Plugin auto migrate (#5668)

* Improved handling of race condition when saving setting value

* Improvements for managing pending migrations

- Inform user if there are outstanding migrations
- reload plugin registry (if necessary)

* Increase django-q polling time

According to this thread, should reduce multiple workers taking the same task:

https://github.com/Koed00/django-q/issues/183#issuecomment-239676084

* Revert default behavior

* Better logging

* Remove comment

* Update unit test

* Revert maintenance mode behaviour

* raise ValidationError in settings

InvenTree/common/models.py

@@ -595,6 +595,8 @@ class BaseInvenTreeSetting(models.Model):
         if change_user is not None and not change_user.is_staff:
             return
 
+        attempts = int(kwargs.get('attempts', 3))
+
         filters = {
             'key__iexact': key,
 
@@ -615,8 +617,22 @@ class BaseInvenTreeSetting(models.Model):
         if setting.is_bool():
             value = InvenTree.helpers.str2bool(value)
 
-        setting.value = str(value)
-        setting.save()
+        try:
+            setting.value = str(value)
+            setting.save()
+        except ValidationError as exc:
+            # We need to know about validation errors
+            raise exc
+        except IntegrityError:
+            # Likely a race condition has caused a duplicate entry to be created
+            if attempts > 0:
+                # Try again
+                logger.info("Duplicate setting key '%s' for %s - trying again", key, str(cls))
+                cls.set_setting(key, value, change_user, create=create, attempts=attempts - 1, **kwargs)
+        except Exception as exc:
+            # Some other error
+            logger.exception("Error setting setting '%s' for %s: %s", key, str(cls), str(type(exc)))
+            pass
 
     key = models.CharField(max_length=50, blank=False, unique=False, help_text=_('Settings key (must be unique - case insensitive)'))
 
@@ -1050,6 +1066,13 @@ class InvenTreeSetting(BaseInvenTreeSetting):
             'hidden': True,
         },
 
+        '_PENDING_MIGRATIONS': {
+            'name': _('Pending migrations'),
+            'description': _('Number of pending database migrations'),
+            'default': 0,
+            'validator': int,
+        },
+
         'INVENTREE_INSTANCE': {
             'name': _('Server Instance Name'),
             'default': 'InvenTree',

InvenTree/common/tests.py

@@ -335,8 +335,10 @@ class GlobalSettingsApiTest(InvenTreeAPITestCase):
 
         response = self.get(url, expected_code=200)
 
+        n_public_settings = len([k for k in InvenTreeSetting.SETTINGS.keys() if not k.startswith('_')])
+
         # Number of results should match the number of settings
-        self.assertEqual(len(response.data), len(InvenTreeSetting.SETTINGS.keys()))
+        self.assertEqual(len(response.data), n_public_settings)
 
     def test_company_name(self):
         """Test a settings object lifecycle e2e."""