最近使用nginx+unicorn+sinatra的api服务器要上线了，首选的是易于配置、扩展的gem，god。

• Config file is written in Ruby
• Easily write your own custom conditions in Ruby
• Supports both poll and event based conditions
• Different poll conditions can have different intervals
• Integrated notification system (write your own too!)
• Easily control non-daemonizing scripts

简单配置

loop do
  puts 'Hello'
  sleep 1
end

God.watch do |w|
  w.name = "unicorn"
  w.start = "ruby /full/path/to/app.rb"
  w.keepalive
end