Limit async transition to one at a time for object

src/ralph/lib/transitions/async.py

@@ -58,7 +58,7 @@ def run_async_transition(job_id):
 def _perform_async_transition(transition_job):
     transition = transition_job.transition
     obj = transition_job.obj
-    _check_instances_for_transition([obj], transition)
+    _check_instances_for_transition([obj], transition, check_async_job=False)
     _check_action_with_instances([obj], transition)
 
     # check if this job isn't already finished

src/ralph/lib/transitions/models.py

@@ -31,7 +31,7 @@
     get_field_by_relation_path
 )
 from ralph.attachments.models import Attachment
-from ralph.lib.external_services.models import Job
+from ralph.lib.external_services.models import Job, JobStatus
 from ralph.lib.mixins.models import TimeStampMixin
 from ralph.lib.transitions.conf import (
     DEFAULT_ASYNC_TRANSITION_SERVICE_NAME,
@@ -147,7 +147,9 @@ def _check_and_get_transition(obj, transition, field):
     return transition
 
 
-def _check_instances_for_transition(instances, transition):
+def _check_instances_for_transition(
+    instances, transition, check_async_job=True
+):
     """Check in respect of the instances source status.
 
     Args:
@@ -169,6 +171,22 @@ def _check_instances_for_transition(instances, transition):
             for instance, error_details in error.items():
                 errors[instance].append(error_details)
 
+    if transition.is_async and check_async_job:
+        for instance in instances:
+            if TransitionJob.objects.filter(
+                object_id=instance.id,
+                content_type=ContentType.objects.get_for_model(instance),
+                status__in=(JobStatus.STARTED, JobStatus.QUEUED)
+            ).exists():
+                logger.warning(
+                    'Another async transition is already running for {}'.format(
+                        instance,
+                    )
+                )
+                errors[instance].append(
+                    'Another async transition for this object is already stared'
+                )
+
     if errors:
         raise TransitionNotAllowedError(
             'Transition {} is not allowed for objects'.format(transition.name),

src/ralph/lib/transitions/tests/test_actions.py

@@ -14,7 +14,11 @@
     OfficeInfrastructureFactory,
     WarehouseFactory
 )
-from ralph.lib.transitions.models import TransitionsHistory
+from ralph.lib.transitions.models import (
+    JobStatus,
+    TransitionJob,
+    TransitionsHistory
+)
 from ralph.lib.transitions.tests import TransitionTestCase
 from ralph.licences.tests.factories import LicenceFactory
 
@@ -198,6 +202,34 @@ def test_async_gui(self):
         history = self.get_transition_history(bo.pk)
         self.assertIn(self.user.username, history.kwargs['user'])
 
+    def test_async_gui_running_new_when_another_in_progress_should_return_error(self):  # noqa
+        # mock another async job running
+        TransitionJob.objects.create(
+            obj=self.bo,
+            transition=self.transition_2,
+            status=JobStatus.STARTED,
+            service_name='ASYNC',
+        )
+        request = self.client.post(
+            reverse(
+                'admin:back_office_backofficeasset_transition',
+                args=(self.bo.id, self.transition_2.id)
+            ),
+            self.prepare_gui_data(),
+            follow=True
+        )
+        self.assertTrue(
+            request.redirect_chain[0][0],
+            reverse(
+                'admin:back_office_backofficeasset_change',
+                args=(self.bo.id,)
+            )
+        )
+        self.assertIn(
+            'Another async transition for this object is already stared',
+            str(list(request.context['messages'])[1])
+        )
+
     def test_api_options(self):
         request = self.api_client.options(
             reverse(