CustomUser on separate database issues - multiple-databases

Question

I want to use the users from a legacy database but keep everything else on the 'default' database.
The main issue I have atm is that I can't get the database router to properly forward queries to the appropriate database. Namely when I run the migrations 2 times, the second time I get an error
~> DJANGO_SETTINGS_MODULE=settings python manage.py makemigrations
Migrations for 'myapp':
myapp/migrations/0001_initial.py
- Create model CustomUser
~> DJANGO_SETTINGS_MODULE=settings python manage.py makemigrations
Traceback (most recent call last):
File "manage.py", line 21, in <module>
main()
File "manage.py", line 17, in main
execute_from_command_line(sys.argv)
File "/home/manos/workspace/umed/common/oauth2_test/.env/lib/python3.7/site-packages/django/core/management/__init__.py", line 401, in execute_from_command_line
utility.execute()
File "/home/manos/workspace/umed/common/oauth2_test/.env/lib/python3.7/site-packages/django/core/management/__init__.py", line 395, in execute
self.fetch_command(subcommand).run_from_argv(self.argv)
File "/home/manos/workspace/umed/common/oauth2_test/.env/lib/python3.7/site-packages/django/core/management/base.py", line 328, in run_from_argv
self.execute(*args, **cmd_options)
File "/home/manos/workspace/umed/common/oauth2_test/.env/lib/python3.7/site-packages/django/core/management/base.py", line 369, in execute
output = self.handle(*args, **options)
File "/home/manos/workspace/umed/common/oauth2_test/.env/lib/python3.7/site-packages/django/core/management/base.py", line 83, in wrapped
res = handle_func(*args, **kwargs)
File "/home/manos/workspace/umed/common/oauth2_test/.env/lib/python3.7/site-packages/django/core/management/commands/makemigrations.py", line 101, in handle
loader.check_consistent_history(connection)
File "/home/manos/workspace/umed/common/oauth2_test/.env/lib/python3.7/site-packages/django/db/migrations/loader.py", line 299, in check_consistent_history
connection.alias,
django.db.migrations.exceptions.InconsistentMigrationHistory: Migration admin.0001_initial is applied before its dependency myapp.0001_initial on database 'auth_db'.
So I assume it tries to run the admin stuff inside the auth_db instead of default database. But I can't really figure out what I'm doing wrong since the routing seems correct.
Simplified code below
models.py
class CustomUser(AbstractUser):
password = models.CharField(max_length=128)
username = models.CharField(unique=True, max_length=32)
class Meta:
managed = False
db_table = 'myauthdb_user'
objects = UserManager()
db.py
class AuthRouter:
""" Forwards queries for users models to the auth database. """
def db_for_read(self, model, **hints):
if model.__name__ == 'CustomUser':
return 'auth_db'
return None
settings.py
DATABASE_ROUTERS = ['db.AuthRouter']
DATABASES = {
'default': {
'ENGINE': 'django.db.backends.sqlite3',
'NAME': join(BASE_DIR, 'db.app'),
},
'auth_db': {
'ENGINE': 'django.db.backends.postgresql',
'NAME': 'postgres',
'USER': 'postgres',
'PASSWORD': 'postgres',
'HOST': 'localhost',
},
}
I can use the ORM just fine e.g. CustomUser.objects.all(). But the migration issue is a huge problem. A naive solution is to disable the admin but I feel the underlying problem is still there.