Basic ADS client

[renuka-fernando]

Add basic ADS client

Related issue: envoyproxy/ratelimit#201
Related PR: envoyproxy/ratelimit#373

Signed-off-by: Renuka Fernando renukapiyumal@gmail.com

[renuka-fernando]

Hey @alecholmez,

I found this xDS client sample, https://github.com/grpc/grpc-go/tree/master/examples/features/xds
But I am not sure that we can use this, in its sample client, it is just a call to the method "SayHello". It is not to send the Discovery Request.

Client: https://github.com/grpc/grpc-go/blob/master/examples/features/xds/client/main.go#L68

[alecholmez]

So we can actually do something similar, I've written an envoy xDS client before let me see if I can dig that up...

This code: https://github.com/greymatter-io/gm-fabric-go/blob/main/discovery/xds.go
Is rather old and only works for V2 and hasn't been touched in years haha, but it's a similar concept.

[renuka-fernando]

Thank you for your response. But the link https://github.com/greymatter-io/gm-fabric-go/blob/main/discovery/xds.go is not visible to me, it gives me 404.

[renuka-fernando]

Hey, @alecholmez,

When you get a chance, could you please review this PR?

[github-actions]

This pull request has been automatically marked as stale because it has not had activity in the last 30 days. It will be closed in 7 days if no further activity occurs. Please feel free to give a status update now, ping for review, or re-open when it's ready. Thank you for your contributions!

[renuka-fernando]

Hi @kyessenov @sunjayBhatia @alecholmez ,

Could you please have a look? This is related to the envoy rate limit service configuration update feature via xDS protocol. There, rate limit service works as the xDS client and GCP as xDS server. Since the rate limit service requires an xDS client in golang we wanted to have a generic golang xDS client in GCP repo. It is really grateful if you could have a look.

Thanks.

[renuka-fernando]

Hi @alecholmez,

Could you please have a look? Please let me know if any changes are required for the basic ADS client.

[alecholmez]

I think overall this looks good. Just some cleanup here and there and we can get this in.

One recommendation I might have would be to change the folder structure:

pkg/client/sotw/v3/client.go

I imagine we might want more of these. Maybe a delta client, xDS client, delta xDS client, etc...

[renuka-fernando]

I think overall this looks good. Just some cleanup here and there and we can get this in.

One recommendation I might have would be to change the folder structure:

pkg/client/sotw/v3/client.go

I imagine we might want more of these. Maybe a delta client, xDS client, delta xDS client, etc...

Hi @alecholmez,

Thank you for your comments.

Moved the client.go file as requested to pkg/client/sotw/v3/client.go.
So later we can add delta client as pkg/client/delta/v3/client.go.

[alecholmez]

Great! I'm letting the build run and hopefully we can get this in shortly.

[alecholmez]

@renuka-fernando looks like the build failed. Can you look into this?

[renuka-fernando]

@alecholmez could you please check now?

[renuka-fernando]

Hi @alecholmez,

Could you please run the failed build again and please review the PR? The issue with the build is fixed now: #625

[alecholmez]

@renuka-fernando looks like this one still failed can you check it out?

[alecholmez]

This looks good thanks for the contributions!