refactor: move logic to create client to utils/kubernetes pkg

- expose `CreateKubeClient` as public function
- make `GetKubeConfig` into a private `getKubeConfig` function (can be exposed as a public function in the future if needed)
Signed-off-by: vadasambar <surajrbanakar@gmail.com>

cluster-autoscaler/config/autoscaling_options.go

@@ -221,10 +221,8 @@ type AutoscalingOptions struct {
 	AWSUseStaticInstanceList bool
 	// GCEOptions contain autoscaling options specific to GCE cloud provider.
 	GCEOptions GCEOptions
-	// Kubernetes master location.
-	Kubernetes string
-	// Path to kube configuration if available
-	KubeConfigPath string
+	// KubeClientOpts specify options for kube client
+	KubeClientOpts KubeClientOptions
 	// ClusterAPICloudConfigAuthoritative tells the Cluster API provider to treat the CloudConfig option as authoritative and
 	// not use KubeConfigPath as a fallback when it is not provided.
 	ClusterAPICloudConfigAuthoritative bool
@@ -276,3 +274,13 @@ type AutoscalingOptions struct {
 	// based on the latency between the CA and the api-server
 	DynamicNodeDeleteDelayAfterTaintEnabled bool
 }
+
+// KubeClientOptions specify options for kube client
+type KubeClientOptions struct {
+	// Master specifies master location.
+	Master string
+	// Path to kube configuration if available
+	KubeConfigPath string
+	// APIContentType specifies type of requests sent to APIServer.
+	APIContentType string
+}

cluster-autoscaler/main.go

@@ -60,7 +60,6 @@ import (
 	"k8s.io/autoscaler/cluster-autoscaler/utils/units"
 	"k8s.io/autoscaler/cluster-autoscaler/version"
 	"k8s.io/client-go/informers"
-	kube_client "k8s.io/client-go/kubernetes"
 	"k8s.io/client-go/rest"
 	"k8s.io/client-go/tools/leaderelection"
 	"k8s.io/client-go/tools/leaderelection/resourcelock"
@@ -351,10 +350,13 @@ func createAutoscalingOptions() config.AutoscalingOptions {
 		StatusTaints:                     *statusTaintsFlag,
 		BalancingExtraIgnoredLabels:      *balancingIgnoreLabelsFlag,
 		BalancingLabels:                  *balancingLabelsFlag,
-		Kubernetes:                       *kubernetes,
-		KubeConfigPath:                   *kubeConfigFile,
-		NodeDeletionDelayTimeout:         *nodeDeletionDelayTimeout,
-		AWSUseStaticInstanceList:         *awsUseStaticInstanceList,
+		KubeClientOpts: config.KubeClientOptions{
+			Master:         *kubernetes,
+			KubeConfigPath: *kubeConfigFile,
+			APIContentType: *kubeAPIContentType,
+		},
+		NodeDeletionDelayTimeout: *nodeDeletionDelayTimeout,
+		AWSUseStaticInstanceList: *awsUseStaticInstanceList,
 		GCEOptions: config.GCEOptions{
 			ConcurrentRefreshes:             *concurrentGceRefreshes,
 			MigInstancesMinRefreshWaitTime:  *gceMigInstancesMinRefreshWaitTime,
@@ -390,10 +392,6 @@ func createAutoscalingOptions() config.AutoscalingOptions {
 	}
 }
 
-func createKubeClient(kubeConfig *rest.Config) kube_client.Interface {
-	return kube_client.NewForConfigOrDie(kubeConfig)
-}
-
 func registerSignalHandlers(autoscaler core.Autoscaler) {
 	sigs := make(chan os.Signal, 1)
 	signal.Notify(sigs, os.Interrupt, os.Kill, syscall.SIGTERM, syscall.SIGQUIT)
@@ -413,7 +411,7 @@ func buildAutoscaler(debuggingSnapshotter debuggingsnapshot.DebuggingSnapshotter
 	// Create basic config from flags.
 	autoscalingOptions := createAutoscalingOptions()
 
-	kubeClient := createKubeClient(getKubeConfig())
+	kubeClient := kube_util.CreateKubeClient(&autoscalingOptions.KubeClientOpts)
 
 	// Informer transform to trim ManagedFields for memory efficiency.
 	trim := func(obj interface{}) (interface{}, error) {
@@ -592,7 +590,8 @@ func main() {
 			klog.Fatalf("Unable to get hostname: %v", err)
 		}
 
-		kubeClient := createKubeClient(kube_util.GetKubeConfig(createAutoscalingOptions()))
+		kubeClientOpts := createAutoscalingOptions().KubeClientOpts
+		kubeClient := kube_util.CreateKubeClient(&kubeClientOpts)
 
 		// Validate that the client is ok.
 		_, err = kubeClient.CoreV1().Nodes().List(ctx.TODO(), metav1.ListOptions{})

cluster-autoscaler/utils/kubernetes/client.go

@@ -21,13 +21,19 @@ import (
 
 	"k8s.io/autoscaler/cluster-autoscaler/config"
 
+	kube_client "k8s.io/client-go/kubernetes"
 	"k8s.io/client-go/rest"
 	"k8s.io/client-go/tools/clientcmd"
 	"k8s.io/klog/v2"
 )
 
-// GetKubeConfig returns the rest config from AutoscalingOptions.
-func GetKubeConfig(opts config.AutoscalingOptions) *rest.Config {
+// CreateKubeClient creates kube client based on AutoscalingOptions.KubeClientOptions
+func CreateKubeClient(opts *config.KubeClientOptions) kube_client.Interface {
+	return kube_client.NewForConfigOrDie(getKubeConfig(opts))
+}
+
+// getKubeConfig returns the rest config from AutoscalingOptions.KubeClientOptions.
+func getKubeConfig(opts *config.KubeClientOptions) *rest.Config {
 	var kubeConfig *rest.Config
 	var err error
 
@@ -39,7 +45,7 @@ func GetKubeConfig(opts config.AutoscalingOptions) *rest.Config {
 			klog.Fatalf("Failed to build config: %v", err)
 		}
 	} else {
-		url, err := url.Parse(opts.Kubernetes)
+		url, err := url.Parse(opts.Master)
 		if err != nil {
 			klog.Fatalf("Failed to parse Kubernetes url: %v", err)
 		}
@@ -50,7 +56,7 @@ func GetKubeConfig(opts config.AutoscalingOptions) *rest.Config {
 		}
 	}
 
-	kubeConfig.ContentType = opts.KubeAPIContentType
+	kubeConfig.ContentType = opts.APIContentType
 
 	return kubeConfig
 }