gem_kit-plugin

The smallest possible plugin for gem kit. It adds one command, which prints a page telling you how it got there. That is all it does — it exists to be read.

$ gem kit plugin
gem kit plugin

You are looking at a command that came from a different gem.
...

Two files.

# lib/gem_kit/plugin.rb
require "gem_kit"
require "gem_kit/release/cli"

GemKit::Release.plugin do
  desc "plugin", "Explain how a gem adds a command to `gem kit` (this one did)"
  def plugin
    $stdout.puts(GemKit::Plugin::HELP)
  end
end

# lib/rubygems_plugin.rb
require_relative "gem_kit/plugin"

RubyGems loads rubygems_plugin.rb from every installed gem on every gem invocation, so installing the gem is the whole installation. Nothing to wire up.

The command is then not second-class — it is listed by gem kit, documented by gem kit help plugin, and takes --gem like the built-in ones:

$ gem kit
Commands:
  gem kit bump [SEGMENT]          # Move the gem version, refusing to bump on...
  gem kit plugin                  # Explain how a gem adds a command to `gem ...
  gem kit release                 # Gate, build and push this gem
  ...

1. Depend on gem_kit-release.
2. Put your commands in a GemKit::Release.plugin block.
3. Ship a lib/rubygems_plugin.rb that requires the file holding it.

The block is evaluated on the Thor class, so the whole Thor DSL is in scope: desc, long_desc, method_option, map for an alias, and register for a Thor::Group generator — which is how gem kit setup is built.

Keep rubygems_plugin.rb to the one require. It runs on every gem list too, and anything heavy in there is a tax on all of them.

# Gemfile
gem "gem_kit-plugin", group: :development

direnv allow      # or: nix develop
bin/test

MIT