From 5a672975e4bed0731c3910c3dd5d640fc87cec2f Mon Sep 17 00:00:00 2001
From: Cheng Xing <cxing@google.com>
Date: Thu, 3 Dec 2020 19:28:38 -0800
Subject: [PATCH] Introduce http-endpoint flag

---
 README.md                         |  2 +-
 cmd/csi-attacher/main.go          | 20 ++++++++++++++++----
 deploy/kubernetes/deployment.yaml |  6 +++---
 3 files changed, 20 insertions(+), 8 deletions(-)

diff --git a/README.md b/README.md
index 4fa2ba445..0b251d4b3 100644
--- a/README.md
+++ b/README.md
@@ -101,7 +101,7 @@ When CSI driver supports `LIST_VOLUMES` and `LIST_VOLUMES_PUBLISHED_NODES` capab
 
 ### HTTP endpoint
 
-The external-attacher optionally exposes an HTTP endpoint at address:port specified by `--metrics-address` argument. When set, these two paths are exposed:
+The external-attacher optionally exposes an HTTP endpoint at address:port specified by `--http-endpoint` argument. When set, these two paths are exposed:
 
 * Metrics path, as set by `--metrics-path` argument (default is `/metrics`).
 * Leader election health check at `/healthz/leader-election`. It is recommended to run a liveness probe against this endpoint when leader election is used to kill external-attacher leader that fails to connect to the API server to renew its leadership. See https://github.com/kubernetes-csi/csi-lib-utils/issues/66 for details.
diff --git a/cmd/csi-attacher/main.go b/cmd/csi-attacher/main.go
index 100d28c72..7e1d18247 100644
--- a/cmd/csi-attacher/main.go
+++ b/cmd/csi-attacher/main.go
@@ -67,7 +67,8 @@ var (
 
 	reconcileSync = flag.Duration("reconcile-sync", 1*time.Minute, "Resync interval of the VolumeAttachment reconciler.")
 
-	metricsAddress = flag.String("metrics-address", "", "The TCP network address where the prometheus metrics endpoint will listen (example: `:8080`). The default is empty string, which means metrics endpoint is disabled.")
+	metricsAddress = flag.String("metrics-address", "", "(deprecated) The TCP network address where the prometheus metrics endpoint will listen (example: `:8080`). The default is empty string, which means metrics endpoint is disabled. Only one of `--metrics-address` and `--http-endpoint` can be set.")
+	httpEndpoint   = flag.String("http-endpoint", "", "The TCP network address where the HTTP server for diagnostics, including metrics and leader election health check, will listen (example: :8080). The default is empty string, which means the server is disabled. Only one of `--metrics-address` and `--http-endpoint` can be set.")
 	metricsPath    = flag.String("metrics-path", "/metrics", "The HTTP path where prometheus metrics will be exposed. Default is `/metrics`.")
 )
 
@@ -91,6 +92,15 @@ func main() {
 	}
 	klog.Infof("Version: %s", version)
 
+	if *metricsAddress != "" && *httpEndpoint != "" {
+		klog.Error("only one of `--metrics-address` and `--http-endpoint` can be set.")
+		os.Exit(1)
+	}
+	addr := *metricsAddress
+	if addr == "" {
+		addr = *httpEndpoint
+	}
+
 	// Create the client config. Use kubeconfig if given, otherwise assume in-cluster.
 	config, err := buildConfig(*kubeconfig)
 	if err != nil {
@@ -138,11 +148,11 @@ func main() {
 
 	// Prepare http endpoint for metrics + leader election healthz
 	mux := http.NewServeMux()
-	if *metricsAddress != "" {
+	if addr != "" {
 		metricsManager.RegisterToServer(mux, *metricsPath)
 		metricsManager.SetDriverName(csiAttacher)
 		go func() {
-			err := http.ListenAndServe(*metricsAddress, mux)
+			err := http.ListenAndServe(addr, mux)
 			if err != nil {
 				klog.Fatalf("Failed to start Prometheus metrics endpoint on specified address (%q) and path (%q): %s", *metricsAddress, *metricsPath, err)
 			}
@@ -219,7 +229,9 @@ func main() {
 		// Name of config map with leader election lock
 		lockName := "external-attacher-leader-" + csiAttacher
 		le := leaderelection.NewLeaderElection(leClientset, lockName, run)
-		le.PrepareHealthCheck(mux, leaderelection.DefaultHealthCheckTimeout)
+		if *httpEndpoint != "" {
+			le.PrepareHealthCheck(mux, leaderelection.DefaultHealthCheckTimeout)
+		}
 
 		if *leaderElectionNamespace != "" {
 			le.WithNamespace(*leaderElectionNamespace)
diff --git a/deploy/kubernetes/deployment.yaml b/deploy/kubernetes/deployment.yaml
index efc462b97..9c7872c40 100644
--- a/deploy/kubernetes/deployment.yaml
+++ b/deploy/kubernetes/deployment.yaml
@@ -38,7 +38,7 @@ spec:
             - "--v=5"
             - "--csi-address=$(ADDRESS)"
             - "--leader-election"
-            - "--metrics-address=:8080"
+            - "--http-endpoint=:8080"
           env:
             - name: MY_NAME
               valueFrom:
@@ -52,13 +52,13 @@ spec:
               mountPath: /var/lib/csi/sockets/pluginproxy/
           ports:
             - containerPort: 8080
-              name: metrics
+              name: http-endpoint
               protocol: TCP
           livenessProbe:
             failureThreshold: 1
             httpGet:
               path: /healthz/leader-election
-              port: metrics
+              port: http-endpoint
             initialDelaySeconds: 10
             timeoutSeconds: 10
             periodSeconds: 20