nous.migration

nous.migration is yet another SQLAlchemy based database schema migration tool.

Installation

To install it, add:

[migration]
recipe = zc.recipe.egg
eggs=
  nous.migration

to your buildout.cfg

You might want to add your databse driver pakcage and your application
package like this:

[migration]
recipe = zc.recipe.egg
eggs=
  psycopg2
  nous.some_app
  nous.migration

Configuration

Add to your development.ini or some other kind of ini:

[nous.migration]
app = app:busy
package = busy.migration

migrator expects sqlalchemy configuration to be present in the app section, for example:

[app:busy]
sqlalchemy.url = postgresql:///development

I might add sqlalchemy configuration to the migration section too if someone will ask.

You can also add:

vcs = git
schema_diff_cmd = git diff src/busy/models/schema.sql

so that add_script command would add the files to the version control system, and populate them with the delta of your schema automatically.

These two settings might go the setup.cfg as they are not really deployment related and are never required to run your application.

Usage

bin/migrate development.ini [upgrade|downgrade|setup|add_script] [version]

Integrating with your application

Add something like this:

    engine = engine_from_config(conf, 'sqlalchemy.')
    DBMigrator(engine, 'busy.migration').set_up_migration(init_migration=DBSetUp(), run_scripts=False)

to your setup_app, or in your initialize_sql

DBSetUp is a class that has an "upgrade" method that initializes your schema.

You can do it in multiple ways, you can add a migration script that sets up your tables and then migrate that using migration scripts:

    DBMigrator(engine, 'busy.migration').set_up_migration(run_scripts=True)

Or you can have a canonical schema set up and initialize it all at once and just mark all the scripts as 'done'

    DBMigrator(engine, 'busy.migration').set_up_migration(init_migration=DBSetUp(), run_scripts=False)

Requirements:

• Python