django-mcmo 2.1

Installation

As straightforward as it can be, using pip:

pip install django-mcmo

Usage

In your manage.py file, replace the line:

from django.core import management

by:

from mcmo import management

You can now use applications that concurrently define overrides for django.core management commands. Both commands will be called.

For example, if you are using djinga and django-extra_keywords, which both override Django’s makemessages management command, both commands from both applications will be called subsequently.

The first command which will be called will be the one relative to the application in the latest position in the INSTALLED_APPS.

Alternative usage

In your manage.py is automatically generated (e.g. if you are using buildout with djangorecipebook or djangorecipe), simply make sure that the statement:

import mcmo

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.

Limitations

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.