var notFoundHandler http.Handler = http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		http.Error(w, "Metrics Resource Not found", http.StatusNotFound)
	})

	// Require that metrics path has one component at least.
	if path == "/" {
		return notFoundHandler
	}

	if isListingRequest {
		handler := h.listMetrics(path)
		if handler == nil {