If you are planning to use database migrations, you need to let Alembic know the current state of the database.
Presuming you’ve just started off by running
on the latest master branch commit (this should happen on a vanilla master branch,
i.e. without any of your changes to the database schema),
tell Alembic that you are on the latest database schema:
PYTHONPATH=. alembic -x config=config.yaml stamp head
Generate migration script
To generate a migration script, after having stamped the latest master commit (see above), ensure that the app is stopped, check out the branch with the relevant DB schema changes, and run the following:
PYTHONPATH=. alembic -x config=config.yaml revision --autogenerate -m "Revision description"
Review the resulting migration file under
alembic/versions at hand of the documentation.
Applying migration scripts
If the database has been stamped, as outlined above, the migration manager service will automatically apply any pending migration scripts upon starting the app.
To manually apply migration scripts, after ensuring that the app is stopped, check out the branch with pending migration scripts, and run the following to upgrade:
PYTHONPATH=. alembic -x config=config.yaml upgrade head