right way to create a django data migration that creates a group? - django

Question

I would like to create data migrations that create Permissions and Groups, so that my other developers can just run the migrations and get everything set up. I was able to create the migrations and run them just fine, but now I'm getting an error when running my tests.
But if I do this:
from django.contrib.auth.models import Group
def add_operations_group(apps, schema_editor):
Group.objects.get_or_create(name='operations')
I get:
django.db.utils.OperationalError: no such table: auth_group
If I do this:
def add_operations_group(apps, schema_editor):
Group = apps.get_model("django.contrib.auth", "group")
Group.objects.get_or_create(name='operations')
I get:
LookupError: No installed app with label 'django.contrib.auth'
Is there a way to do this? Or is there a "Django Way" to make sure things like permissions and groups are created?

Answer 1

This is how I do it:
from django.db import models, migrations
def apply_migration(apps, schema_editor):
Group = apps.get_model('auth', 'Group')
Group.objects.bulk_create([
Group(name=u'group1'),
Group(name=u'group2'),
Group(name=u'group3'),
])
def revert_migration(apps, schema_editor):
Group = apps.get_model('auth', 'Group')
Group.objects.filter(
name__in=[
u'group1',
u'group2',
u'group3',
]
).delete()
class Migration(migrations.Migration):
dependencies = [
('someapp', 'XXXX_some_migration'),
]
operations = [
migrations.RunPython(apply_migration, revert_migration)
]
Although, there must be a more Djangonic way.

Answer 2

Answer from César is correct. To make it more Django create the migration file automatically by going to your django app root folder and entering:
python manage.py makemigrations <yourappname> --empty
Note: You may need python3 instead of python depending on your system configuration.
This creates an empty migration file in a sub directory of your app called 0001_initial.py
You can then alter it as per César instructions. Which worked correctly with Django 2.2