Add support for moving `/push_rules` off of main process (#17037)

1 files changed, 16 insertions, 3 deletions

diff --git a/synapse/handlers/room_member.py b/synapse/handlers/room_member.py
index 9e9f6cd062..ee2e807afc 100644
--- a/synapse/handlers/room_member.py
+++ b/synapse/handlers/room_member.py
@@ -51,6 +51,7 @@ from synapse.handlers.worker_lock import NEW_EVENT_DURING_PURGE_LOCK_NAME
 from synapse.logging import opentracing
 from synapse.metrics import event_processing_positions
 from synapse.metrics.background_process_metrics import run_as_background_process
+from synapse.replication.http.push import ReplicationCopyPusherRestServlet
 from synapse.storage.databases.main.state_deltas import StateDelta
 from synapse.types import (
     JsonDict,
@@ -181,6 +182,10 @@ class RoomMemberHandler(metaclass=abc.ABCMeta):
             hs.config.server.forgotten_room_retention_period
         )
 
+        self._is_push_writer = hs.get_instance_name() in hs.config.worker.writers.push
+        self._push_writer = hs.config.worker.writers.push[0]
+        self._copy_push_client = ReplicationCopyPusherRestServlet.make_client(hs)
+
     def _on_user_joined_room(self, event_id: str, room_id: str) -> None:
         """Notify the rate limiter that a room join has occurred.
 
@@ -1301,9 +1306,17 @@ class RoomMemberHandler(metaclass=abc.ABCMeta):
                     old_room_id, new_room_id, user_id
                 )
                 # Copy over push rules
-                await self.store.copy_push_rules_from_room_to_room_for_user(
-                    old_room_id, new_room_id, user_id
-                )
+                if self._is_push_writer:
+                    await self.store.copy_push_rules_from_room_to_room_for_user(
+                        old_room_id, new_room_id, user_id
+                    )
+                else:
+                    await self._copy_push_client(
+                        instance_name=self._push_writer,
+                        user_id=user_id,
+                        old_room_id=old_room_id,
+                        new_room_id=new_room_id,
+                    )
             except Exception:
                 logger.exception(
                     "Error copying tags and/or push rules from rooms %s to %s for user %s. "