Installing

tgext.evolve can be installed from pypi:

pip install tgext.evolve

should just work for most of the users.

Enabling

To enable tgext.evolve put inside your application config/app_cfg.py the following:

import tgext.evolve
tgext.evolve.plugme(base_config, options={
    'evolutions': [
        # ... Your evolutions ...
    ]
})

or you can use tgext.pluggable when available:

from tgext.pluggable import plug
plug(base_config, 'tgext.evolve', evolutions=[
    # ... Your evolutions ...
])

tgext.evolve can then be disabled using the tgext.evolve.enabled = false option in your configuration files. This is often the case during test suites.

Using Evolutions

Evolutions are a subclass of tgext.evolve.Evolution that must provide an evolution_id property and an evolve() method.

Here is a sample evolution that does not much apart waiting for 10 seconds:

import time
from tgext.evolve import Evolution

class TestEvolution1(Evolution):
    evolution_id = 'test_evolution_1'

    def evolve(self):
        time.sleep(10)

Please note that in case you modify data or touch the database through model.DBSession or other manners you must flush and commit your UnitOfWork and Transaction yourself as evolutions are performed outside the transaction manager in a separated thread.

Then you can register your evolution with something like:

from tgext.pluggable import plug
plug(base_config, 'tgext.evolve', evolutions=[
    TestEvolution1
])

In case your evolution requires parameters you can register an instance of it instead of registering the class.

ChangeLog