mysql.rb

  # run in non-daemonized mode (so you can monitor it) with `god -c /path/to/mysql.god -D`
  # run normally with `god -c /path/to/mysql.god`

  # Settings for email notifications (optional)
  God::Contacts::Email.defaults do |d|
    d.from_email = '[email protected]'
    d.from_name = 'God'
    d.delivery_method = :smtp # this can also be :sendmail
    d.server_host = 'smtp.myapp.com'
    d.server_port = 25
    d.server_auth = true
    d.server_domain = 'myapp.com'
    d.server_user = '[email protected]'
    d.server_password = 'password'
  end

  # you can create as many email entries as you'd like
  God.contact(:email) do |c|
    c.name = 'me'
    c.to_email = '[email protected]'
  end

  God.watch do |w|
    # you can name this whatever you want
    w.name = "mySQL Server"

    # polling interval
    w.interval = 30.seconds

    # command to start service
    w.start = "/etc/init.d/mysqld start && /etc/init.d/httpd restart"

    # command to stop service
    w.stop = "/etc/init.d/mysqld stop"

    # command to restart service
    w.restart = "/etc/init.d/mysqld restart && /etc/init.d/httpd restart"

    # how long to wait after starting service before monitoring resumes
    w.start_grace = 20.seconds

    # how long to wait after restarting service before monitoring resumes
    w.restart_grace = 20.seconds

    # location of pid file
    w.pid_file = "/var/run/mysqld/mysqld.pid"

    # tell god to delete the pid file when mysqld crashes
    w.behavior(:clean_pid_file)

    # 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
      end
      # failsafe
      on.condition(:tries) do |c|
        c.times = 8
        c.within = 2.minutes
        c.transition = :start
      end
    end

    # start if process is not running
    w.transition(:up, :start) do |on|
      on.condition(:process_exits) do |c|
        # send an email to me to notify me that the service has crashed
        c.notify = 'me'
      end
    end

    # lifecycle
    w.lifecycle do |on|
      # If the service keeps triggering a restart over and over, it is considered to be "flapping".
      on.condition(:flapping) do |c|
        c.to_state = [:start, :restart]
        c.times = 5
        c.within = 1.minute
        c.transition = :unmonitored
        # If the service is flapping, wait 10 minutes, then try to start/restart again.
        c.retry_in = 10.minutes
        c.retry_times = 5
        c.retry_within = 2.hours
      end
    end
  end