Understanding how tasks are imported

Behind-the-scenes when you decorate a function with task() or periodic_task(), the function registers itself with an in-memory registry. When a task function is called, a reference is put into the queue, along with the arguments the function was called with, etc. The message is then read by the consumer, and the task function is looked-up in the consumer’s registry. Because of the way this works, it is strongly recommended that all decorated functions be imported when the consumer starts up.

If a task is not recognized, the consumer will raise a HueyException.

The consumer is executed with a single required parameter, the import path to a Huey object. It will import the Huey instance along with anything else in the module, so you must be sure imports of your tasks occur with the import of the Huey object.

Suggested organization of code

Generally, I structure things like this, which makes it very easy to avoid circular imports.

• config.py, the module containing the Huey object.

  # config.py
  from huey import RedisHuey
  
  huey = RedisHuey('testing')
  

• tasks.py, the module containing any decorated functions. Imports the huey object from the config.py module:

  # tasks.py
  from config import huey
  
  @huey.task()
  def add(a, b):
      return a + b
  

• main.py / app.py, the “main” module. Imports both the config.py module and the tasks.py module.

  # main.py
  from config import huey  # import the "huey" object.
  from tasks import add  # import any tasks / decorated functions
  
  
  if __name__ == '__main__':
      result = add(1, 2)
      print('1 + 2 = %s' % result.get(blocking=True))
  

To run the consumer, point it at main.huey, in this way, both the huey instance and the task functions are imported in a centralized location.

huey_consumer main.huey