Celery factory function vs importing celery

Question

I am developing a Flask application and leveraging blueprints. I plan to use celery task queues. I am trying to understand the benefit or reason to use something like

def make_celery(app):
    celery = Celery(app.import_name, broker=app.config['CELERY_BROKER_URL'])
    celery.conf.update(app.config)
    TaskBase = celery.Task
    class ContextTask(TaskBase):
        abstract = True
        def __call__(self, *args, **kwargs):
            with app.app_context():
                return TaskBase.__call__(self, *args, **kwargs)
    celery.Task = ContextTask
    return celery

and then doing

celery = make_celery(app) 

and importing it into my tasks.py versus just importing and creating a celery instances in my tasks.py like

from celery import Celery

app = Celery('hello', broker='amqp://guest@localhost//')
@app.task
def mytask():

Answer 1

If You are writing a simple task, it is better to import celery & decorate your function.

If You are creating some complex tasks, it is better to sublcass Task. Here You will get the power of OOP. You can break your code into small blocks. That makes it easier to unit test your code. Also if you want some custom config for all of your tasks, you can have a custom baseclass & you can inherit from it for all the tasks.