multiple_db_migrate_override.py

from django.conf import settings
from django.core.management.commands.migrate import Command as MigrateCommand

# The value is the key that goes in the `DATABASES` settings.
# Ideally set in the Django settings as well, so it can be project-wide accessible
SOURCE_DB_LABEL = 'source_db'


class Command(MigrateCommand):
    def handle(self, *args, **options):
        if options['database'] == SOURCE_DB_LABEL and settings.PRODUCTION:
            raise NotImplementedError('Not allowed to migrate source database in production as of now.')
        super().handle(*args, **options)