kubernetes: lazily initialize kubeclient scheme

Use sync.OnceValue to initialize the kubeclient scheme, codec factory,
and parameter codec as a single lazy-loaded bundle.

Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>

Author: tonistiigi

driver/kubernetes/execconn/execconn.go

@@ -29,7 +29,7 @@ func ExecConn(ctx context.Context, restClient rest.Interface, restConfig *rest.C
 			Stdout:    true,
 			Stderr:    true,
 			TTY:       false,
-		}, kubeclient.ParameterCodec)
+		}, kubeclient.ParameterCodec())
 	exec, err := remotecommand.NewSPDYExecutor(restConfig, "POST", req.URL())
 	if err != nil {
 		return nil, err

driver/kubernetes/kubeclient/client.go

@@ -61,7 +61,7 @@ func newRESTClient(config *rest.Config, httpClient *http.Client, gv schema.Group
 	cfg := *config
 	cfg.GroupVersion = &gv
 	cfg.APIPath = apiPath
-	cfg.NegotiatedSerializer = rest.CodecFactoryForGeneratedClient(Scheme, Codecs).WithoutConversion()
+	cfg.NegotiatedSerializer = rest.CodecFactoryForGeneratedClient(Scheme(), Codecs()).WithoutConversion()
 	if cfg.UserAgent == "" {
 		cfg.UserAgent = rest.DefaultKubernetesUserAgent()
 	}
@@ -80,7 +80,7 @@ func (c *deploymentClient) Get(ctx context.Context, name string, opts metav1.Get
 		Namespace(c.namespace).
 		Resource("deployments").
 		Name(name).
-		VersionedParams(&opts, ParameterCodec).
+		VersionedParams(&opts, ParameterCodec()).
 		Do(ctx).
 		Into(result)
 	return result, err
@@ -92,7 +92,7 @@ func (c *deploymentClient) Create(ctx context.Context, deployment *appsv1.Deploy
 		UseProtobufAsDefault().
 		Namespace(c.namespace).
 		Resource("deployments").
-		VersionedParams(&opts, ParameterCodec).
+		VersionedParams(&opts, ParameterCodec()).
 		Body(deployment).
 		Do(ctx).
 		Into(result)
@@ -121,7 +121,7 @@ func (c *configMapClient) Create(ctx context.Context, configMap *corev1.ConfigMa
 		UseProtobufAsDefault().
 		Namespace(c.namespace).
 		Resource("configmaps").
-		VersionedParams(&opts, ParameterCodec).
+		VersionedParams(&opts, ParameterCodec()).
 		Body(configMap).
 		Do(ctx).
 		Into(result)
@@ -135,7 +135,7 @@ func (c *configMapClient) Update(ctx context.Context, configMap *corev1.ConfigMa
 		Namespace(c.namespace).
 		Resource("configmaps").
 		Name(configMap.Name).
-		VersionedParams(&opts, ParameterCodec).
+		VersionedParams(&opts, ParameterCodec()).
 		Body(configMap).
 		Do(ctx).
 		Into(result)
@@ -164,7 +164,7 @@ func (c *podClient) List(ctx context.Context, opts metav1.ListOptions) (*corev1.
 		UseProtobufAsDefault().
 		Namespace(c.namespace).
 		Resource("pods").
-		VersionedParams(&opts, ParameterCodec).
+		VersionedParams(&opts, ParameterCodec()).
 		Do(ctx).
 		Into(result)
 	return result, err

driver/kubernetes/kubeclient/scheme.go

@@ -1,6 +1,8 @@
 package kubeclient
 
 import (
+	"sync"
+
 	appsv1 "k8s.io/api/apps/v1"
 	corev1 "k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
@@ -10,12 +12,33 @@ import (
 	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
 )
 
-var Scheme = runtime.NewScheme()
-var Codecs = serializer.NewCodecFactory(Scheme)
-var ParameterCodec = runtime.NewParameterCodec(Scheme)
+type schemeData struct {
+	scheme         *runtime.Scheme
+	codecs         serializer.CodecFactory
+	parameterCodec runtime.ParameterCodec
+}
+
+var loadSchemeData = sync.OnceValue(func() schemeData {
+	s := runtime.NewScheme()
+	metav1.AddToGroupVersion(s, schema.GroupVersion{Version: "v1"})
+	utilruntime.Must(corev1.AddToScheme(s))
+	utilruntime.Must(appsv1.AddToScheme(s))
+
+	return schemeData{
+		scheme:         s,
+		codecs:         serializer.NewCodecFactory(s),
+		parameterCodec: runtime.NewParameterCodec(s),
+	}
+})
+
+func Scheme() *runtime.Scheme {
+	return loadSchemeData().scheme
+}
+
+func Codecs() serializer.CodecFactory {
+	return loadSchemeData().codecs
+}
 
-func init() {
-	metav1.AddToGroupVersion(Scheme, schema.GroupVersion{Version: "v1"})
-	utilruntime.Must(corev1.AddToScheme(Scheme))
-	utilruntime.Must(appsv1.AddToScheme(Scheme))
+func ParameterCodec() runtime.ParameterCodec {
+	return loadSchemeData().parameterCodec
 }