go_proto_compiler: integration with proto_lang_toolchain

[franciscocpg]

What version of rules_go are you using?

v0.20.1

What version of gazelle are you using?

0.18.2

What version of Bazel are you using?

3.6.0

Does this issue reproduce with the latest releases of all the above?

Not applicable

What operating system and processor architecture are you using?

Linux x86)64

Any other potentially useful information about your toolchain?

Not applicable

What did you do?

This is more a question related to #2489.

I was able to fix the issue reported there, but I want to use pre-built binaries just like this instead of compiling protobuf. Is there a way to do that?

What did you expect to see?

Not applicable

What did you see instead?

Not applicable

[jayconrod]

There's no way to do that at the moment.

It looks like proto_lang_toolchain provides a way to define the command that language rules like go_proto_library should use. go_proto_library doesn't actually integrate with that, so it wouldn't work today. So that might be a way to implement this.

[franciscocpg]

Hi @jayconrod

Thank you for answering.

I'd like to help with this, but I have no idea where to begin.

Where should I start looking to add support for proto_lang_toolchain in the go_proto_library rule?

[jayconrod]

Sorry, this needs more experimentation and design before there's an implementation plan, and I don't have bandwidth to do that right now.

[ar3s3ru]

Hey @jayconrod, how can we move forward this issue?

I'd like to see this solved, and can definitely give a hand here.

[jayconrod]

Sorry, I have zero bandwidth to work on this or review changes here.

[ar3s3ru]

@jayconrod understandable. Can you pull in someone else that can help out here?

[jayconrod]

cc @bazelbuild/go-maintainers if anyone's interested in looking at this.

[linzhp]

Ideally, this should work with Bazel's --proto_compiler, but Bazel doesn't pass that option to Starlark, so there is no way for go_proto_library to get that (#2018). That said, there is a workaround though: bazelbuild/bazel#8485 (comment)