Build: skip duplicated commands (#10573)

* Build: skip duplicated commands

Sometimes it happens the web servers are congested and the builder retries the
API call to save the command in the database. However, one of the first attempts
finally ended up working resulting in the command being saved twice.

This small chunk of code checks for the existence of the command before saving
it into the database and logs a warning and return 204 if it already exists,
instead of re-saving it again.

It's not a perfect solution, but it could help under similar circumstances.

Related #10567

* Test case for duplicated BuildCommandResult

* Add `start_date` to the filter

* Typo

* Update readthedocs/api/v2/views/model_views.py

Co-authored-by: Santos Gallegos <[email protected]>

---------

Co-authored-by: Santos Gallegos <[email protected]>

Author: humitos

readthedocs/api/v2/views/model_views.py

@@ -336,6 +336,14 @@ def perform_create(self, serializer):
         build_api_key = self.request.build_api_key
         if not build_api_key.project.builds.filter(pk=build_pk).exists():
             raise PermissionDenied()
+
+        if BuildCommandResult.objects.filter(
+            build=serializer.validated_data["build"],
+            start_time=serializer.validated_data["start_time"],
+        ).exists():
+            log.warning("Build command is duplicated. Skipping...")
+            return
+
         return super().perform_create(serializer)
 
     def get_queryset_for_api_key(self, api_key):

readthedocs/rtd_tests/tests/test_api.py

@@ -909,6 +909,48 @@ def test_build_read_and_write_endpoints_for_build_api_token(self):
             resp = client.patch(f"/api/v2/build/{build.pk}/")
             self.assertEqual(resp.status_code, 404)
 
+    def test_build_commands_duplicated_command(self):
+        """Sending the same request twice should only create one BuildCommandResult."""
+        project = get(
+            Project,
+            language="en",
+        )
+        version = project.versions.first()
+        build = Build.objects.create(project=project, version=version)
+
+        self.assertEqual(BuildCommandResult.objects.count(), 0)
+
+        client = APIClient()
+        _, build_api_key = BuildAPIKey.objects.create_key(project)
+        client.credentials(HTTP_AUTHORIZATION=f"Token {build_api_key}")
+
+        now = timezone.now()
+        start_time = now - datetime.timedelta(seconds=5)
+        end_time = now
+
+        data = {
+            "build": build.pk,
+            "command": "git status",
+            "description": "Git status",
+            "exit_code": 0,
+            "start_time": start_time,
+            "end_time": end_time,
+        }
+
+        response = client.post(
+            "/api/v2/command/",
+            data,
+            format="json",
+        )
+        self.assertEqual(response.status_code, 201)
+        response = client.post(
+            "/api/v2/command/",
+            data,
+            format="json",
+        )
+        self.assertEqual(response.status_code, 201)
+        self.assertEqual(BuildCommandResult.objects.count(), 1)
+
     def test_build_commands_read_only_endpoints_for_normal_user(self):
         user_normal = get(User, is_staff=False)
         user_admin = get(User, is_staff=True)