pymigration 0.0.1

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.


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 it works
=================

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::

# -*- coding: utf-8 -*-
#hello_world.py

"""
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 get_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.



Supported databases engines
==================

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

You can do anything!


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