Add etcd_server_range_duration_seconds metrics

[lavacat]

What would you like to be added?

We already have etcd_server_apply_duration_seconds metrics.

But Range doesn't go through Applier. The only metrics we have about Range timing is grpc_server_handled_total{grpc_method="Range"} provided by grpc_middleware. Problem is that this grpc metric also includes timing of linearizableReadNotify.

Please add etcd_server_range_duration_seconds in txn.Range

Why is this needed?

better observability

[RaviHari]

I would like to work on this

[stale[bot]]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed after 21 days if no further activity occurs. Thank you for your contributions.

[jmhbnz]

Discussed during sig-etcd triage meeting. This would be a good candidate for a new contributor. The original pr #16902 was abandoned by the previous contributor so we need to recreate this, and add a test.

[thedtripp]

Hello @jmhbnz. I'd like to take a crack at this one. I'm a new contributor looking for mentorship.

[jmhbnz]

Hello @jmhbnz. I'd like to take a crack at this one. I'm a new contributor looking for mentorship.

Thanks for volunteering @thedtripp! Assigned to you. Please start by recreating the earlier proposed changes from #16902. Then we need a second commit to add a basic test verifying the new metric works. Let us know how you go and if you have any questions 🙏🏻

/assign @thedtripp

[thedtripp]

@jmhbnz I made a PR: https://github.com/etcd-io/etcd/pull/17983

[thedtripp]

@jmhbnz @ivanvc @ahrtr Thank you for guiding me through that first PR. Any suggestions on where I should focus for my next contribution?

[jmhbnz]

@jmhbnz @ivanvc @ahrtr Thank you for guiding me through that first PR. Any suggestions on where I should focus for my next contribution?

Most welcome! For a much quicker next contribution we need to update our website community page https://github.com/etcd-io/website/issues/850. If you're interested please feel free to leave a comment and I will assign it to you. Alternatively please take a look at our help wanted issues.

[thedtripp]

@jmhbnz @ivanvc @ahrtr Thank you for guiding me through that first PR. Any suggestions on where I should focus for my next contribution?

Most welcome! For a much quicker next contribution we need to update our website community page etcd-io/website#850. If you're interested please feel free to leave a comment and I will assign it to you. Alternatively please take a look at our help wanted issues.

Sure! I'm happy to work on this.

[thedtripp]

Hey Team, Is this issue ready to be closed or does it need further action?

[ivanvc]

I'm closing this, as it was completed by https://github.com/etcd-io/etcd/pull/17983. Thanks, @thedtripp. Please re-open it @ahrtr / @jmhbnz if you think we need to backport this.