Distributed Task Queue for Django
|Authors:||Ask Solem (email@example.com)|
celery is a distributed task queue framework for Django. More information will follow.
You can install celery either via the Python Package Index (PyPI) or from source.
To install using pip,:
$ pip install celery
To install using easy_install,:
$ easy_install celery
If you have downloaded a source tarball you can install it by doing the following,:
$ python setup.py build # python setup.py install # as root
Have to write a cool tutorial, but here is some simple usage info.
Note If you’re running SQLite as the database backend, celeryd will only be able to process one message at a time, this because SQLite doesn’t allow concurrent writes.
>>> from celery.task import tasks >>> from celery.log import setup_logger >>> def do_something(some_arg, **kwargs): ... logger = setup_logger(**kwargs) ... logger.info("Did something: %s" % some_arg) >>> task.register(do_something, "do_something")
Note Task functions only supports keyword arguments.
Tell the celery daemon to run a task
>>> from celery.task import delay_task >>> delay_task("do_something", some_arg="foo bar baz")
Running the celery daemon
$ cd mydjangoproject $ env DJANGO_SETTINGS_MODULE=settings celeryd [....] [2009-04-23 17:44:05,115: INFO/Process-1] Did something: foo bar baz [2009-04-23 17:44:05,118: INFO/MainProcess] Waiting for queue.
Autodiscovery of tasks
celery has an autodiscovery feature like the Django Admin, that automatically loads any tasks.py module in the applications listed in settings.INSTALLED_APPS.
A good place to add this command could be in your urls.py,
from celery.task import tasks tasks.autodiscover()
Then you can add new tasks in your applications tasks.py module,
from celery.task import tasks from celery.log import setup_logger from clickcounter.models import ClickCount def increment_click(for_url, **kwargs): logger = setup_logger(**kwargs) clicks_for_url, cr = ClickCount.objects.get_or_create(url=for_url) clicks_for_url.clicks = clicks_for_url.clicks + 1 clicks_for_url.save() logger.info("Incremented click count for %s (not at %d)" % ( for_url, clicks_for_url.clicks) tasks.register(increment_click, "increment_click")
Periodic tasks are tasks that are run every n seconds. They don’t support extra arguments. Here’s an example of a periodic task:
>>> from celery.task import tasks, PeriodicTask >>> class MyPeriodicTask(PeriodicTask): ... name = "foo.my-periodic-task" ... run_every = 30 # seconds ... ... def run(self, **kwargs): ... logger = self.get_logger(**kwargs) ... logger.info("Running periodic task!") ... >>> tasks.register(MyPeriodicTask)
For periodic tasks to work you need to add celery to INSTALLED_APPS, and issue a syncdb.
This software is licensed under the New BSD License. See the LICENSE file in the top distribution directory for the full license text.