Pymigration

A generic tool for migrate in python.

Pymigration brings migrations to Python applications. Its main objectives are to provide a simple, stable and database-independent migration layer to prevent all the hassle schema changes over time bring to your applications.

We try to make Pymigration both as easy-to-use and intuitive as possible, by making it automate most of your schema-changing tasks, while at the same time providing a powerful set of tools for large or complex projects.

Version

0.0.7

Install

If you have pip available on your system, just type::

pip install pymigration

If you’ve already got an old version of pymigration, and want to upgrade, use:

pip install --upgrade pymigration

Understanding how to use

The first thing you’ll need is a migration file. There are some example migration files in the “pymigrations” directory. The migration files have the following format::

The folder pymigrations need be a module (__init__.py most be present in pymigrations folder).

# -*- coding: utf-8 -*-

"""
    migrate all the world of test
    greetings world
"""

version = "0.0.1"

def up():
    """ HeLo World and migrate the world """
    print "HeLo World and migrate the world"

def down():
    """roolback the world"""
    print "Bye World and roolback the world"

Pymigration uses the version information to track the migrations schema and to decide the order of execution of the scripts. Pymigration will go through all .py files in your directory and execute all of them in their creation (date) order.

Second, you have to configure access to your current version so Pymigration can execute DDL. Just create a file named “conf.py”, with the following content (there is also an example in the “pymigration” directory):

# -*- coding: utf-8 -*-
import settings

folder = "{PATH_PYMIGRATION}/version.txt".format(**vars(settings))

It is possible to override the way Pymigration retrieve the current version. To do so, you just need do implement the methods get_current_version and set_current_version:

# -*- coding: utf-8 -*-

folder = "/version_folder"

def current_version():
    with open("{folder}/version.txt".format(folder=folder)) as f:
        version = f.read()
    return version

def set_current_version(version):
    with open("{folder}/version.txt".format(folder=folder)) as f:
        f.write(version)

Migrating to a specific version

If you want, you can migrate your database schema to a specific version by informing the --to (or -t) parameter. The attribute version of the migration file will be used as unique identifier:

$ pymigration --to=00.00.01

If you don’t specify any version, using --up or --down, Pymigration will migrate the schema to the latest version available in the migrations directories specified in the config file.

You can do anything!

You can use this project to run migrations on MySQL, Oracle, MS-SQL, redis, filesystem, solr, elasticsearch or any database server.

Getting involved !

Pymigration's development may be viewed and followed on github::

http://github.com/globocom/pymigration

Retrieve the source code using 'git'::

$ git clone git@github.com:globocom/pymigration.git

Install package in 'development mode' and run tests with run::

$ git clone git@github.com:globocom/pymigration.git
$ cd pymigration
$ ./run unit