Document protobuf dependencies

[cortopy]

Please describe your use case / problem. I'm trying to create a ExtAuth filter following the auth service Envoy's spec for v2 and grpc protocol.

Describe the solution you'd like There are quite a number of imports from external definition files. Some of them are easier to find than others, but I can't find all of them.

So far I have managed to locate some using the buf.build registry and git repos:

• google: https://buf.build/googleapis/googleapis or https://github.com/googleapis/googleapis/tree/master/google/api
• opencensus: buf.build/beta/opencensus or https://github.com/census-instrumentation/opencensus-proto
• udpa: buf.build/beta/udpa or https://github.com/cncf/udpa

However, there are others like udpa/core/v1/authority.proto or udpa/core/v1/collection_entry.proto which I've not been able to find

It would be nice if there was a README file somewhere like https://github.com/emissary-ingress/emissary/tree/master/api/envoy/README.md that lists where to find all the dependencies required to build the proto files

Describe alternatives you've considered buf.build and google searches but I can't find all the dependencies

[jzapal]

I have a similar problem. Is there any example GRPC filter available to see anywhere for the reference?