goreplay output-http-stats（HTTP请求统计） 源码分析

 -output-http-stats  //每5秒钟输出一次输出队列的状态
        Report http output queue stats to console every N milliseconds. See output-http-stats-ms
  -output-http-stats-ms int
        Report http output queue stats to console every N milliseconds. default: 5000 (default 5000)

 if o.config.Stats {
  o.queueStats = NewGorStat("output_http", o.config.StatsMs)
 }

// PluginWrite writes message to this plugin
// 统计信息收集
func (o *HTTPOutput) PluginWrite(msg *Message) (n int, err error) {
 if !isRequestPayload(msg.Meta) {
  return len(msg.Data), nil
 }

 select {
 case <-o.stop:
  return 0, ErrorStopped
 case o.queue <- msg:
 }

 if o.config.Stats {
  o.queueStats.Write(len(o.queue))
 }
 if len(o.queue) > 0 {
  // try to start a new worker to serve
  if atomic.LoadInt32(&o.activeWorkers) < int32(o.config.WorkersMax) {
   go o.startWorker()
   atomic.AddInt32(&o.activeWorkers, 1)
  }
 }
 return len(msg.Data) + len(msg.Meta), nil
}

// NewGorStat统计类
func NewGorStat(statName string, rateMs int) (s *GorStat) {
 s = new(GorStat)
 s.statName = statName
 s.rateMs = rateMs
 s.latest = 0
 s.mean = 0
 s.max = 0
 s.count = 0

 if Settings.Stats {
  go s.reportStats()
 }
 return
}

//写入时做统计
func (s *GorStat) Write(latest int) {
 if Settings.Stats {
  if latest > s.max {
   s.max = latest
  }
  if latest != 0 {
   s.mean = ((s.mean * s.count) + latest) / (s.count + 1)
  }
  s.latest = latest
  s.count = s.count + 1
 }
}

//打印输出，简单的sleep
func (s *GorStat) reportStats() {
 Debug(0, "\n", s.statName+":latest,mean,max,count,count/second,gcount")
 for {
  Debug(0, "\n", s)
  s.Reset()
  time.Sleep(time.Duration(s.rateMs) * time.Millisecond)
 }

//字符串类型转换
func (s *GorStat) String() string {
 return s.statName + ":" + strconv.Itoa(s.latest) + "," + strconv.Itoa(s.mean) + "," + strconv.Itoa(s.max) + "," + strconv.Itoa(s.count) + "," + strconv.Itoa(s.count/(s.rateMs/1000.0)) + "," + strconv.Itoa(runtime.NumGoroutine())
}