工作线程池

Question

在http://marcio.io/2015/07/handling-1-million-requests-per-minute-with-golang/提供的示例中，该示例已在许多地方被引用。

func (d *Dispatcher) dispatch() {
for {
    select {
    case job := <-JobQueue:
        // a job request has been received
        go func(job Job) {
            // try to obtain a worker job channel that is available.
            // this will block until a worker is idle
            jobChannel := <-d.WorkerPool

            // dispatch the job to the worker job channel
            jobChannel <- job
         }(job)
    }
}
}

在调度服务了MaxWorker数量的作业之后，工作池(chan作业)不会耗尽吗？因为在第一次调用第一个类型dispatcher.Run()之后，<-d.WorkerPool正在从通道中拉出，而作业通道没有被补充？或者我是不是漏掉了什么？WorkerPool如何获得可用工作渠道的补充？

go func(job Job) {
            // try to obtain a worker job channel that is available.
            // this will block until a worker is idle
            jobChannel := <-d.WorkerPool

            // dispatch the job to the worker job channel
            jobChannel <- job
        }(job)

Answer 1

如果你仔细阅读worker的代码，你会注意到

w.WorkerPool <- w.JobChannel

每次循环开始时，worker本身的通道就被放回原处

我将整个函数复制到下面：

func (w Worker) Start() {
    go func() {
        for {
            // register the current worker into the worker queue.
            w.WorkerPool <- w.JobChannel

            select {
            case job := <-w.JobChannel:
                // we have received a work request.
                if err := job.Payload.UploadToS3(); err != nil {
                    log.Errorf("Error uploading to S3: %s", err.Error())
                }

            case <-w.quit:
                // we have received a signal to stop
                return
            }
        }
    }()
}