Check for pending/outstanding changes

[sondrelg]

As a part of our CI/CD pipelines for Django projects, we tend to include a check for any model changes that haven't been reflected in a migration file, using:

python manage.py makemigrations --check --dry-run

This exits with exit code 1 if the Django migration framework detects new changes, and fails our pipeline. This is great, since we generally want all model changes to be declared in migration files before deploying our application.

Does something like this exist for alembic? I wasn't able to find anything in the CLI or previous discussions/issues 🙂

[zzzeek]

yes, there's a recipe for this case here (that should really be in the cookbook) and there are projects on pypi that do this also such as https://github.com/4Catalyzer/alembic-autogen-check https://pypi.org/project/sqlalchemy-diff/

[sondrelg]

Thanks @zzzeek 👏 Ended up writing this, in case it's helpful for anyone else. Seems to do the trick

import os
import pprint
import sys

from alembic.autogenerate import compare_metadata
from alembic.runtime.migration import MigrationContext
from sqlalchemy import create_engine

# Import metadata here

engine = create_engine(str(os.environ['DATABASE_URL'].replace('+asyncpg', '')))
metadata = BaseMeta.metadata
migration_context = MigrationContext.configure(engine.connect())

if diff := compare_metadata(migration_context, BaseMeta.metadata):
    pprint.pprint(diff, indent=2, width=10)
    print(
        'There are changes in the database models not reflect in migration files. '
        'Create migration files for these by running `alembic revision --autogenerate '
        '-m "your message"´'
    )
    sys.exit(1)
else:
    print('Migrations are up to date')
    sys.exit(0)