tgext.celery

tgext.celery is a TurboGears2 extension that integrates celery into a turbogears application


Keywords
turbogears2.extension
License
MIT
Install
pip install tgext.celery==0.1.1

Documentation

About tgext.celery

tgext.celery is a TurboGears2 extension that integrates celery into a turbogears application

I tested this extension just with the celery[mongodb]==3.1 bundle of celery and pymongo==3.5.1 using mongodb as both message broker and result backend

integrates both celery beat and celery worker

Installing

tgext.celery can be installed from pypi:

pip install tgext.celery

should just work for most of the users.

Plugging

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

from tgext.pluggable import plug
plug(base_config, 'tgext.celery')

put in your *.ini file the options that you want to pass to your celery application prefixed by `celery.`:

#celery config
celery.CELERY_TASK_SERIALIZER = json
celery.CELERY_RESULT_SERIALIZER = json
celery.CELERY_ACCEPT_CONTENT = json
celery.CELERY_TIMEZONE = UTC
celery.BROKER_URL = mongodb://localhost:27017/dbname
celery.CELERY_RESULT_BACKEND = mongodb://localhost:27017/dbname
celery.CELERYD_POOL = celery.concurrency.threads.TaskPool
celery.CELERY_INCLUDE = myproject.lib.celery.tasks
celery.CELERYD_CONCURRENCY = 3
celery.WITHOUT_GOSSIP = true
celery.WITHOUT_HEARTBEAT = true
celery.WITHOUT_MINGLE = true

see http://docs.celeryproject.org/en/3.1/configuration.html#configuration for other options

disabling gossip, heartbeat and mingle can be dono only from the celery worker cli, we added them to the configuration. We reccomend to disable them if you aren't using monitoring tools, because of a bug: https://github.com/celery/celery/issues/1047 that will fill your db with GBs of messages.

you can pass other options (that override the other in the .ini file) when plugging this extension this is convenient because the options in the .ini file aren't evaluated:

plug(
    base_config,
    'tgext.celery',
    celery_config={
        'CELERY_MONGODB_BACKEND_SETTINGS': {
            'database': 'dbname',
        },
        'CELERYBEAT_SCHEDULE': {
            'delete-unassociated-images-every-12-hours': {
                'task': 'delete_unassociated_images',
                'schedule': timedelta(hours=12),
            },
        },
    },
)

Writing tasks

Remember to set the CELERY_INCLUDE option here's an example with a task:

from __future__ import absolute_import

from myproject import model

from tgext.celery.celery import celery_app

import logging

logger = logging.getLogger(__name__)

celery_app.config_from_object(config['celery_configuration_object'])


@celery_app.task(name='delete_unassociated_images')
def delete_unassociated_images():
    logger.info('started')
    model.Image.query.remove({'post_id': None})
    logger.info('finished')

Executing

tgext.celery sets two gearbox commands, you can run celery with:

gearbox celeryworker -c production.ini --logfile=/var/log/circus/myproject_celery_worker_tasks.log

and:

gearbox celerybeat -c production.ini

in a production environment you should put these commands in a circus watcher or supervisord