Add transaction handling to the interval sources

Adds transaction handling to the delete and save methods.

Signed-off-by: Roberto Rosario <roberto.rosario@mayan-edms.com>

HISTORY.rst

@@ -15,6 +15,8 @@
 - Delete periodic task on document type delete. Closes Gitlab
   issue #715. Thanks to Rob de Canha-Knight (@rssfed23) for the
   report and research.
+- Add transaction handling to the interval sources delete and save
+  methods.
 
 3.3.5 (2019-12-13)
 ==================

mayan/apps/sources/models/base.py

@@ -217,26 +217,28 @@ class IntervalBaseModel(OutOfProcessSource):
 
     def delete(self, *args, **kwargs):
         pk = self.pk
-        super(IntervalBaseModel, self).delete(*args, **kwargs)
-        self._delete_periodic_task(pk=pk)
+        with transaction.atomic():
+            super(IntervalBaseModel, self).delete(*args, **kwargs)
+            self._delete_periodic_task(pk=pk)
 
     def save(self, *args, **kwargs):
         new_source = not self.pk
-        super(IntervalBaseModel, self).save(*args, **kwargs)
+        with transaction.atomic():
+            super(IntervalBaseModel, self).save(*args, **kwargs)
 
-        if not new_source:
-            self._delete_periodic_task()
+            if not new_source:
+                self._delete_periodic_task()
 
-        interval_instance, created = IntervalSchedule.objects.get_or_create(
-            every=self.interval, period='seconds'
-        )
-        # Create a new interval or reuse someone else's
-        PeriodicTask.objects.create(
-            name=self._get_periodic_task_name(),
-            interval=interval_instance,
-            task='mayan.apps.sources.tasks.task_check_interval_source',
-            kwargs=json.dumps({'source_id': self.pk})
-        )
+            interval_instance, created = IntervalSchedule.objects.get_or_create(
+                every=self.interval, period='seconds'
+            )
+            # Create a new interval or reuse someone else's
+            PeriodicTask.objects.create(
+                name=self._get_periodic_task_name(),
+                interval=interval_instance,
+                task='mayan.apps.sources.tasks.task_check_interval_source',
+                kwargs=json.dumps({'source_id': self.pk})
+            )
 
 
 class SourceLog(models.Model):