PrometheusReporter thread is not daemon

[RobertoUa]

The thread should be daemon by default and users should be allowed to configure it.

[ivantopo]

Hey @RobertoUa, could you please explain a bit more what you mean by this?

[RobertoUa]

sorry, I meant thread. I have to call sys.exit(0) because app doesn't finish

[ivantopo]

Oh, now I see what you mean! So, this is not specific to the Prometheus module, it actually is part of Kamon core, we even have tests to ensure that this works this way! Instead of sys.exit, just make Kamon stop all reporters (that's either Kamon.stopModules() in Kamon 2.x or Kamon.stopAllReporters() in Kamon 1.x) and then the application will be able to stop without issues.

The goal with that was to allow the reporters to push out the very last data they have before shutting down, which is specially important when running short-lived processes.

[RobertoUa]

I see, thanks! But maybe we can allow configuring it? I don't want to call Kamon.stopAllReporters() this seems wrong, and not obvious (I had to debug for a long time to find out which thread is daemon) every other dependency I can configure to make threads daemon.