✨(backend) allow configuring trace sampling

Add a configuration knob for the trace sampling rate, so we can
enable tracing on middleware and cache spans when debugging slow
requests in production.

Sampling is set to 0 by default, so tracing stays fully off unless
explicitly enabled.

CHANGELOG.md

@@ -10,7 +10,6 @@ and this project adheres to
 
 ### Fixed
 
-- 🐛(backend) acknowledge unknown LiveKit webhook events instead of 422
 - 🔒️(backend) enforce display name setting on rename API
 
 ## [1.31.0] - 2026-09-08

src/backend/core/services/livekit_events.py

@@ -52,6 +52,12 @@ class InvalidPayloadError(LiveKitWebhookError):
     status_code = 400
 
 
+class UnsupportedEventTypeError(LiveKitWebhookError):
+    """Unsupported event type."""
+
+    status_code = 422
+
+
 class ActionFailedError(LiveKitWebhookError):
     """Webhook action fails to process or complete."""
 
@@ -68,7 +74,6 @@ class LiveKitWebhookEventType(Enum):
     # Participant events
     PARTICIPANT_JOINED = "participant_joined"
     PARTICIPANT_LEFT = "participant_left"
-    PARTICIPANT_CONNECTION_ABORTED = "participant_connection_aborted"
 
     # Track events
     TRACK_PUBLISHED = "track_published"
@@ -148,13 +153,10 @@ class LiveKitEventsService:
 
         try:
             webhook_type = LiveKitWebhookEventType(data.event)
-        except ValueError:
-            logger.warning(
-                "Ignoring unknown LiveKit webhook event type '%s' for room '%s'",
-                data.event,
-                room_name,
-            )
-            return
+        except ValueError as e:
+            raise UnsupportedEventTypeError(
+                f"Unknown webhook type: {data.event}"
+            ) from e
 
         # Handle according to received webhook type
         handler = self._webhook_handlers.get(webhook_type.value)

src/backend/core/tests/rooms/test_api_rooms_webhook.py

@@ -94,7 +94,7 @@ def test_invalid_payload(client, auth_token, mock_livekit_config):
 
 
 def test_unknown_event_type(client, mock_livekit_config):
-    """Should acknowledge (200) an unknown event type rather than reject it."""
+    """Should return 422 for unknown event type."""
     event_data = json.dumps({"event": "unknown_event_type"})
 
     # Generate auth token for this specific payload
@@ -112,8 +112,10 @@ def test_unknown_event_type(client, mock_livekit_config):
         HTTP_AUTHORIZATION=auth_token,
     )
 
-    assert response.status_code == 200
-    assert response.json() == {"status": "success"}
+    assert response.status_code == 422
+    assert response.json() == {
+        "status": "error",
+    }
 
 
 @mock.patch.object(LiveKitEventsService, "_handle_room_finished")

src/backend/core/tests/services/test_livekit_events.py

@@ -16,6 +16,7 @@ from core.services.livekit_events import (
     AuthenticationError,
     InvalidPayloadError,
     LiveKitEventsService,
+    UnsupportedEventTypeError,
     api,
 )
 from core.services.lobby import LobbyService
@@ -664,27 +665,22 @@ def test_receive_missing_auth(service):
 
 
 @mock.patch.object(api.WebhookReceiver, "receive")
-def test_receive_unknown_event_is_acknowledged(mock_receive, service, caplog):
-    """Unknown event types are logged and ignored, not rejected.
-
-    LiveKit adds event types over time and does not retry 4xx responses, so
-    raising here would silently drop the event.
-    """
+def test_receive_unsupported_event(mock_receive, service):
+    """Should raise LiveKitWebhookError for unsupported events."""
     mock_request = mock.MagicMock()
     mock_request.headers = {"Authorization": "test_token"}
     mock_request.body = b"{}"
 
+    # Mock returned data with unsupported event type
     mock_data = mock.MagicMock()
     mock_data.room.name = str(uuid.uuid4())
-    mock_data.event = "some_future_event"
+    mock_data.event = "unsupported_event"
     mock_receive.return_value = mock_data
 
-    with caplog.at_level("WARNING", logger="core.services.livekit_events"):
-        service.receive(mock_request)  # must not raise
-
-    assert "Ignoring unknown LiveKit webhook event type 'some_future_event'" in (
-        caplog.text
-    )
+    with pytest.raises(
+        UnsupportedEventTypeError, match="Unknown webhook type: unsupported_event"
+    ):
+        service.receive(mock_request)
 
 
 @mock.patch.object(api.WebhookReceiver, "receive")

src/backend/meet/settings.py

@@ -469,6 +469,9 @@ class Base(Configuration):
 
     # Sentry
     SENTRY_DSN = values.Value(None, environ_name="SENTRY_DSN")
+    SENTRY_TRACES_SAMPLE_RATE = values.FloatValue(
+        0.0, environ_name="SENTRY_TRACES_SAMPLE_RATE", environ_prefix=None
+    )
 
     # Easy thumbnails
     THUMBNAIL_EXTENSION = "webp"
@@ -1211,7 +1214,14 @@ class Base(Configuration):
                 dsn=cls.SENTRY_DSN,
                 environment=cls.__name__.lower(),  # build, test, development, production
                 release=get_release(),
-                integrations=[DjangoIntegration()],
+                traces_sample_rate=cls.SENTRY_TRACES_SAMPLE_RATE,
+                integrations=[
+                    DjangoIntegration(
+                        transaction_style="url",
+                        middleware_spans=True,
+                        cache_spans=True,
+                    )
+                ],
             )
             sentry_sdk.set_tag("application", "backend")