我应该使用普通的Python代码还是Celery？ Django的。

Question

I have a heavy function (a lot of calculations are done) which outputs a individual number for each user in my Django project. This number changes just a little over time so to minimize the server load I thought about running the function once a day, save the output and just reference the output. I know that these kinda things are usually handled with Celery but the package requires a lot of site packages and extra modules so I thought about writing a simple function like:

x0 = #last.time function was called
x1 = datetime.now
if x0-x1 > 1 day:
  def whatever():
    ....
    x0 = datetime.now
    return ....

I like to keep my code clean and not to install Packages which are not really required so I would like to know if there are any downsides by "just" using Python or any gain when I would do that with Celery . The task does not need to be asynchronous so I don't care about that. Is there a clear "Use case" when Celery should be used and when not? Is there a performance loss/gain?

I hope somebody can explain that properly.

Answer 1

Celery is a clear winner but I would like to explain this with pros and cons.

Pros :

• You can control celery from Django very easily. Running a celery task, cancelling task, checking state/progress of task can be done within django.

• A periodical task running with celery is very simple, just register the task from django run the celery worker and voila you are done. No need to mess around with crontab or background processes.

• Celery is very easy to setup and run. You might already know that if you have gone through the introduction of celery.

Cons

• One of the cons is that you need to have at least one result backend with either redis, rabbitmq or any other one running with celery for queuing purposes. Although RabbitMq is not a heavy you need to install it once.

• One more is that celery worker itself takes some memory but that won't be an issue if you are on a server, on local memory consumption might seem high to you.

I would suggest celery because it would provide you more control over your task rather than a simple background process.