Hi Anton:

In message <1702595412.18.0.970424296848.issue2551309@roundup.psfhosted.org>,
Anton Savchuk writes:
>Hello! I'm also interested in polling IMAP mailboxes when using
>containerized Roundup. Documentation says the only way is using cron tasks. 
>
>I think I have an idea. It would be possible to implement built-in
>scheduler using native Python sched module.

How would sched be invoked? Out of the main loop in the server, a
separate thread, a subprocess started from the main server?

Running roundup-server in the current containerization was a "get
something running" attempt.  For real deployments (50+
connections/sec) running Roundup via wSGI under gunicorn (as is done
with bugs.python.org) is the "production" deployment method.

Will using the sched module work if there is no master roundup-server?
IIUC wSGI instances basically sit idle until triggered from
upstream. I'm not sure how only one instance of sched can be run in
such an environment.

Also roundup-server can run in either forking or threaded mode. By
default we chose forking (multiprocess). In the future this may be
extended to include a subinterpreter method rather than a fork. Can
sched work in a threaded environment? (There is a report that threads
respond faster (2x+) under light load, but the response times increase
faster than the forking model under load. Why I'm not sure.)

I'd like to use subinterpreters in roundup-server when it is
implemented in a future Python. It will make roundup-server scale
better (not to gunicorn levels but) and be usable in more scenarios.
But it is too early to understand how sched and subinterpreter will
co-exist.

https://tonybaloney.github.io/posts/sub-interpreter-web-workers.html
https://realpython.com/python312-subinterpreters/
https://peps.python.org/pep-0734/

Hopefully subinterpreter will be like multiprocess.

Thoughts?

Have a great weekend.