return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		tc, ok := r.Context().Value(mcontext.ContextTraceKey).(*mcontext.TraceCtxt)

		claims, groups, owner, authErr := metricsRequestAuthenticate(r)
		if authErr != nil || (claims != nil && !claims.VerifyIssuer("prometheus", true)) {
			if ok {
				tc.FuncName = "handler.MetricsAuth"
				tc.ResponseRecorder.LogErrBody = true
			}