#1: Autoconfigure metric registry support

[hmtang]

Signed-off-by: Sunny hmtang@gmail.com
[resolves #1]

[onobc]

Thanks @hmtang for the contribution. I have made a few request for changes. Let us know if you have any questions or need further clarifications - we are excited to have you on the project. Thank you.

[hmtang]

Thanks a lot for the feedbacks. I would be out for a short trip in next week. I would look into this when I get back. Appreciate your time on the reviews.

[making]

I don't think we need MetricCollectingServerInterceptor if we support ObservationGrpcServerInterceptor which can output similar metrics and traces at the same time.

[onobc]

I don't think we need MetricCollectingServerInterceptor if we support ObservationGrpcServerInterceptor which can output similar metrics and traces at the same time.

I agree w/ this @making . I think we should just add auto-configuration for the Micrometer Observations API (which gives metrics and tracing) and if users want to only use Micrometer metrics they can add it in via interceptor themselves.

We have started taking this approach in our newer Spring projects (e.g. Spring Pulsar only provides support for Observations API). Most Spring projects were incepted prior to the availability of Observations API therefore Micrometer support was already in place.

@dsyer do you agree w/ this?

[dsyer]

100%

[hmtang]

Tried to change to include only AutoConfiguration for the Metric, I am not entire sure about whether this is enough for the change. Please have a look. Thanks a lot.

[onobc]

Nice work @hmtang ! A have added a few comments/suggestions.

Besides the suggestions, once we get the base configuration in this PR we will definitely want to document how to enable observations in a Spring gRPC application. There are quite a few moving pieces and it can be confusing. It does not have to be in this PR though as it may get large.

We did this exact thing for Spring Pulsar docs and we can clone/own those or just point to the SB docs on this topic.

We may want to create a sample that uses Micrometer observations as well (we did the same thing in Spring Pulsar here.

[hmtang]

Thanks for the reviews. I have pushed a new changes for the requested changes.

[dsyer]

"This branch cannot be rebased safely" according to github, so you need to rebase. Probably a good idea to squash your commits into one as well and force push back to your fork.

[onobc]

Thanks again for the great contribution @hmtang . I am closing this PR in favor of 7fed50a.

I added a follow-on commit to your commit (see details in commit message if you are interested. I add a couple more tests).

[onobc]

"This branch cannot be rebased safely" according to github, so you need to rebase. Probably a good idea to squash your commits into one as well and force push back to your fork.

Sorry @dsyer ,
I went ahead and handled that locally when I added polish commit. Next time I will assign the PR to myself to give a signal.