Add method label for prometheus middleware metrics (#3226)

Co-authored-by: 蓝益尤 <lan.yiyou@intellif.com>

rest/handler/prometheushandler.go

@@ -18,7 +18,7 @@ var (
 		Subsystem: "requests",
 		Name:      "duration_ms",
 		Help:      "http server requests duration(ms).",
-		Labels:    []string{"path"},
+		Labels:    []string{"path", "method"},
 		Buckets:   []float64{5, 10, 25, 50, 100, 250, 500, 1000},
 	})
 
@@ -27,19 +27,19 @@ var (
 		Subsystem: "requests",
 		Name:      "code_total",
 		Help:      "http server requests error count.",
-		Labels:    []string{"path", "code"},
+		Labels:    []string{"path", "code", "method"},
 	})
 )
 
 // PrometheusHandler returns a middleware that reports stats to prometheus.
-func PrometheusHandler(path string) func(http.Handler) http.Handler {
+func PrometheusHandler(path, method string) func(http.Handler) http.Handler {
 	return func(next http.Handler) http.Handler {
 		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 			startTime := timex.Now()
 			cw := &response.WithCodeResponseWriter{Writer: w}
 			defer func() {
-				metricServerReqDur.Observe(int64(timex.Since(startTime)/time.Millisecond), path)
-				metricServerReqCodeTotal.Inc(path, strconv.Itoa(cw.Code))
+				metricServerReqDur.Observe(int64(timex.Since(startTime)/time.Millisecond), path, method)
+				metricServerReqCodeTotal.Inc(path, strconv.Itoa(cw.Code), method)
 			}()
 
 			next.ServeHTTP(cw, r)