ProtoPlugin

gem install proto_plugin

Creating a protoc plugin is as simple as creating a new executable script.

The name of the file must follow the format protoc-gen-[plugin-name]. As an example, the below file could be named protoc-gen-mycoolplugin.

#! /usr/bin/env ruby

require "proto_plugin"

class MyCoolPlugin < ProtoPlugin::Base
  def run
    request.file_to_generate.each do |f|
      name = File.basename(f.name, ".proto")

      add_file(name: "#{name}.txt", content: <<~TXT)
        This file was generated from #{name}.proto!
      TXT
    end
  end
end

MyCoolPlugin.run!

To invoke the plugin, first make sure you have protoc installed. Then in a terminal, run:

protoc --plugin=path/to/protoc-gen-mycoolplugin --mycoolplugin_out=. input.proto

If the executable script is in your $PATH, for example installed via a gem, you can omit the --plugin argument.

protoc --mycoolplugin_out=. input.proto

See exe/protoc-gen-proto-plugin-demo in this repo as another example of a plugin. Since it should be in your $PATH (you did install this gem right?) you can invoke it with:

protoc --proto-plugin-demo_out=. input.proto

After checking out the repo, run bin/setup to install dependencies. Then, run bin/rake to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and the created tag, and push the .gem file to rubygems.org.

Bug reports and pull requests are welcome on GitHub at https://github.com/cocoahero/proto_plugin.

The gem is available as open source under the terms of the MIT License.