Remove tchannel reporter from agent

[pavolloffay]

Remove tchannel reporter from agent.

• agent by default uses grpc reporter
• tchannel reporter was deprecated in 1.16 Deprecate tchannel #1975.

TODO:

• changelog
• docs Remove tchannel port from collector documentation#381
• remove generated classes

[pavolloffay]

This might also close #1193 and #983

[eundoosong]

If it's ok, I'd like to give it a shot

[pavolloffay]

I have already started working on this one.

[pavolloffay]

@yurishkuro any concerns from your side?

[yurishkuro]

Yes, we’re still using it.

[pavolloffay]

Are there any plans to migrate to gRPC inside Uber?

[pavolloffay]

Tchannel (14267) is used for:

• send span data from agent to collector
• send sampling configuration from collector to agent
• send baggage restriction from collector to agent - however this hasn't been fully open-sourced Baggage Whitelisting #373

For sampling strategies we have implemented gRPC pipe, but not for baggage restrictions.

Also, the tchannel receiver (14267) is also implemented in the OpenTelemetry collector.

[objectiser]

Also, the tchannel receiver (14267) is also implemented in the OpenTelemetry collector.

This should be removed soon: open-telemetry/opentelemetry-collector#267

[yurishkuro]

I don't know how "doable" this is, but if we could refactor all tchannel code into a complete separate location, then we could copy all of it into our internal repo, and then delete from master. My main concern is that it might be complicated to rip it out from Agent's builder.

NB: yes, we do plan to migrate to gRPC internally, but the work hasn't been prioritize yet, there are some dependencies on the load balancing behavior. We can probably commit to have it done in Q2 (cc @vprithvi )

[pavolloffay]

I was able to move all tchannel to a single top level package and then use it in the current build #2112.

We could merge that and then in a second PR remove the tchannel from our components.