feat: (AAP-28246) - only delete the event stream when no activations using it (#986)

Author: hsong-rh

src/aap_eda/api/views/webhook.py

@@ -93,6 +93,13 @@ def retrieve(self, request, *args, **kwargs):
     )
     def destroy(self, request, *args, **kwargs):
         webhook = self.get_object()
+
+        ref_count = webhook.activations.count()
+        if ref_count > 0:
+            raise api_exc.Conflict(
+                f"Event stream '{webhook.name}' is being referenced by "
+                f"{ref_count} activation(s) and cannot be deleted"
+            )
         self.perform_destroy(webhook)
         return Response(status=status.HTTP_204_NO_CONTENT)
 

tests/integration/api/test_webhook.py

@@ -301,6 +301,25 @@ def test_delete_webhook(
     assert response.status_code == status.HTTP_204_NO_CONTENT
 
 
+@pytest.mark.django_db
+def test_delete_webhook_with_exception(
+    admin_client: APIClient,
+    default_activation: models.Activation,
+    default_webhook: models.Webhook,
+):
+    activation = default_activation
+    activation.webhooks.add(default_webhook)
+
+    response = admin_client.delete(
+        f"{api_url_v1}/webhooks/{default_webhook.id}/"
+    )
+    assert response.status_code == status.HTTP_409_CONFLICT
+    assert (
+        f"Event stream '{default_webhook.name}' is being referenced by "
+        "1 activation(s) and cannot be deleted"
+    ) in response.data["detail"]
+
+
 @pytest.mark.django_db
 def test_post_webhook_with_bad_uuid(
     admin_client: APIClient,