Configure Celery

Celery is an asynchronous task queue. It's a part of RhodeCode scheduler functionality. Celery makes certain heavy tasks perform more efficiently. Most important it allows sending notification emails, create repository forks, and import repositories in async way. It is also used for bi-directional repository sync in scheduler.

If you decide to use Celery you also need a working message queue. There are two fully supported message brokers is rabbitmq and redis (recommended).

Since release 4.18.X we recommend using redis as a backend since it's generally easier to work with, and results in simpler stack as redis is generally recommended for caching purposes.

In order to install and configure Celery, follow these steps:

1. Install RabbitMQ or Redis for a message queue, see the documentation on the Celery website for redis installation or rabbitmq installation

1a. If you choose RabbitMQ example configuration after installation would look like that:

sudo rabbitmqctl add_user rcuser secret_password
sudo rabbitmqctl add_vhost rhodevhost
sudo rabbitmqctl set_user_tags rcuser rhodecode
sudo rabbitmqctl set_permissions -p rhodevhost rcuser ".*" ".*" ".*"

2. Enable celery, and install celery worker process script using the enable-module:

   rccontrol enable-module celery {instance-id}
   

3. Configure Celery in the :file:`home/{user}/.rccontrol/{instance-id}/rhodecode.ini` file. Set the broker_url as minimal settings required to enable operation. If used our example data from pt 1a, here is how the broker url should look like:

   # for Redis
   celery.broker_url = redis://localhost:6379/8
   
   # for RabbitMQ
   celery.broker_url = amqp://rcuser:secret_password@localhost:5672/rhodevhost
   

   Full configuration example is below:

   # Set this section of the ini file to match your Celery installation
   ####################################
   ###        CELERY CONFIG        ####
   ####################################
   
   use_celery = true
   celery.broker_url = redis://localhost:6379/8
   
   # maximum tasks to execute before worker restart
   celery.max_tasks_per_child = 20
   
   ## tasks will never be sent to the queue, but executed locally instead.
   celery.task_always_eager = false