Rake tasks for Unicorn: start stop restart increment decrement pstree

unicorn.rake

namespace :unicorn do

  ##
  # Tasks

  desc "Start unicorn"
  task(:start) {
    config = rails_root + "config/unicorn.rb"
    sh "bundle exec unicorn --daemonize --config-file #{config}"
  }

  desc "Stop unicorn"
  task(:stop) { unicorn_signal :QUIT }

  desc "Restart unicorn with USR2"
  task(:restart) { unicorn_signal :USR2 }

  desc "Increment number of worker processes"
  task(:increment) { unicorn_signal :TTIN }

  desc "Decrement number of worker processes"
  task(:decrement) { unicorn_signal :TTOU }

  desc "Unicorn pstree (depends on pstree command)"
  task(:pstree) do
    sh "pstree '#{unicorn_pid}'"
  end

  ##
  # Helpers

  def unicorn_signal signal
    Process.kill signal, unicorn_pid
  end

  def unicorn_pid
    begin
      File.read(rails_root + "tmp/pids/unicorn.pid").to_i
    rescue Errno::ENOENT
      raise "Unicorn doesn't seem to be running"
    end
  end

  def rails_root
    require "pathname"
    Pathname.new(__FILE__) + "../../.."
  end

end