south_jurisdiction 0.1.2

South migrations with database jurisdictions for Django

Motivation

South isn’t great at handling differing requirements from multiple databases in a django application.

South assumes that there will at least be a south_migration_history table available at the point of running migrate against a given database.

This is fine when your django app is only dealing with one default database, but becomes much less pleasant when wanting to add extra database sources that perhaps south shouldn’t have jurisdiction over.

Let’s say your django.conf settings look something like:

DATABASES = {
    'default': {
        ...
        'NAME': 'my_own_db',
        ...
    },

    'super_secure': {
        ...
        'NAME': 'super_secure',
        ...
    }
}

You wouldn’t want syncdb to create tables in the super_secure DB, and that would be achieved by creating a database router, along with an allow_syncdb method and include that in a DATABASE_ROUTER setting. Done.

You also wouldn’t want migrate to do anything in super_secure. As it stands, south fails at this because the first thing it does is see if there are any migrations in the database by looking at the south_migration_history table. Because syncdb didn’t create this you get FAILURE.

Solution

South jurisdiction introduces a new setting to the django settings module:

SOUTH_MANAGED_DBS = []

This is intended to be populated with the keys of the databases that you want south to manage. In the above example it would read:

SOUTH_MANAGED_DBS = ['default']

Any attempt to migrate on a database not included in SOUTH_MANAGED_DBS is rejected gracefully.

If this setting is not included in your django settings module then all databases will be looked at for migration as normal.

Configuration

• Add "south_jurisdiction" to INSTALLED_APPS in your settings, after the "south" app.

• Use the new SOUTH_MANAGED_DBS setting available to you.

• If you don’t want to run the south_jurisdiction tests, use the SKIP_SOUTH_TESTS setting in the same way as you do for south.