Document how files are generated and maybe automate it

[krnowak]

We have some generated files in the repo. Some of them are generated during make precommit (like api/core/numberkind_string.go by the stringer utility). But some of them were generated just once and just lay there:

• example/grpc/api/hello-service.pb.go
  • documented in example/grpc/README.md, seems to work, but I had to build protoc-gen-go first myself.
• exporters/trace/jaeger/internal/gen-go/*
  • not documented

Would be nice to document it and add some make target (like make generate-misc) so it regenerates the files above. It's something maybe we could do as a part of a release process.

[ilyakaznacheev]

What about proto generation? How do you fix all the versions of protoc and plugins?

[MadVikingGod]

The current state of affairs is:

• There are a number of stringers run by make precommit
• Semconv is made via the semconv tool, and is documented int the RELEASING.md
• The only outstanding one is the thrift code in jaeger. I couldn't find the history of how we adopted this code.

[MrAlias]

• The only outstanding one is the thrift code in jaeger. I couldn't find the history of how we adopted this code.

IIRC, that was a manual copy paste.

[pellared]

AFAIK all code generation is now automated.