Check for pending Django migrations

Question

In Django, is there an easy way to check whether all database migrations have been run? I've found manage.py migrate --list, which gives me the information I want, but the format isn't very machine readable.

For context: I have a script that shouldn't start running until the database has been migrated. For various reasons, it would be tricky to send a signal from the process that's running the migrations. So I'd like to have my script periodically check the database to see if all the migrations have run.

Answer 1

Shell

The only simple solution I've found so far is running

./manage.py showmigrations | grep '\[ \]'

which will output an empty string in case all migrations have been applied.

However, it is closely tied to the output format.

Python

I checked the source code of migrate command and it seems like this should do the trick:

from django.db.migrations.executor import MigrationExecutor
from django.db import connections, DEFAULT_DB_ALIAS


def is_database_synchronized(database):
    connection = connections[database]
    connection.prepare_database()
    executor = MigrationExecutor(connection)
    targets = executor.loader.graph.leaf_nodes()
    return not executor.migration_plan(targets)

# Usage example.
if is_database_synchronized(DEFAULT_DB_ALIAS):
    # All migrations have been applied.
    pass
else:
    # Unapplied migrations found.
    pass