🛂(backend) stop throttling collaboration servers

We observe some throttling pick here and there.
We observed that when the collaboration has a
problem, it is retrying to connect, leading to more
requests to the django backend. At one point, the
throttling is reached and the user would not
be able to use the application anymore.
Now when the request comes from a collaboration
server, we do not throttle it anymore.

src/backend/core/api/throttling.py

@@ -1,5 +1,8 @@
 """Throttling modules for the API."""
 
+from django.conf import settings
+
+from lasuite.drf.throttling import MonitoredScopedRateThrottle
 from rest_framework.throttling import UserRateThrottle
 from sentry_sdk import capture_message
 
@@ -19,3 +22,30 @@ class UserListThrottleSustained(UserRateThrottle):
     """Throttle for the user list endpoint."""
 
     scope = "user_list_sustained"
+
+
+class DocumentThrottle(MonitoredScopedRateThrottle):
+    """
+    Throttle for document-related endpoints, with an exception for requests from the
+    collaboration server.
+    """
+
+    scope = "document"
+
+    def allow_request(self, request, view):
+        """
+        Override to skip throttling for requests from the collaboration server.
+
+        Verifies the X-Y-Provider-Key header contains a valid Y_PROVIDER_API_KEY.
+        Using a custom header instead of Authorization to avoid triggering
+        authentication middleware.
+        """
+
+        y_provider_header = request.headers.get("X-Y-Provider-Key", "")
+
+        # Check if this is a valid y-provider request and exempt from throttling
+        y_provider_key = getattr(settings, "Y_PROVIDER_API_KEY", None)
+        if y_provider_key and y_provider_header == y_provider_key:
+            return True
+
+        return super().allow_request(request, view)

src/backend/core/api/viewsets.py

@@ -55,7 +55,11 @@ from core.utils import extract_attachments, filter_descendants
 
 from . import permissions, serializers, utils
 from .filters import DocumentFilter, ListDocumentFilter, UserSearchFilter
-from .throttling import UserListThrottleBurst, UserListThrottleSustained
+from .throttling import (
+    DocumentThrottle,
+    UserListThrottleBurst,
+    UserListThrottleSustained,
+)
 
 logger = logging.getLogger(__name__)
 
@@ -373,6 +377,7 @@ class DocumentViewSet(
     permission_classes = [
         permissions.DocumentPermission,
     ]
+    throttle_classes = [DocumentThrottle]
     throttle_scope = "document"
     queryset = models.Document.objects.select_related("creator").all()
     serializer_class = serializers.DocumentSerializer