god script for unicorn + rvm

gistfile1.rb

# http://unicorn.bogomips.org/SIGNALS.html
# change these to match your app
app_name = "APP_NAME"
rvm_string = "RVM_STRING"
user = "USER"

pid_file = "/srv/webapps/#{app_name}/shared/pids/#{app_name}.pid"
gem_home = "/usr/local/rvm/gems/#{rvm_string}"
app_root = "/srv/webapps/#{app_name}/current"

rails_env = ENV['RAILS_ENV'] || 'production'


set_path = "cd #{app_root}; rvm use #{rvm_string}; export GEM_HOME=#{gem_home}"
unicorn_cmd = "#{set_path}; #{gem_home}/bin/unicorn_rails -c #{rails_root}/config/unicorn.rb -E #{rails_env} -D"

God.watch do |w|
  w.name = "unicorn"
  w.interval = 30.seconds # default

  # unicorn needs to be run from the rails root
  w.start = unicorn_cmd

  # QUIT gracefully shuts down workers
  w.stop = "kill -QUIT `cat #{pid_file}`"

  # USR2 causes the master to re-create itself and spawn a new worker pool
  w.restart = "kill -USR2 `cat #{pid_file}`"

  w.start_grace = 10.seconds
  w.restart_grace = 10.seconds
  w.pid_file = pid_file

  w.uid = user
  w.gid = user

  w.behavior(:clean_pid_file)

  w.start_if do |start|
    start.condition(:process_running) do |c|
      c.interval = 5.seconds
      c.running = false
    end
  end

  w.restart_if do |restart|
    restart.condition(:memory_usage) do |c|
      c.above = 150.megabytes
      c.times = [3, 5] # 3 out of 5 intervals
    end

    restart.condition(:cpu_usage) do |c|
      c.above = 50.percent
      c.times = 5
    end
  end

  # lifecycle
  w.lifecycle do |on|
    on.condition(:flapping) do |c|
      c.to_state = [:start, :restart]
      c.times = 5
      c.within = 5.minute
      c.transition = :unmonitored
      c.retry_in = 10.minutes
      c.retry_times = 5
      c.retry_within = 2.hours
    end
  end
end