Additional concurrency checks on jobs

docker-app/qfieldcloud/core/utils2/jobs.py

@@ -52,6 +52,7 @@ def apply_deltas(
         status=[
             models.Job.Status.PENDING,
             models.Job.Status.QUEUED,
+            models.Job.Status.STARTED,
         ],
     )
 

docker-app/worker_wrapper/wrapper.py

@@ -107,13 +107,39 @@ def after_docker_exception(self) -> None:
         pass
 
     def run(self):
+        """The main and first method to be called on `JobRun`.
+
+        Should not be overloaded by inheriting classes,
+        they should use `before_docker_run`, `after_docker_run`
+        and `after_docker_exception` hooks.
+        """
         feedback = {}
 
         try:
             self.job.status = Job.Status.STARTED
             self.job.started_at = timezone.now()
             self.job.save(update_fields=["status", "started_at"])
 
+            # # # CONCURRENCY CHECK # # #
+            # safety check whether there are no concurrent jobs running for that particular project
+            # if there are, reset the job back to `PENDING`
+            concurrent_jobs_count = (
+                self.job.project.jobs.filter(
+                    status__in=[Job.Status.QUEUED, Job.Status.STARTED],
+                )
+                .exclude(pk=self.job.pk)
+                .count()
+            )
+
+            if concurrent_jobs_count > 0:
+                self.job.status = Job.Status.PENDING
+                self.job.started_at = None
+                self.job.save(update_fields=["status", "started_at"])
+                logger.warning(f"Concurrent jobs occured for job {self.job}.")
+                # sentry_sdk
+                return
+            # # # /CONCURRENCY CHECK # # #
+
             self.before_docker_run()
 
             command = self.get_command()