Fix allocator metrics endpoint (#3921)

* updated metrics to use healthserver instead of default mux to create the tcp connection

cmd/allocator/main.go

@@ -217,8 +217,8 @@ func main() {
 	if !validPort(conf.GRPCPort) && !validPort(conf.HTTPPort) {
 		logger.WithField("grpc-port", conf.GRPCPort).WithField("http-port", conf.HTTPPort).Fatal("Must specify a valid gRPC port or an HTTP port for the allocator service")
 	}
-
-	health, closer := setupMetricsRecorder(conf)
+	healthserver := &httpserver.Server{Logger: logger}
+	health, closer := setupMetricsRecorder(conf, healthserver)
 	defer closer()
 
 	kubeClient, agonesClient, err := getClients(conf)
@@ -307,7 +307,6 @@ func main() {
 	}
 
 	// Finally listen on 8080 (http), used to serve /live and /ready handlers for Kubernetes probes.
-	healthserver := httpserver.Server{Logger: logger}
 	healthserver.Handle("/", health)
 	go func() { _ = healthserver.Run(listenCtx, 0) }()
 

cmd/allocator/metrics.go

@@ -14,9 +14,8 @@
 package main
 
 import (
-	"net/http"
-
 	"agones.dev/agones/pkg/metrics"
+	"agones.dev/agones/pkg/util/httpserver"
 	"github.com/heptiolabs/healthcheck"
 	prom "github.com/prometheus/client_golang/prometheus"
 	"go.opencensus.io/plugin/ocgrpc"
@@ -33,7 +32,7 @@ func registerMetricViews() {
 	}
 }
 
-func setupMetricsRecorder(conf config) (health healthcheck.Handler, closer func()) {
+func setupMetricsRecorder(conf config, healthserver *httpserver.Server) (health healthcheck.Handler, closer func()) {
 	health = healthcheck.NewHandler()
 	closer = func() {}
 
@@ -54,7 +53,7 @@ func setupMetricsRecorder(conf config) (health healthcheck.Handler, closer func(
 		if err != nil {
 			logger.WithError(err).Fatal("Could not register prometheus exporter")
 		}
-		http.Handle("/metrics", metricHandler)
+		healthserver.Handle("/metrics", metricHandler)
 		health = healthcheck.NewMetricsHandler(registry, "agones")
 	}