refactor

metrics/metrics.go

@@ -91,29 +91,38 @@ func InitPrometheus(prometheusHost, prometheusPort, prometheusEntry string) {
 	go func() {
 
 		if strings.HasPrefix(prometheusHost, "unix:") {
-			socketPath := prometheusHost[5:]
+			socketPath := prometheusHost[5:] // trim the "unix:" prefix
 			glog.Infof("Starting Prometheus on Unix socket %v, entry point is /%v", socketPath, prometheusEntry)
-			_ := os.Remove(socketPath) // allow failure
-			unixListener, err := net.Listen("unix", socketPath)
-			if err != nil {
-				glog.Errorf("Error starting Prometheus on socket %v: %v", socketPath, err)
-				os.Exit(1)
-			}
-			if err := http.Serve(unixListener, nil); err != nil {
-				glog.Errorf("Error starting Prometheus at socket %v: %v", socketPath, err)
-				os.Exit(1)
-			}
-			return
-		}
-
-		glog.Infof("Starting Prometheus on IP port %v:%v, entry point is /%v", prometheusHost, prometheusPort, prometheusEntry)
-		if err := http.ListenAndServe(prometheusHost+":"+prometheusPort, nil); err != nil {
-			glog.Errorf("Error starting Prometheus at port %v:%v: %v", prometheusHost, prometheusPort, err)
-			os.Exit(1)
+			serveOnUnixSocket(socketPath)
+		} else {
+			ipPort := prometheusHost+":"+prometheusPort
+			glog.Infof("Starting Prometheus on IP port %v:%v, entry point is /%v", ipPort, prometheusEntry)
+			serveOnIpPort(ipPort)
 		}
+
 	}()
 }
 
+func serveOnUnixSocket(socketPath string) {
+	_ = os.Remove(socketPath) // allow failure
+	unixListener, err := net.Listen("unix", socketPath)
+	if err != nil {
+		glog.Errorf("Error starting Prometheus on socket %v: %v", socketPath, err)
+		os.Exit(1)
+	}
+	if err := http.Serve(unixListener, nil); err != nil {
+		glog.Errorf("Error starting Prometheus at socket %v: %v", socketPath, err)
+		os.Exit(1)
+	}
+}
+
+func serveOnIpPort(ipPort string) {
+	if err := http.ListenAndServe(ipPort, nil); err != nil {
+		glog.Errorf("Error starting Prometheus at ip port %v: %v", ipPort, err)
+		os.Exit(1)
+	}
+}
+
 const (
 	RecordEntryTypeStart = iota
 	RecordEntryTypeSend  = iota