guard-rails/lib/guard/rails.rb

require 'guard'
require 'guard/guard'
require 'rbconfig'

module Guard
  class Rails < ::Guard::Guard
    attr_reader :options

    def initialize(watchers = [], options = {})
      super
      @options = {
        :port => 3000,
        :environment => 'development',
        :start_on_start => true,
        :force_run => false
      }.merge(options)
    end

    def start
      UI.info "Guard::Rails restarting app on port #{options[:port]} using #{options[:environment]} environment."
      run_all if options[:start_on_start]
    end

    def run_all
      Notifier.notify("Rails restarting on port #{options[:port]} in #{options[:environment]} environment...", :title => "Restarting Rails...", :image => :pending)
      stop_rails ; start_rails
      Notifier.notify("Rails restarted on port #{options[:port]}.", :title => "Rails restarted!", :image => :success)
    end

    def stop
      Notifier.notify("Until next time...", :title => "Rails shutting down.", :image => :pending)
      stop_rails
    end

    def run_on_change(paths)
      run_all
    end

    private
    def pid_file
      File.expand_path("tmp/pids/#{options[:environment]}.pid")
    end

    def start_rails
      kill_unmanaged_pid! if options[:force_run]
      system %{sh -c 'cd #{Dir.pwd} && rails s -e #{options[:environment]} -p #{options[:port]} --pid #{pid_file} &'}
      while !File.file?(pid_file)
        sleep 0.5
      end
      UI.info "Rails restarted, pid #{File.read(pid_file)}"
    end

    def stop_rails
      if File.file?(pid_file)
        system %{kill -INT #{File.read(pid_file).strip}}
      end
    end

    def unmanaged_pid
      if RbConfig::CONFIG['host_os'] =~ /darwin/
        %x{lsof -P}.each_line { |line|
          if line["*:#{options[:port]} "]
            return line.split("\s")[1]
          end
        }
      end
      nil
    end

    def kill_unmanaged_pid!
      if pid = unmanaged_pid
        system %{kill -INT #{pid}}
      end
    end
  end
end