🚧(backend) update recording metadata alongside recording state changes

Previously, this was handled manually by the client, sending notifications to
other participants and keeping the recording state only in memory. There was no
shared or persisted state, so leaving and rejoining a meeting lost this
information. Delegating this responsibility solely to the client was a poor
choice.

The backend now owns this responsibility and relies on LiveKit webhooks to keep
room metadata in sync with the egress lifecycle.

This also reveals that the room.isRecording attribute does not update as fast
as the egress stop event, which is unexpected and should be investigated
further.

This will make state management working when several room’s owner will be in
the same meeting, which is expected to arrive any time soon.

src/backend/core/services/livekit_events.py

@@ -11,7 +11,7 @@ from django.conf import settings
 
 from livekit import api
 
-from core import models
+from core import models, utils
 from core.recording.services.recording_events import (
     RecordingEventsError,
     RecordingEventsService,
@@ -138,6 +138,24 @@ class LiveKitEventsService:
         # pylint: disable=not-callable
         handler(data)
 
+    def _handle_egress_started(self, data):
+        """Handle 'egress_started' event."""
+
+        try:
+            recording = models.Recording.objects.get(
+                worker_id=data.egress_info.egress_id
+            )
+        except models.Recording.DoesNotExist as err:
+            raise ActionFailedError(
+                f"Recording with worker ID {data.egress_info.egress_id} does not exist"
+            ) from err
+
+        try:
+            room_name = str(recording.room.id)
+            utils.update_room_metadata(room_name, {"recording_status": "started"})
+        except utils.MetadataUpdateException as e:
+            logger.exception("Failed to update room's metadata: %s", e)
+
     def _handle_egress_ended(self, data):
         """Handle 'egress_ended' event."""
 
@@ -150,6 +168,14 @@ class LiveKitEventsService:
                 f"Recording with worker ID {data.egress_info.egress_id} does not exist"
             ) from err
 
+        try:
+            room_name = str(recording.room.id)
+            utils.update_room_metadata(
+                room_name, {}, ["recording_mode", "recording_status"]
+            )
+        except utils.MetadataUpdateException as e:
+            logger.exception("Failed to update room's metadata: %s", e)
+
         if (
             data.egress_info.status == api.EgressStatus.EGRESS_LIMIT_REACHED
             and recording.status == models.RecordingStatusChoices.ACTIVE