJoinedLeftRoomRestServlet(ReplicationEndpoint):
diff --git a/synapse/replication/http/send_event.py b/synapse/replication/http/send_event.py
index b74b088ff4..c981723c1a 100644
--- a/synapse/replication/http/send_event.py
+++ b/synapse/replication/http/send_event.py
@@ -119,11 +119,11 @@ class ReplicationSendEventRestServlet(ReplicationEndpoint):
             "Got event to send with ID: %s into room: %s", event.event_id, event.room_id
         )
 
-        await self.event_creation_handler.persist_and_notify_client_event(
+        stream_id = await self.event_creation_handler.persist_and_notify_client_event(
             requester, event, context, ratelimit=ratelimit, extra_users=extra_users
         )
 
-        return 200, {}
+        return 200, {"stream_id": stream_id}
 
 
 def register_servlets(hs, http_server):
diff --git a/synapse/replication/http/streams.py b/synapse/replication/http/streams.py
index b705a8e16c..bde97eef32 100644
--- a/synapse/replication/http/streams.py
+++ b/synapse/replication/http/streams.py
@@ -51,10 +51,7 @@ class ReplicationGetStreamUpdates(ReplicationEndpoint):
         super().__init__(hs)
 
         self._instance_name = hs.get_instance_name()
-
-        # We pull the streams from the replication handler (if we try and make
-        # them ourselves we end up in an import loop).
-        self.streams = hs.get_tcp_replication().get_streams()
+        self.streams = hs.get_replication_streams()
 
     @staticmethod
     def _serialize_payload(stream_name, from_token, upto_token):
diff --git a/synapse/replication/tcp/client.py b/synapse/replication/tcp/client.py
index 28826302f5..508ad1b720 100644
--- a/synapse/replication/tcp/client.py
+++ b/synapse/replication/tcp/client.py
@@ -14,19 +14,23 @@
 # limitations under the License.
 """A replication client for use by synapse workers.
 """
-
+import heapq
 import logging
-from typing import TYPE_CHECKING, Tuple
+from typing import TYPE_CHECKING, Dict, List, Tuple
 
+from twisted.internet.defer import Deferred
 from twisted.internet.protocol import ReconnectingClientFactory
 
 from synapse.api.constants import EventTypes
+from synapse.logging.context import PreserveLoggingContext, make_deferred_yieldable
 from synapse.replication.tcp.protocol import ClientReplicationStreamProtocol
 from synapse.replication.tcp.streams.events import (
     EventsStream,
     EventsStreamEventRow,
     EventsStreamRow,
 )
+from synapse.util.async_helpers import timeout_deferred
+from synapse.util.metrics import Measure
 
 if TYPE_CHECKING:
     from synapse.server import HomeServer
@@ -35,6 +39,10 @@ if TYPE_CHECKING:
 logger = logging.getLogger(__name__)
 
 
+# How long we allow callers to wait for replication updates before timing out.
+_WAIT_FOR_REPLICATION_TIMEOUT_SECONDS = 30
+
+
 class DirectTcpReplicationClientFactory(ReconnectingClientFactory):
     """Factory for building connections to the master. Will reconnect if the
     connection is lost.
@@ -92,6 +100,16 @@ class ReplicationDataHandler:
         self.store = hs.get_datastore()
         self.pusher_pool = hs.get_pusherpool()
         self.notifier = hs.get_notifier()
+        self._reactor = hs.get_reactor()
+        self._clock = hs.get_clock()
+        self._streams = hs.get_replication_streams()
+        self._instance_name = hs.get_instance_name()
+
+        # Map from stream to list of deferreds waiting for the stream to
+        # arrive at a particular position. The lists are sorted by stream position.
+        self._streams_to_waiters = (
+            {}
+        )  # type: Dict[str, List[Tuple[int, Deferred[None]]]]
 
     async def on_rdata(
         self, stream_name: str, instance_name: str, token: int, rows: list
@@ -131,8 +149,76 @@ class ReplicationDataHandler:
 
             await self.pusher_pool.on_new_notifications(token, token)
 
+        # Notify any waiting deferreds. The list is ordered by position so we
+        # just iterate through the list until we reach a position that is
+        # greater than the received row position.
+        waiting_list = self._streams_to_waiters.get(stream_name, [])
+
+        # Index of first item with a position after the current token, i.e we
+        # have called all deferreds before this index. If not overwritten by
+        # loop below means either a) no items in list so no-op or b) all items
+        # in list were called and so the list should be cleared. Setting it to
+        # `len(list)` works for both cases.
+        index_of_first_deferred_not_called = len(waiting_list)
+
+        for idx, (position, deferred) in enumerate(waiting_list):
+            if position <= token:
+                try:
+                    with PreserveLoggingContext():
+                        deferred.callback(None)
+                except Exception:
+                    # The deferred has been cancelled or timed out.
+                    pass
+            else:
+                # The list is sorted by position so we don't need to continue
+                # checking any futher entries in the list.
+                index_of_first_deferred_not_called = idx
+                break
+
+        # Drop all entries in the waiting list that were called in the above
+        # loop. (This maintains the order so no need to resort)
+        waiting_list[:] = waiting_list[index_of_first_deferred_not_called:]
+
     async def on_position(self, stream_name: str, instance_name: str, token: int):
         self.store.process_replication_rows(stream_name, instance_name, token, [])
 
     def on_remote_server_up(self, server: str):
         """Called when get a new REMOTE_SERVER_UP command."""
+
+    async def wait_for_stream_position(
+        self, instance_name: str, stream_name: str, position: int
+    ):
+        """Wait until this instance has received updates up to and including
+        the given stream position.
+        """
+
+        if instance_name == self._instance_name:
+            # We don't get told about updates written by this process, and
+            # anyway in that case we don't need to wait.
+            return
+
+        current_position = self._streams[stream_name].current_token(self._instance_name)
+        if position <= current_position:
+            # We're already past the position
+            return
+
+        # Create a new deferred that times out after N seconds, as we don't want
+        # to wedge here forever.
+        deferred = Deferred()
+        deferred = timeout_deferred(
+            deferred, _WAIT_FOR_REPLICATION_TIMEOUT_SECONDS, self._reactor
+        )
+
+        waiting_list = self._streams_to_waiters.setdefault(stream_name, [])
+
+        # We insert into the list using heapq as it is more efficient than
+        # pushing then resorting each time.
+        heapq.heappush(waiting_list, (position, deferred))
+
+        # We measure here to get in flight counts and average waiting time.
+        with Measure(self._clock, "repl.wait_for_stream_position"):
+            logger.info("Waiting for repl stream %r to reach %s", stream_name, position)
+            await make_deferred_yieldable(deferred)
+            logger.info(
+                "Finished waiting for repl stream %r to reach %s", stream_name, position
+            )
diff --git a/synapse/rest/admin/rooms.py b/synapse/rest/admin/rooms.py
index 7d40001988..0a13e1ed34 100644
--- a/synapse/rest/admin/rooms.py
+++ b/synapse/rest/admin/rooms.py
@@ -59,6 +59,7 @@ class ShutdownRoomRestServlet(RestServlet):
         self.event_creation_handler = hs.get_event_creation_handler()
         self.room_member_handler = hs.get_room_member_handler()
         self.auth = hs.get_auth()
+        self._replication = hs.get_replication_data_handler()
 
     async def on_POST(self, request, room_id):
         requester = await self.auth.get_user_by_req(request)
@@ -73,7 +74,7 @@ class ShutdownRoomRestServlet(RestServlet):
         message = content.get("message", self.DEFAULT_MESSAGE)
         room_name = content.get("room_name", "Content Violation Notification")
 
-        info = await self._room_creation_handler.create_room(
+        info, stream_id = await self._room_creation_handler.create_room(
             room_creator_requester,
             config={
                 "preset": "public_chat",
@@ -94,6 +95,13 @@ class ShutdownRoomRestServlet(RestServlet):
         # desirable in case the first attempt at blocking the room failed below.
         await self.store.block_room(room_id, requester_user_id)
 
+        # We now wait for the create room to come back in via replication so
+        # that we can assume that all the joins/invites have propogated before
+        # we try and auto join below.
+        #
+        # TODO: Currently the events stream is written to from master
+        await self._replication.wait_for_stream_position("master", "events", stream_id)
+
         users = await self.state.get_current_users_in_room(room_id)
         kicked_users = []
         failed_to_kick_users = []
diff --git a/synapse/rest/client/v1/room.py b/synapse/rest/client/v1/room.py
index 6b5830cc3f..105e0cf4d2 100644
--- a/synapse/rest/client/v1/room.py
+++ b/synapse/rest/client/v1/room.py
@@ -93,7 +93,7 @@ class RoomCreateRestServlet(TransactionRestServlet):
     async def on_POST(self, request):
         requester = await self.auth.get_user_by_req(request)
 
-        info = await self._room_creation_handler.create_room(
+        info, _ = await self._room_creation_handler.create_room(
             requester, self.get_room_config(request)
         )
 
@@ -202,7 +202,7 @@ class RoomStateEventRestServlet(TransactionRestServlet):
 
         if event_type == EventTypes.Member:
             membership = content.get("membership", None)
-            event = await self.room_member_handler.update_membership(
+            event_id, _ = await self.room_member_handler.update_membership(
                 requester,
                 target=UserID.from_string(state_key),
                 room_id=room_id,
@@ -210,14 +210,18 @@ class RoomStateEventRestServlet(TransactionRestServlet):
                 content=content,
             )
         else:
-            event = await self.event_creation_handler.create_and_send_nonmember_event(
+            (
+                event,
+                _,
+            ) = await self.event_creation_handler.create_and_send_nonmember_event(
                 requester, event_dict, txn_id=txn_id
             )
+            event_id = event.event_id
 
         ret = {}  # type: dict
-        if event:
-            set_tag("event_id", event.event_id)
-            ret = {"event_id": event.event_id}
+        if event_id:
+            set_tag("event_id", event_id)
+            ret = {"event_id": event_id}
         return 200, ret
 
 
@@ -247,7 +251,7 @@ class RoomSendEventRestServlet(TransactionRestServlet):
         if b"ts" in request.args and requester.app_service:
             event_dict["origin_server_ts"] = parse_integer(request, "ts", 0)
 
-        event = await self.event_creation_handler.create_and_send_nonmember_event(
+        event, _ = await self.event_creation_handler.create_and_send_nonmember_event(
             requester, event_dict, txn_id=txn_id
         )
 
@@ -781,7 +785,7 @@ class RoomRedactEventRestServlet(TransactionRestServlet):
         requester = await self.auth.get_user_by_req(request)
         content = parse_json_object_from_request(request)
 
-        event = await self.event_creation_handler.create_and_send_nonmember_event(
+        event, _ = await self.event_creation_handler.create_and_send_nonmember_event(
             requester,
             {
                 "type": EventTypes.Redaction,
diff --git a/synapse/rest/client/v2_alpha/relations.py b/synapse/rest/client/v2_alpha/relations.py
index 63f07b63da..89002ffbff 100644
--- a/synapse/rest/client/v2_alpha/relations.py
+++ b/synapse/rest/client/v2_alpha/relations.py
@@ -111,7 +111,7 @@ class RelationSendServlet(RestServlet):
             "sender": requester.user.to_string(),
         }
 
-        event = await self.event_creation_handler.create_and_send_nonmember_event(
+        event, _ = await self.event_creation_handler.create_and_send_nonmember_event(
             requester, event_dict=event_dict, txn_id=txn_id
         )
 
diff --git a/synapse/server.py b/synapse/server.py
index c530f1aa1a..ca2deb49bb 100644
--- a/synapse/server.py
+++ b/synapse/server.py
@@ -90,6 +90,7 @@ from synapse.push.pusherpool import PusherPool
 from synapse.replication.tcp.client import ReplicationDataHandler
 from synapse.replication.tcp.handler import ReplicationCommandHandler
 from synapse.replication.tcp.resource import ReplicationStreamer
+from synapse.replication.tcp.streams import STREAMS_MAP
 from synapse.rest.media.v1.media_repository import (
     MediaRepository,
     MediaRepositoryResource,
@@ -210,6 +211,7 @@ class HomeServer(object):
         "storage",
         "replication_streamer",
         "replication_data_handler",
+        "replication_streams",
     ]
 
     REQUIRED_ON_MASTER_STARTUP = ["user_directory_handler", "stats_handler"]
@@ -583,6 +585,9 @@ class HomeServer(object):
     def build_replication_data_handler(self):
         return ReplicationDataHandler(self)
 
+    def build_replication_streams(self):
+        return {stream.NAME: stream(self) for stream in STREAMS_MAP.values()}
+
     def remove_pusher(self, app_id, push_key, user_id):
         return self.get_pusherpool().remove_pusher(app_id, push_key, user_id)
 
diff --git a/synapse/server.pyi b/synapse/server.pyi
index 9e7fad7e6e..fe8024d2d4 100644
--- a/synapse/server.pyi
+++ b/synapse/server.pyi
@@ -1,3 +1,5 @@
+from typing import Dict
+
 import twisted.internet
 
 import synapse.api.auth
@@ -28,6 +30,7 @@ import synapse.server_notices.server_notices_sender
 import synapse.state
 import synapse.storage
 from synapse.events.builder import EventBuilderFactory
+from synapse.replication.tcp.streams import Stream
 
 class HomeServer(object):
     @property
@@ -136,3 +139,5 @@ class HomeServer(object):
         pass
     def get_pusherpool(self) -> synapse.push.pusherpool.PusherPool:
         pass
+    def get_replication_streams(self) -> Dict[str, Stream]:
+        pass
diff --git a/synapse/server_notices/server_notices_manager.py b/synapse/server_notices/server_notices_manager.py
index 999c621b92..bf2454c01c 100644
--- a/synapse/server_notices/server_notices_manager.py
+++ b/synapse/server_notices/server_notices_manager.py
@@ -83,10 +83,10 @@ class ServerNoticesManager(object):
         if state_key is not None:
             event_dict["state_key"] = state_key
 
-        res = await self._event_creation_handler.create_and_send_nonmember_event(
+        event, _ = await self._event_creation_handler.create_and_send_nonmember_event(
             requester, event_dict, ratelimit=False
         )
-        return res
+        return event
 
     @cached()
     async def get_or_create_notice_room_for_user(self, user_id):
@@ -143,7 +143,7 @@ class ServerNoticesManager(object):
             }
 
         requester = create_requester(self.server_notices_mxid)
-        info = await self._room_creation_handler.create_room(
+        info, _ = await self._room_creation_handler.create_room(
             requester,
             config={
                 "preset": RoomCreationPreset.PRIVATE_CHAT,
diff --git a/synapse/storage/data_stores/main/events_worker.py b/synapse/storage/data_stores/main/events_worker.py
index 9130b74eb5..b880a71782 100644
--- a/synapse/storage/data_stores/main/events_worker.py
+++ b/synapse/storage/data_stores/main/events_worker.py
@@ -1289,12 +1289,12 @@ class EventsWorkerStore(SQLBaseStore):
     async def is_event_after(self, event_id1, event_id2):
         """Returns True if event_id1 is after event_id2 in the stream
         """
-        to_1, so_1 = await self._get_event_ordering(event_id1)
-        to_2, so_2 = await self._get_event_ordering(event_id2)
+        to_1, so_1 = await self.get_event_ordering(event_id1)
+        to_2, so_2 = await self.get_event_ordering(event_id2)
         return (to_1, so_1) > (to_2, so_2)
 
     @cachedInlineCallbacks(max_entries=5000)
-    def _get_event_ordering(self, event_id):
+    def get_event_ordering(self, event_id):
         res = yield self.db.simple_select_one(
             table="events",
             retcols=["topological_ordering", "stream_ordering"],
diff --git a/synapse/storage/data_stores/main/roommember.py b/synapse/storage/data_stores/main/roommember.py
index 1e9c850152..7c5ca81ae0 100644
--- a/synapse/storage/data_stores/main/roommember.py
+++ b/synapse/storage/data_stores/main/roommember.py
@@ -1069,6 +1069,8 @@ class RoomMemberStore(RoomMemberWorkerStore, RoomMemberBackgroundUpdateStore):
         with self._stream_id_gen.get_next() as stream_ordering:
             yield self.db.runInteraction("locally_reject_invite", f, stream_ordering)
 
+        return stream_ordering
+
     def forget(self, user_id, room_id):
         """Indicate that user_id wishes to discard history for room_id."""
 
diff --git a/tests/federation/test_complexity.py b/tests/federation/test_complexity.py
index 94980733c4..0c9987be54 100644
--- a/tests/federation/test_complexity.py
+++ b/tests/federation/test_complexity.py
@@ -79,7 +79,9 @@ class RoomComplexityTests(unittest.FederatingHomeserverTestCase):
 
         # Mock out some things, because we don't want to test the whole join
         fed_transport.client.get_json = Mock(return_value=defer.succeed({"v1": 9999}))
-        handler.federation_handler.do_invite_join = Mock(return_value=defer.succeed(1))
+        handler.federation_handler.do_invite_join = Mock(
+            return_value=defer.succeed(("", 1))
+        )
 
         d = handler._remote_join(
             None,
@@ -115,7 +117,9 @@ class RoomComplexityTests(unittest.FederatingHomeserverTestCase):
 
         # Mock out some things, because we don't want to test the whole join
         fed_transport.client.get_json = Mock(return_value=defer.succeed(None))
-        handler.federation_handler.do_invite_join = Mock(return_value=defer.succeed(1))
+        handler.federation_handler.do_invite_join = Mock(
+            return_value=defer.succeed(("", 1))
+        )
 
         # Artificially raise the complexity
         self.hs.get_datastore().get_current_state_event_counts = lambda x: defer.succeed(
diff --git a/tests/handlers/test_typing.py b/tests/handlers/test_typing.py
index 51e2b37218..2fa8d4739b 100644
--- a/tests/handlers/test_typing.py
+++ b/tests/handlers/test_typing.py
@@ -86,7 +86,10 @@ class TypingNotificationsTestCase(unittest.HomeserverTestCase):
         reactor.pump((1000,))
 
         hs = self.setup_test_homeserver(
-            notifier=Mock(), http_client=mock_federation_client, keyring=mock_keyring
+            notifier=Mock(),
+            http_client=mock_federation_client,
+            keyring=mock_keyring,
+            replication_streams={},
         )
 
         hs.datastores = datastores
diff --git a/tests/storage/test_cleanup_extrems.py b/tests/storage/test_cleanup_extrems.py
index 0e04b2cf92..43425c969a 100644
--- a/tests/storage/test_cleanup_extrems.py
+++ b/tests/storage/test_cleanup_extrems.py
@@ -39,7 +39,7 @@ class CleanupExtremBackgroundUpdateStoreTestCase(HomeserverTestCase):
         # Create a test user and room
         self.user = UserID("alice", "test")
         self.requester = Requester(self.user, None, False, None, None)
-        info = self.get_success(self.room_creator.create_room(self.requester, {}))
+        info, _ = self.get_success(self.room_creator.create_room(self.requester, {}))
         self.room_id = info["room_id"]
 
     def run_background_update(self):
@@ -261,7 +261,7 @@ class CleanupExtremDummyEventsTestCase(HomeserverTestCase):
         self.user = UserID.from_string(self.register_user("user1", "password"))
         self.token1 = self.login("user1", "password")
         self.requester = Requester(self.user, None, False, None, None)
-        info = self.get_success(self.room_creator.create_room(self.requester, {}))
+        info, _ = self.get_success(self.room_creator.create_room(self.requester, {}))
         self.room_id = info["room_id"]
         self.event_creator = homeserver.get_event_creation_handler()
         homeserver.config.user_consent_version = self.CONSENT_VERSION
diff --git a/tests/storage/test_event_metrics.py b/tests/storage/test_event_metrics.py
index a7b7fd36d3..a7b85004e5 100644
--- a/tests/storage/test_event_metrics.py
+++ b/tests/storage/test_event_metrics.py
@@ -33,7 +33,7 @@ class ExtremStatisticsTestCase(HomeserverTestCase):
         events = [(3, 2), (6, 2), (4, 6)]
 
         for event_count, extrems in events:
-            info = self.get_success(room_creator.create_room(requester, {}))
+            info, _ = self.get_success(room_creator.create_room(requester, {}))
             room_id = info["room_id"]
 
             last_event = None
diff --git a/tests/test_federation.py b/tests/test_federation.py
index 13ff14863e..c5099dd039 100644
--- a/tests/test_federation.py
+++ b/tests/test_federation.py
@@ -28,13 +28,13 @@ class MessageAcceptTests(unittest.HomeserverTestCase):
         user_id = UserID("us", "test")
         our_user = Requester(user_id, None, False, None, None)
         room_creator = self.homeserver.get_room_creation_handler()
-        room = ensureDeferred(
+        room_deferred = ensureDeferred(
             room_creator.create_room(
                 our_user, room_creator.PRESETS_DICT["public_chat"], ratelimit=False
             )
         )
         self.reactor.advance(0.1)
-        self.room_id = self.successResultOf(room)["room_id"]
+        self.room_id = self.successResultOf(room_deferred)[0]["room_id"]
 
         self.store = self.homeserver.get_datastore()
 

From 4429764c9f00bd1d266f08e08a20daac1b849d46 Mon Sep 17 00:00:00 2001
From: Patrick Cloke <clokep@users.noreply.github.com>
Date: Fri, 22 May 2020 09:30:07 -0400
Subject: [PATCH 12/16] Return 200 OK for all OPTIONS requests (#7534)

---
 changelog.d/7534.misc         |  1 +
 synapse/app/generic_worker.py |  5 ++--
 synapse/app/homeserver.py     | 14 +++++----
 synapse/http/server.py        | 23 +++++++++++++--
 tests/test_server.py          | 53 +++++++++++++++++++++++++++++++++++
 5 files changed, 85 insertions(+), 11 deletions(-)
 create mode 100644 changelog.d/7534.misc

diff --git a/changelog.d/7534.misc b/changelog.d/7534.misc
new file mode 100644
index 0000000000..9088fb65b8
--- /dev/null
+++ b/changelog.d/7534.misc
@@ -0,0 +1 @@
+All endpoints now respond with a 200 OK for `OPTIONS` requests.
\ No newline at end of file
diff --git a/synapse/app/generic_worker.py b/synapse/app/generic_worker.py
index a45c876213..a37520000a 100644
--- a/synapse/app/generic_worker.py
+++ b/synapse/app/generic_worker.py
@@ -22,7 +22,6 @@ from typing import Dict, Iterable
 from typing_extensions import ContextManager
 
 from twisted.internet import defer, reactor
-from twisted.web.resource import NoResource
 
 import synapse
 import synapse.events
@@ -41,7 +40,7 @@ from synapse.config.logger import setup_logging
 from synapse.federation import send_queue
 from synapse.federation.transport.server import TransportLayerServer
 from synapse.handlers.presence import BasePresenceHandler, get_interested_parties
-from synapse.http.server import JsonResource
+from synapse.http.server import JsonResource, OptionsResource
 from synapse.http.servlet import RestServlet, parse_json_object_from_request
 from synapse.http.site import SynapseSite
 from synapse.logging.context import LoggingContext
@@ -566,7 +565,7 @@ class GenericWorkerServer(HomeServer):
                 if name == "replication":
                     resources[REPLICATION_PREFIX] = ReplicationRestResource(self)
 
-        root_resource = create_resource_tree(resources, NoResource())
+        root_resource = create_resource_tree(resources, OptionsResource())
 
         _base.listen_tcp(
             bind_addresses,
diff --git a/synapse/app/homeserver.py b/synapse/app/homeserver.py
index d7f337e586..93a5ba2100 100644
--- a/synapse/app/homeserver.py
+++ b/synapse/app/homeserver.py
@@ -31,7 +31,7 @@ from prometheus_client import Gauge
 from twisted.application import service
 from twisted.internet import defer, reactor
 from twisted.python.failure import Failure
-from twisted.web.resource import EncodingResourceWrapper, IResource, NoResource
+from twisted.web.resource import EncodingResourceWrapper, IResource
 from twisted.web.server import GzipEncoderFactory
 from twisted.web.static import File
 
@@ -52,7 +52,11 @@ from synapse.config._base import ConfigError
 from synapse.config.homeserver import HomeServerConfig
 from synapse.federation.transport.server import TransportLayerServer
 from synapse.http.additional_resource import AdditionalResource
-from synapse.http.server import RootRedirect
+from synapse.http.server import (
+    OptionsResource,
+    RootOptionsRedirectResource,
+    RootRedirect,
+)
 from synapse.http.site import SynapseSite
 from synapse.logging.context import LoggingContext
 from synapse.metrics import METRICS_PREFIX, MetricsResource, RegistryProxy
@@ -121,11 +125,11 @@ class SynapseHomeServer(HomeServer):
 
         # try to find something useful to redirect '/' to
         if WEB_CLIENT_PREFIX in resources:
-            root_resource = RootRedirect(WEB_CLIENT_PREFIX)
+            root_resource = RootOptionsRedirectResource(WEB_CLIENT_PREFIX)
         elif STATIC_PREFIX in resources:
-            root_resource = RootRedirect(STATIC_PREFIX)
+            root_resource = RootOptionsRedirectResource(STATIC_PREFIX)
         else:
-            root_resource = NoResource()
+            root_resource = OptionsResource()
 
         root_resource = create_resource_tree(resources, root_resource)
 
diff --git a/synapse/http/server.py b/synapse/http/server.py
index 042a605198..33fcfbea6e 100644
--- a/synapse/http/server.py
+++ b/synapse/http/server.py
@@ -350,9 +350,6 @@ class JsonResource(HttpServer, resource.Resource):
                 register_paths, so will return (possibly via Deferred) either
                 None, or a tuple of (http code, response body).
         """
-        if request.method == b"OPTIONS":
-            return _options_handler, "options_request_handler", {}
-
         request_path = request.path.decode("ascii")
 
         # Loop through all the registered callbacks to check if the method
@@ -448,6 +445,26 @@ class RootRedirect(resource.Resource):
         return resource.Resource.getChild(self, name, request)
 
 
+class OptionsResource(resource.Resource):
+    """Responds to OPTION requests for itself and all children."""
+
+    def render_OPTIONS(self, request):
+        code, response_json_object = _options_handler(request)
+
+        return respond_with_json(
+            request, code, response_json_object, send_cors=False, canonical_json=False,
+        )
+
+    def getChildWithDefault(self, path, request):
+        if request.method == b"OPTIONS":
+            return self  # select ourselves as the child to render
+        return resource.Resource.getChildWithDefault(self, path, request)
+
+
+class RootOptionsRedirectResource(OptionsResource, RootRedirect):
+    pass
+
+
 def respond_with_json(
     request,
     code,
diff --git a/tests/test_server.py b/tests/test_server.py
index 0d57eed268..437f925bf9 100644
--- a/tests/test_server.py
+++ b/tests/test_server.py
@@ -27,6 +27,7 @@ from synapse.api.errors import Codes, RedirectException, SynapseError
 from synapse.http.server import (
     DirectServeResource,
     JsonResource,
+    OptionsResource,
     wrap_html_request_handler,
 )
 from synapse.http.site import SynapseSite, logger
@@ -168,6 +169,58 @@ class JsonResourceTests(unittest.TestCase):
         self.assertEqual(channel.json_body["errcode"], "M_UNRECOGNIZED")
 
 
+class OptionsResourceTests(unittest.TestCase):
+    def setUp(self):
+        self.reactor = ThreadedMemoryReactorClock()
+
+        class DummyResource(Resource):
+            isLeaf = True
+
+            def render(self, request):
+                return request.path
+
+        # Setup a resource with some children.
+        self.resource = OptionsResource()
+        self.resource.putChild(b"res", DummyResource())
+
+    def _make_request(self, method, path):
+        """Create a request from the method/path and return a channel with the response."""
+        request, channel = make_request(self.reactor, method, path, shorthand=False)
+        request.prepath = []  # This doesn't get set properly by make_request.
+
+        # Create a site and query for the resource.
+        site = SynapseSite("test", "site_tag", {}, self.resource, "1.0")
+        request.site = site
+        resource = site.getResourceFor(request)
+
+        # Finally, render the resource and return the channel.
+        render(request, resource, self.reactor)
+        return channel
+
+    def test_unknown_options_request(self):
+        """An OPTIONS requests to an unknown URL still returns 200 OK."""
+        channel = self._make_request(b"OPTIONS", b"/foo/")
+        self.assertEqual(channel.result["code"], b"200")
+        self.assertEqual(channel.result["body"], b"{}")
+
+    def test_known_options_request(self):
+        """An OPTIONS requests to an known URL still returns 200 OK."""
+        channel = self._make_request(b"OPTIONS", b"/res/")
+        self.assertEqual(channel.result["code"], b"200")
+        self.assertEqual(channel.result["body"], b"{}")
+
+    def test_unknown_request(self):
+        """A non-OPTIONS request to an unknown URL should 404."""
+        channel = self._make_request(b"GET", b"/foo/")
+        self.assertEqual(channel.result["code"], b"404")
+
+    def test_known_request(self):
+        """A non-OPTIONS request to an known URL should query the proper resource."""
+        channel = self._make_request(b"GET", b"/res/")
+        self.assertEqual(channel.result["code"], b"200")
+        self.assertEqual(channel.result["body"], b"/res/")
+
+
 class WrapHtmlRequestHandlerTests(unittest.TestCase):
     class TestResource(DirectServeResource):
         callback = None

From e5c67d04dbe5ed45d659e826a5dfcd5044a4e374 Mon Sep 17 00:00:00 2001
From: Erik Johnston <erik@matrix.org>
Date: Fri, 22 May 2020 16:11:35 +0100
Subject: [PATCH 13/16] Add option to move event persistence off master (#7517)

---
 changelog.d/7517.feature                      |   1 +
 scripts/synapse_port_db                       |   3 +
 synapse/app/generic_worker.py                 |  53 +++++++-
 synapse/config/logger.py                      |   1 +
 synapse/config/workers.py                     |  30 ++++-
 synapse/handlers/federation.py                |  16 ++-
 synapse/handlers/message.py                   |  12 +-
 synapse/handlers/presence.py                  |   6 +
 synapse/handlers/room.py                      |   7 ++
 synapse/handlers/room_member.py               |  39 ++++--
 synapse/replication/http/__init__.py          |   4 +-
 synapse/replication/http/_base.py             |   3 +
 synapse/replication/http/membership.py        |  40 +++++-
 synapse/replication/http/presence.py          | 116 ++++++++++++++++++
 synapse/replication/tcp/handler.py            |  10 ++
 synapse/rest/admin/rooms.py                   |  11 +-
 synapse/storage/data_stores/__init__.py       |   6 +-
 synapse/storage/data_stores/main/devices.py   |  30 +++--
 synapse/storage/data_stores/main/events.py    |  34 ++++-
 .../storage/data_stores/main/events_worker.py |   2 +-
 .../storage/data_stores/main/roommember.py    |  25 ----
 synapse/storage/persist_events.py             |   6 +
 22 files changed, 382 insertions(+), 73 deletions(-)
 create mode 100644 changelog.d/7517.feature
 create mode 100644 synapse/replication/http/presence.py

diff --git a/changelog.d/7517.feature b/changelog.d/7517.feature
new file mode 100644
index 0000000000..6062f0061c
--- /dev/null
+++ b/changelog.d/7517.feature
@@ -0,0 +1 @@
+Add option to move event persistence off master.
diff --git a/scripts/synapse_port_db b/scripts/synapse_port_db
index acd9ac4b75..9a0fbc61d8 100755
--- a/scripts/synapse_port_db
+++ b/scripts/synapse_port_db
@@ -196,6 +196,9 @@ class MockHomeserver:
     def get_reactor(self):
         return reactor
 
+    def get_instance_name(self):
+        return "master"
+
 
 class Porter(object):
     def __init__(self, **kwargs):
diff --git a/synapse/app/generic_worker.py b/synapse/app/generic_worker.py
index a37520000a..2906b93f6a 100644
--- a/synapse/app/generic_worker.py
+++ b/synapse/app/generic_worker.py
@@ -39,7 +39,11 @@ from synapse.config.homeserver import HomeServerConfig
 from synapse.config.logger import setup_logging
 from synapse.federation import send_queue
 from synapse.federation.transport.server import TransportLayerServer
-from synapse.handlers.presence import BasePresenceHandler, get_interested_parties
+from synapse.handlers.presence import (
+    BasePresenceHandler,
+    PresenceState,
+    get_interested_parties,
+)
 from synapse.http.server import JsonResource, OptionsResource
 from synapse.http.servlet import RestServlet, parse_json_object_from_request
 from synapse.http.site import SynapseSite
@@ -47,6 +51,10 @@ from synapse.logging.context import LoggingContext
 from synapse.metrics import METRICS_PREFIX, MetricsResource, RegistryProxy
 from synapse.metrics.background_process_metrics import run_as_background_process
 from synapse.replication.http import REPLICATION_PREFIX, ReplicationRestResource
+from synapse.replication.http.presence import (
+    ReplicationBumpPresenceActiveTime,
+    ReplicationPresenceSetState,
+)
 from synapse.replication.slave.storage._base import BaseSlavedStore
 from synapse.replication.slave.storage.account_data import SlavedAccountDataStore
 from synapse.replication.slave.storage.appservice import SlavedApplicationServiceStore
@@ -247,6 +255,9 @@ class GenericWorkerPresence(BasePresenceHandler):
         # but we haven't notified the master of that yet
         self.users_going_offline = {}
 
+        self._bump_active_client = ReplicationBumpPresenceActiveTime.make_client(hs)
+        self._set_state_client = ReplicationPresenceSetState.make_client(hs)
+
         self._send_stop_syncing_loop = self.clock.looping_call(
             self.send_stop_syncing, UPDATE_SYNCING_USERS_MS
         )
@@ -304,10 +315,6 @@ class GenericWorkerPresence(BasePresenceHandler):
                 self.users_going_offline.pop(user_id, None)
                 self.send_user_sync(user_id, False, last_sync_ms)
 
-    def set_state(self, user, state, ignore_status_msg=False):
-        # TODO Hows this supposed to work?
-        return defer.succeed(None)
-
     async def user_syncing(
         self, user_id: str, affect_presence: bool
     ) -> ContextManager[None]:
@@ -386,6 +393,42 @@ class GenericWorkerPresence(BasePresenceHandler):
             if count > 0
         ]
 
+    async def set_state(self, target_user, state, ignore_status_msg=False):
+        """Set the presence state of the user.
+        """
+        presence = state["presence"]
+
+        valid_presence = (
+            PresenceState.ONLINE,
+            PresenceState.UNAVAILABLE,
+            PresenceState.OFFLINE,
+        )
+        if presence not in valid_presence:
+            raise SynapseError(400, "Invalid presence state")
+
+        user_id = target_user.to_string()
+
+        # If presence is disabled, no-op
+        if not self.hs.config.use_presence:
+            return
+
+        # Proxy request to master
+        await self._set_state_client(
+            user_id=user_id, state=state, ignore_status_msg=ignore_status_msg
+        )
+
+    async def bump_presence_active_time(self, user):
+        """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
+
+        # Proxy request to master
+        user_id = user.to_string()
+        await self._bump_active_client(user_id=user_id)
+
 
 class GenericWorkerTyping(object):
     def __init__(self, hs):
diff --git a/synapse/config/logger.py b/synapse/config/logger.py
index a25c70e928..49f6c32beb 100644
--- a/synapse/config/logger.py
+++ b/synapse/config/logger.py
@@ -257,5 +257,6 @@ def setup_logging(
     logging.warning("***** STARTING SERVER *****")
     logging.warning("Server %s version %s", sys.argv[0], get_version_string(synapse))
     logging.info("Server hostname: %s", config.server_name)
+    logging.info("Instance name: %s", hs.get_instance_name())
 
     return logger
diff --git a/synapse/config/workers.py b/synapse/config/workers.py
index c80c338584..ed06b91a54 100644
--- a/synapse/config/workers.py
+++ b/synapse/config/workers.py
@@ -15,7 +15,7 @@
 
 import attr
 
-from ._base import Config
+from ._base import Config, ConfigError
 
 
 @attr.s
@@ -27,6 +27,17 @@ class InstanceLocationConfig:
     port = attr.ib(type=int)
 
 
+@attr.s
+class WriterLocations:
+    """Specifies the instances that write various streams.
+
+    Attributes:
+        events: The instance that writes to the event and backfill streams.
+    """
+
+    events = attr.ib(default="master", type=str)
+
+
 class WorkerConfig(Config):
     """The workers are processes run separately to the main synapse process.
     They have their own pid_file and listener configuration. They use the
@@ -83,11 +94,26 @@ class WorkerConfig(Config):
                     bind_addresses.append("")
 
         # A map from instance name to host/port of their HTTP replication endpoint.
-        instance_map = config.get("instance_map", {}) or {}
+        instance_map = config.get("instance_map") or {}
         self.instance_map = {
             name: InstanceLocationConfig(**c) for name, c in instance_map.items()
         }
 
+        # Map from type of streams to source, c.f. WriterLocations.
+        writers = config.get("stream_writers") or {}
+        self.writers = WriterLocations(**writers)
+
+        # Check that the configured writer for events also appears in
+        # `instance_map`.
+        if (
+            self.writers.events != "master"
+            and self.writers.events not in self.instance_map
+        ):
+            raise ConfigError(
+                "Instance %r is configured to write events but does not appear in `instance_map` config."
+                % (self.writers.events,)
+            )
+
     def read_arguments(self, args):
         # We support a bunch of command line arguments that override options in
         # the config. A lot of these options have a worker_* prefix when running
diff --git a/synapse/handlers/federation.py b/synapse/handlers/federation.py
index e354c803db..75ec90d267 100644
--- a/synapse/handlers/federation.py
+++ b/synapse/handlers/federation.py
@@ -126,11 +126,10 @@ class FederationHandler(BaseHandler):
         self._server_notices_mxid = hs.config.server_notices_mxid
         self.config = hs.config
         self.http_client = hs.get_simple_http_client()
+        self._instance_name = hs.get_instance_name()
         self._replication = hs.get_replication_data_handler()
 
-        self._send_events_to_master = ReplicationFederationSendEventsRestServlet.make_client(
-            hs
-        )
+        self._send_events = ReplicationFederationSendEventsRestServlet.make_client(hs)
         self._notify_user_membership_change = ReplicationUserJoinedLeftRoomRestServlet.make_client(
             hs
         )
@@ -1243,6 +1242,10 @@ class FederationHandler(BaseHandler):
 
             content: The event content to use for the join event.
         """
+        # TODO: We should be able to call this on workers, but the upgrading of
+        # room stuff after join currently doesn't work on workers.
+        assert self.config.worker.worker_app is None
+
         logger.debug("Joining %s to %s", joinee, room_id)
 
         origin, event, room_version_obj = await self._make_and_verify_event(
@@ -1314,7 +1317,7 @@ class FederationHandler(BaseHandler):
             #
             # TODO: Currently the events stream is written to from master
             await self._replication.wait_for_stream_position(
-                "master", "events", max_stream_id
+                self.config.worker.writers.events, "events", max_stream_id
             )
 
             # Check whether this room is the result of an upgrade of a room we already know
@@ -2854,8 +2857,9 @@ class FederationHandler(BaseHandler):
             backfilled: Whether these events are a result of
                 backfilling or not
         """
-        if self.config.worker_app:
-            result = await self._send_events_to_master(
+        if self.config.worker.writers.events != self._instance_name:
+            result = await self._send_events(
+                instance_name=self.config.worker.writers.events,
                 store=self.store,
                 event_and_contexts=event_and_contexts,
                 backfilled=backfilled,
diff --git a/synapse/handlers/message.py b/synapse/handlers/message.py
index f445e2aa2a..ea25f0515a 100644
--- a/synapse/handlers/message.py
+++ b/synapse/handlers/message.py
@@ -366,10 +366,11 @@ class EventCreationHandler(object):
         self.notifier = hs.get_notifier()
         self.config = hs.config
         self.require_membership_for_aliases = hs.config.require_membership_for_aliases
+        self._instance_name = hs.get_instance_name()
 
         self.room_invite_state_types = self.hs.config.room_invite_state_types
 
-        self.send_event_to_master = ReplicationSendEventRestServlet.make_client(hs)
+        self.send_event = ReplicationSendEventRestServlet.make_client(hs)
 
         # This is only used to get at ratelimit function, and maybe_kick_guest_users
         self.base_handler = BaseHandler(hs)
@@ -835,8 +836,9 @@ class EventCreationHandler(object):
         success = False
         try:
             # If we're a worker we need to hit out to the master.
-            if self.config.worker_app:
-                result = await self.send_event_to_master(
+            if self.config.worker.writers.events != self._instance_name:
+                result = await self.send_event(
+                    instance_name=self.config.worker.writers.events,
                     event_id=event.event_id,
                     store=self.store,
                     requester=requester,
@@ -902,9 +904,9 @@ class EventCreationHandler(object):
         """Called when we have fully built the event, have already
         calculated the push actions for the event, and checked auth.
 
-        This should only be run on master.
+        This should only be run on the instance in charge of persisting events.
         """
-        assert not self.config.worker_app
+        assert self.config.worker.writers.events == self._instance_name
 
         if ratelimit:
             # We check if this is a room admin redacting an event so that we
diff --git a/synapse/handlers/presence.py b/synapse/handlers/presence.py
index 9ea11c0754..3594f3b00f 100644
--- a/synapse/handlers/presence.py
+++ b/synapse/handlers/presence.py
@@ -193,6 +193,12 @@ class BasePresenceHandler(abc.ABC):
     ) -> None:
         """Set the presence state of the user. """
 
+    @abc.abstractmethod
+    async def bump_presence_active_time(self, user: UserID):
+        """We've seen the user do something that indicates they're interacting
+        with the app.
+        """
+
 
 class PresenceHandler(BasePresenceHandler):
     def __init__(self, hs: "synapse.server.HomeServer"):
diff --git a/synapse/handlers/room.py b/synapse/handlers/room.py
index 2698a129ca..61db3ccc43 100644
--- a/synapse/handlers/room.py
+++ b/synapse/handlers/room.py
@@ -89,6 +89,8 @@ class RoomCreationHandler(BaseHandler):
         self.room_member_handler = hs.get_room_member_handler()
         self.config = hs.config
 
+        self._replication = hs.get_replication_data_handler()
+
         # linearizer to stop two upgrades happening at once
         self._upgrade_linearizer = Linearizer("room_upgrade_linearizer")
 
@@ -752,6 +754,11 @@ class RoomCreationHandler(BaseHandler):
         if room_alias:
             result["room_alias"] = room_alias.to_string()
 
+        # Always wait for room creation to progate before returning
+        await self._replication.wait_for_stream_position(
+            self.hs.config.worker.writers.events, "events", last_stream_id
+        )
+
         return result, last_stream_id
 
     async def _send_events_for_new_room(
diff --git a/synapse/handlers/room_member.py b/synapse/handlers/room_member.py
index 691b6705b2..0f7af982f0 100644
--- a/synapse/handlers/room_member.py
+++ b/synapse/handlers/room_member.py
@@ -26,6 +26,9 @@ from synapse.api.constants import EventTypes, Membership
 from synapse.api.errors import AuthError, Codes, SynapseError
 from synapse.events import EventBase
 from synapse.events.snapshot import EventContext
+from synapse.replication.http.membership import (
+    ReplicationLocallyRejectInviteRestServlet,
+)
 from synapse.types import Collection, Requester, RoomAlias, RoomID, UserID
 from synapse.util.async_helpers import Linearizer
 from synapse.util.distributor import user_joined_room, user_left_room
@@ -44,11 +47,6 @@ class RoomMemberHandler(object):
     __metaclass__ = abc.ABCMeta
 
     def __init__(self, hs):
-        """
-
-        Args:
-            hs (synapse.server.HomeServer):
-        """
         self.hs = hs
         self.store = hs.get_datastore()
         self.auth = hs.get_auth()
@@ -71,6 +69,17 @@ class RoomMemberHandler(object):
         self._enable_lookup = hs.config.enable_3pid_lookup
         self.allow_per_room_profiles = self.config.allow_per_room_profiles
 
+        self._event_stream_writer_instance = hs.config.worker.writers.events
+        self._is_on_event_persistence_instance = (
+            self._event_stream_writer_instance == hs.get_instance_name()
+        )
+        if self._is_on_event_persistence_instance:
+            self.persist_event_storage = hs.get_storage().persistence
+        else:
+            self._locally_reject_client = ReplicationLocallyRejectInviteRestServlet.make_client(
+                hs
+            )
+
         # This is only used to get at ratelimit function, and
         # maybe_kick_guest_users. It's fine there are multiple of these as
         # it doesn't store state.
@@ -121,6 +130,22 @@ class RoomMemberHandler(object):
         """
         raise NotImplementedError()
 
+    async def locally_reject_invite(self, user_id: str, room_id: str) -> int:
+        """Mark the invite has having been rejected even though we failed to
+        create a leave event for it.
+        """
+        if self._is_on_event_persistence_instance:
+            return await self.persist_event_storage.locally_reject_invite(
+                user_id, room_id
+            )
+        else:
+            result = await self._locally_reject_client(
+                instance_name=self._event_stream_writer_instance,
+                user_id=user_id,
+                room_id=room_id,
+            )
+            return result["stream_id"]
+
     @abc.abstractmethod
     async def _user_joined_room(self, target: UserID, room_id: str) -> None:
         """Notifies distributor on master process that the user has joined the
@@ -1015,9 +1040,7 @@ class RoomMemberMasterHandler(RoomMemberHandler):
             #
             logger.warning("Failed to reject invite: %s", e)
 
-            stream_id = await self.store.locally_reject_invite(
-                target.to_string(), room_id
-            )
+            stream_id = await self.locally_reject_invite(target.to_string(), room_id)
             return None, stream_id
 
     async def _user_joined_room(self, target: UserID, room_id: str) -> None:
diff --git a/synapse/replication/http/__init__.py b/synapse/replication/http/__init__.py
index a909744e93..19b69e0e11 100644
--- a/synapse/replication/http/__init__.py
+++ b/synapse/replication/http/__init__.py
@@ -19,6 +19,7 @@ from synapse.replication.http import (
     federation,
     login,
     membership,
+    presence,
     register,
     send_event,
     streams,
@@ -35,10 +36,11 @@ class ReplicationRestResource(JsonResource):
     def register_servlets(self, hs):
         send_event.register_servlets(hs, self)
         federation.register_servlets(hs, self)
+        presence.register_servlets(hs, self)
+        membership.register_servlets(hs, self)
 
         # The following can't currently be instantiated on workers.
         if hs.config.worker.worker_app is None:
-            membership.register_servlets(hs, self)
             login.register_servlets(hs, self)
             register.register_servlets(hs, self)
             devices.register_servlets(hs, self)
diff --git a/synapse/replication/http/_base.py b/synapse/replication/http/_base.py
index c3136a4eb9..793cef6c26 100644
--- a/synapse/replication/http/_base.py
+++ b/synapse/replication/http/_base.py
@@ -142,6 +142,7 @@ class ReplicationEndpoint(object):
         """
         clock = hs.get_clock()
         client = hs.get_simple_http_client()
+        local_instance_name = hs.get_instance_name()
 
         master_host = hs.config.worker_replication_host
         master_port = hs.config.worker_replication_http_port
@@ -151,6 +152,8 @@ class ReplicationEndpoint(object):
         @trace(opname="outgoing_replication_request")
         @defer.inlineCallbacks
         def send_request(instance_name="master", **kwargs):
+            if instance_name == local_instance_name:
+                raise Exception("Trying to send HTTP request to self")
             if instance_name == "master":
                 host = master_host
                 port = master_port
diff --git a/synapse/replication/http/membership.py b/synapse/replication/http/membership.py
index 050fd34562..a7174c4a8f 100644
--- a/synapse/replication/http/membership.py
+++ b/synapse/replication/http/membership.py
@@ -14,12 +14,16 @@
 # limitations under the License.
 
 import logging
+from typing import TYPE_CHECKING
 
 from synapse.http.servlet import parse_json_object_from_request
 from synapse.replication.http._base import ReplicationEndpoint
 from synapse.types import Requester, UserID
 from synapse.util.distributor import user_joined_room, user_left_room
 
+if TYPE_CHECKING:
+    from synapse.server import HomeServer
+
 logger = logging.getLogger(__name__)
 
 
@@ -106,6 +110,7 @@ class ReplicationRemoteRejectInviteRestServlet(ReplicationEndpoint):
         self.federation_handler = hs.get_handlers().federation_handler
         self.store = hs.get_datastore()
         self.clock = hs.get_clock()
+        self.member_handler = hs.get_room_member_handler()
 
     @staticmethod
     def _serialize_payload(requester, room_id, user_id, remote_room_hosts, content):
@@ -149,12 +154,44 @@ class ReplicationRemoteRejectInviteRestServlet(ReplicationEndpoint):
             #
             logger.warning("Failed to reject invite: %s", e)
 
-            stream_id = await self.store.locally_reject_invite(user_id, room_id)
+            stream_id = await self.member_handler.locally_reject_invite(
+                user_id, room_id
+            )
             event_id = None
 
         return 200, {"event_id": event_id, "stream_id": stream_id}
 
 
+class ReplicationLocallyRejectInviteRestServlet(ReplicationEndpoint):
+    """Rejects the invite for the user and room locally.
+
+    Request format:
+
+        POST /_synapse/replication/locally_reject_invite/:room_id/:user_id
+
+        {}
+    """
+
+    NAME = "locally_reject_invite"
+    PATH_ARGS = ("room_id", "user_id")
+
+    def __init__(self, hs: "HomeServer"):
+        super().__init__(hs)
+
+        self.member_handler = hs.get_room_member_handler()
+
+    @staticmethod
+    def _serialize_payload(room_id, user_id):
+        return {}
+
+    async def _handle_request(self, request, room_id, user_id):
+        logger.info("locally_reject_invite: %s out of room: %s", user_id, room_id)
+
+        stream_id = await self.member_handler.locally_reject_invite(user_id, room_id)
+
+        return 200, {"stream_id": stream_id}
+
+
 class ReplicationUserJoinedLeftRoomRestServlet(ReplicationEndpoint):
     """Notifies that a user has joined or left the room
 
@@ -208,3 +245,4 @@ def register_servlets(hs, http_server):
     ReplicationRemoteJoinRestServlet(hs).register(http_server)
     ReplicationRemoteRejectInviteRestServlet(hs).register(http_server)
     ReplicationUserJoinedLeftRoomRestServlet(hs).register(http_server)
+    ReplicationLocallyRejectInviteRestServlet(hs).register(http_server)
diff --git a/synapse/replication/http/presence.py b/synapse/replication/http/presence.py
new file mode 100644
index 0000000000..ea1b33331b
--- /dev/null
+++ b/synapse/replication/http/presence.py
@@ -0,0 +1,116 @@
+# -*- coding: utf-8 -*-
+# Copyright 2020 The Matrix.org Foundation C.I.C.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# 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 typing import TYPE_CHECKING
+
+from synapse.http.servlet import parse_json_object_from_request
+from synapse.replication.http._base import ReplicationEndpoint
+from synapse.types import UserID
+
+if TYPE_CHECKING:
+    from synapse.server import HomeServer
+
+logger = logging.getLogger(__name__)
+
+
+class ReplicationBumpPresenceActiveTime(ReplicationEndpoint):
+    """We've seen the user do something that indicates they're interacting
+    with the app.
+
+    The POST looks like:
+
+        POST /_synapse/replication/bump_presence_active_time/<user_id>
+
+        200 OK
+
+        {}
+    """
+
+    NAME = "bump_presence_active_time"
+    PATH_ARGS = ("user_id",)
+    METHOD = "POST"
+    CACHE = False
+
+    def __init__(self, hs: "HomeServer"):
+        super().__init__(hs)
+
+        self._presence_handler = hs.get_presence_handler()
+
+    @staticmethod
+    def _serialize_payload(user_id):
+        return {}
+
+    async def _handle_request(self, request, user_id):
+        await self._presence_handler.bump_presence_active_time(
+            UserID.from_string(user_id)
+        )
+
+        return (
+            200,
+            {},
+        )
+
+
+class ReplicationPresenceSetState(ReplicationEndpoint):
+    """Set the presence state for a user.
+
+    The POST looks like:
+
+        POST /_synapse/replication/presence_set_state/<user_id>
+
+        {
+            "state": { ... },
+            "ignore_status_msg": false,
+        }
+
+        200 OK
+
+        {}
+    """
+
+    NAME = "presence_set_state"
+    PATH_ARGS = ("user_id",)
+    METHOD = "POST"
+    CACHE = False
+
+    def __init__(self, hs: "HomeServer"):
+        super().__init__(hs)
+
+        self._presence_handler = hs.get_presence_handler()
+
+    @staticmethod
+    def _serialize_payload(user_id, state, ignore_status_msg=False):
+        return {
+            "state": state,
+            "ignore_status_msg": ignore_status_msg,
+        }
+
+    async def _handle_request(self, request, user_id):
+        content = parse_json_object_from_request(request)
+
+        await self._presence_handler.set_state(
+            UserID.from_string(user_id), content["state"], content["ignore_status_msg"]
+        )
+
+        return (
+            200,
+            {},
+        )
+
+
+def register_servlets(hs, http_server):
+    ReplicationBumpPresenceActiveTime(hs).register(http_server)
+    ReplicationPresenceSetState(hs).register(http_server)
diff --git a/synapse/replication/tcp/handler.py b/synapse/replication/tcp/handler.py
index acfa66a7a8..03300e5336 100644
--- a/synapse/replication/tcp/handler.py
+++ b/synapse/replication/tcp/handler.py
@@ -38,7 +38,9 @@ from synapse.replication.tcp.commands import (
 from synapse.replication.tcp.protocol import AbstractConnection
 from synapse.replication.tcp.streams import (
     STREAMS_MAP,
+    BackfillStream,
     CachesStream,
+    EventsStream,
     FederationStream,
     Stream,
 )
@@ -87,6 +89,14 @@ class ReplicationCommandHandler:
                 self._streams_to_replicate.append(stream)
                 continue
 
+            if isinstance(stream, (EventsStream, BackfillStream)):
+                # Only add EventStream and BackfillStream as a source on the
+                # instance in charge of event persistence.
+                if hs.config.worker.writers.events == hs.get_instance_name():
+                    self._streams_to_replicate.append(stream)
+
+                continue
+
             # Only add any other streams if we're on master.
             if hs.config.worker_app is not None:
                 continue
diff --git a/synapse/rest/admin/rooms.py b/synapse/rest/admin/rooms.py
index 0a13e1ed34..8173baef8f 100644
--- a/synapse/rest/admin/rooms.py
+++ b/synapse/rest/admin/rooms.py
@@ -100,7 +100,9 @@ class ShutdownRoomRestServlet(RestServlet):
         # we try and auto join below.
         #
         # TODO: Currently the events stream is written to from master
-        await self._replication.wait_for_stream_position("master", "events", stream_id)
+        await self._replication.wait_for_stream_position(
+            self.hs.config.worker.writers.events, "events", stream_id
+        )
 
         users = await self.state.get_current_users_in_room(room_id)
         kicked_users = []
@@ -113,7 +115,7 @@ class ShutdownRoomRestServlet(RestServlet):
 
             try:
                 target_requester = create_requester(user_id)
-                await self.room_member_handler.update_membership(
+                _, stream_id = await self.room_member_handler.update_membership(
                     requester=target_requester,
                     target=target_requester.user,
                     room_id=room_id,
@@ -123,6 +125,11 @@ class ShutdownRoomRestServlet(RestServlet):
                     require_consent=False,
                 )
 
+                # Wait for leave to come in over replication before trying to forget.
+                await self._replication.wait_for_stream_position(
+                    self.hs.config.worker.writers.events, "events", stream_id
+                )
+
                 await self.room_member_handler.forget(target_requester.user, room_id)
 
                 await self.room_member_handler.update_membership(
diff --git a/synapse/storage/data_stores/__init__.py b/synapse/storage/data_stores/__init__.py
index 791961b296..599ee470d4 100644
--- a/synapse/storage/data_stores/__init__.py
+++ b/synapse/storage/data_stores/__init__.py
@@ -66,9 +66,9 @@ class DataStores(object):
 
                     self.main = main_store_class(database, db_conn, hs)
 
-                    # If we're on a process that can persist events (currently
-                    # master), also instantiate a `PersistEventsStore`
-                    if hs.config.worker.worker_app is None:
+                    # If we're on a process that can persist events also
+                    # instantiate a `PersistEventsStore`
+                    if hs.config.worker.writers.events == hs.get_instance_name():
                         self.persist_events = PersistEventsStore(
                             hs, database, self.main
                         )
diff --git a/synapse/storage/data_stores/main/devices.py b/synapse/storage/data_stores/main/devices.py
index 0e8378714a..417ac8dc7c 100644
--- a/synapse/storage/data_stores/main/devices.py
+++ b/synapse/storage/data_stores/main/devices.py
@@ -689,6 +689,25 @@ class DeviceWorkerStore(SQLBaseStore):
             desc="make_remote_user_device_cache_as_stale",
         )
 
+    def mark_remote_user_device_list_as_unsubscribed(self, user_id):
+        """Mark that we no longer track device lists for remote user.
+        """
+
+        def _mark_remote_user_device_list_as_unsubscribed_txn(txn):
+            self.db.simple_delete_txn(
+                txn,
+                table="device_lists_remote_extremeties",
+                keyvalues={"user_id": user_id},
+            )
+            self._invalidate_cache_and_stream(
+                txn, self.get_device_list_last_stream_id_for_remote, (user_id,)
+            )
+
+        return self.db.runInteraction(
+            "mark_remote_user_device_list_as_unsubscribed",
+            _mark_remote_user_device_list_as_unsubscribed_txn,
+        )
+
 
 class DeviceBackgroundUpdateStore(SQLBaseStore):
     def __init__(self, database: Database, db_conn, hs):
@@ -969,17 +988,6 @@ class DeviceStore(DeviceWorkerStore, DeviceBackgroundUpdateStore):
             desc="update_device",
         )
 
-    @defer.inlineCallbacks
-    def mark_remote_user_device_list_as_unsubscribed(self, user_id):
-        """Mark that we no longer track device lists for remote user.
-        """
-        yield self.db.simple_delete(
-            table="device_lists_remote_extremeties",
-            keyvalues={"user_id": user_id},
-            desc="mark_remote_user_device_list_as_unsubscribed",
-        )
-        self.get_device_list_last_stream_id_for_remote.invalidate((user_id,))
-
     def update_remote_device_list_cache_entry(
         self, user_id, device_id, content, stream_id
     ):
diff --git a/synapse/storage/data_stores/main/events.py b/synapse/storage/data_stores/main/events.py
index a97f8b3934..a6572571b4 100644
--- a/synapse/storage/data_stores/main/events.py
+++ b/synapse/storage/data_stores/main/events.py
@@ -138,10 +138,10 @@ class PersistEventsStore:
         self._backfill_id_gen = self.store._backfill_id_gen  # type: StreamIdGenerator
         self._stream_id_gen = self.store._stream_id_gen  # type: StreamIdGenerator
 
-        # This should only exist on master for now
+        # This should only exist on instances that are configured to write
         assert (
-            hs.config.worker.worker_app is None
-        ), "Can only instantiate PersistEventsStore on master"
+            hs.config.worker.writers.events == hs.get_instance_name()
+        ), "Can only instantiate EventsStore on master"
 
     @_retry_on_integrity_error
     @defer.inlineCallbacks
@@ -1590,3 +1590,31 @@ class PersistEventsStore:
                 if not ev.internal_metadata.is_outlier()
             ],
         )
+
+    async def locally_reject_invite(self, user_id: str, room_id: str) -> int:
+        """Mark the invite has having been rejected even though we failed to
+        create a leave event for it.
+        """
+
+        sql = (
+            "UPDATE local_invites SET stream_id = ?, locally_rejected = ? WHERE"
+            " room_id = ? AND invitee = ? AND locally_rejected is NULL"
+            " AND replaced_by is NULL"
+        )
+
+        def f(txn, stream_ordering):
+            txn.execute(sql, (stream_ordering, True, room_id, user_id))
+
+            # We also clear this entry from `local_current_membership`.
+            # Ideally we'd point to a leave event, but we don't have one, so
+            # nevermind.
+            self.db.simple_delete_txn(
+                txn,
+                table="local_current_membership",
+                keyvalues={"room_id": room_id, "user_id": user_id},
+            )
+
+        with self._stream_id_gen.get_next() as stream_ordering:
+            await self.db.runInteraction("locally_reject_invite", f, stream_ordering)
+
+        return stream_ordering
diff --git a/synapse/storage/data_stores/main/events_worker.py b/synapse/storage/data_stores/main/events_worker.py
index b880a71782..213d69100a 100644
--- a/synapse/storage/data_stores/main/events_worker.py
+++ b/synapse/storage/data_stores/main/events_worker.py
@@ -76,7 +76,7 @@ class EventsWorkerStore(SQLBaseStore):
     def __init__(self, database: Database, db_conn, hs):
         super(EventsWorkerStore, self).__init__(database, db_conn, hs)
 
-        if hs.config.worker_app is None:
+        if hs.config.worker.writers.events == hs.get_instance_name():
             # We are the process in charge of generating stream ids for events,
             # so instantiate ID generators based on the database
             self._stream_id_gen = StreamIdGenerator(
diff --git a/synapse/storage/data_stores/main/roommember.py b/synapse/storage/data_stores/main/roommember.py
index 7c5ca81ae0..137ebac833 100644
--- a/synapse/storage/data_stores/main/roommember.py
+++ b/synapse/storage/data_stores/main/roommember.py
@@ -1046,31 +1046,6 @@ class RoomMemberStore(RoomMemberWorkerStore, RoomMemberBackgroundUpdateStore):
     def __init__(self, database: Database, db_conn, hs):
         super(RoomMemberStore, self).__init__(database, db_conn, hs)
 
-    @defer.inlineCallbacks
-    def locally_reject_invite(self, user_id, room_id):
-        sql = (
-            "UPDATE local_invites SET stream_id = ?, locally_rejected = ? WHERE"
-            " room_id = ? AND invitee = ? AND locally_rejected is NULL"
-            " AND replaced_by is NULL"
-        )
-
-        def f(txn, stream_ordering):
-            txn.execute(sql, (stream_ordering, True, room_id, user_id))
-
-            # We also clear this entry from `local_current_membership`.
-            # Ideally we'd point to a leave event, but we don't have one, so
-            # nevermind.
-            self.db.simple_delete_txn(
-                txn,
-                table="local_current_membership",
-                keyvalues={"room_id": room_id, "user_id": user_id},
-            )
-
-        with self._stream_id_gen.get_next() as stream_ordering:
-            yield self.db.runInteraction("locally_reject_invite", f, stream_ordering)
-
-        return stream_ordering
-
     def forget(self, user_id, room_id):
         """Indicate that user_id wishes to discard history for room_id."""
 
diff --git a/synapse/storage/persist_events.py b/synapse/storage/persist_events.py
index 12e1ffb9a2..f159400a87 100644
--- a/synapse/storage/persist_events.py
+++ b/synapse/storage/persist_events.py
@@ -786,3 +786,9 @@ class EventsPersistenceStorage(object):
 
         for user_id in left_users:
             await self.main_store.mark_remote_user_device_list_as_unsubscribed(user_id)
+
+    async def locally_reject_invite(self, user_id: str, room_id: str) -> int:
+        """Mark the invite has having been rejected even though we failed to
+        create a leave event for it.
+        """
+        return await self.persist_events_store.locally_reject_invite(user_id, room_id)

From 2901f54359bba1ccbe2aac52fd9ff255aa6072b7 Mon Sep 17 00:00:00 2001
From: Erik Johnston <erik@matrix.org>
Date: Fri, 22 May 2020 17:42:39 +0100
Subject: [PATCH 14/16] Fix missing CORS headers on OPTION responses (#7560)

Broke in #7534.
---
 changelog.d/7560.misc  |  1 +
 synapse/http/server.py |  2 +-
 tests/test_server.py   | 28 ++++++++++++++++++++++++++++
 3 files changed, 30 insertions(+), 1 deletion(-)
 create mode 100644 changelog.d/7560.misc

diff --git a/changelog.d/7560.misc b/changelog.d/7560.misc
new file mode 100644
index 0000000000..9088fb65b8
--- /dev/null
+++ b/changelog.d/7560.misc
@@ -0,0 +1 @@
+All endpoints now respond with a 200 OK for `OPTIONS` requests.
\ No newline at end of file
diff --git a/synapse/http/server.py b/synapse/http/server.py
index 33fcfbea6e..9cc2e2e154 100644
--- a/synapse/http/server.py
+++ b/synapse/http/server.py
@@ -452,7 +452,7 @@ class OptionsResource(resource.Resource):
         code, response_json_object = _options_handler(request)
 
         return respond_with_json(
-            request, code, response_json_object, send_cors=False, canonical_json=False,
+            request, code, response_json_object, send_cors=True, canonical_json=False,
         )
 
     def getChildWithDefault(self, path, request):
diff --git a/tests/test_server.py b/tests/test_server.py
index 437f925bf9..e9a43b1e45 100644
--- a/tests/test_server.py
+++ b/tests/test_server.py
@@ -203,12 +203,40 @@ class OptionsResourceTests(unittest.TestCase):
         self.assertEqual(channel.result["code"], b"200")
         self.assertEqual(channel.result["body"], b"{}")
 
+        # Ensure the correct CORS headers have been added
+        self.assertTrue(
+            channel.headers.hasHeader(b"Access-Control-Allow-Origin"),
+            "has CORS Origin header",
+        )
+        self.assertTrue(
+            channel.headers.hasHeader(b"Access-Control-Allow-Methods"),
+            "has CORS Methods header",
+        )
+        self.assertTrue(
+            channel.headers.hasHeader(b"Access-Control-Allow-Headers"),
+            "has CORS Headers header",
+        )
+
     def test_known_options_request(self):
         """An OPTIONS requests to an known URL still returns 200 OK."""
         channel = self._make_request(b"OPTIONS", b"/res/")
         self.assertEqual(channel.result["code"], b"200")
         self.assertEqual(channel.result["body"], b"{}")
 
+        # Ensure the correct CORS headers have been added
+        self.assertTrue(
+            channel.headers.hasHeader(b"Access-Control-Allow-Origin"),
+            "has CORS Origin header",
+        )
+        self.assertTrue(
+            channel.headers.hasHeader(b"Access-Control-Allow-Methods"),
+            "has CORS Methods header",
+        )
+        self.assertTrue(
+            channel.headers.hasHeader(b"Access-Control-Allow-Headers"),
+            "has CORS Headers header",
+        )
+
     def test_unknown_request(self):
         """A non-OPTIONS request to an unknown URL should 404."""
         channel = self._make_request(b"GET", b"/foo/")

From f4269694ce51a04761e43fc5897d6f8fe0ea18cc Mon Sep 17 00:00:00 2001
From: Richard van der Hoff <1389908+richvdh@users.noreply.github.com>
Date: Fri, 22 May 2020 21:47:07 +0100
Subject: [PATCH 15/16] Optimise some references to hs.config (#7546)

These are surprisingly expensive, and we only really need to do them at startup.
---
 changelog.d/7546.misc                         |   1 +
 synapse/handlers/message.py                   |   8 +-
 .../resource_limits_server_notices.py         |  15 ++-
 .../data_stores/main/monthly_active_users.py  |  28 +++--
 .../test_resource_limits_server_notices.py    |  60 +++++-----
 tests/storage/test_client_ips.py              |  13 +--
 tests/storage/test_monthly_active_users.py    | 110 ++++++++++--------
 tests/test_mau.py                             |  63 +++++-----
 8 files changed, 162 insertions(+), 136 deletions(-)
 create mode 100644 changelog.d/7546.misc

diff --git a/changelog.d/7546.misc b/changelog.d/7546.misc
new file mode 100644
index 0000000000..0a9704789b
--- /dev/null
+++ b/changelog.d/7546.misc
@@ -0,0 +1 @@
+Optimise some references to `hs.config`.
diff --git a/synapse/handlers/message.py b/synapse/handlers/message.py
index ea25f0515a..681f92cafd 100644
--- a/synapse/handlers/message.py
+++ b/synapse/handlers/message.py
@@ -366,7 +366,9 @@ class EventCreationHandler(object):
         self.notifier = hs.get_notifier()
         self.config = hs.config
         self.require_membership_for_aliases = hs.config.require_membership_for_aliases
-        self._instance_name = hs.get_instance_name()
+        self._is_event_writer = (
+            self.config.worker.writers.events == hs.get_instance_name()
+        )
 
         self.room_invite_state_types = self.hs.config.room_invite_state_types
 
@@ -836,7 +838,7 @@ class EventCreationHandler(object):
         success = False
         try:
             # If we're a worker we need to hit out to the master.
-            if self.config.worker.writers.events != self._instance_name:
+            if not self._is_event_writer:
                 result = await self.send_event(
                     instance_name=self.config.worker.writers.events,
                     event_id=event.event_id,
@@ -906,7 +908,7 @@ class EventCreationHandler(object):
 
         This should only be run on the instance in charge of persisting events.
         """
-        assert self.config.worker.writers.events == self._instance_name
+        assert self._is_event_writer
 
         if ratelimit:
             # We check if this is a room admin redacting an event so that we
diff --git a/synapse/server_notices/resource_limits_server_notices.py b/synapse/server_notices/resource_limits_server_notices.py
index d97166351e..73f2cedb5c 100644
--- a/synapse/server_notices/resource_limits_server_notices.py
+++ b/synapse/server_notices/resource_limits_server_notices.py
@@ -48,6 +48,12 @@ class ResourceLimitsServerNotices(object):
 
         self._notifier = hs.get_notifier()
 
+        self._enabled = (
+            hs.config.limit_usage_by_mau
+            and self._server_notices_manager.is_enabled()
+            and not hs.config.hs_disabled
+        )
+
     async def maybe_send_server_notice_to_user(self, user_id):
         """Check if we need to send a notice to this user, this will be true in
         two cases.
@@ -61,14 +67,7 @@ class ResourceLimitsServerNotices(object):
         Returns:
             Deferred
         """
-        if self._config.hs_disabled is True:
-            return
-
-        if self._config.limit_usage_by_mau is False:
-            return
-
-        if not self._server_notices_manager.is_enabled():
-            # Don't try and send server notices unless they've been enabled
+        if not self._enabled:
             return
 
         timestamp = await self._store.user_last_seen_monthly_active(user_id)
diff --git a/synapse/storage/data_stores/main/monthly_active_users.py b/synapse/storage/data_stores/main/monthly_active_users.py
index 925bc5691b..a42c52f323 100644
--- a/synapse/storage/data_stores/main/monthly_active_users.py
+++ b/synapse/storage/data_stores/main/monthly_active_users.py
@@ -122,6 +122,10 @@ class MonthlyActiveUsersStore(MonthlyActiveUsersWorkerStore):
     def __init__(self, database: Database, db_conn, hs):
         super(MonthlyActiveUsersStore, self).__init__(database, db_conn, hs)
 
+        self._limit_usage_by_mau = hs.config.limit_usage_by_mau
+        self._mau_stats_only = hs.config.mau_stats_only
+        self._max_mau_value = hs.config.max_mau_value
+
         # Do not add more reserved users than the total allowable number
         # cur = LoggingTransaction(
         self.db.new_transaction(
@@ -130,7 +134,7 @@ class MonthlyActiveUsersStore(MonthlyActiveUsersWorkerStore):
             [],
             [],
             self._initialise_reserved_users,
-            hs.config.mau_limits_reserved_threepids[: self.hs.config.max_mau_value],
+            hs.config.mau_limits_reserved_threepids[: self._max_mau_value],
         )
 
     def _initialise_reserved_users(self, txn, threepids):
@@ -142,6 +146,15 @@ class MonthlyActiveUsersStore(MonthlyActiveUsersWorkerStore):
             threepids (list[dict]): List of threepid dicts to reserve
         """
 
+        # XXX what is this function trying to achieve?  It upserts into
+        # monthly_active_users for each *registered* reserved mau user, but why?
+        #
+        #  - shouldn't there already be an entry for each reserved user (at least
+        #    if they have been active recently)?
+        #
+        #  - if it's important that the timestamp is kept up to date, why do we only
+        #    run this at startup?
+
         for tp in threepids:
             user_id = self.get_user_id_by_threepid_txn(txn, tp["medium"], tp["address"])
 
@@ -191,8 +204,7 @@ class MonthlyActiveUsersStore(MonthlyActiveUsersWorkerStore):
 
             txn.execute(sql, query_args)
 
-            max_mau_value = self.hs.config.max_mau_value
-            if self.hs.config.limit_usage_by_mau:
+            if self._limit_usage_by_mau:
                 # If MAU user count still exceeds the MAU threshold, then delete on
                 # a least recently active basis.
                 # Note it is not possible to write this query using OFFSET due to
@@ -210,13 +222,13 @@ class MonthlyActiveUsersStore(MonthlyActiveUsersWorkerStore):
                             LIMIT ?
                         )
                         """
-                    txn.execute(sql, (max_mau_value,))
+                    txn.execute(sql, ((self._max_mau_value),))
                 # Need if/else since 'AND user_id NOT IN ({})' fails on Postgres
                 # when len(reserved_users) == 0. Works fine on sqlite.
                 else:
                     # Must be >= 0 for postgres
                     num_of_non_reserved_users_to_remove = max(
-                        max_mau_value - len(reserved_users), 0
+                        self._max_mau_value - len(reserved_users), 0
                     )
 
                     # It is important to filter reserved users twice to guard
@@ -335,7 +347,7 @@ class MonthlyActiveUsersStore(MonthlyActiveUsersWorkerStore):
         Args:
             user_id(str): the user_id to query
         """
-        if self.hs.config.limit_usage_by_mau or self.hs.config.mau_stats_only:
+        if self._limit_usage_by_mau or self._mau_stats_only:
             # Trial users and guests should not be included as part of MAU group
             is_guest = yield self.is_guest(user_id)
             if is_guest:
@@ -356,11 +368,11 @@ class MonthlyActiveUsersStore(MonthlyActiveUsersWorkerStore):
                 # In the case where mau_stats_only is True and limit_usage_by_mau is
                 # False, there is no point in checking get_monthly_active_count - it
                 # adds no value and will break the logic if max_mau_value is exceeded.
-                if not self.hs.config.limit_usage_by_mau:
+                if not self._limit_usage_by_mau:
                     yield self.upsert_monthly_active_user(user_id)
                 else:
                     count = yield self.get_monthly_active_count()
-                    if count < self.hs.config.max_mau_value:
+                    if count < self._max_mau_value:
                         yield self.upsert_monthly_active_user(user_id)
             elif now - last_seen_timestamp > LAST_SEEN_GRANULARITY:
                 yield self.upsert_monthly_active_user(user_id)
diff --git a/tests/server_notices/test_resource_limits_server_notices.py b/tests/server_notices/test_resource_limits_server_notices.py
index 406f29a7c0..99908edba3 100644
--- a/tests/server_notices/test_resource_limits_server_notices.py
+++ b/tests/server_notices/test_resource_limits_server_notices.py
@@ -27,20 +27,33 @@ from synapse.server_notices.resource_limits_server_notices import (
 )
 
 from tests import unittest
+from tests.unittest import override_config
+from tests.utils import default_config
 
 
 class TestResourceLimitsServerNotices(unittest.HomeserverTestCase):
-    def make_homeserver(self, reactor, clock):
-        hs_config = self.default_config()
-        hs_config["server_notices"] = {
-            "system_mxid_localpart": "server",
-            "system_mxid_display_name": "test display name",
-            "system_mxid_avatar_url": None,
-            "room_name": "Server Notices",
-        }
+    def default_config(self):
+        config = default_config("test")
 
-        hs = self.setup_test_homeserver(config=hs_config)
-        return hs
+        config.update(
+            {
+                "admin_contact": "mailto:user@test.com",
+                "limit_usage_by_mau": True,
+                "server_notices": {
+                    "system_mxid_localpart": "server",
+                    "system_mxid_display_name": "test display name",
+                    "system_mxid_avatar_url": None,
+                    "room_name": "Server Notices",
+                },
+            }
+        )
+
+        # apply any additional config which was specified via the override_config
+        # decorator.
+        if self._extra_config is not None:
+            config.update(self._extra_config)
+
+        return config
 
     def prepare(self, reactor, clock, hs):
         self.server_notices_sender = self.hs.get_server_notices_sender()
@@ -60,7 +73,6 @@ class TestResourceLimitsServerNotices(unittest.HomeserverTestCase):
         )
         self._send_notice = self._rlsn._server_notices_manager.send_notice
 
-        self.hs.config.limit_usage_by_mau = True
         self.user_id = "@user_id:test"
 
         self._rlsn._server_notices_manager.get_or_create_notice_room_for_user = Mock(
@@ -68,21 +80,17 @@ class TestResourceLimitsServerNotices(unittest.HomeserverTestCase):
         )
         self._rlsn._store.add_tag_to_room = Mock(return_value=defer.succeed(None))
         self._rlsn._store.get_tags_for_room = Mock(return_value=defer.succeed({}))
-        self.hs.config.admin_contact = "mailto:user@test.com"
-
-    def test_maybe_send_server_notice_to_user_flag_off(self):
-        """Tests cases where the flags indicate nothing to do"""
-        # test hs disabled case
-        self.hs.config.hs_disabled = True
 
+    @override_config({"hs_disabled": True})
+    def test_maybe_send_server_notice_disabled_hs(self):
+        """If the HS is disabled, we should not send notices"""
         self.get_success(self._rlsn.maybe_send_server_notice_to_user(self.user_id))
-
         self._send_notice.assert_not_called()
-        # Test when mau limiting disabled
-        self.hs.config.hs_disabled = False
-        self.hs.config.limit_usage_by_mau = False
-        self.get_success(self._rlsn.maybe_send_server_notice_to_user(self.user_id))
 
+    @override_config({"limit_usage_by_mau": False})
+    def test_maybe_send_server_notice_to_user_flag_off(self):
+        """If mau limiting is disabled, we should not send notices"""
+        self.get_success(self._rlsn.maybe_send_server_notice_to_user(self.user_id))
         self._send_notice.assert_not_called()
 
     def test_maybe_send_server_notice_to_user_remove_blocked_notice(self):
@@ -153,13 +161,12 @@ class TestResourceLimitsServerNotices(unittest.HomeserverTestCase):
 
         self._send_notice.assert_not_called()
 
+    @override_config({"mau_limit_alerting": False})
     def test_maybe_send_server_notice_when_alerting_suppressed_room_unblocked(self):
         """
         Test that when server is over MAU limit and alerting is suppressed, then
         an alert message is not sent into the room
         """
-        self.hs.config.mau_limit_alerting = False
-
         self._rlsn._auth.check_auth_blocking = Mock(
             return_value=defer.succeed(None),
             side_effect=ResourceLimitError(
@@ -170,12 +177,11 @@ class TestResourceLimitsServerNotices(unittest.HomeserverTestCase):
 
         self.assertEqual(self._send_notice.call_count, 0)
 
+    @override_config({"mau_limit_alerting": False})
     def test_check_hs_disabled_unaffected_by_mau_alert_suppression(self):
         """
         Test that when a server is disabled, that MAU limit alerting is ignored.
         """
-        self.hs.config.mau_limit_alerting = False
-
         self._rlsn._auth.check_auth_blocking = Mock(
             return_value=defer.succeed(None),
             side_effect=ResourceLimitError(
@@ -187,12 +193,12 @@ class TestResourceLimitsServerNotices(unittest.HomeserverTestCase):
         # Would be better to check contents, but 2 calls == set blocking event
         self.assertEqual(self._send_notice.call_count, 2)
 
+    @override_config({"mau_limit_alerting": False})
     def test_maybe_send_server_notice_when_alerting_suppressed_room_blocked(self):
         """
         When the room is already in a blocked state, test that when alerting
         is suppressed that the room is returned to an unblocked state.
         """
-        self.hs.config.mau_limit_alerting = False
         self._rlsn._auth.check_auth_blocking = Mock(
             return_value=defer.succeed(None),
             side_effect=ResourceLimitError(
diff --git a/tests/storage/test_client_ips.py b/tests/storage/test_client_ips.py
index bf674dd184..3b483bc7f0 100644
--- a/tests/storage/test_client_ips.py
+++ b/tests/storage/test_client_ips.py
@@ -23,6 +23,7 @@ from synapse.http.site import XForwardedForRequest
 from synapse.rest.client.v1 import login
 
 from tests import unittest
+from tests.unittest import override_config
 
 
 class ClientIpStoreTestCase(unittest.HomeserverTestCase):
@@ -137,9 +138,8 @@ class ClientIpStoreTestCase(unittest.HomeserverTestCase):
             ],
         )
 
+    @override_config({"limit_usage_by_mau": False, "max_mau_value": 50})
     def test_disabled_monthly_active_user(self):
-        self.hs.config.limit_usage_by_mau = False
-        self.hs.config.max_mau_value = 50
         user_id = "@user:server"
         self.get_success(
             self.store.insert_client_ip(
@@ -149,9 +149,8 @@ class ClientIpStoreTestCase(unittest.HomeserverTestCase):
         active = self.get_success(self.store.user_last_seen_monthly_active(user_id))
         self.assertFalse(active)
 
+    @override_config({"limit_usage_by_mau": True, "max_mau_value": 50})
     def test_adding_monthly_active_user_when_full(self):
-        self.hs.config.limit_usage_by_mau = True
-        self.hs.config.max_mau_value = 50
         lots_of_users = 100
         user_id = "@user:server"
 
@@ -166,9 +165,8 @@ class ClientIpStoreTestCase(unittest.HomeserverTestCase):
         active = self.get_success(self.store.user_last_seen_monthly_active(user_id))
         self.assertFalse(active)
 
+    @override_config({"limit_usage_by_mau": True, "max_mau_value": 50})
     def test_adding_monthly_active_user_when_space(self):
-        self.hs.config.limit_usage_by_mau = True
-        self.hs.config.max_mau_value = 50
         user_id = "@user:server"
         active = self.get_success(self.store.user_last_seen_monthly_active(user_id))
         self.assertFalse(active)
@@ -184,9 +182,8 @@ class ClientIpStoreTestCase(unittest.HomeserverTestCase):
         active = self.get_success(self.store.user_last_seen_monthly_active(user_id))
         self.assertTrue(active)
 
+    @override_config({"limit_usage_by_mau": True, "max_mau_value": 50})
     def test_updating_monthly_active_user_when_space(self):
-        self.hs.config.limit_usage_by_mau = True
-        self.hs.config.max_mau_value = 50
         user_id = "@user:server"
         self.get_success(self.store.register_user(user_id=user_id, password_hash=None))
 
diff --git a/tests/storage/test_monthly_active_users.py b/tests/storage/test_monthly_active_users.py
index bc53bf0951..447fcb3a1c 100644
--- a/tests/storage/test_monthly_active_users.py
+++ b/tests/storage/test_monthly_active_users.py
@@ -19,94 +19,106 @@ from twisted.internet import defer
 from synapse.api.constants import UserTypes
 
 from tests import unittest
+from tests.unittest import default_config, override_config
 
 FORTY_DAYS = 40 * 24 * 60 * 60
 
 
+def gen_3pids(count):
+    """Generate `count` threepids as a list."""
+    return [
+        {"medium": "email", "address": "user%i@matrix.org" % i} for i in range(count)
+    ]
+
+
 class MonthlyActiveUsersTestCase(unittest.HomeserverTestCase):
-    def make_homeserver(self, reactor, clock):
+    def default_config(self):
+        config = default_config("test")
 
-        hs = self.setup_test_homeserver()
-        self.store = hs.get_datastore()
-        hs.config.limit_usage_by_mau = True
-        hs.config.max_mau_value = 50
+        config.update({"limit_usage_by_mau": True, "max_mau_value": 50})
 
+        # apply any additional config which was specified via the override_config
+        # decorator.
+        if self._extra_config is not None:
+            config.update(self._extra_config)
+
+        return config
+
+    def prepare(self, reactor, clock, homeserver):
+        self.store = homeserver.get_datastore()
         # Advance the clock a bit
         reactor.advance(FORTY_DAYS)
 
-        return hs
-
+    @override_config({"max_mau_value": 3, "mau_limit_reserved_threepids": gen_3pids(3)})
     def test_initialise_reserved_users(self):
-        self.hs.config.max_mau_value = 5
+        threepids = self.hs.config.mau_limits_reserved_threepids
+
+        # register three users, of which two have reserved 3pids, and a third
+        # which is a support user.
         user1 = "@user1:server"
-        user1_email = "user1@matrix.org"
+        user1_email = threepids[0]["address"]
         user2 = "@user2:server"
-        user2_email = "user2@matrix.org"
+        user2_email = threepids[1]["address"]
         user3 = "@user3:server"
-        user3_email = "user3@matrix.org"
 
-        threepids = [
-            {"medium": "email", "address": user1_email},
-            {"medium": "email", "address": user2_email},
-            {"medium": "email", "address": user3_email},
-        ]
-        self.hs.config.mau_limits_reserved_threepids = threepids
-        # -1 because user3 is a support user and does not count
-        user_num = len(threepids) - 1
-
-        self.store.register_user(user_id=user1, password_hash=None)
-        self.store.register_user(user_id=user2, password_hash=None)
-        self.store.register_user(
-            user_id=user3, password_hash=None, user_type=UserTypes.SUPPORT
-        )
+        self.store.register_user(user_id=user1)
+        self.store.register_user(user_id=user2)
+        self.store.register_user(user_id=user3, user_type=UserTypes.SUPPORT)
         self.pump()
 
         now = int(self.hs.get_clock().time_msec())
         self.store.user_add_threepid(user1, "email", user1_email, now, now)
         self.store.user_add_threepid(user2, "email", user2_email, now, now)
 
+        # XXX why are we doing this here? this function is only run at startup
+        # so it is odd to re-run it here.
         self.store.db.runInteraction(
             "initialise", self.store._initialise_reserved_users, threepids
         )
         self.pump()
 
-        active_count = self.store.get_monthly_active_count()
+        # the number of users we expect will be counted against the mau limit
+        # -1 because user3 is a support user and does not count
+        user_num = len(threepids) - 1
 
-        # Test total counts, ensure user3 (support user) is not counted
-        self.assertEquals(self.get_success(active_count), user_num)
+        # Check the number of active users. Ensure user3 (support user) is not counted
+        active_count = self.get_success(self.store.get_monthly_active_count())
+        self.assertEquals(active_count, user_num)
 
-        # Test user is marked as active
+        # Test each of the registered users is marked as active
         timestamp = self.store.user_last_seen_monthly_active(user1)
         self.assertTrue(self.get_success(timestamp))
         timestamp = self.store.user_last_seen_monthly_active(user2)
         self.assertTrue(self.get_success(timestamp))
 
-        # Test that users are never removed from the db.
+        # Test that users with reserved 3pids are not removed from the MAU table
+        # XXX some of this is redundant. poking things into the config shouldn't
+        # work, and in any case it's not obvious what we expect to happen when
+        # we advance the reactor.
         self.hs.config.max_mau_value = 0
-
         self.reactor.advance(FORTY_DAYS)
         self.hs.config.max_mau_value = 5
-
         self.store.reap_monthly_active_users()
         self.pump()
 
         active_count = self.store.get_monthly_active_count()
         self.assertEquals(self.get_success(active_count), user_num)
 
-        # Test that regular users are removed from the db
+        # Add some more users and check they are counted as active
         ru_count = 2
         self.store.upsert_monthly_active_user("@ru1:server")
         self.store.upsert_monthly_active_user("@ru2:server")
         self.pump()
-
         active_count = self.store.get_monthly_active_count()
         self.assertEqual(self.get_success(active_count), user_num + ru_count)
-        self.hs.config.max_mau_value = user_num
+
+        # now run the reaper and check that the number of active users is reduced
+        # to max_mau_value
         self.store.reap_monthly_active_users()
         self.pump()
 
         active_count = self.store.get_monthly_active_count()
-        self.assertEquals(self.get_success(active_count), user_num)
+        self.assertEquals(self.get_success(active_count), 3)
 
     def test_can_insert_and_count_mau(self):
         count = self.store.get_monthly_active_count()
@@ -136,8 +148,8 @@ class MonthlyActiveUsersTestCase(unittest.HomeserverTestCase):
         result = self.store.user_last_seen_monthly_active(user_id3)
         self.assertNotEqual(self.get_success(result), 0)
 
+    @override_config({"max_mau_value": 5})
     def test_reap_monthly_active_users(self):
-        self.hs.config.max_mau_value = 5
         initial_users = 10
         for i in range(initial_users):
             self.store.upsert_monthly_active_user("@user%d:server" % i)
@@ -158,19 +170,19 @@ class MonthlyActiveUsersTestCase(unittest.HomeserverTestCase):
         count = self.store.get_monthly_active_count()
         self.assertEquals(self.get_success(count), 0)
 
+    # Note that below says mau_limit (no s), this is the name of the config
+    # value, although it gets stored on the config object as mau_limits.
+    @override_config({"max_mau_value": 5, "mau_limit_reserved_threepids": gen_3pids(5)})
     def test_reap_monthly_active_users_reserved_users(self):
         """ Tests that reaping correctly handles reaping where reserved users are
         present"""
-
-        self.hs.config.max_mau_value = 5
-        initial_users = 5
+        threepids = self.hs.config.mau_limits_reserved_threepids
+        initial_users = len(threepids)
         reserved_user_number = initial_users - 1
-        threepids = []
         for i in range(initial_users):
             user = "@user%d:server" % i
-            email = "user%d@example.com" % i
+            email = "user%d@matrix.org" % i
             self.get_success(self.store.upsert_monthly_active_user(user))
-            threepids.append({"medium": "email", "address": email})
             # Need to ensure that the most recent entries in the
             # monthly_active_users table are reserved
             now = int(self.hs.get_clock().time_msec())
@@ -182,7 +194,6 @@ class MonthlyActiveUsersTestCase(unittest.HomeserverTestCase):
                     self.store.user_add_threepid(user, "email", email, now, now)
                 )
 
-        self.hs.config.mau_limits_reserved_threepids = threepids
         self.store.db.runInteraction(
             "initialise", self.store._initialise_reserved_users, threepids
         )
@@ -279,11 +290,11 @@ class MonthlyActiveUsersTestCase(unittest.HomeserverTestCase):
         self.pump()
         self.assertEqual(self.get_success(count), 0)
 
+    # Note that the max_mau_value setting should not matter.
+    @override_config(
+        {"limit_usage_by_mau": False, "mau_stats_only": True, "max_mau_value": 1}
+    )
     def test_track_monthly_users_without_cap(self):
-        self.hs.config.limit_usage_by_mau = False
-        self.hs.config.mau_stats_only = True
-        self.hs.config.max_mau_value = 1  # should not matter
-
         count = self.store.get_monthly_active_count()
         self.assertEqual(0, self.get_success(count))
 
@@ -294,9 +305,8 @@ class MonthlyActiveUsersTestCase(unittest.HomeserverTestCase):
         count = self.store.get_monthly_active_count()
         self.assertEqual(2, self.get_success(count))
 
+    @override_config({"limit_usage_by_mau": False, "mau_stats_only": False})
     def test_no_users_when_not_tracking(self):
-        self.hs.config.limit_usage_by_mau = False
-        self.hs.config.mau_stats_only = False
         self.store.upsert_monthly_active_user = Mock()
 
         self.store.populate_monthly_active_users("@user:sever")
diff --git a/tests/test_mau.py b/tests/test_mau.py
index eb159e3ba5..8a97f0998d 100644
--- a/tests/test_mau.py
+++ b/tests/test_mau.py
@@ -17,47 +17,44 @@
 
 import json
 
-from mock import Mock
-
-from synapse.api.auth_blocking import AuthBlocking
 from synapse.api.constants import LoginType
 from synapse.api.errors import Codes, HttpResponseException, SynapseError
 from synapse.rest.client.v2_alpha import register, sync
 
 from tests import unittest
+from tests.unittest import override_config
+from tests.utils import default_config
 
 
 class TestMauLimit(unittest.HomeserverTestCase):
 
     servlets = [register.register_servlets, sync.register_servlets]
 
-    def make_homeserver(self, reactor, clock):
+    def default_config(self):
+        config = default_config("test")
 
-        self.hs = self.setup_test_homeserver(
-            "red", http_client=None, federation_client=Mock()
+        config.update(
+            {
+                "registrations_require_3pid": [],
+                "limit_usage_by_mau": True,
+                "max_mau_value": 2,
+                "mau_trial_days": 0,
+                "server_notices": {
+                    "system_mxid_localpart": "server",
+                    "room_name": "Test Server Notice Room",
+                },
+            }
         )
 
-        self.store = self.hs.get_datastore()
+        # apply any additional config which was specified via the override_config
+        # decorator.
+        if self._extra_config is not None:
+            config.update(self._extra_config)
 
-        self.hs.config.registrations_require_3pid = []
-        self.hs.config.enable_registration_captcha = False
-        self.hs.config.recaptcha_public_key = []
+        return config
 
-        self.hs.config.limit_usage_by_mau = True
-        self.hs.config.hs_disabled = False
-        self.hs.config.max_mau_value = 2
-        self.hs.config.server_notices_mxid = "@server:red"
-        self.hs.config.server_notices_mxid_display_name = None
-        self.hs.config.server_notices_mxid_avatar_url = None
-        self.hs.config.server_notices_room_name = "Test Server Notice Room"
-        self.hs.config.mau_trial_days = 0
-
-        # AuthBlocking reads config options during hs creation. Recreate the
-        # hs' copy of AuthBlocking after we've updated config values above
-        self.auth_blocking = AuthBlocking(self.hs)
-        self.hs.get_auth()._auth_blocking = self.auth_blocking
-
-        return self.hs
+    def prepare(self, reactor, clock, homeserver):
+        self.store = homeserver.get_datastore()
 
     def test_simple_deny_mau(self):
         # Create and sync so that the MAU counts get updated
@@ -66,6 +63,9 @@ class TestMauLimit(unittest.HomeserverTestCase):
         token2 = self.create_user("kermit2")
         self.do_sync_for_user(token2)
 
+        # check we're testing what we think we are: there should be two active users
+        self.assertEqual(self.get_success(self.store.get_monthly_active_count()), 2)
+
         # We've created and activated two users, we shouldn't be able to
         # register new users
         with self.assertRaises(SynapseError) as cm:
@@ -93,9 +93,8 @@ class TestMauLimit(unittest.HomeserverTestCase):
         token3 = self.create_user("kermit3")
         self.do_sync_for_user(token3)
 
+    @override_config({"mau_trial_days": 1})
     def test_trial_delay(self):
-        self.hs.config.mau_trial_days = 1
-
         # We should be able to register more than the limit initially
         token1 = self.create_user("kermit1")
         self.do_sync_for_user(token1)
@@ -127,8 +126,8 @@ class TestMauLimit(unittest.HomeserverTestCase):
         self.assertEqual(e.code, 403)
         self.assertEqual(e.errcode, Codes.RESOURCE_LIMIT_EXCEEDED)
 
+    @override_config({"mau_trial_days": 1})
     def test_trial_users_cant_come_back(self):
-        self.auth_blocking._mau_trial_days = 1
         self.hs.config.mau_trial_days = 1
 
         # We should be able to register more than the limit initially
@@ -176,11 +175,11 @@ class TestMauLimit(unittest.HomeserverTestCase):
         self.assertEqual(e.code, 403)
         self.assertEqual(e.errcode, Codes.RESOURCE_LIMIT_EXCEEDED)
 
+    @override_config(
+        # max_mau_value should not matter
+        {"max_mau_value": 1, "limit_usage_by_mau": False, "mau_stats_only": True}
+    )
     def test_tracked_but_not_limited(self):
-        self.auth_blocking._max_mau_value = 1  # should not matter
-        self.auth_blocking._limit_usage_by_mau = False
-        self.hs.config.mau_stats_only = True
-
         # Simply being able to create 2 users indicates that the
         # limit was not reached.
         token1 = self.create_user("kermit1")

From d14c4d6b6d02e8c55a6647ce0f0b3b44356d6173 Mon Sep 17 00:00:00 2001
From: Richard van der Hoff <1389908+richvdh@users.noreply.github.com>
Date: Sat, 23 May 2020 01:20:10 +0100
Subject: [PATCH 16/16] Simplify reap_monthly_active_users (#7558)

we can use `make_in_list_sql_clause` rather than doing our own half-baked
equivalent, which has the benefit of working just fine with empty lists.

(This has quite a lot of tests, so I think it's pretty safe)
---
 changelog.d/7558.misc                         |  1 +
 .../data_stores/main/monthly_active_users.py  | 96 ++++++++-----------
 2 files changed, 40 insertions(+), 57 deletions(-)
 create mode 100644 changelog.d/7558.misc

diff --git a/changelog.d/7558.misc b/changelog.d/7558.misc
new file mode 100644
index 0000000000..f8f4111136
--- /dev/null
+++ b/changelog.d/7558.misc
@@ -0,0 +1 @@
+Simplify `reap_monthly_active_users`.
diff --git a/synapse/storage/data_stores/main/monthly_active_users.py b/synapse/storage/data_stores/main/monthly_active_users.py
index a42c52f323..1310d39069 100644
--- a/synapse/storage/data_stores/main/monthly_active_users.py
+++ b/synapse/storage/data_stores/main/monthly_active_users.py
@@ -17,7 +17,7 @@ import logging
 from twisted.internet import defer
 
 from synapse.storage._base import SQLBaseStore
-from synapse.storage.database import Database
+from synapse.storage.database import Database, make_in_list_sql_clause
 from synapse.util.caches.descriptors import cached
 
 logger = logging.getLogger(__name__)
@@ -187,75 +187,57 @@ class MonthlyActiveUsersStore(MonthlyActiveUsersWorkerStore):
             """
 
             thirty_days_ago = int(self._clock.time_msec()) - (1000 * 60 * 60 * 24 * 30)
-            query_args = [thirty_days_ago]
-            base_sql = "DELETE FROM monthly_active_users WHERE timestamp < ?"
 
-            # Need if/else since 'AND user_id NOT IN ({})' fails on Postgres
-            # when len(reserved_users) == 0. Works fine on sqlite.
-            if len(reserved_users) > 0:
-                # questionmarks is a hack to overcome sqlite not supporting
-                # tuples in 'WHERE IN %s'
-                question_marks = ",".join("?" * len(reserved_users))
+            in_clause, in_clause_args = make_in_list_sql_clause(
+                self.database_engine, "user_id", reserved_users
+            )
 
-                query_args.extend(reserved_users)
-                sql = base_sql + " AND user_id NOT IN ({})".format(question_marks)
-            else:
-                sql = base_sql
-
-            txn.execute(sql, query_args)
+            txn.execute(
+                "DELETE FROM monthly_active_users WHERE timestamp < ? AND NOT %s"
+                % (in_clause,),
+                [thirty_days_ago] + in_clause_args,
+            )
 
             if self._limit_usage_by_mau:
                 # If MAU user count still exceeds the MAU threshold, then delete on
                 # a least recently active basis.
                 # Note it is not possible to write this query using OFFSET due to
                 # incompatibilities in how sqlite and postgres support the feature.
-                # sqlite requires 'LIMIT -1 OFFSET ?', the LIMIT must be present
-                # While Postgres does not require 'LIMIT', but also does not support
+                # Sqlite requires 'LIMIT -1 OFFSET ?', the LIMIT must be present,
+                # 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
-                if len(reserved_users) == 0:
-                    sql = """
-                        DELETE FROM monthly_active_users
-                        WHERE user_id NOT IN (
-                            SELECT user_id FROM monthly_active_users
-                            ORDER BY timestamp DESC
-                            LIMIT ?
-                        )
-                        """
-                    txn.execute(sql, ((self._max_mau_value),))
-                # Need if/else since 'AND user_id NOT IN ({})' fails on Postgres
-                # when len(reserved_users) == 0. Works fine on sqlite.
-                else:
-                    # Must be >= 0 for postgres
-                    num_of_non_reserved_users_to_remove = max(
-                        self._max_mau_value - len(reserved_users), 0
+
+                # Limit must be >= 0 for postgres
+                num_of_non_reserved_users_to_remove = max(
+                    self._max_mau_value - len(reserved_users), 0
+                )
+
+                # It is important to filter reserved users twice to guard
+                # against the case where the reserved user is present in the
+                # SELECT, meaning that a legitimate mau is deleted.
+                sql = """
+                    DELETE FROM monthly_active_users
+                    WHERE user_id NOT IN (
+                        SELECT user_id FROM monthly_active_users
+                        WHERE NOT %s
+                        ORDER BY timestamp DESC
+                        LIMIT ?
                     )
+                    AND NOT %s
+                """ % (
+                    in_clause,
+                    in_clause,
+                )
 
-                    # It is important to filter reserved users twice to guard
-                    # against the case where the reserved user is present in the
-                    # SELECT, meaning that a legitmate mau is deleted.
-                    sql = """
-                        DELETE FROM monthly_active_users
-                        WHERE user_id NOT IN (
-                            SELECT user_id FROM monthly_active_users
-                            WHERE user_id NOT IN ({})
-                            ORDER BY timestamp DESC
-                            LIMIT ?
-                        )
-                        AND user_id NOT IN ({})
-                    """.format(
-                        question_marks, question_marks
-                    )
+                query_args = (
+                    in_clause_args
+                    + [num_of_non_reserved_users_to_remove]
+                    + in_clause_args
+                )
+                txn.execute(sql, query_args)
 
-                    query_args = [
-                        *reserved_users,
-                        num_of_non_reserved_users_to_remove,
-                        *reserved_users,
-                    ]
-
-                    txn.execute(sql, query_args)
-
-            # It seems poor to invalidate the whole cache, Postgres supports
+            # It seems poor to invalidate the whole cache. Postgres supports
             # 'Returning' which would allow me to invalidate only the
             # specific users, but sqlite has no way to do this and instead
             # I would need to SELECT and the DELETE which without locking