Maintenance Mode Improvements (#6451)

* Custom migration step in tasks.py

- Add custom management command
- Wraps migration step in maintenance mode

* Rename custom management command to "runmigrations"

- Add command to isRunningMigrations

* Add new data checks

* Update database readiness checks

- Set maintenance mode while performing certain management commands

* Remove unused import

* Re-add syncdb command

* Log warning msg

* Catch another potential error vector

InvenTree/label/apps.py

@@ -12,6 +12,8 @@ from django.conf import settings
 from django.core.exceptions import AppRegistryNotReady
 from django.db.utils import IntegrityError, OperationalError, ProgrammingError
 
+from maintenance_mode.core import maintenance_mode_on, set_maintenance_mode
+
 import InvenTree.helpers
 import InvenTree.ready
 
@@ -32,13 +34,10 @@ class LabelConfig(AppConfig):
         ):
             return
 
-        if InvenTree.ready.isRunningMigrations():
-            return
+        if not InvenTree.ready.canAppAccessDatabase(allow_test=False):
+            return  # pragma: no cover
 
-        if (
-            InvenTree.ready.canAppAccessDatabase(allow_test=False)
-            and not InvenTree.ready.isImportingData()
-        ):
+        with maintenance_mode_on():
             try:
                 self.create_labels()  # pragma: no cover
             except (
@@ -52,6 +51,8 @@ class LabelConfig(AppConfig):
                     'Database was not ready for creating labels', stacklevel=2
                 )
 
+        set_maintenance_mode(False)
+
     def create_labels(self):
         """Create all default templates."""
         # Test if models are ready