gRPC interface reflection.

[aaronc]

Description

ref: #5921

This PR adds a new gRPC service to do interface registry reflection. Specifically, it adds 2 RPC endpoints:

• ListAllInterfaces: list all the interfaces registered in the registry.
• ListImplementations: given an interface name, list all its implementations.

---

Before we can merge this PR, please make sure that all the following items have been
checked off. If any of the checklist items are not applicable, please leave them but
write a little note why.

• Targeted PR against correct branch (see CONTRIBUTING.md)
• Linked to Github issue with discussion and accepted design OR link to spec that describes this work.
• Code follows the module structure standards.
• Wrote unit and integration tests
• Updated relevant documentation (docs/) or specification (x/<module>/spec/)
• Added relevant godoc comments.
• Added a relevant changelog entry to the Unreleased section in CHANGELOG.md
• Re-reviewed Files changed in the Github PR explorer
• Review Codecov Report in the comment section below once CI passes

[codecov]

Codecov Report

Merging #6722 into master will decrease coverage by 0.01%.
The diff coverage is 45.23%.

@@            Coverage Diff             @@
##           master    #6722      +/-   ##
==========================================
- Coverage   54.68%   54.66%   -0.02%     
==========================================
  Files         540      541       +1     
  Lines       36856    36887      +31     
==========================================
+ Hits        20153    20165      +12     
- Misses      15060    15077      +17     
- Partials     1643     1645       +2     

[odeke-em]

Thank you for this change @aaronc, just a drive by code review from me.

[alexanderbez]

Can you add a bit more to the PR body @aaronc? Thanks for listing the ref, I just wanna be sure of what this changeset includes and why :)

[amaury1093]

@alexanderbez I just updated the PR desc answering the "what" question.

Concerning the "why", tbh I'm not 100% sure, I see it as a nice-to-have, same as the gRPC reflection itself. Aaron might have a clearer idea.

[odeke-em]

I believe it is going to serve a big role when we have types.Any DB compression, but also for any service to get a listing of all available types instead of sweating with manually passing them around and registering which is quite painful to do currently. With this federated service, one just connects to a specific address and gets a listing of all types registered and can do their job trivially.

…

On Mon, Aug 17, 2020 at 9:42 AM Amaury Martiny ***@***.***> wrote: @alexanderbez <https://github.com/alexanderbez> I just updated the PR desc answering the "what" question. Concerning the "why", tbh I'm not 100% sure, I see it as a nice-to-have, same as the gRPC reflection itself. Aaron might have a clearer idea. — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#6722 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ABFL3V5FUBWXJLWKPS7ILF3SBFMXFANCNFSM4OZYUC7A> .

[alexanderbez]

🎉