protoc-gen-debug

Debugging a protoc plugin is difficult because protoc communicates with plugins using protobuf, a binary format that is not human-readable.

As a result, it’s not easy to reproduce or inspect the input that protoc sends to a plugin, which makes setting breakpoints and using a debugger cumbersome.

This plugin addresses that issue by capturing and dumping protoc’s input, allowing you to easily reuse it for debugging and developing other plugins.

Installation

You can install it from the Github Release or with the command below.

go install github.com/pubg/protoc-gen-debug@latest

Example

Dump protoc's input

protoc \
    --debug_out=./ \
    --debug_opt=dump_binary=true \
    --debug_opt=dump_json=true \
    --debug_opt=file_binary=request.pb.bin \
    --debug_opt=file_json=request.pb.json \
    --debug_opt=parameter=expose_all=true:foo=bar \
    -I ./ \
    ./example.proto

Run your plugin with the dumped input via command-line

cat request.pb.bin | ./protoc-gen-myplugin
cat request.pb.bin | go run ./cmd/main.go

Run your plugin with the dumped input via Goland

1. Check Redirect input from
2. Set dumped file path
3. Run as Debug Mode
4. Happy Debugging!

Options

Option	Description	Type	Default
dump_binary	Enable or not to dump binary format	bool	true
file_binary	File name to save protoc's input	string	request.pb.bin
dump_json	Enable or not to dump json format	bool	false
file_json	File name to save protoc's input	string	request.pb.json
dump_text	Enable or not to dump text format	bool	false
file_text	File name to save protoc's input	string	request.pb.txt
parameter	Parameters for other plugins	colon seperated string	""