client-go: factor the dynamic client similarly to others

All other clients:

 - expose a New() method that takes a rest.Interface
 - expose their RESTClient()
 - return pointers to the type, not instances of an interface that the
   type implements

For code that is generic over all Kubernetes clients, and for general
developer experience, it's best to make sure that this client adheres to
these common practices.

Signed-off-by: Steve Kuznetsov <skuznets@redhat.com>

staging/src/k8s.io/client-go/dynamic/simple.go

@@ -31,11 +31,11 @@ import (
 	"k8s.io/client-go/rest"
 )
 
-type dynamicClient struct {
-	client *rest.RESTClient
+type DynamicClient struct {
+	client rest.Interface
 }
 
-var _ Interface = &dynamicClient{}
+var _ Interface = &DynamicClient{}
 
 // ConfigFor returns a copy of the provided config with the
 // appropriate dynamic client defaults set.
@@ -50,9 +50,14 @@ func ConfigFor(inConfig *rest.Config) *rest.Config {
 	return config
 }
 
-// NewForConfigOrDie creates a new Interface for the given config and
+// New creates a new DynamicClient for the given RESTClient.
+func New(c rest.Interface) *DynamicClient {
+	return &DynamicClient{client: c}
+}
+
+// NewForConfigOrDie creates a new DynamicClient for the given config and
 // panics if there is an error in the config.
-func NewForConfigOrDie(c *rest.Config) Interface {
+func NewForConfigOrDie(c *rest.Config) *DynamicClient {
 	ret, err := NewForConfig(c)
 	if err != nil {
 		panic(err)
@@ -63,7 +68,7 @@ func NewForConfigOrDie(c *rest.Config) Interface {
 // NewForConfig creates a new dynamic client or returns an error.
 // NewForConfig is equivalent to NewForConfigAndClient(c, httpClient),
 // where httpClient was generated with rest.HTTPClientFor(c).
-func NewForConfig(inConfig *rest.Config) (Interface, error) {
+func NewForConfig(inConfig *rest.Config) (*DynamicClient, error) {
 	config := ConfigFor(inConfig)
 
 	httpClient, err := rest.HTTPClientFor(config)
@@ -75,7 +80,7 @@ func NewForConfig(inConfig *rest.Config) (Interface, error) {
 
 // NewForConfigAndClient creates a new dynamic client for the given config and http client.
 // Note the http client provided takes precedence over the configured transport values.
-func NewForConfigAndClient(inConfig *rest.Config, h *http.Client) (Interface, error) {
+func NewForConfigAndClient(inConfig *rest.Config, h *http.Client) (*DynamicClient, error) {
 	config := ConfigFor(inConfig)
 	// for serializing the options
 	config.GroupVersion = &schema.GroupVersion{}
@@ -85,16 +90,16 @@ func NewForConfigAndClient(inConfig *rest.Config, h *http.Client) (Interface, er
 	if err != nil {
 		return nil, err
 	}
-	return &dynamicClient{client: restClient}, nil
+	return &DynamicClient{client: restClient}, nil
 }
 
 type dynamicResourceClient struct {
-	client    *dynamicClient
+	client    *DynamicClient
 	namespace string
 	resource  schema.GroupVersionResource
 }
 
-func (c *dynamicClient) Resource(resource schema.GroupVersionResource) NamespaceableResourceInterface {
+func (c *DynamicClient) Resource(resource schema.GroupVersionResource) NamespaceableResourceInterface {
 	return &dynamicResourceClient{client: c, resource: resource}
 }