Nix prometheus exporter

As I am currently setting up monitoring my systems with prometheus, I was wondering if there is a prometheus exporter that would be able to collect some nix related metrics.

I’m not even sure how those would look like or what they would cover, but I am interested in exploring those.

If such a thing does not yet exist, what metrics would be interesting?

Currently I can think about these:

  • number of GC roots
  • total time spent building (per build user)
  • current number of builds running
  • total count of builds per status (success/fail) and build user(?)

Any other ideas? Also where would one find those metrics? The number of GC roots is easy, though I currently wouldn’t even know how I’d be able to check those other data points…