Add filegroup for options proto files

[kellycampbell]

This allows other projects to generate proto code for other languages, e.g. py_proto_library

[achew22]

Perfect, thanks so much for your contribution! If you have any more issues please open an issue and let's work through it.

It looks like there is a formatting issue with your change. Could you run buildifier (bazel run :buildifier) and update the PR? Thanks

PS: I recently learned about the --override_repository flag which can be used like --override_repository "com_github_grpc_ecosystem_grpc_gateway=/path/to/a/local/copy/that/you/want/to/test/with" if you want to test out changes like this in your repo without having to rewrite your WORKSPACE.

[codecov-io]

Codecov Report

Merging #821 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #821   +/-   ##
=======================================
  Coverage   49.32%   49.32%           
=======================================
  Files          39       39           
  Lines        3751     3751           
=======================================
  Hits         1850     1850           
  Misses       1723     1723           
  Partials      178      178

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update d8ad87e...ba17731. Read the comment docs.

[achew22]

I was thinking about this, and as a curiosity, what are the circumstances where you need a py_proto_library for this? I expect these protos to really only be consumed by the swagger code generator

[kellycampbell]

We have python gRPC backends which implement the services defined with rest annotations and documented using these swagger annotations.

It only needs them because they're imported and referenced by our services .profo file. If I run protoc for python it errors out if it can't find these options protos. Nothing in our python code actually needs the annotations.

Ideally, the py_proto_library rule should be able to use the proto provider from the proto_library to find the files, but currently the one we're using doesn't. (https://github.com/pubref/rules_protobuf/tree/master/python)

[achew22]

That's an unfortunate outcome but it makes sense that proto works that way. I meant to merge earlier, but forgot to click the button. Sorry about that