go-proto-filename-prefixer

go-proto-filename-prefixer

Proto filename conflict problem: https://github.com/golang/protobuf/issues/1122

This is a small tool to quick fix this problem by updating the embedded filename inside the generated protobuf go files.

How it works

1. Scan the specified directory for any '*.pb.go' files whichs looks like a generated proto file.
2. Parse the raw desc part of the file, convert the hex back to FileDescriptorProto
3. Prepend the specified string to name field, update any dependency field that point to other proto under the target directory.
4. Marshal to hex string and replace back to the pb.go file, also update header information.
5. Check if there is any 'XXX_grpc.pb.go' file, if yes, update the Metadata line field.

Usage

1. Install binary

   go install github.com/tuimeo/go-proto-filename-prefixer@latest

2. Add script in your build process, right after the generation of go proto file. (Usualy after protoc / buf command line)

   go-proto-filename-prefixer <directory where pb.go files resident> <prefix to add>

Example

You have project struct as followed:

*project root <-- proto include path
   api/    <-- proto files, also generated pb.go files

Your generated file will have embeded filename like api/common.proto.

Run this command under project root:

go-proto-filename-prefixer api foo/bar/

Then the embeded filename will become foo/bar/api/common.proto, which will help to avoid conflic.

To get verbose output, run with -v at the end like this:

go-proto-filename-prefixer api foo/bar/ -v

Misc

If you want to inspect the embedded information:

1. Open the pb.go file, locate to the hex part. Copy just the hex part.
2. Run read -d '!' -s desc; echo $desc | tr '\t,\n' ' ' | sed 's/0x//g' | sed 's/ //g'; unset desc, paste in, press "!". Then copy the output again. This step just prepare the data for decoder.
3. Goto https://protobuf-decoder.netlify.app/, paste in.