link-migration 0.0.18

A generic tool for migrate in python.

Link Migration

A generic tool for migrate in python.

Link Migration 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 Link Migration 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

0.0.12

Install

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

pip install link-migration

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

pip install --upgrade link-migration

Understanding how to use

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

The folder link-migrations need be a module (__init__.py most be present in link-migrations 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"

Link Migration uses the version information to track the migrations schema and to decide the order of execution of the scripts. Link Migration 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 Link Migration can execute DDL. Just create a file named “conf.py”, with the following content (there is also an example in the “link-migration” directory):

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

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

It is possible to override the way Link Migration 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:

$ link-migration --to=00.00.01

If you don’t specify any version, using --up or --down, Link Migration 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 !

Link Migration's development may be viewed and followed on github::

http://github.com/globocom/link-migration

Retrieve the source code using 'git'::

$ git clone [e-mail]:globocom/link-migration.git

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

$ git clone [e-mail]:globocom/link-migration.git
$ cd link-migration
$ ./run unit