fix(collector): fix the problem that prometheus cannot display the in…

…dicators collected by collector (#1851)

collector/webui/webserver.go

@@ -21,12 +21,22 @@ import (
 	"context"
 	"time"
 
+	"github.com/apache/incubator-pegasus/collector/metrics"
 	"github.com/kataras/iris/v12"
+	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/promhttp"
 )
 
 // StartWebServer starts an iris-powered HTTP server.
 func StartWebServer() {
+	registry := prometheus.NewRegistry()
+	for _, cV := range metrics.CounterMetricsMap {
+		registry.MustRegister(cV)
+	}
+	for _, gV := range metrics.GaugeMetricsMap {
+		registry.MustRegister(gV)
+	}
+
 	app := iris.New()
 	app.Get("/", indexHandler)
 	app.Get("/tables", tablesHandler)