monitor-redis-resque.rb

# Redis
God.watch do |w|
  w.name          = "redis"
  w.interval      = 30.seconds
  w.start         = "/etc/init.d/redis start"
  w.stop          = "/etc/init.d/redis stop"
  w.restart       = "/etc/init.d/redis restart"
  w.start_grace   = 10.seconds
  w.restart_grace = 10.seconds

  #this depends on an /etc/init.d/redis script that handles creating a pid file here
  w.pid_file = '/var/run/redis.pid' 

  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
end

# Resque
God.watch do |w|
  w.name          = "resque-1.8.0"
  w.interval      = 30.seconds
  w.start         = "cd /var/www/apps/firefly/current && rake environment RAILS_ENV=production resque:work QUEUE=high,medium,low"
  w.start_grace   = 10.seconds
  
  # retart if memory gets too high
  w.transition(:up, :restart) do |on|
    on.condition(:memory_usage) do |c|
      c.above = 350.megabytes
      c.times = 2
    end
  end
  
  # determine the state on startup
  w.transition(:init, { true => :up, false => :start }) do |on|
    on.condition(:process_running) do |c|
      c.running = true
    end
  end
  
  # determine when process has finished starting
  w.transition([:start, :restart], :up) do |on|
    on.condition(:process_running) do |c|
      c.running = true
      c.interval = 5.seconds
    end
    
    # failsafe
    on.condition(:tries) do |c|
      c.times = 5
      c.transition = :start
      c.interval = 5.seconds
    end
  end
  
  # start if process is not running
  w.transition(:up, :start) do |on|
    on.condition(:process_running) do |c|
      c.running = false
    end
  end
end