Is there a way to restrict how many CPUs ruff uses?

[trampgeek]

Hi guys - thanks for a great tool.

I'm using ruff in a student coding environment (Moodle/CodeRunner) in which jobs are run with a strict ulimit on the number of processes. I'd like to be able to limit how many processes ruff can use in this environment.

I thought the RAYON_NUM_THREADS environment variable might do the trick but I find commands like

ulimit -u 8; RAYON_NUM_THREADS=4 ruff check plotriverflow.py

still result in a stream of output lines:

bash: fork: retry: Resource temporarily unavailable
bash: fork: retry: Resource temporarily unavailable
etc

Is there an easy way to limit ruff's CPU use?

[MichaReiser]

I'd have expected that RAYON_NUM_THREADS works but it's possible that we spawn some threads in other locations (e.g. directory walking uses threads too and it doesn't use rayon). I'm afraid, there's no single variable to control this today

[trampgeek]

OK, that's a shame, but thanks for the prompt response. We can work around the problem for any given number of cores, but it would have been nice to have a solution that was independent of the server configuration. But ruff's great - thanks again.