Add grpc netty keep-alive-time configuration option

[spike83]

While using gRPC server side stream we are facing stream termination due to short tcp idle time on loadbalancer. There is configuration options in netty server which are not exposed presently.
With this the netty keep-alive is exposed as quarkus.grpc.server.netty.keep-alive-timewhere we can set a Duration.

[gsmet]

Thanks. Added a small comment but I'll let @michalszynkiewicz and @cescoffier handle this one.

[cescoffier]

Can you add a test?

[spike83]

Can you add a test?

@cescoffier Sure, what kind of test would you expect. You may point me to some similar tests?

[michalszynkiewicz]

Can you add a test?

@cescoffier Sure, what kind of test would you expect. You may point me to some similar tests?

I can't speak for Clement but I think the following would be good to test:

• the connection times out successfully after keep-alive time + epsilon
• the connection doesn't time out if it doesn't

I think it would be okay to add the tests to extensions/grpc/deployment. You can find a few examples there already.

[cescoffier]

@michalszynkiewicz what should we do with this PR?

[michalszynkiewicz]

I just came back from PTO, I added creating a test for it to my todo list.
Do you think it's worth merging without a test?

[spike83]

Unfortunately this went out of my focus. Sorry for that. I was looking into testing a while ago and had no clue how to nail it down. In the meantime we found that we need some gossip on higher level which keeps the connection open anyway. But it would be great if you could finish it. Thanks.

[cescoffier]

We should rebase and see what's the CI says.

[gsmet]

This PR now conflicts with the main branch. I personally think it could be merged even without a test. But that's not my say.

@cescoffier @michalszynkiewicz what should we do with it?

[michalszynkiewicz]

@gsmet it should already be in: #14957
sorry, I forgot to close the original

[gsmet]

Great, thanks!