go: add go_package options to proto files

[google]

go: add go_package options to proto files

[suyashkumar]

Hi @tmc -- great question. If I recall correctly, the team initially looked into including the go_package options in the protocol buffer generator itself--but that required some other changes to inject the right context to generate the go_package path. We also didn't want to manually add the go_package option into the protos if it wasn't automatically added from the core proto generator, because re-running the generator as is would produce different output.

That's why we went with the interim approach to unblock the go modules migration asap--a generation script that manages building the go protos, which handles inserting the right go_package reliably during the generation process for now. This script needed to exist anyway to help manage rebuilding the go protos after any proto change (and hopefully as a user, it handles everything for you regardless of where the go_package temporarily lived).

We're planning on implementing the relevant changes needed to add the option to proto generator as well in the near future. We can keep this issue open and post updates here as that comes to fruition.

Let us know if you have any other context on your use cases that are impacted by this! Thank you!

[OliverCardoza]

Building protos which import the FHIR protos is pretty burdensome in cases where generating Go libraries is needed. IIUC the only way is to add hundreds of --go_opt and --go_grpc_opts args in the protoc call.

for resource in resources:
  go_opts+=("--go_opt=Mproto/google/fhir/proto/r4/core/resources/${resource}.proto=${GOOGLE_FHIR_PATH}/google/fhir/proto/r4/core/resources/${resource}_go_proto")
done

protoc "${go_opts[@]}" [...]

Other prominent Google protos declare go_package in the proto file:

• protocolbuffers/protobuf - any.proto: link
• googleapis/googleapis - fhir.proto: link

I recognize complexity to add this but fwiw I think all Go users will thank you 😄