add logger to OutlierDetectionLoadBalancer

[s-matyukevich]

Right now there is no visibility at all into what OutlierDetection lb is doing.

This PR is intended to fix this problem by adding ChannelLogger to the load balancer. Here are the different types of message that will be logged (taken from my end-to-end test):

[2023-02-07 05:37:12 525] [FINEST ] [Channel<1>: (logs-backend-rpc-test-server.service-discovery.all-clusters.local-dc.fabric.dog:50051)] OutlierDetection lb created.

[2023-02-07 05:37:12 532] [FINEST ] [Channel<1>: (logs-backend-rpc-test-server.service-discovery.all-clusters.local-dc.fabric.dog:50051)] Received resolution result: ResolvedAddresses{addresses=[[[logs-backend-rpc-test-server.service-discovery.all-clusters.local-dc.fabric.dog/10.131.230.154:50051]/{}], [[logs-backend-rpc-test-server.service-discovery.all-clusters.local-dc.fabric.dog/10.135.101.119:50051]/{}], [[logs-backend-rpc-test-server.service-discovery.all-clusters.local-dc.fabric.dog/10.131.193.5:50051]/{}], [[logs-backend-rpc-test-server.service-discovery.all-clusters.local-dc.fabric.dog/10.135.43.140:50051]/{}]], attributes={io.grpc.internal.RetryingNameResolver.RESOLUTION_RESULT_LISTENER_KEY=io.grpc.internal.RetryingNameResolver$ResolutionResultListener@4612c26d}, loadBalancingPolicyConfig=io.grpc.util.OutlierDetectionLoadBalancer$OutlierDetectionLoadBalancerConfig@5c9a2c13} 

[2023-02-07 05:37:22 546] [FINEST ] [Channel<1>: (logs-backend-rpc-test-server.service-discovery.all-clusters.local-dc.fabric.dog:50051)] FailurePercentage algorithm detected outlier: AddressTracker{subchannels=[OutlierDetectionSubchannel{addresses=[[[logs-backend-rpc-test-server.service-discovery.all-clusters.local-dc.fabric.dog/10.135.101.119:50051]/{}]]}]}

Also, a similar message will be added for the SuccessRate algorithm.

[2023-02-07 05:37:22 546] [FINER  ] [Channel<1>: (logs-backend-rpc-test-server.service-discovery.all-clusters.local-dc.fabric.dog:50051)] Subchannel ejected: OutlierDetectionSubchannel{addresses=[[[logs-backend-rpc-test-server.service-discovery.all-clusters.local-dc.fabric.dog/10.135.101.119:50051]/{}]]} 

A similar message will be added for the uneject event.

I used FINEST level everywhere except for actual ejection/unejection events, which are logged with FINER.
I also added the list of affected addresses to every log message, because this allows us to easily find misbehaving upstream server.

[temawi]

Thanks for adding this. Generally looks good, I just had a question on one of the log statements.

[temawi]

Can we please get the parameters for the failure percentage algorithm logged the same way you did with success rate? After that I think we can get this merged.

[s-matyukevich]

Done. b360b89

I added failureRate parameter to the FailurePercentage algorithm log message, as this is the only dynamically calculated parameter. I also added successRate to the SuccessRate algorithm log message for consistency.

[s-matyukevich]

Right now the CI is failing with javadoc: error - Error fetching URL: https://developers.google.com/protocol-buffers/docs/reference/java/ which I don't think is realted to my change. I rebased on master and got the same error.

[temawi]

Thank you!

[temawi]

Right now the CI is failing with javadoc: error - Error fetching URL: https://developers.google.com/protocol-buffers/docs/reference/java/ which I don't think is realted to my change. I rebased on master and got the same error.

@ejona pushed an empty commit to have the PR pick up the fix to the build from master. This is merged now, thanks for putting this together.