diff --git a/synapse/handlers/federation_event.py b/synapse/handlers/federation_event.py
index 9d9f1696f2..16f20c8be7 100644
--- a/synapse/handlers/federation_event.py
+++ b/synapse/handlers/federation_event.py
@@ -793,7 +793,7 @@ class FederationEventHandler:
if existing:
if not existing.internal_metadata.is_outlier():
logger.info(
- "Ignoring received event %s which we have already seen",
+ "_process_pulled_event: Ignoring received event %s which we have already seen",
event_id,
)
return
@@ -1329,6 +1329,53 @@ class FederationEventHandler:
marker_event,
)
+ async def backfill_event_id(
+ self, destination: str, room_id: str, event_id: str
+ ) -> EventBase:
+ """Backfill a single event and persist it as a non-outlier which means
+ we also pull in all of the state and auth events necessary for it.
+
+ Args:
+ destination: The homeserver to pull the given event_id from.
+ room_id: The room where the event is from.
+ event_id: The event ID to backfill.
+
+ Raises:
+ FederationError if we are unable to find the event from the destination
+ """
+ logger.info(
+ "backfill_event_id: event_id=%s from destination=%s", event_id, destination
+ )
+
+ room_version = await self._store.get_room_version(room_id)
+
+ event_from_response = await self._federation_client.get_pdu(
+ [destination],
+ event_id,
+ room_version,
+ )
+
+ if not event_from_response:
+ raise FederationError(
+ "ERROR",
+ 404,
+ "Unable to find event_id=%s from destination=%s to backfill."
+ % (event_id, destination),
+ affected=event_id,
+ )
+
+ # Persist the event we just fetched, including pulling all of the state
+ # and auth events to de-outlier it. This also sets up the necessary
+ # `state_groups` for the event.
+ await self._process_pulled_events(
+ destination,
+ [event_from_response],
+ # Prevent notifications going to clients
+ backfilled=True,
+ )
+
+ return event_from_response
+
async def _get_events_and_persist(
self, destination: str, room_id: str, event_ids: Collection[str]
) -> None:
|
