prometheus-ecs-discovery exits with 2 on SIGTERM

[iGEL]

When I send TERM to prometheus-ecs-discovery, it exits with the status 2. An exit status between 1 and 127 usually indicates an error, so we report this.

When a program ends because of a signal, it should exit with the exit code 128 + Signal number, see https://wiki.jenkins.io/display/JENKINS/Job+Exit+Status. When Docker wants to stop a container, it sends the TERM signal (TERM = 15) to the process in the container, so that process should terminate with code 143.

It would be great if prometheus-ecs-discovery would exit with 143 when receiving TERM instead of 2, so we don't get reports of failed processes just because we deployed it for example.

[toymachiner62]

I'm having the same issue when trying to call prometheus-ecs-discover -help and it's returning exit code 2. According to this thread golang/go#37533 I think by adding a help flag it will return a status code 0. The only reason it's returning a status code 2 is b/c the help flag isn't explicitly defined.

My use case is that i'm trying to verify in my docker image that I can call the prometheus-ecs-discovery executable as a sanity check but it's failing my circleci build due to returning exit code 2.