[Django]-Resetting Django Migrations in a Production System

The solution I have come up with for this issue comes in steps:

Step 1
Create migrations to delete any models or fields you want and run them locally, your dev system must be in sync with all other developer systems as well as production…if this is not the case you need to ensure it is!

Step 2

1. Delete the local migration files (a good option is a change of the command I have below, I currently have a directory structure with my applications for my system in a directory called /apps/)

Run calling python manage.py delete_local_migration_files (if you name it that way)

import os

import django.apps
from django.conf import settings
from django.core.management.base import BaseCommand


def delete_migrations(app):
    print(f"Deleting {app}'s migration files")
    migrations_dir = os.path.join(settings.BASE_DIR, f'apps{os.path.sep}{app}{os.path.sep}migrations')

    if os.path.exists(migrations_dir):
        for the_file in os.listdir(migrations_dir):
            file_path = os.path.join(migrations_dir, the_file)
            try:
                if os.path.isfile(file_path):
                    os.unlink(file_path)
            except Exception as e:
                print(e)

            f = open(f"{os.path.join(migrations_dir, '__init__.py')}", "w")
            f.close()

    else:
        print('-' * 20, migrations_dir, 'does not exist')


class Command(BaseCommand):
    """
    Resets migrations and clears directories
    """
    help = 'reset migrations'

    def handle(self, *args, **options):
        set_of_apps = set()
        disregard = []

        # get all apps
        for model in django.apps.apps.get_models():
            if model._meta.app_label not in disregard:
                set_of_apps.add(model._meta.app_label)

        for app in set_of_apps:
            delete_migrations(app)

Step 3

1. Delete the migrations from the database (you can use the command below, it should work universally for any setup that uses Postgres but you will have to update the connection string as needed)

Run calling python manage.py delete_migrations_from_db (if you name it that way)

import os

import psycopg2
from django.conf import settings
from django.core.management import call_command
from django.core.management.base import BaseCommand
from django.db import connections


class Command(BaseCommand):
    help = 'Migrate on every database in settings.py'

    def handle(self, *args, **options):
        db_list = settings.DATABASES
        # del db_list['default']

        for db, _ in db_list.items():
            # we have the db name, now lets remove the migration tables in each

            try:
                host = os.environ['_HOST']
                user = os.environ['_USER']
                port = os.environ['_PORT']
                password = os.environ['_PASSWORD']

                conn_str = f"host={host} port={port} user={user} password={password}"

                conn = psycopg2.connect(conn_str)
                conn.autocommit = True
                with connections[db].cursor() as cursor:
                    delete_statement = 'DELETE from public.django_migrations'
                    cursor.execute(delete_statement)
                    print(f'Migration table cleared: {db}')
            except psycopg2.Error as ex:
                raise SystemExit(f'Error: {ex}')

        print('Done!')

Step 4
Call python manage.py makemigrations to reinitialize the initial migration files

Step 5
Call python manage.py migrate --database=[YourDB] --fake to reinitialize the initial migration files. The --fake arg allows the DB structure to not be changed while the history is restored in the Database (if you want an easy command for running this migration command in all DBs, you can use something like the code below)

Called using python manage.py migrate_all --fake (depending on naming)

from django.conf import settings
from django.core.management import call_command
from django.core.management.base import BaseCommand


class Command(BaseCommand):
    help = 'Migrate on every database in settings.py'


    def add_arguments(self, parser):
        parser.add_argument(
            '--fake',
            action='store_true',
            help='fake migrations',
        )

    def handle(self, *args, **options):
        db_list = settings.DATABASES


        for db, _ in db_list.items():
            self.stdout.write('Migrating database {}'.format(db))

            if options['fake']:
                call_command('migrate', '--fake', database=db)
            else:
                # no fake, call regularly
                call_command('migrate', database=db)


        self.stdout.write('Done!')