Django app with long running calculations
I think Celery is a good approach. Not sure if you need Redis/RabbitMQ as a broker or you could just use MySQL - it depends on your tasks. Celery workers could be runned on the different servers, so Celery supports distributed queues.
Another approach - implement some queue engine with python, database as a broker and a cron for job executions. But it could be a dirty way with a lots of pain and bugs.
So I think that Celery is a more nice way to do it.
I'm creating a Django web app which features potentially very long running calculations of up to an hour. The calculations are simulation models built in Python. The web app sends inputs to the simulation model and after some time receives the answer. Also, the user should be able to close his browser after starting the simulation and if he logs in the next day the results should be there.
From my research it seems like I can use Celery together with Redis/RabbitMQ as broker to run the calculation in the background. Ideally I would want to display progress updates using ajax, so that the page updates without a user refresh when the calculation is complete.
I want to host the app on Heroku, so the calculation will also be running on the Heroku server. How hard will it be if I want to move the calculation engine to another server? It might be useful if the calculation engine is on a different server.
So my question is, is my this a good approach above or what other options can I look at?