Lack of process_* metrics about client_python

[brian-brazil]

Are you doing anything that'd make /proc inaccessible?

[hynek]

Not that I’d know of.

They’re run using runit and inside envconsul. The latter is the only recent change I can think of. Other than that, it’s regular processes in an LXC container with a distinct user.

Are you saying that /proc problems are the only possible reason why those metrics might be missing?

[brian-brazil]

With the current implementation, yes. We read from /proc/self/stat.

[hynek]

I've added a

with open("/proc/self/stat", "rb") as f:
    print(f.read())¬

block to the app's startup and before calling generate_latest(core.REGISTRY) and in both cases I get a legit-looking output back.

I suppose it's too late at that point anyway because something goes wrong write registering metrics?

[hynek]

OK it was /proc but not the self thing (free -m stopped working too). Seems like procfs crashed and I needed to reboot the container.

It may be nice if the docs mentioned this error case? Or a log message a la “could not access XYZ, process metrics won't be collected”?

[brian-brazil]

I don't think we need to document that if kernel is hosed things will break. We don't log as that could get spammy in other circumstances.

[hynek]

OK. Maybe if someone runs into it, they find this ticket. :)