Add gRPC proto def for rate-limit xDS Config communication

[renuka-fernando]

Description

Proto for xDS communication as in the discussion #201 (comment).
xDS implementation: #373

[mattklein123]

Thanks for working on this. Can you add more comments so it's easier to understand how this is going to be used in the context of ADS? Thank you.

[renuka-fernando]

I had a discussion with @alecholmez about adding this along with ADS. We can use ADS for this and there is no ADS client in go-control-plane hence, I will add an xDS client in this repo.

For writing the xDS server we can use go-control-plane and use Snapshots to update the rate limits. This PR envoyproxy/go-control-plane#598 will register the rate limit config as a known type in go-control-plane.

[mattklein123]

I had a discussion with @alecholmez about adding this along with ADS. We can use ADS for this and there is no ADS client in go-control-plane hence, I will add an xDS client in this repo.

Please don't add the ADS client in this repo. I think it belongs in GCP so it can be used in other places.

[renuka-fernando]

I had a discussion with @alecholmez about adding this along with ADS. We can use ADS for this and there is no ADS client in go-control-plane hence, I will add an xDS client in this repo.

Please don't add the ADS client in this repo. I think it belongs in GCP so it can be used in other places.

Used the ADS streaming client https://github.com/envoyproxy/go-control-plane/blob/129d0216a4efb985b22349fb45c1444d4f0e7900/envoy/service/discovery/v3/ads.pb.go#L228
Please find the xDS implementation in #373

[renuka-fernando]

Could you please retrigger the build? This is an intermitten issue, which will be fixed with #370

[mattklein123]

This looks fine but one thing I'm wondering is can we share the protos from xds/envoy for some of the core structures?

[kkcmadhu]

this app prodvides an http endpoint /json to get the current rate limit as jason.
A HTTP endpoint to add /modify the current config will be great too..

irrespective of GRPC or HTTP, do we think we will need some kind of role support to control who can modify this config?

[renuka-fernando]

Hi @mattklein123,

ADS Client implementation is merged envoyproxy/go-control-plane#604 and updated the go-control-plane version to reflect the client implementation. Could you please review this PR?

Thanks.

[renuka-fernando]

Closing this PR. The proto file is included in #373 as a single commit.