django-kronos 0.7

Kronos is a Django application that makes it easy to define and schedule tasks with cron.

Kronos
======

.. image:: https://secure.travis-ci.org/jgorset/django-kronos.png?branch=master

Kronos makes it really easy to schedule tasks with cron.

Installation
------------

::

$ pip install django-kronos

... and add ``kronos`` to ``INSTALLED_APPS``.

Usage
-----

Define tasks
^^^^^^^^^^^^

Kronos collects tasks from ``cron`` modules in your project root and each of your applications::

# app/cron.py

import kronos
import random

@kronos.register('0 0 * * *')
def complain():
complaints = [
"I forgot to migrate our applications's cron jobs to our new server! Darn!",
"I'm out of complaints! Damnit!"
]

print random.choice(complaints)

Kronos works with Django management commands, too::

# app/management/commands/task.py

from django.core.management.base import NoArgsCommand

import kronos

@kronos.register('0 0 * * *')
class Command(NoArgsCommand):
def handle_noargs(self, **options):
print('Hello, world!')

If your management command accepts arguments, just pass them in the decorator::

# app/management/commands/task.py

from django.core.management.base import BaseCommand

import kronos

@kronos.register('0 0 * * *', args={'-l': 'nb'})
class Command(BaseCommand):

option_list = BaseCommand.option_list + (
make_option('-l', '--language',
dest = 'language',
type = 'string',
default = 'en')
)

def handle(self, *args, **options):
if options['language'] == 'en':
print('Hello, world!')

if options['language'] == 'nb':
print('Hei, verden!')


Run tasks manually
^^^^^^^^^^^^^^^^^^

::

$ python manage.py runtask complain
I forgot to migrate our applications's cron jobs to our new server! Darn!

Keep in mind that if the registered task is a django command you have to run it
in the normal way::

$ python manage.py task


List all registered tasks
^^^^^^^^^^^^^^^^^^

::

$ python manage.py showtasks
* List of tasks registered in Kronos *
>> Kronos tasks
>> my_task_one
>> my_task_two
>> Django tasks
>> my_django_task


Register tasks with cron
^^^^^^^^^^^^^^^^^^^^^^^^

::

$ python manage.py installtasks
Installed 1 task.

You can review the crontab with a ``crontab -l`` command::

$ crontab -l
0 0 * * * /usr/bin/python /path/to/manage.py runtask complain --settings=myprpoject.settings $KRONOS_BREAD_CRUMB
0 0 * * * /usr/bin/python /path/to/manage.py task --settings=myprpoject.settings $KRONOS_BREAD_CRUMB

Usually this line will work pretty well for you, but there can be some rare
cases when it requires modification. You can achieve it with a number of
settings variables used by kronos:

KRONOS_PYTHON
Python interpreter to build a crontab line (defaults to the interpreter you used to
invoke the management command).

KRONOS_MANAGE
Management command to build a crontab line (defaults to ``manage.py`` in the current
working directory).

KRONOS_PYTHONPATH
Extra path which will be added as a ``--pythonpath`` option to the management command.

KRONOS_POSTFIX
Extra string added at the end of the command. For dirty thinks like '> /dev/null 2>&1'

Define these variables in your ``settings.py`` file if you wish to alter crontab lines.

The env variable ``$KRONOS_BREAD_CRUMB`` is defined to detect which tasks have to be deleted after
being installed.

Contribute
----------

* Fork the repository.
* Do your thing.
* Open a pull request.
* Receive cake.

I love you
----------

Johannes Gorset made this. You should `tweet me <http://twitter.com/jgorset>`_ if you can't get it
to work. In fact, you should tweet me anyway.


0.7.0
+++++

* You may now pass arguments to Django management commands registered with Kronos.
* Kronos is now compatible with Python 3.
* Kronos will now log errors when it fails to load tasks.

0.6.0
+++++

* You may now register Django management commands.

0.5.0
+++++

* You may now list commands with ``python manage.py showtasks``.

0.4.0
+++++

* You may now postfix commands with ``KRONOS_POSTFIX``.

0.3.0
+++++

* You may now customize the interpreter, management path and python path for tasks with the ``KRONOS_PYTHON``,
``KRONOS_MANAGE`` and ``KRONOS_PYTHONPATH`` settings, respectively.

0.2.3
+++++

* Kronos now supports Django 1.4-style projects.
* Fixed a bug that caused installation to fail for users that didn't already have a crontab.

0.2.2
+++++

* Fixed a bug that caused unclosed single quotes in the crontab to raise a ValueError

0.2.1
+++++

* Fixed a bug that caused 'cron'-modules in the project root to be ignored.

0.2.0
+++++

* Kronos will now collect tasks from a 'cron' module in the project root.