server_timing.go

server_timing.go

func serverTiming(next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		start := time.Now()
		w.Header().Add("Trailer", "Server-Timing")
		defer func() {
			dur := time.Since(start).Seconds()
			w.Header().Set("Server-Timing", fmt.Sprintf("total;dur=%f", dur))
		}()
		next.ServeHTTP(w, r)
	})
}