From 4dd49959fa22ef44687029f0f557f33f42ae61e7 Mon Sep 17 00:00:00 2001
From: k8s-infra-cherrypick-robot
 <90416843+k8s-infra-cherrypick-robot@users.noreply.github.com>
Date: Thu, 28 Aug 2025 10:41:09 -0700
Subject: [PATCH] Metrics: Fix
 `nginx_ingress_controller_config_last_reload_successful`. (#13860)

Signed-off-by: Roman Orudzhov <roman.orudzhov@flant.com>
Co-authored-by: Roman Orudzhov <roman.orudzhov@flant.com>
---
 internal/ingress/controller/controller.go | 22 ++++++++++++++--------
 internal/ingress/controller/nginx.go      |  2 ++
 2 files changed, 16 insertions(+), 8 deletions(-)

diff --git a/internal/ingress/controller/controller.go b/internal/ingress/controller/controller.go
index 0894c0dfc..87a343962 100644
--- a/internal/ingress/controller/controller.go
+++ b/internal/ingress/controller/controller.go
@@ -192,7 +192,18 @@ func (n *NGINXController) syncIngress(interface{}) error {
 	n.metricCollector.SetSSLExpireTime(servers)
 	n.metricCollector.SetSSLInfo(servers)
 
+	hash, err := hashstructure.Hash(pcfg, hashstructure.FormatV1, &hashstructure.HashOptions{
+		TagName: "json",
+	})
+	if err != nil {
+		klog.Errorf("unexpected error hashing configuration: %v", err)
+	}
+
 	if n.runningConfig.Equal(pcfg) {
+		if !n.lastConfigSuccess {
+			n.metricCollector.ConfigSuccess(hash, true)
+			n.lastConfigSuccess = true
+		}
 		klog.V(3).Infof("No configuration change detected, skipping backend reload")
 		return nil
 	}
@@ -202,19 +213,13 @@ func (n *NGINXController) syncIngress(interface{}) error {
 	if !utilingress.IsDynamicConfigurationEnough(pcfg, n.runningConfig) {
 		klog.InfoS("Configuration changes detected, backend reload required")
 
-		hash, err := hashstructure.Hash(pcfg, hashstructure.FormatV1, &hashstructure.HashOptions{
-			TagName: "json",
-		})
-		if err != nil {
-			klog.Errorf("unexpected error hashing configuration: %v", err)
-		}
-
 		pcfg.ConfigurationChecksum = fmt.Sprintf("%v", hash)
 
 		err = n.OnUpdate(*pcfg)
 		if err != nil {
 			n.metricCollector.IncReloadErrorCount()
 			n.metricCollector.ConfigSuccess(hash, false)
+			n.lastConfigSuccess = false
 			klog.Errorf("Unexpected failure reloading the backend:\n%v", err)
 			n.recorder.Eventf(k8s.IngressPodDetails, apiv1.EventTypeWarning, "RELOAD", fmt.Sprintf("Error reloading NGINX: %v", err))
 			return err
@@ -223,6 +228,7 @@ func (n *NGINXController) syncIngress(interface{}) error {
 		klog.InfoS("Backend successfully reloaded")
 		n.metricCollector.ConfigSuccess(hash, true)
 		n.metricCollector.IncReloadCount()
+		n.lastConfigSuccess = true
 
 		n.recorder.Eventf(k8s.IngressPodDetails, apiv1.EventTypeNormal, "RELOAD", "NGINX reload triggered due to a change in configuration")
 	}
@@ -243,7 +249,7 @@ func (n *NGINXController) syncIngress(interface{}) error {
 	}
 
 	retriesRemaining := retry.Steps
-	err := wait.ExponentialBackoff(retry, func() (bool, error) {
+	err = wait.ExponentialBackoff(retry, func() (bool, error) {
 		err := n.configureDynamically(pcfg)
 		if err == nil {
 			klog.V(2).Infof("Dynamic reconfiguration succeeded.")
diff --git a/internal/ingress/controller/nginx.go b/internal/ingress/controller/nginx.go
index 20fad5afb..adb524560 100644
--- a/internal/ingress/controller/nginx.go
+++ b/internal/ingress/controller/nginx.go
@@ -264,6 +264,8 @@ type NGINXController struct {
 	validationWebhookServer *http.Server
 
 	command NginxExecTester
+
+	lastConfigSuccess bool
 }
 
 // Start starts a new NGINX master process running in the foreground.