Metrics handler for Gin

metrics_handler.go

// Metrics handler collects metrics about registered handlers:
// latency, requests count, request and response size etc.
func Metrics() gin.HandlerFunc {
  return func(c *gin.Context) {
    path := getHandlerName(c)

    timerMetric := metrics.GetOrRegisterTimer("call."+path+".Latency", nil)
    start := time.Now()
    c.Next()
    timerMetric.UpdateSince(start)

    metrics.GetOrRegisterGauge("call."+path+".RequestSize", nil).Update(int64(c.Request.ContentLength))
    metrics.GetOrRegisterGauge("call."+path+".ResponseSize", nil).Update(int64(c.Writer.Size()))
  }
}

// Gets short handler name
func getHandlerName(c *gin.Context) string {
  handlerName := c.HandlerName()
  path := handlerName
  lastIndex := strings.LastIndex(handlerName, ".")
  if lastIndex != -1 {
    path = handlerName[lastIndex+1:]
  }
  return path
}