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HOWTO Hunt (Resque) Daemons with Bluepill

I've blogged on using God for process monitoring in the past and I really wish I'd gone with Bluepill instead.

It's DSL is extremely compact and throws much of the 'boilerplate' that God requires; the CLI tool also provides far better feedback and bluepill log makes life so much easier rather than having to tail -f some log file.

RAILS_ROOT  = ENV['RAILS_ROOT'] || "/home/appuser/sites/foo"
RAILS_ENV = 'production'

Bluepill.application("app_name", :log_file => "/home/appuser/sites/foo/log/resque_workers.log") do |app|
  app.uid = app.gid = "appuser"  
  5.times do |i|
    app.process("resque_worker_#{i}") do |process|
      process.working_dir = RAILS_ROOT
      process.group = "resque"
      process.pid_file = "/home/appuser/sites/foo/tmp/resque_worker_#{i}.pid"
      process.start_command = "/usr/bin/env VERBOSE=true RAILS_ENV=#{RAILS_ENV} QUEUE=* rake resque:work --trace"
      process.stop_command = "kill -QUIT {{PID}}"
      process.monitor_children do |c|
        c.stop_command = "kill -USR1 {{PID}}"
        c.checks :mem_usage, :every => 30.seconds, :below => 100.megabytes, :fires => :stop
      process.daemonize = true
      process.start_grace_time = 3.seconds
      process.stop_grace_time = 5.seconds
      process.restart_grace_time = 8.seconds

      process.checks :mem_usage, :below => 350.megabytes, :every => 1.minute, :times => 3

Don't forget to throw this in as an initialiser as well:

# add as an initializer
Resque.after_fork do |job|

It may not hurt to add the resque-ensure-connected gem as well to your Gemfile. Just go with bluepill load /home/appuser/sites/foo/config/resque.pill to whip those daemons into shape!

You may also want to monitor Redis and simply create an upstart script to launch bluepill.