Function instrumentHandlerFunc

tutorials/whatsup/reference/main.go:228–281

(tracer *tracing.Tracer, reg prometheus.Registerer, handlerName string, handler http.Handler)

}

func instrumentHandlerFunc(tracer *tracing.Tracer, reg prometheus.Registerer, handlerName string, handler http.Handler) (string, http.HandlerFunc) {
	reg = prometheus.WrapRegistererWith(prometheus.Labels{"handler": handlerName}, reg)

	requestDuration := promauto.With(reg).NewHistogramVec(
		prometheus.HistogramOpts{
			Name:    "http_request_duration_seconds",
			Help:    "Tracks the latencies for HTTP requests.",
			Buckets: []float64{0.1, 0.3, 0.6, 1, 3, 6, 9, 20},
		},
		[]string{"method", "code"},
	)
	requestSize := promauto.With(reg).NewSummaryVec(
		prometheus.SummaryOpts{
			Name: "http_request_size_bytes",
			Help: "Tracks the size of HTTP requests.",
		},
		[]string{"method", "code"},
	)
	requestsTotal := promauto.With(reg).NewCounterVec(
		prometheus.CounterOpts{
			Name: "http_requests_total",
			Help: "Tracks the number of HTTP requests.",
		}, []string{"method", "code"},
	)
	responseSize := promauto.With(reg).NewSummaryVec(
		prometheus.SummaryOpts{
			Name: "http_response_size_bytes",
			Help: "Tracks the size of HTTP responses.",
		},
		[]string{"method", "code"},
	)

	base := promhttp.InstrumentHandlerRequestSize(
		requestSize,
		promhttp.InstrumentHandlerCounter(
			requestsTotal,
			promhttp.InstrumentHandlerResponseSize(
				responseSize,
				promhttp.InstrumentHandlerDuration(
					requestDuration,
					http.HandlerFunc(func(writer http.ResponseWriter, r *http.Request) {
						handler.ServeHTTP(writer, r)
					}),
					promhttp.WithExemplarFromContext(getExemplarFn),
				),
			),
			promhttp.WithExemplarFromContext(getExemplarFn),
		),
	)

	// Wrap with tracing. This will be visited as a first middleware.
	base = tracinghttp.NewMiddleware(tracer).WrapHandler(handlerName, base)
	return handlerName, base.ServeHTTP
}

func instrumentRoundTripper(reg prometheus.Registerer, clientName string, rt http.RoundTripper) http.RoundTripper {
	reg = prometheus.WrapRegistererWith(prometheus.Labels{"client": clientName}, reg)