dry-skeleton CLI "wrapper"

dry-skeleton.rb

#!/usr/bin/env ruby

require "bundler/setup"
require "inflecto"
require "thor"

module Dry
  module Skeleton
    class CLI < Thor
      desc "generate APP", "Generate an app"
      def generate(generator_name, *args)
        # app_name could be:
        #
        # - dry_web_roda (should look for a matching gem)
        # - icelab/dry_web_roda (a github-hosted project, latest tag)
        # - icelab/dry_web_roda#master (a github-hosted project, master branch)

        # Helpful notes about programatically working with gems: https://gist.github.com/adamjmurray/3154437
        if generator_name !=~ %r[/]
          # It's a gem, look for an already installed copy
          installed_gem = Gem::Specification.find_by_name(generator_name)

          # Or install it fresh
          unless installed_gem
            require "rubygems/commands/install_command"
            cmd = Gem::Commands::InstallCommand.new
            cmd.handle_options [generator_name]

            begin
              cmd.execute
            rescue Gem::SystemExitException => e
              unless SystemExit.new(e.exit_code).success?
                abort "Failed to install #{generator_name} gem"
              end
            end
          end
        else
          # This is a github-style name so let's fetch it:
          #
          # - Clone the repo into ~/.dry-skeleton/gems (TODO)

          # - Add ~/.dry-skeleton/gems to gem path
          path_with_skeletons = ["~/.dry-skeleton/gems", Gem.path].join(":")
          env_with_path = ENV.to_h.merge("GEM_PATH" => path_with_skeletons)
          Gem.paths = env_with_path
        end

        # Now load and require the skeleton gem
        gem generator_name
        require generator_name

        # Get its generator at an expected constant (e.g. MyGeneratorName::Generator)
        generator = Inflecto.constantize(Inflecto.camelize("#{generator_name}/generator")).new

        # The skeleton's generator should provide a Thor CLI app, which we can
        # then forward the rest of the args to, and it can handle the
        # generation from there
        generator.cli.start(*args) # TODO: work out how to properly pass the args
      end
    end
  end
end

Dry::Skeleton::CLI.start(ARGV)