Move EventStream handling into default ReplicationDataHandler (#7493)

This is so that the logic can happen on both master and workers when we move event persistence out.

synapse/replication/tcp/client.py

@@ -16,12 +16,17 @@
 """
 
 import logging
-from typing import TYPE_CHECKING
+from typing import TYPE_CHECKING, Tuple
 
 from twisted.internet.protocol import ReconnectingClientFactory
 
-from synapse.replication.slave.storage._base import BaseSlavedStore
+from synapse.api.constants import EventTypes
 from synapse.replication.tcp.protocol import ClientReplicationStreamProtocol
+from synapse.replication.tcp.streams.events import (
+    EventsStream,
+    EventsStreamEventRow,
+    EventsStreamRow,
+)
 
 if TYPE_CHECKING:
     from synapse.server import HomeServer
@@ -83,8 +88,10 @@ class ReplicationDataHandler:
     to handle updates in additional ways.
     """
 
-    def __init__(self, store: BaseSlavedStore):
-        self.store = store
+    def __init__(self, hs: "HomeServer"):
+        self.store = hs.get_datastore()
+        self.pusher_pool = hs.get_pusherpool()
+        self.notifier = hs.get_notifier()
 
     async def on_rdata(
         self, stream_name: str, instance_name: str, token: int, rows: list
@@ -102,6 +109,28 @@ class ReplicationDataHandler:
         """
         self.store.process_replication_rows(stream_name, instance_name, token, rows)
 
+        if stream_name == EventsStream.NAME:
+            # We shouldn't get multiple rows per token for events stream, so
+            # we don't need to optimise this for multiple rows.
+            for row in rows:
+                if row.type != EventsStreamEventRow.TypeId:
+                    continue
+                assert isinstance(row, EventsStreamRow)
+
+                event = await self.store.get_event(
+                    row.data.event_id, allow_rejected=True
+                )
+                if event.rejected_reason:
+                    continue
+
+                extra_users = ()  # type: Tuple[str, ...]
+                if event.type == EventTypes.Member:
+                    extra_users = (event.state_key,)
+                max_token = self.store.get_room_max_stream_ordering()
+                self.notifier.on_new_room_event(event, token, max_token, extra_users)
+
+            await self.pusher_pool.on_new_notifications(token, token)
+
     async def on_position(self, stream_name: str, instance_name: str, token: int):
         self.store.process_replication_rows(stream_name, instance_name, token, [])