💩(backend) notify the summary service when a new recording is available

Draft a piece of code to try the feature in staging. I'll consolidate this
implementation ASAP, as soon we have a first implementation functional.

What's missing?
- when owners are multiple
- retry when the backend cannot reach the summary service
- factorize the key oneliner, duplicated from the egress service
- optimize SQL query
- unit tests

src/backend/core/recording/event/notification.py

@@ -0,0 +1,93 @@
+"""Service to notify external services when a new recording is ready."""
+
+import logging
+
+from django.conf import settings
+
+import requests
+
+from core import models
+
+logger = logging.getLogger(__name__)
+
+
+class NotificationService:
+    """Service for processing recordings and notifying external services."""
+
+    def notify_external_services(self, recording):
+        """Process a recording based on its mode."""
+
+        if recording.mode == models.RecordingModeChoices.TRANSCRIPT:
+            return self._notify_summary_service(recording)
+
+        if recording.mode == models.RecordingModeChoices.SCREEN_RECORDING:
+            logger.warning(
+                "Screen recording mode not implemented for recording %s", recording.id
+            )
+            return False
+
+        logger.error(
+            "Unknown recording mode %s for recording %s",
+            recording.mode,
+            recording.id,
+        )
+        return False
+
+    @staticmethod
+    def _notify_summary_service(recording):
+        """Notify summary service about a new recording."""
+
+        if (
+            not settings.SUMMARY_SERVICE_ENDPOINT
+            or not settings.SUMMARY_SERVICE_API_TOKEN
+        ):
+            logger.error("Summary service not configured")
+            return False
+
+        owner_access = (
+            models.RecordingAccess.objects.select_related("user")
+            .filter(
+                role=models.RoleChoices.OWNER,
+                recording_id=recording.id,
+            )
+            .first()
+        )
+
+        if not owner_access:
+            logger.error("No owner found for recording %s", recording.id)
+            return False
+
+        key = f"{settings.RECORDING_OUTPUT_FOLDER}/{recording.id}.ogg"
+
+        payload = {
+            "filename": key,
+            "email": owner_access.user.email,
+            "sub": owner_access.user.sub,
+        }
+
+        headers = {
+            "Content-Type": "application/json",
+            "Authorization": f"Bearer {settings.SUMMARY_SERVICE_API_TOKEN}",
+        }
+
+        try:
+            response = requests.post(
+                settings.SUMMARY_SERVICE_ENDPOINT,
+                json=payload,
+                headers=headers,
+                timeout=30,
+            )
+            response.raise_for_status()
+        except requests.HTTPError as exc:
+            logger.exception(
+                "Summary service HTTP error for recording %s. URL: %s. Exception: %s",
+                recording.id,
+                settings.SUMMARY_SERVICE_ENDPOINT,
+                exc,
+            )
+            return False
+
+        return True
+
+
+notification_service = NotificationService()