Split presence out of master (#9820)

4 files changed, 32 insertions, 58 deletions

diff --git a/synapse/replication/http/_base.py b/synapse/replication/http/_base.py
index ece03467b5..5685cf2121 100644
--- a/synapse/replication/http/_base.py
+++ b/synapse/replication/http/_base.py
@@ -158,7 +158,10 @@ class ReplicationEndpoint(metaclass=abc.ABCMeta):
     def make_client(cls, hs):
         """Create a client that makes requests.
 
-        Returns a callable that accepts the same parameters as `_serialize_payload`.
+        Returns a callable that accepts the same parameters as
+        `_serialize_payload`, and also accepts an optional `instance_name`
+        parameter to specify which instance to hit (the instance must be in
+        the `instance_map` config).
         """
         clock = hs.get_clock()
         client = hs.get_simple_http_client()
diff --git a/synapse/replication/slave/storage/presence.py b/synapse/replication/slave/storage/presence.py
deleted file mode 100644
index 57327d910d..0000000000
--- a/synapse/replication/slave/storage/presence.py
+++ /dev/null
@@ -1,50 +0,0 @@
-# Copyright 2016 OpenMarket Ltd
-#
-# 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.
-
-from synapse.replication.tcp.streams import PresenceStream
-from synapse.storage import DataStore
-from synapse.storage.database import DatabasePool
-from synapse.storage.databases.main.presence import PresenceStore
-from synapse.util.caches.stream_change_cache import StreamChangeCache
-
-from ._base import BaseSlavedStore
-from ._slaved_id_tracker import SlavedIdTracker
-
-
-class SlavedPresenceStore(BaseSlavedStore):
-    def __init__(self, database: DatabasePool, db_conn, hs):
-        super().__init__(database, db_conn, hs)
-        self._presence_id_gen = SlavedIdTracker(db_conn, "presence_stream", "stream_id")
-
-        self._presence_on_startup = self._get_active_presence(db_conn)  # type: ignore
-
-        self.presence_stream_cache = StreamChangeCache(
-            "PresenceStreamChangeCache", self._presence_id_gen.get_current_token()
-        )
-
-    _get_active_presence = DataStore._get_active_presence
-    take_presence_startup_info = DataStore.take_presence_startup_info
-    _get_presence_for_user = PresenceStore.__dict__["_get_presence_for_user"]
-    get_presence_for_users = PresenceStore.__dict__["get_presence_for_users"]
-
-    def get_current_presence_token(self):
-        return self._presence_id_gen.get_current_token()
-
-    def process_replication_rows(self, stream_name, instance_name, token, rows):
-        if stream_name == PresenceStream.NAME:
-            self._presence_id_gen.advance(instance_name, token)
-            for row in rows:
-                self.presence_stream_cache.entity_has_changed(row.user_id, token)
-                self._get_presence_for_user.invalidate((row.user_id,))
-        return super().process_replication_rows(stream_name, instance_name, token, rows)
diff --git a/synapse/replication/tcp/handler.py b/synapse/replication/tcp/handler.py
index 2ce1b9f222..7ced4c543c 100644
--- a/synapse/replication/tcp/handler.py
+++ b/synapse/replication/tcp/handler.py
@@ -55,6 +55,8 @@ from synapse.replication.tcp.streams import (
     CachesStream,
     EventsStream,
     FederationStream,
+    PresenceFederationStream,
+    PresenceStream,
     ReceiptsStream,
     Stream,
     TagAccountDataStream,
@@ -99,6 +101,10 @@ class ReplicationCommandHandler:
         self._instance_id = hs.get_instance_id()
         self._instance_name = hs.get_instance_name()
 
+        self._is_presence_writer = (
+            hs.get_instance_name() in hs.config.worker.writers.presence
+        )
+
         self._streams = {
             stream.NAME: stream(hs) for stream in STREAMS_MAP.values()
         }  # type: Dict[str, Stream]
@@ -153,6 +159,14 @@ class ReplicationCommandHandler:
 
                 continue
 
+            if isinstance(stream, (PresenceStream, PresenceFederationStream)):
+                # Only add PresenceStream as a source on the instance in charge
+                # of presence.
+                if self._is_presence_writer:
+                    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
@@ -350,7 +364,7 @@ class ReplicationCommandHandler:
     ) -> Optional[Awaitable[None]]:
         user_sync_counter.inc()
 
-        if self._is_master:
+        if self._is_presence_writer:
             return self._presence_handler.update_external_syncs_row(
                 cmd.instance_id, cmd.user_id, cmd.is_syncing, cmd.last_sync_ms
             )
@@ -360,7 +374,7 @@ class ReplicationCommandHandler:
     def on_CLEAR_USER_SYNC(
         self, conn: IReplicationConnection, cmd: ClearUserSyncsCommand
     ) -> Optional[Awaitable[None]]:
-        if self._is_master:
+        if self._is_presence_writer:
             return self._presence_handler.update_external_syncs_clear(cmd.instance_id)
         else:
             return None
diff --git a/synapse/replication/tcp/streams/_base.py b/synapse/replication/tcp/streams/_base.py
index 9d75a89f1c..b03824925a 100644
--- a/synapse/replication/tcp/streams/_base.py
+++ b/synapse/replication/tcp/streams/_base.py
@@ -272,15 +272,22 @@ class PresenceStream(Stream):
     NAME = "presence"
     ROW_TYPE = PresenceStreamRow
 
-    def __init__(self, hs):
+    def __init__(self, hs: "HomeServer"):
         store = hs.get_datastore()
 
-        if hs.config.worker_app is None:
-            # on the master, query the presence handler
+        if hs.get_instance_name() in hs.config.worker.writers.presence:
+            # on the presence writer, query the presence handler
             presence_handler = hs.get_presence_handler()
-            update_function = presence_handler.get_all_presence_updates
+
+            from synapse.handlers.presence import PresenceHandler
+
+            assert isinstance(presence_handler, PresenceHandler)
+
+            update_function = (
+                presence_handler.get_all_presence_updates
+            )  # type: UpdateFunction
         else:
-            # Query master process
+            # Query presence writer process
             update_function = make_http_update_function(hs, self.NAME)
 
         super().__init__(