refactor: use common sidecar flags functionality

Author: DerekFrank

cmd/csi-attacher/main.go

@@ -31,8 +31,6 @@ import (
 	utilfeature "k8s.io/apiserver/pkg/util/feature"
 	"k8s.io/client-go/informers"
 	"k8s.io/client-go/kubernetes"
-	"k8s.io/client-go/rest"
-	"k8s.io/client-go/tools/clientcmd"
 	"k8s.io/client-go/util/workqueue"
 	utilflag "k8s.io/component-base/cli/flag"
 	"k8s.io/component-base/featuregate"
@@ -48,6 +46,7 @@ import (
 	"github.com/container-storage-interface/spec/lib/go/csi"
 	"github.com/kubernetes-csi/csi-lib-utils/connection"
 	"github.com/kubernetes-csi/csi-lib-utils/leaderelection"
+	libconfig "github.com/kubernetes-csi/csi-lib-utils/config"
 	"github.com/kubernetes-csi/csi-lib-utils/metrics"
 	"github.com/kubernetes-csi/csi-lib-utils/rpc"
 	"github.com/kubernetes-csi/csi-lib-utils/standardflags"
@@ -65,34 +64,15 @@ const (
 
 // Command line flags
 var (
-	kubeconfig    = flag.String("kubeconfig", "", "Absolute path to the kubeconfig file. Required only when running out of cluster.")
 	resync        = flag.Duration("resync", 10*time.Minute, "Resync interval of the controller.")
-	csiAddress    = flag.String("csi-address", "/run/csi/socket", "Address of the CSI driver socket.")
-	showVersion   = flag.Bool("version", false, "Show version.")
 	timeout       = flag.Duration("timeout", 15*time.Second, "Timeout for waiting for attaching or detaching the volume.")
 	workerThreads = flag.Uint("worker-threads", 10, "Number of attacher worker threads")
 	maxEntries    = flag.Int("max-entries", 0, "Max entries per each page in volume lister call, 0 means no limit.")
 
-	retryIntervalStart = flag.Duration("retry-interval-start", time.Second, "Initial retry interval of failed create volume or deletion. It doubles with each failure, up to retry-interval-max.")
-	retryIntervalMax   = flag.Duration("retry-interval-max", 5*time.Minute, "Maximum retry interval of failed create volume or deletion.")
-
-	enableLeaderElection        = flag.Bool("leader-election", false, "Enable leader election.")
-	leaderElectionNamespace     = flag.String("leader-election-namespace", "", "Namespace where the leader election resource lives. Defaults to the pod namespace if not set.")
-	leaderElectionLeaseDuration = flag.Duration("leader-election-lease-duration", 15*time.Second, "Duration, in seconds, that non-leader candidates will wait to force acquire leadership. Defaults to 15 seconds.")
-	leaderElectionRenewDeadline = flag.Duration("leader-election-renew-deadline", 10*time.Second, "Duration, in seconds, that the acting leader will retry refreshing leadership before giving up. Defaults to 10 seconds.")
-	leaderElectionRetryPeriod   = flag.Duration("leader-election-retry-period", 5*time.Second, "Duration, in seconds, the LeaderElector clients should wait between tries of actions. Defaults to 5 seconds.")
-
 	defaultFSType = flag.String("default-fstype", "", "The default filesystem type of the volume to publish. Defaults to empty string")
 
 	reconcileSync = flag.Duration("reconcile-sync", 1*time.Minute, "Resync interval of the VolumeAttachment reconciler.")
 
-	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`.")
-
-	kubeAPIQPS   = flag.Float64("kube-api-qps", 5, "QPS to use while communicating with the kubernetes apiserver. Defaults to 5.0.")
-	kubeAPIBurst = flag.Int("kube-api-burst", 10, "Burst to use while communicating with the kubernetes apiserver. Defaults to 10.")
-
 	maxGRPCLogLength = flag.Int("max-grpc-log-length", -1, "The maximum amount of characters logged for every grpc responses. Defaults to no limit")
 
 	featureGates map[string]bool
@@ -111,6 +91,7 @@ func main() {
 	c := logsapi.NewLoggingConfiguration()
 	logsapi.AddGoFlags(c, flag.CommandLine)
 	logs.InitLogs()
+	standardflags.RegisterCommonFlags(flag.CommandLine)
 	standardflags.AddAutomaxprocs(klog.Infof)
 	flag.Parse()
 	logger := klog.Background()
@@ -124,29 +105,27 @@ func main() {
 		klog.FlushAndExit(klog.ExitFlushTimeout, 1)
 	}
 
-	if *showVersion {
+	if standardflags.Configuration.ShowVersion {
 		fmt.Println(os.Args[0], version)
 		return
 	}
 	logger.Info("Version", "version", version)
 
-	if *metricsAddress != "" && *httpEndpoint != "" {
+	if standardflags.Configuration.MetricsAddress != "" && standardflags.Configuration.HttpEndpoint != "" {
 		logger.Error(nil, "Only one of `--metrics-address` and `--http-endpoint` can be set")
 		klog.FlushAndExit(klog.ExitFlushTimeout, 1)
 	}
-	addr := *metricsAddress
+	addr := standardflags.Configuration.MetricsAddress
 	if addr == "" {
-		addr = *httpEndpoint
+		addr = standardflags.Configuration.HttpEndpoint
 	}
 
 	// Create the client config. Use kubeconfig if given, otherwise assume in-cluster.
-	config, err := buildConfig(*kubeconfig)
+	config, err := libconfig.BuildConfig(standardflags.Configuration.KubeConfig, standardflags.Configuration)
 	if err != nil {
 		logger.Error(err, "Failed to build a Kubernetes config")
 		klog.FlushAndExit(klog.ExitFlushTimeout, 1)
 	}
-	config.QPS = (float32)(*kubeAPIQPS)
-	config.Burst = *kubeAPIBurst
 	config.ContentType = runtime.ContentTypeProtobuf
 
 	if *workerThreads == 0 {
@@ -167,9 +146,9 @@ func main() {
 	// Connect to CSI.
 	connection.SetMaxGRPCLogLength(*maxGRPCLogLength)
 	ctx := context.Background()
-	csiConn, err := connection.Connect(ctx, *csiAddress, metricsManager, connection.OnConnectionLoss(connection.ExitOnConnectionLoss()))
+	csiConn, err := connection.Connect(ctx, standardflags.Configuration.CSIAddress, metricsManager, connection.OnConnectionLoss(connection.ExitOnConnectionLoss()))
 	if err != nil {
-		logger.Error(err, "Failed to connect to the CSI driver", "csiAddress", *csiAddress)
+		logger.Error(err, "Failed to connect to the CSI driver", "csiAddress", standardflags.Configuration.CSIAddress)
 		klog.FlushAndExit(klog.ExitFlushTimeout, 1)
 	}
 
@@ -194,9 +173,9 @@ func main() {
 	translator := csitrans.New()
 	if translator.IsMigratedCSIDriverByName(csiAttacher) {
 		metricsManager = metrics.NewCSIMetricsManagerWithOptions(csiAttacher, metrics.WithMigration())
-		migratedCsiClient, err := connection.Connect(ctx, *csiAddress, metricsManager, connection.OnConnectionLoss(connection.ExitOnConnectionLoss()))
+		migratedCsiClient, err := connection.Connect(ctx, standardflags.Configuration.CSIAddress, metricsManager, connection.OnConnectionLoss(connection.ExitOnConnectionLoss()))
 		if err != nil {
-			logger.Error(err, "Failed to connect to the CSI driver", "csiAddress", *csiAddress, "migrated", true)
+			logger.Error(err, "Failed to connect to the CSI driver", "csiAddress", standardflags.Configuration.CSIAddress, "migrated", true)
 			klog.FlushAndExit(klog.ExitFlushTimeout, 1)
 		}
 		csiConn.Close()
@@ -216,13 +195,13 @@ func main() {
 	// Prepare http endpoint for metrics + leader election healthz
 	mux := http.NewServeMux()
 	if addr != "" {
-		metricsManager.RegisterToServer(mux, *metricsPath)
+		metricsManager.RegisterToServer(mux, standardflags.Configuration.MetricsPath)
 		metricsManager.SetDriverName(csiAttacher)
 		go func() {
-			logger.Info("ServeMux listening", "address", addr, "metricsPath", *metricsPath)
+			logger.Info("ServeMux listening", "address", addr, "metricsPath", standardflags.Configuration.MetricsPath)
 			err := http.ListenAndServe(addr, mux)
 			if err != nil {
-				logger.Error(err, "Failed to start HTTP server at specified address and metrics path", "address", addr, "metricsPath", *metricsPath)
+				logger.Error(err, "Failed to start HTTP server at specified address and metrics path", "address", addr, "metricsPath", standardflags.Configuration.MetricsPath)
 				klog.FlushAndExit(klog.ExitFlushTimeout, 1)
 			}
 		}()
@@ -291,8 +270,8 @@ func main() {
 		handler,
 		factory.Storage().V1().VolumeAttachments(),
 		factory.Core().V1().PersistentVolumes(),
-		workqueue.NewTypedItemExponentialFailureRateLimiter[string](*retryIntervalStart, *retryIntervalMax),
-		workqueue.NewTypedItemExponentialFailureRateLimiter[string](*retryIntervalStart, *retryIntervalMax),
+		workqueue.NewTypedItemExponentialFailureRateLimiter[string](standardflags.Configuration.RetryIntervalStart, standardflags.Configuration.RetryIntervalMax),
+		workqueue.NewTypedItemExponentialFailureRateLimiter[string](standardflags.Configuration.RetryIntervalStart, standardflags.Configuration.RetryIntervalMax),
 		supportsListVolumesPublishedNodes,
 		*reconcileSync,
 	)
@@ -332,49 +311,15 @@ func main() {
 		}
 	}
 
-	if !*enableLeaderElection {
-		run(klog.NewContext(context.Background(), logger))
-	} else {
-		// Create a new clientset for leader election. When the attacher
-		// gets busy and its client gets throttled, the leader election
-		// can proceed without issues.
-		leClientset, err := kubernetes.NewForConfig(config)
-		if err != nil {
-			logger.Error(err, "Failed to create leaderelection client")
-			klog.FlushAndExit(klog.ExitFlushTimeout, 1)
-		}
-
-		// Name of config map with leader election lock
-		lockName := "external-attacher-leader-" + csiAttacher
-		le := leaderelection.NewLeaderElection(leClientset, lockName, run)
-		if *httpEndpoint != "" {
-			le.PrepareHealthCheck(mux, leaderelection.DefaultHealthCheckTimeout)
-		}
-
-		if *leaderElectionNamespace != "" {
-			le.WithNamespace(*leaderElectionNamespace)
-		}
-
-		le.WithLeaseDuration(*leaderElectionLeaseDuration)
-		le.WithRenewDeadline(*leaderElectionRenewDeadline)
-		le.WithRetryPeriod(*leaderElectionRetryPeriod)
-		if utilfeature.DefaultFeatureGate.Enabled(features.ReleaseLeaderElectionOnExit) {
-			le.WithReleaseOnCancel(true)
-			le.WithContext(ctx)
-		}
-
-		if err := le.Run(); err != nil {
-			logger.Error(err, "Failed to initialize leader election")
-			klog.FlushAndExit(klog.ExitFlushTimeout, 1)
-		}
-	}
-}
-
-func buildConfig(kubeconfig string) (*rest.Config, error) {
-	if kubeconfig != "" {
-		return clientcmd.BuildConfigFromFlags("", kubeconfig)
-	}
-	return rest.InClusterConfig()
+	leaderelection.RunWithLeaderElection(
+		ctx,
+		config,
+		standardflags.Configuration,
+		run,
+		"external-attacher-leader-" + csiAttacher,
+		mux,
+		utilfeature.DefaultFeatureGate.Enabled(features.ReleaseLeaderElectionOnExit),
+	)
 }
 
 func supportsControllerCapabilities(ctx context.Context, csiConn *grpc.ClientConn) (bool, bool, bool, bool, error) {