addressing review comments

addressing review comments, adding run group

cmd/adapter/adapter.go

@@ -17,6 +17,7 @@ limitations under the License.
 package main
 
 import (
+	"context"
 	"crypto/tls"
 	"crypto/x509"
 	"flag"
@@ -30,6 +31,7 @@ import (
 	"time"
 
 	"github.com/prometheus/exporter-toolkit/web"
+	"github.com/oklog/run"
 	corev1 "k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	openapinamer "k8s.io/apiserver/pkg/endpoints/openapi"
@@ -94,10 +96,12 @@ type PrometheusAdapter struct {
 	MetricsRelistInterval time.Duration
 	// MetricsMaxAge is the period to query available metrics for
 	MetricsMaxAge time.Duration
-
-	secureMetricsPort string
-	tlsConfig         string
-	metricsHost       string
+	// MetricsPort is the port to expose the prometheus adapter self metrics
+	MetricsPort string
+	// TLSConfig is the tls config for exposing the prometheus adapter self metrics
+	TLSConfig   string
+	// MetricsHost is the host to expose the prometheus adapter self metrics
+	MetricsHost string
 	metricsConfig *adaptercfg.MetricsDiscoveryConfig
 }
 
@@ -161,12 +165,9 @@ func (cmd *PrometheusAdapter) addFlags() {
 		"interval at which to re-list the set of all available metrics from Prometheus")
 	cmd.Flags().DurationVar(&cmd.MetricsMaxAge, "metrics-max-age", cmd.MetricsMaxAge, ""+
 		"period for which to query the set of available metrics from Prometheus")
-	cmd.Flags().StringVar(&cmd.secureMetricsPort, "secure-metrics-port", cmd.secureMetricsPort,
-		"Secure port for metrics")
-	cmd.Flags().StringVar(&cmd.metricsHost, "metrics-host", cmd.metricsHost,
-		"Host for exposing metrics")
-	cmd.Flags().StringVar(&cmd.tlsConfig, "tls-config", cmd.tlsConfig,
-		"TLS configuration for metrics server")
+	cmd.Flags().StringVar(&cmd.MetricsPort, "metrics-port", cmd.MetricsPort, "Port to expose prometheus-adapter self metrics on. (default:8080) ")
+	cmd.Flags().StringVar(&cmd.MetricsHost, "metrics-host", cmd.MetricsHost, "Host to expose prometheus-adapter self metrics on. (default:0.0.0.0)")
+	cmd.Flags().StringVar(&cmd.TLSConfig, "tls-config", cmd.TLSConfig, "Optional TLS configuration for metrics server")
 }
 
 func (cmd *PrometheusAdapter) loadConfig() error {
@@ -298,6 +299,8 @@ func main() {
 	cmd := &PrometheusAdapter{
 		PrometheusURL:         "https://localhost",
 		MetricsRelistInterval: 10 * time.Minute,
+		MetricsHost:           "::",
+		MetricsPort:           "8080",
 	}
 	cmd.Name = "prometheus-metrics-adapter"
 
@@ -363,8 +366,24 @@ func main() {
 	}
 
 	apiServerConfig(config)
-	cmd.setupMetricsServer()
+	ctx := context.Background()
+	var g run.Group
 
+	metricsServer := cmd.setupMetricsServer()
+	{
+		g.Add(func() error{
+			return web.ListenAndServe(&metricsServer, cmd.TLSConfig, adapterLogger{})
+		}, func(error) {
+			ctxShutDown, cancel := context.WithTimeout(ctx, 3*time.Second)
+			defer cancel()
+			metricsServer.Shutdown(ctxShutDown)
+		})
+	}
+	
+
+	if err := g.Run(); err != nil {
+		klog.Fatalf("unable to run group : %v", err)
+	}
 	// run the server
 	if err := cmd.Run(stopCh); err != nil {
 		klog.Fatalf("unable to run custom metrics adapter: %v", err)
@@ -375,15 +394,14 @@ func apiServerConfig(config *customexternalmetrics.Config) {
 	config.GenericConfig.EnableMetrics = false
 }
 
-func (cmd PrometheusAdapter) setupMetricsServer() {
+func (cmd *PrometheusAdapter) setupMetricsServer() http.Server{
 
 	mux := http.NewServeMux()
 	mux.Handle("/metrics", legacyregistry.Handler())
 
-	serverAddress := net.JoinHostPort(cmd.metricsHost, cmd.secureMetricsPort)
-	metricsServer := http.Server{Handler: mux, Addr: serverAddress}
+	serverAddress := net.JoinHostPort(cmd.MetricsHost, cmd.MetricsPort)
+	return http.Server{Handler: mux, Addr: serverAddress}
 
-	go web.ListenAndServe(&metricsServer, cmd.tlsConfig, adapterLogger{})
 }
 
 // makeKubeconfigHTTPClient constructs an HTTP for connecting with the given auth options.

deploy/manifests/custom-metrics-apiserver-deployment.yaml

@@ -29,7 +29,7 @@ spec:
         - --metrics-relist-interval=1m
         - --v=10
         - --config=/etc/adapter/config.yaml
-        - --secure-metrics-port=9090
+        - --metrics-port=9090
         - --metrics-host=0.0.0.0
         - --tls-config=/etc/tls/config.yaml
         ports:
@@ -46,9 +46,6 @@ spec:
         - mountPath: /etc/tls
           name: metricstlsconfig
           readOnly: false
-        - mountPath: /etc/certs
-          name: servingcerts
-          readOnly: false
       volumes:
       - name: volume-serving-cert
         secret:
@@ -58,9 +55,8 @@ spec:
           name: adapter-config
       - name: tmp-vol
         emptyDir: {}
-      - configMap:
+      - name: metricstlsconfig
+        configMap:
           name: metrics-tls-config
-        name: metricstlsconfig
-      - secret:
-          secretName: pa-metrics-serving-certs
-        name: servingcerts
+
+

go.mod

@@ -3,6 +3,7 @@ module sigs.k8s.io/prometheus-adapter
 go 1.16
 
 require (
+	github.com/oklog/run v1.1.0
 	github.com/onsi/ginkgo v1.16.4
 	github.com/onsi/gomega v1.15.0
 	github.com/prometheus/client_golang v1.11.0

go.sum

@@ -457,6 +457,8 @@ github.com/nxadm/tail v1.4.8 h1:nPr65rt6Y5JFSKQO7qToXr7pePgD6Gwiw05lkbyAQTE=
 github.com/nxadm/tail v1.4.8/go.mod h1:+ncqLTQzXmGhMZNUePPaPqPvBxHAIsmXswZKocGu+AU=
 github.com/oklog/oklog v0.3.2/go.mod h1:FCV+B7mhrz4o+ueLpx+KqkyXRGMWOYEvfiXtdGtbWGs=
 github.com/oklog/run v1.0.0/go.mod h1:dlhp/R75TPv97u0XWUtDeV/lRKWPKSdTuV0TZvrmrQA=
+github.com/oklog/run v1.1.0 h1:GEenZ1cK0+q0+wsJew9qUg/DyD8k3JzYsZAi5gYi2mA=
+github.com/oklog/run v1.1.0/go.mod h1:sVPdnTZT1zYwAJeCMu2Th4T21pA3FPOQRfWjQlk7DVU=
 github.com/oklog/ulid v1.3.1/go.mod h1:CirwcVhetQ6Lv90oh/F+FBtV6XMibvdAFo93nm5qn4U=
 github.com/olekukonko/tablewriter v0.0.0-20170122224234-a0225b3f23b5/go.mod h1:vsDQFd/mU46D+Z4whnwzcISnGGzXWMclvtLoiIKAKIo=
 github.com/onsi/ginkgo v0.0.0-20170829012221-11459a886d9c/go.mod h1:lLunBs/Ym6LB5Z9jYTR76FiuTmxDTDusOGeTQH+WWjE=