OpenTelemetry support

[Gorbush]

Hi.

Is there any plan to support traces and metrics for OpenTelemetry?
https://opentelemetry.io/
We use HoneyComb for that and need to get the metrics for BazelRemote instances.
https://www.honeycomb.io/

Thank you!

[mostynb]

Hi.

Re metrics: bazel-remote currently supports prometheus. I'm not sure of the current status of opentelemetry metrics, is it still kind of immature?

Re tracing: I have been holding off adding this feature because I'm not sure how useful it would be. For bazel-remote installs that only use the disk cache, I suspect that disk iowait metrics are probably more useful than traces for individual requests. Maybe things are different for installs that use s3/gcs/azblob/http backends though?