Refactor metric prometheus leader helper

internal/ingress/controller/controller.go

@@ -124,10 +124,7 @@ func (n *NGINXController) syncIngress(interface{}) error {
 	ings := n.store.ListIngresses(nil)
 	hosts, servers, pcfg := n.getConfiguration(ings)
 
-	if n.isLeader() {
-		klog.V(2).Infof("Updating ssl expiration metrics.")
 	n.metricCollector.SetSSLExpireTime(servers)
-	}
 
 	if n.runningConfig.Equal(pcfg) {
 		klog.V(3).Infof("No configuration change detected, skipping backend reload.")

internal/ingress/controller/nginx.go

@@ -31,7 +31,6 @@ import (
 	"strconv"
 	"strings"
 	"sync"
-	"sync/atomic"
 	"syscall"
 	"text/template"
 	"time"
@@ -268,8 +267,6 @@ type NGINXController struct {
 
 	metricCollector metric.Collector
 
-	currentLeader uint32
-
 	validationWebhookServer *http.Server
 
 	command NginxExecTester
@@ -296,14 +293,12 @@ func (n *NGINXController) Start() {
 				go n.syncStatus.Run(stopCh)
 			}
 
-			n.setLeader(true)
 			n.metricCollector.OnStartedLeading(electionID)
 			// manually update SSL expiration metrics
 			// (to not wait for a reload)
 			n.metricCollector.SetSSLExpireTime(n.runningConfig.Servers)
 		},
 		OnStoppedLeading: func() {
-			n.setLeader(false)
 			n.metricCollector.OnStoppedLeading(electionID)
 		},
 		PodName:      n.podInfo.Name,
@@ -1192,15 +1187,3 @@ func buildRedirects(servers []*ingress.Server) []*redirect {
 
 	return redirectServers
 }
-
-func (n *NGINXController) setLeader(leader bool) {
-	var i uint32
-	if leader {
-		i = 1
-	}
-	atomic.StoreUint32(&n.currentLeader, i)
-}
-
-func (n *NGINXController) isLeader() bool {
-	return atomic.LoadUint32(&n.currentLeader) != 0
-}

internal/ingress/metric/main.go

@@ -18,9 +18,12 @@ package metric
 
 import (
 	"os"
+	"sync/atomic"
 	"time"
 
 	"github.com/prometheus/client_golang/prometheus"
+	"k8s.io/klog"
+
 	"k8s.io/apimachinery/pkg/util/sets"
 	"k8s.io/ingress-nginx/internal/ingress"
 	"k8s.io/ingress-nginx/internal/ingress/annotations/class"
@@ -153,6 +156,11 @@ func (c *collector) Stop() {
 }
 
 func (c *collector) SetSSLExpireTime(servers []*ingress.Server) {
+	if !isLeader() {
+		return
+	}
+
+	klog.V(2).Infof("Updating ssl expiration metrics.")
 	c.ingressController.SetSSLExpireTime(servers)
 }
 
@@ -162,11 +170,30 @@ func (c *collector) SetHosts(hosts sets.String) {
 
 // OnStartedLeading indicates the pod was elected as the leader
 func (c *collector) OnStartedLeading(electionID string) {
+	setLeader(true)
 	c.ingressController.OnStartedLeading(electionID)
 }
 
 // OnStoppedLeading indicates the pod stopped being the leader
 func (c *collector) OnStoppedLeading(electionID string) {
+	setLeader(false)
 	c.ingressController.OnStoppedLeading(electionID)
 	c.ingressController.RemoveAllSSLExpireMetrics(c.registry)
 }
+
+var (
+	currentLeader uint32
+)
+
+func setLeader(leader bool) {
+	var i uint32
+	if leader {
+		i = 1
+	}
+
+	atomic.StoreUint32(&currentLeader, i)
+}
+
+func isLeader() bool {
+	return atomic.LoadUint32(&currentLeader) != 0
+}