django: data migrate permissions

Question

I have a bunch of new permissions which I need to migrate. I tried doing it through data migration but complains about ContentType not being available.

Answer 1

Here are steps for adding custom permissions to the User model:

First create a migration file, for example under your authentication application,

Here i named it 0002_permission_fixtures.py:

account (your authentication application)
 |_migrations
   |__ 0001_initial.py
   |__ 0002_permission_fixtures.py
   |__ __init__.py

Then adding your permission objects, as follow:

# -*- coding: utf-8 -*-
from __future__ import unicode_literals
from django.db import migrations


def forwards_func(apps, schema_editor):
    # Get models that we needs them
    user = apps.get_model("auth", "User")
    permission = apps.get_model("auth", "Permission")
    content_type = apps.get_model("contenttypes", "ContentType")
    # Get user content type object
    uct = content_type.objects.get_for_model(user)
    db_alias = schema_editor.connection.alias
    # Adding your custom permissions to User model: 
    permission.objects.using(db_alias).bulk_create([
        permission(codename='add_sample', name='Can add sample', content_type=uct),
        permission(codename='change_sample', name='Can change sample', content_type=uct),
        permission(codename='delete_sample', name='Can delete sample', content_type=uct),
    ])


class Migration(migrations.Migration):
    dependencies = [
    ('contenttypes', '__latest__'),
            ]

    operations = [
        migrations.RunPython(
            forwards_func,
        ),
    ]

To run this migration, first migrate contenttype model, and then migrate your application (here is account).

$ python manage.py migrate contenttypes
$ python manage.py migrate account

Answer 2

Here is a quick and dirty way to ensure all permissions for all apps have been created:

def add_all_permissions():
    from django.apps import apps
    from django.contrib.auth.management import create_permissions

    for app_config in apps.get_app_configs():
        app_config.models_module = True
        create_permissions(app_config, verbosity=0)
        app_config.models_module = None

Answer 3

There are 2 ways to solve this:

1) The ugly way:

Run manage.py migrate auth before your wanted migration

2) Recommended way:

from django.contrib.auth.management import create_permissions

def add_permissions(apps, schema_editor):
    apps.models_module = True

    create_permissions(apps, verbosity=0)
    apps.models_module = None

    # rest of code here....