Allows multiple apps to override the same management command in Django
© 2014 Thomas Khyn
MCMO stands for ‘Management Command Multiple Override’. This django app allows multiple apps to override the same management command without evicting any.
Supports Django 1.4 to 1.7 and matching Python 2 and 3 versions.
As straightforward as it can be, using pip:
pip install django-mcmo
In your manage.py file, replace the line:
from django.core import management
from mcmo import management
You can now use applications that concurrently define overrides for django.core management commands. Both commands will be called.
The first command which will be called will be the one relative to the application in the latest position in the INSTALLED_APPS.
is executed before calling django.management.execute_from_command_line.
Importing the package patches the django.core.management module, which functions are then enabled for multiple-override support.
The same-name overrides should all derive from the same command class, or at least from on of Django’s base command classes (AppCommand, LabelCommand or NoArgsCommand).
django-mcmo will raise a warning (but the execution will carry on) in case of subclassing inconsistencies. For example, if the command cmd in app1 inherits from AppCommand and the command cmd in app2 inherits from NoArgsCommand. Indeed, as only one command is likely to be executed, the obtained results may not be consistent, depend on the relative position of the apps in INSTALLED_APPS, or raise an exception regarding arguments presence, absence or type.
In practice, same-name commands will only be met when two 3rd party apps override a Django core management command. They will therefore derive from the same Command base class, and cause no issue in 99.9% of the cases.
django-mcmo may also emmit warning messages if the same option is explicitly added in the same command of two distinct apps with command classes not being subclasses of each other.