Django-celery + Redis notes

djanog-celery-and-redis-on-osx-lion.md

Django-celery + Redis notes

Installation and Setup

1. Install redis on OSX (10.7) Lion I used:

    $ brew install redis
   

2. In the project and virtualenv I wanted to use django-celery in I installed the following.

    $ pip install django-celery
    $ pip install redis
   

3. Add djcelery to your INSTALLED_APPS in your Django settings.py file.

4. Added the following django-celery settings toward the end of my Django settings.py file.

    BROKER_HOST = "localhost"
    BROKER_BACKEND="redis"
    REDIS_PORT=6379
    REDIS_HOST = "localhost"
    BROKER_USER = ""
    BROKER_PASSWORD =""
    BROKER_VHOST = "0"
    REDIS_DB = 0
    REDIS_CONNECT_RETRY = True
    CELERY_SEND_EVENTS=True
    CELERY_RESULT_BACKEND='redis'
    CELERY_TASK_RESULT_EXPIRES =  10
    CELERYBEAT_SCHEDULER="djcelery.schedulers.DatabaseScheduler"
   

5. In your local development settings file it might be good to add CELERY_ALWAYS_EAGER = True. This blocks the run tests (sans celery) that way you can test and develop easier.

6. Open a terminal window and start redis.

    redis-server /usr/local/etc/redis.conf
   

7. Open another terminal window and start a celery worker server for testing.

    $ python manage.py celeryd -l info
   

Example Task

• Add the following code in a tasks.py file in a folder for one of your apps that's in your INSTALLED_APPS in your Django settings.py file.

    from celery.decorators import task
  
    @task()
    def add(x, y):
        return x + y
  

• Now you should be able to play around with Django-celery from the command line. Open another terminal window and do the following:

    $ django-admin.py shell
    >>> result = add.delay(4, 4)
    >>> result.ready() # returns True if the task has finished processing.
    False
    >>> result.result # task is not ready, so no return value yet.
    None
    >>> result.get()   # Waits until the task is done and returns the retval.
    8
    >>> result.result # direct access to result, doesn't re-raise errors.
    8
    >>> result.successful() # returns True if the task didn't end in failure.
    True