通过Mongrel集群使用Starling和多个Mongrel实例

这个 rooster rails插件专门解决您的问题。它使用rufus调度程序并确保环境只加载一次。

2. 当获得锁时,检查Starling中的消息
3. 如果消息存在,则说明其他进程已计划该作业
4. 再次将消息设置为队列并退出。
5. 如果找不到消息,请安排作业,设置消息并退出

下面是实现这一点的代码:

    starling = MemCache.new("#{Settings[:starling][:host]}:#{Settings[:starling][:port]}")
    mutex_filename = "#{RAILS_ROOT}/config/file.lock"
    scheduler = Rufus::Scheduler.start_new


    # The filelock method, taken from Ruby Cookbook
    # This will ensure unblocking of the files
    def flock(file, mode)
      success = file.flock(mode)
      if success
        begin
          yield file
        ensure
          file.flock(File::LOCK_UN)
        end
      end
      return success
    end

    # open_lock method, taken from Ruby Cookbook
    # This will create and hold the locks
    def open_lock(filename, openmode = "r", lockmode = nil)
      if openmode == 'r' || openmode == 'rb'
        lockmode ||= File::LOCK_SH
      else
        lockmode ||= File::LOCK_EX
      end
      value = nil
      # Kernerl's open method, gives IO Object, in our case, a file
      open(filename, openmode) do |f|
        flock(f, lockmode) do
          begin
            value = yield f
          ensure
            f.flock(File::LOCK_UN) # Comment this line out on Windows.
          end
        end
        return value
      end
    end

    # The actual scheduler
    open_lock(mutex_filename, 'r+') do |f|
      puts f.read
      digest_schedule_message = starling.get("digest_scheduler")
      if digest_schedule_message
        puts "Found digest message in Starling. Releasing lock. '#{Time.now}'"
        puts "Message: #{digest_schedule_message.inspect}"
        # Read the message and set it back, so that other processes can read it too
        starling.set "digest_scheduler", digest_schedule_message
      else
        # Schedule job
        puts "Scheduling digest emails now. '#{Time.now}'"
        scheduler.cron("0 9 * * *") do
          puts "Begin sending digests..."
          WeeklyDigest.new.send_digest!
          puts "Done sending digests."
        end
        # Add message in queue
        puts "Done Scheduling. Sending the message to Starling. '#{Time.now}'"
        starling.set "digest_scheduler", :date => Date.today
      end
    end

    # Sleep will ensure all instances have gone thorugh their wait-acquire lock-schedule(or not) cycle
    # This will ensure that on next reboot, starling won't have any stale messages
    puts "Waiting to clear digest messages from Starling."
    sleep(20)
    puts "All digest messages cleared, proceeding with boot."
    starling.get("digest_scheduler")

你为什么不用摩登乘客号(phusion)?我从混血儿搬到了phusion,它工作得很好(时间长度是5分钟)!