Use protobuf for core clients

Signed-off-by: Monis Khan <mok@microsoft.com>

hack/update-codegen.sh

@@ -645,6 +645,7 @@ function codegen::clients() {
         --input-base="k8s.io/api" \
         --plural-exceptions "${PLURAL_EXCEPTIONS}" \
         --apply-configuration-package "${APPLYCONFIG_PKG}" \
+        --prefers-protobuf \
         $(printf -- " --input %s" "${gv_dirs[@]}") \
         "$@"
 

staging/src/k8s.io/apiextensions-apiserver/hack/update-codegen.sh

@@ -52,4 +52,5 @@ kube::codegen::gen_client \
     --output-pkg "${THIS_PKG}/pkg/client" \
     --versioned-name "clientset" \
     --boilerplate "${SCRIPT_ROOT}/hack/boilerplate.go.txt" \
+    --prefers-protobuf \
     "${SCRIPT_ROOT}/pkg/apis"

staging/src/k8s.io/client-go/gentype/type.go

@@ -51,6 +51,8 @@ type Client[T objectWithMeta] struct {
 	namespace      string // "" for non-namespaced clients
 	newObject      func() T
 	parameterCodec runtime.ParameterCodec
+
+	prefersProtobuf bool
 }
 
 // ClientWithList represents a client with support for lists.
@@ -82,26 +84,37 @@ type alsoApplier[T objectWithMeta, C namedObject] struct {
 	client *Client[T]
 }
 
+type Option[T objectWithMeta] func(*Client[T])
+
+func PrefersProtobuf[T objectWithMeta]() Option[T] {
+	return func(c *Client[T]) { c.prefersProtobuf = true }
+}
+
 // NewClient constructs a client, namespaced or not, with no support for lists or apply.
 // Non-namespaced clients are constructed by passing an empty namespace ("").
 func NewClient[T objectWithMeta](
 	resource string, client rest.Interface, parameterCodec runtime.ParameterCodec, namespace string, emptyObjectCreator func() T,
+	options ...Option[T],
 ) *Client[T] {
-	return &Client[T]{
+	c := &Client[T]{
 		resource:       resource,
 		client:         client,
 		parameterCodec: parameterCodec,
 		namespace:      namespace,
 		newObject:      emptyObjectCreator,
 	}
+	for _, option := range options {
+		option(c)
+	}
+	return c
 }
 
 // NewClientWithList constructs a namespaced client with support for lists.
 func NewClientWithList[T objectWithMeta, L runtime.Object](
 	resource string, client rest.Interface, parameterCodec runtime.ParameterCodec, namespace string, emptyObjectCreator func() T,
-	emptyListCreator func() L,
+	emptyListCreator func() L, options ...Option[T],
 ) *ClientWithList[T, L] {
-	typeClient := NewClient[T](resource, client, parameterCodec, namespace, emptyObjectCreator)
+	typeClient := NewClient[T](resource, client, parameterCodec, namespace, emptyObjectCreator, options...)
 	return &ClientWithList[T, L]{
 		typeClient,
 		alsoLister[T, L]{typeClient, emptyListCreator},
@@ -111,8 +124,9 @@ func NewClientWithList[T objectWithMeta, L runtime.Object](
 // NewClientWithApply constructs a namespaced client with support for apply declarative configurations.
 func NewClientWithApply[T objectWithMeta, C namedObject](
 	resource string, client rest.Interface, parameterCodec runtime.ParameterCodec, namespace string, emptyObjectCreator func() T,
+	options ...Option[T],
 ) *ClientWithApply[T, C] {
-	typeClient := NewClient[T](resource, client, parameterCodec, namespace, emptyObjectCreator)
+	typeClient := NewClient[T](resource, client, parameterCodec, namespace, emptyObjectCreator, options...)
 	return &ClientWithApply[T, C]{
 		typeClient,
 		alsoApplier[T, C]{typeClient},
@@ -122,9 +136,9 @@ func NewClientWithApply[T objectWithMeta, C namedObject](
 // NewClientWithListAndApply constructs a client with support for lists and applying declarative configurations.
 func NewClientWithListAndApply[T objectWithMeta, L runtime.Object, C namedObject](
 	resource string, client rest.Interface, parameterCodec runtime.ParameterCodec, namespace string, emptyObjectCreator func() T,
-	emptyListCreator func() L,
+	emptyListCreator func() L, options ...Option[T],
 ) *ClientWithListAndApply[T, L, C] {
-	typeClient := NewClient[T](resource, client, parameterCodec, namespace, emptyObjectCreator)
+	typeClient := NewClient[T](resource, client, parameterCodec, namespace, emptyObjectCreator, options...)
 	return &ClientWithListAndApply[T, L, C]{
 		typeClient,
 		alsoLister[T, L]{typeClient, emptyListCreator},
@@ -146,6 +160,7 @@ func (c *Client[T]) GetNamespace() string {
 func (c *Client[T]) Get(ctx context.Context, name string, options metav1.GetOptions) (T, error) {
 	result := c.newObject()
 	err := c.client.Get().
+		UseProtobufAsDefaultIfPreferred(c.prefersProtobuf).
 		NamespaceIfScoped(c.namespace, c.namespace != "").
 		Resource(c.resource).
 		Name(name).
@@ -181,6 +196,7 @@ func (l *alsoLister[T, L]) list(ctx context.Context, opts metav1.ListOptions) (L
 		timeout = time.Duration(*opts.TimeoutSeconds) * time.Second
 	}
 	err := l.client.client.Get().
+		UseProtobufAsDefaultIfPreferred(l.client.prefersProtobuf).
 		NamespaceIfScoped(l.client.namespace, l.client.namespace != "").
 		Resource(l.client.resource).
 		VersionedParams(&opts, l.client.parameterCodec).
@@ -198,6 +214,7 @@ func (l *alsoLister[T, L]) watchList(ctx context.Context, opts metav1.ListOption
 	}
 	result = l.newList()
 	err = l.client.client.Get().
+		UseProtobufAsDefaultIfPreferred(l.client.prefersProtobuf).
 		NamespaceIfScoped(l.client.namespace, l.client.namespace != "").
 		Resource(l.client.resource).
 		VersionedParams(&opts, l.client.parameterCodec).
@@ -215,6 +232,7 @@ func (c *Client[T]) Watch(ctx context.Context, opts metav1.ListOptions) (watch.I
 	}
 	opts.Watch = true
 	return c.client.Get().
+		UseProtobufAsDefaultIfPreferred(c.prefersProtobuf).
 		NamespaceIfScoped(c.namespace, c.namespace != "").
 		Resource(c.resource).
 		VersionedParams(&opts, c.parameterCodec).
@@ -226,6 +244,7 @@ func (c *Client[T]) Watch(ctx context.Context, opts metav1.ListOptions) (watch.I
 func (c *Client[T]) Create(ctx context.Context, obj T, opts metav1.CreateOptions) (T, error) {
 	result := c.newObject()
 	err := c.client.Post().
+		UseProtobufAsDefaultIfPreferred(c.prefersProtobuf).
 		NamespaceIfScoped(c.namespace, c.namespace != "").
 		Resource(c.resource).
 		VersionedParams(&opts, c.parameterCodec).
@@ -239,6 +258,7 @@ func (c *Client[T]) Create(ctx context.Context, obj T, opts metav1.CreateOptions
 func (c *Client[T]) Update(ctx context.Context, obj T, opts metav1.UpdateOptions) (T, error) {
 	result := c.newObject()
 	err := c.client.Put().
+		UseProtobufAsDefaultIfPreferred(c.prefersProtobuf).
 		NamespaceIfScoped(c.namespace, c.namespace != "").
 		Resource(c.resource).
 		Name(obj.GetName()).
@@ -253,6 +273,7 @@ func (c *Client[T]) Update(ctx context.Context, obj T, opts metav1.UpdateOptions
 func (c *Client[T]) UpdateStatus(ctx context.Context, obj T, opts metav1.UpdateOptions) (T, error) {
 	result := c.newObject()
 	err := c.client.Put().
+		UseProtobufAsDefaultIfPreferred(c.prefersProtobuf).
 		NamespaceIfScoped(c.namespace, c.namespace != "").
 		Resource(c.resource).
 		Name(obj.GetName()).
@@ -267,6 +288,7 @@ func (c *Client[T]) UpdateStatus(ctx context.Context, obj T, opts metav1.UpdateO
 // Delete takes name of the resource and deletes it. Returns an error if one occurs.
 func (c *Client[T]) Delete(ctx context.Context, name string, opts metav1.DeleteOptions) error {
 	return c.client.Delete().
+		UseProtobufAsDefaultIfPreferred(c.prefersProtobuf).
 		NamespaceIfScoped(c.namespace, c.namespace != "").
 		Resource(c.resource).
 		Name(name).
@@ -282,6 +304,7 @@ func (l *alsoLister[T, L]) DeleteCollection(ctx context.Context, opts metav1.Del
 		timeout = time.Duration(*listOpts.TimeoutSeconds) * time.Second
 	}
 	return l.client.client.Delete().
+		UseProtobufAsDefaultIfPreferred(l.client.prefersProtobuf).
 		NamespaceIfScoped(l.client.namespace, l.client.namespace != "").
 		Resource(l.client.resource).
 		VersionedParams(&listOpts, l.client.parameterCodec).
@@ -295,6 +318,7 @@ func (l *alsoLister[T, L]) DeleteCollection(ctx context.Context, opts metav1.Del
 func (c *Client[T]) Patch(ctx context.Context, name string, pt types.PatchType, data []byte, opts metav1.PatchOptions, subresources ...string) (T, error) {
 	result := c.newObject()
 	err := c.client.Patch(pt).
+		UseProtobufAsDefaultIfPreferred(c.prefersProtobuf).
 		NamespaceIfScoped(c.namespace, c.namespace != "").
 		Resource(c.resource).
 		Name(name).
@@ -321,6 +345,7 @@ func (a *alsoApplier[T, C]) Apply(ctx context.Context, obj C, opts metav1.ApplyO
 		return *new(T), fmt.Errorf("obj.Name must be provided to Apply")
 	}
 	err = a.client.client.Patch(types.ApplyPatchType).
+		UseProtobufAsDefaultIfPreferred(a.client.prefersProtobuf).
 		NamespaceIfScoped(a.client.namespace, a.client.namespace != "").
 		Resource(a.client.resource).
 		Name(*obj.GetName()).
@@ -348,6 +373,7 @@ func (a *alsoApplier[T, C]) ApplyStatus(ctx context.Context, obj C, opts metav1.
 
 	result := a.client.newObject()
 	err = a.client.client.Patch(types.ApplyPatchType).
+		UseProtobufAsDefaultIfPreferred(a.client.prefersProtobuf).
 		NamespaceIfScoped(a.client.namespace, a.client.namespace != "").
 		Resource(a.client.resource).
 		Name(*obj.GetName()).

staging/src/k8s.io/client-go/rest/request.go

@@ -176,12 +176,7 @@ func NewRequest(c *RESTClient) *Request {
 		contentTypeNotSet: contentTypeNotSet,
 	}
 
-	switch {
+	r.setAcceptHeader()
-	case len(c.content.AcceptContentTypes) > 0:
-		r.SetHeader("Accept", c.content.AcceptContentTypes)
-	case len(c.content.ContentType) > 0:
-		r.SetHeader("Accept", c.content.ContentType+", */*")
-	}
 	return r
 }
 
@@ -195,6 +190,31 @@ func NewRequestWithClient(base *url.URL, versionedAPIPath string, content Client
 	})
 }
 
+func (r *Request) UseProtobufAsDefaultIfPreferred(prefersProtobuf bool) *Request {
+	if prefersProtobuf {
+		return r.UseProtobufAsDefault()
+	}
+	return r
+}
+
+func (r *Request) UseProtobufAsDefault() *Request {
+	if r.contentTypeNotSet && len(r.contentConfig.AcceptContentTypes) == 0 {
+		r.contentConfig.AcceptContentTypes = "application/vnd.kubernetes.protobuf,application/json"
+		r.contentConfig.ContentType = "application/vnd.kubernetes.protobuf"
+		r.setAcceptHeader()
+	}
+	return r
+}
+
+func (r *Request) setAcceptHeader() {
+	switch {
+	case len(r.contentConfig.AcceptContentTypes) > 0:
+		r.SetHeader("Accept", r.contentConfig.AcceptContentTypes)
+	case len(r.contentConfig.ContentType) > 0:
+		r.SetHeader("Accept", r.contentConfig.ContentType+", */*")
+	}
+}
+
 // Verb sets the verb this request will use.
 func (r *Request) Verb(verb string) *Request {
 	r.verb = verb

staging/src/k8s.io/code-generator/cmd/client-gen/args/args.go

@@ -61,6 +61,9 @@ type Args struct {
 	// If non-empty, Apply functions are generated for each type and reference the apply builders.
 	// If empty (""), Apply functions are not generated.
 	ApplyConfigurationPackage string
+
+	// PrefersProtobuf determines if the generated clientset uses protobuf for API requests.
+	PrefersProtobuf bool
 }
 
 func New() *Args {
@@ -99,6 +102,8 @@ func (args *Args) AddFlags(fs *pflag.FlagSet, inputBase string) {
 		"list of comma separated plural exception definitions in Type:PluralizedType form")
 	fs.StringVar(&args.ApplyConfigurationPackage, "apply-configuration-package", args.ApplyConfigurationPackage,
 		"optional package of apply configurations, generated by applyconfiguration-gen, that are required to generate Apply functions for each type in the clientset. By default Apply functions are not generated.")
+	fs.BoolVar(&args.PrefersProtobuf, "prefers-protobuf", args.PrefersProtobuf,
+		"when set, client-gen will generate a clientset that uses protobuf for API requests")
 
 	// support old flags
 	fs.SetNormalizeFunc(mapFlagName("clientset-path", "output-pkg", fs.GetNormalizeFunc()))

staging/src/k8s.io/code-generator/cmd/client-gen/generators/client_generator.go

@@ -128,7 +128,7 @@ func DefaultNameSystem() string {
 	return "public"
 }
 
-func targetForGroup(gv clientgentypes.GroupVersion, typeList []*types.Type, clientsetDir, clientsetPkg string, groupPkgName string, groupGoName string, apiPath string, inputPkg string, applyBuilderPkg string, boilerplate []byte) generator.Target {
+func targetForGroup(gv clientgentypes.GroupVersion, typeList []*types.Type, clientsetDir, clientsetPkg string, groupPkgName string, groupGoName string, apiPath string, inputPkg string, applyBuilderPkg string, boilerplate []byte, prefersProtobuf bool) generator.Target {
 	subdir := []string{"typed", strings.ToLower(groupPkgName), strings.ToLower(gv.Version.NonEmpty())}
 	gvDir := filepath.Join(clientsetDir, filepath.Join(subdir...))
 	gvPkg := path.Join(clientsetPkg, path.Join(subdir...))
@@ -160,6 +160,7 @@ func targetForGroup(gv clientgentypes.GroupVersion, typeList []*types.Type, clie
 					group:                     gv.Group.NonEmpty(),
 					version:                   gv.Version.String(),
 					groupGoName:               groupGoName,
+					prefersProtobuf:           prefersProtobuf,
 					typeToMatch:               t,
 					imports:                   generator.NewImportTrackerForPackage(gvPkg),
 				})
@@ -424,7 +425,7 @@ func GetTargets(context *generator.Context, args *args.Args) []generator.Target
 				targetForGroup(
 					gv, orderer.OrderTypes(types), clientsetDir, clientsetPkg,
 					group.PackageName, groupGoNames[gv], args.ClientsetAPIPath,
-					inputPath, args.ApplyConfigurationPackage, boilerplate))
+					inputPath, args.ApplyConfigurationPackage, boilerplate, args.PrefersProtobuf))
 			if args.FakeClient {
 				targetList = append(targetList,
 					fake.TargetForGroup(gv, orderer.OrderTypes(types), clientsetDir, clientsetPkg, group.PackageName, groupGoNames[gv], inputPath, args.ApplyConfigurationPackage, boilerplate))

staging/src/k8s.io/code-generator/cmd/client-gen/generators/generator_for_type.go

@@ -41,6 +41,7 @@ type genClientForType struct {
 	group                     string
 	version                   string
 	groupGoName               string
+	prefersProtobuf           bool
 	typeToMatch               *types.Type
 	imports                   namer.ImportTracker
 }
@@ -161,6 +162,7 @@ func (g *genClientForType) GenerateType(c *generator.Context, t *types.Type, w i
 		"subresource":                      false,
 		"subresourcePath":                  "",
 		"GroupGoName":                      g.groupGoName,
+		"prefersProtobuf":                  g.prefersProtobuf,
 		"Version":                          namer.IC(g.version),
 		"CreateOptions":                    c.Universe.Type(types.Name{Package: "k8s.io/apimachinery/pkg/apis/meta/v1", Name: "CreateOptions"}),
 		"DeleteOptions":                    c.Universe.Type(types.Name{Package: "k8s.io/apimachinery/pkg/apis/meta/v1", Name: "DeleteOptions"}),
@@ -483,7 +485,9 @@ var newStruct = []string{
 				c.RESTClient(),
 				$.schemeParameterCodec|raw$,
 				namespace,
-				func() *$.resultType|raw$ { return &$.resultType|raw${} }),
+				func() *$.resultType|raw$ { return &$.resultType|raw${} },
+				$if .prefersProtobuf$gentype.PrefersProtobuf[*$.resultType|raw$](),$end$
+			),
 		}
 	}
 	`,
@@ -496,7 +500,9 @@ var newStruct = []string{
 				c.RESTClient(),
 				$.schemeParameterCodec|raw$,
 				namespace,
-				func() *$.resultType|raw$ { return &$.resultType|raw${} }),
+				func() *$.resultType|raw$ { return &$.resultType|raw${} },
+				$if .prefersProtobuf$gentype.PrefersProtobuf[*$.resultType|raw$](),$end$
+			),
 		}
 	}
 	`,
@@ -510,7 +516,9 @@ var newStruct = []string{
 				$.schemeParameterCodec|raw$,
 				namespace,
 				func() *$.resultType|raw$ { return &$.resultType|raw${} },
-				func() *$.resultType|raw$List { return &$.resultType|raw$List{} }),
+				func() *$.resultType|raw$List { return &$.resultType|raw$List{} },
+				$if .prefersProtobuf$gentype.PrefersProtobuf[*$.resultType|raw$](),$end$
+			),
 		}
 	}
 	`,
@@ -524,7 +532,9 @@ var newStruct = []string{
 				$.schemeParameterCodec|raw$,
 				namespace,
 				func() *$.resultType|raw$ { return &$.resultType|raw${} },
-				func() *$.resultType|raw$List { return &$.resultType|raw$List{} }),
+				func() *$.resultType|raw$List { return &$.resultType|raw$List{} },
+				$if .prefersProtobuf$gentype.PrefersProtobuf[*$.resultType|raw$](),$end$
+			),
 		}
 	}
 	`,
@@ -537,7 +547,9 @@ var newStruct = []string{
 				c.RESTClient(),
 				$.schemeParameterCodec|raw$,
 				"",
-				func() *$.resultType|raw$ { return &$.resultType|raw${} }),
+				func() *$.resultType|raw$ { return &$.resultType|raw${} },
+				$if .prefersProtobuf$gentype.PrefersProtobuf[*$.resultType|raw$](),$end$
+			),
 		}
 	}
 	`,
@@ -550,7 +562,9 @@ var newStruct = []string{
 				c.RESTClient(),
 				$.schemeParameterCodec|raw$,
 				"",
-				func() *$.resultType|raw$ { return &$.resultType|raw${} }),
+				func() *$.resultType|raw$ { return &$.resultType|raw${} },
+				$if .prefersProtobuf$gentype.PrefersProtobuf[*$.resultType|raw$](),$end$
+			),
 		}
 	}
 	`,
@@ -564,7 +578,9 @@ var newStruct = []string{
 				$.schemeParameterCodec|raw$,
 				"",
 				func() *$.resultType|raw$ { return &$.resultType|raw${} },
-				func() *$.resultType|raw$List { return &$.resultType|raw$List{} }),
+				func() *$.resultType|raw$List { return &$.resultType|raw$List{} },
+				$if .prefersProtobuf$gentype.PrefersProtobuf[*$.resultType|raw$](),$end$
+			),
 		}
 	}
 	`,
@@ -578,7 +594,9 @@ var newStruct = []string{
 				$.schemeParameterCodec|raw$,
 				"",
 				func() *$.resultType|raw$ { return &$.resultType|raw${} },
-				func() *$.resultType|raw$List { return &$.resultType|raw$List{} }),
+				func() *$.resultType|raw$List { return &$.resultType|raw$List{} },
+				$if .prefersProtobuf$gentype.PrefersProtobuf[*$.resultType|raw$](),$end$
+			),
 		}
 	}
 	`,
@@ -614,6 +632,7 @@ func (c *$.type|privatePlural$) list(ctx $.context|raw$, opts $.ListOptions|raw$
 	}
 	result = &$.resultType|raw$List{}
 	err = c.GetClient().Get().
+		$if .prefersProtobuf$UseProtobufAsDefault().$end$
 		$if .namespaced$Namespace(c.GetNamespace()).$end$
 		Resource("$.type|resource$").
 		VersionedParams(&opts, $.schemeParameterCodec|raw$).
@@ -633,6 +652,7 @@ func (c *$.type|privatePlural$) $.verb$(ctx $.context|raw$, $.type|private$Name
 	}
 	result = &$.resultType|raw$List{}
 	err = c.GetClient().Get().
+		$if .prefersProtobuf$UseProtobufAsDefault().$end$
 		$if .namespaced$Namespace(c.GetNamespace()).$end$
 		Resource("$.type|resource$").
 		Name($.type|private$Name).
@@ -650,6 +670,7 @@ var getTemplate = `
 func (c *$.type|privatePlural$) $.verb$(ctx $.context|raw$, name string, options $.GetOptions|raw$) (result *$.resultType|raw$, err error) {
 	result = &$.resultType|raw${}
 	err = c.GetClient().Get().
+		$if .prefersProtobuf$UseProtobufAsDefault().$end$
 		$if .namespaced$Namespace(c.GetNamespace()).$end$
 		Resource("$.type|resource$").
 		Name(name).
@@ -665,6 +686,7 @@ var getSubresourceTemplate = `
 func (c *$.type|privatePlural$) $.verb$(ctx $.context|raw$, $.type|private$Name string, options $.GetOptions|raw$) (result *$.resultType|raw$, err error) {
 	result = &$.resultType|raw${}
 	err = c.GetClient().Get().
+		$if .prefersProtobuf$UseProtobufAsDefault().$end$
 		$if .namespaced$Namespace(c.GetNamespace()).$end$
 		Resource("$.type|resource$").
 		Name($.type|private$Name).
@@ -680,6 +702,7 @@ var deleteTemplate = `
 // $.verb$ takes name of the $.type|private$ and deletes it. Returns an error if one occurs.
 func (c *$.type|privatePlural$) $.verb$(ctx $.context|raw$, name string, opts $.DeleteOptions|raw$) error {
 	return c.GetClient().Delete().
+		$if .prefersProtobuf$UseProtobufAsDefault().$end$
 		$if .namespaced$Namespace(c.GetNamespace()).$end$
 		Resource("$.type|resource$").
 		Name(name).
@@ -694,6 +717,7 @@ var createSubresourceTemplate = `
 func (c *$.type|privatePlural$) $.verb$(ctx $.context|raw$, $.type|private$Name string, $.inputType|private$ *$.inputType|raw$, opts $.CreateOptions|raw$) (result *$.resultType|raw$, err error) {
 	result = &$.resultType|raw${}
 	err = c.GetClient().Post().
+		$if .prefersProtobuf$UseProtobufAsDefault().$end$
 		$if .namespaced$Namespace(c.GetNamespace()).$end$
 		Resource("$.type|resource$").
 		Name($.type|private$Name).
@@ -711,6 +735,7 @@ var createTemplate = `
 func (c *$.type|privatePlural$) $.verb$(ctx $.context|raw$, $.inputType|private$ *$.inputType|raw$, opts $.CreateOptions|raw$) (result *$.resultType|raw$, err error) {
 	result = &$.resultType|raw${}
 	err = c.GetClient().Post().
+		$if .prefersProtobuf$UseProtobufAsDefault().$end$
 		$if .namespaced$Namespace(c.GetNamespace()).$end$
 		Resource("$.type|resource$").
 		VersionedParams(&opts, $.schemeParameterCodec|raw$).
@@ -726,6 +751,7 @@ var updateSubresourceTemplate = `
 func (c *$.type|privatePlural$) $.verb$(ctx $.context|raw$, $.type|private$Name string, $.inputType|private$ *$.inputType|raw$, opts $.UpdateOptions|raw$) (result *$.resultType|raw$, err error) {
 	result = &$.resultType|raw${}
 	err = c.GetClient().Put().
+		$if .prefersProtobuf$UseProtobufAsDefault().$end$
 		$if .namespaced$Namespace(c.GetNamespace()).$end$
 		Resource("$.type|resource$").
 		Name($.type|private$Name).
@@ -743,6 +769,7 @@ var updateTemplate = `
 func (c *$.type|privatePlural$) $.verb$(ctx $.context|raw$, $.inputType|private$ *$.inputType|raw$, opts $.UpdateOptions|raw$) (result *$.resultType|raw$, err error) {
 	result = &$.resultType|raw${}
 	err = c.GetClient().Put().
+		$if .prefersProtobuf$UseProtobufAsDefault().$end$
 		$if .namespaced$Namespace(c.GetNamespace()).$end$
 		Resource("$.type|resource$").
 		Name($.inputType|private$.Name).
@@ -763,6 +790,7 @@ func (c *$.type|privatePlural$) $.verb$(ctx $.context|raw$, opts $.ListOptions|r
 	}
 	opts.Watch = true
 	return c.GetClient().Get().
+		$if .prefersProtobuf$UseProtobufAsDefault().$end$
 		$if .namespaced$Namespace(c.GetNamespace()).$end$
 		VersionedParams(&opts, $.schemeParameterCodec|raw$).
 		Timeout(timeout).
@@ -779,6 +807,7 @@ func (c *$.type|privatePlural$) watchList(ctx $.context|raw$, opts $.ListOptions
 	}
     result = &$.resultType|raw$List{}
 	err = c.GetClient().Get().
+		$if .prefersProtobuf$UseProtobufAsDefault().$end$
 		$if .namespaced$Namespace(c.GetNamespace()).$end$
 		Resource("$.type|resource$").
 		VersionedParams(&opts, $.schemeParameterCodec|raw$).
@@ -794,6 +823,7 @@ var patchTemplate = `
 func (c *$.type|privatePlural$) $.verb$(ctx $.context|raw$, name string, pt $.PatchType|raw$, data []byte, opts $.PatchOptions|raw$, subresources ...string) (result *$.resultType|raw$, err error) {
 	result = &$.resultType|raw${}
 	err = c.GetClient().Patch(pt).
+		$if .prefersProtobuf$UseProtobufAsDefault().$end$
 		$if .namespaced$Namespace(c.GetNamespace()).$end$
 		Resource("$.type|resource$").
 		Name(name).
@@ -823,6 +853,7 @@ func (c *$.type|privatePlural$) $.verb$(ctx $.context|raw$, $.inputType|private$
 	}
 	result = &$.resultType|raw${}
 	err = c.GetClient().Patch($.ApplyPatchType|raw$).
+		$if .prefersProtobuf$UseProtobufAsDefault().$end$
 		$if .namespaced$Namespace(c.GetNamespace()).$end$
 		Resource("$.type|resource$").
 		Name(*name).
@@ -849,6 +880,7 @@ func (c *$.type|privatePlural$) $.verb$(ctx $.context|raw$, $.type|private$Name
 
 	result = &$.resultType|raw${}
 	err = c.GetClient().Patch($.ApplyPatchType|raw$).
+		$if .prefersProtobuf$UseProtobufAsDefault().$end$
 		$if .namespaced$Namespace(c.GetNamespace()).$end$
 		Resource("$.type|resource$").
 		Name($.type|private$Name).

staging/src/k8s.io/code-generator/kube_codegen.sh

@@ -433,6 +433,9 @@ function kube::codegen::gen_openapi() {
 #   --plural-exceptions <string = "">
 #     An optional list of comma separated plural exception definitions in Type:PluralizedType form.
 #
+#   --prefers-protobuf
+#     Enables generation of clientsets that use protobuf for API requests.
+#
 function kube::codegen::gen_client() {
     local in_dir=""
     local one_input_api=""
@@ -450,6 +453,7 @@ function kube::codegen::gen_client() {
     local boilerplate="${KUBE_CODEGEN_ROOT}/hack/boilerplate.go.txt"
     local plural_exceptions=""
     local v="${KUBE_VERBOSE:-0}"
+    local prefers_protobuf="false"
 
     while [ "$#" -gt 0 ]; do
         case "$1" in
@@ -509,6 +513,10 @@ function kube::codegen::gen_client() {
                 plural_exceptions="$2"
                 shift 2
                 ;;
+            "--prefers-protobuf")
+                prefers_protobuf="true"
+                shift
+                ;;
             *)
                 if [[ "$1" =~ ^-- ]]; then
                     echo "unknown argument: $1" >&2
@@ -625,6 +633,7 @@ function kube::codegen::gen_client() {
         --apply-configuration-package "${applyconfig_pkg}" \
         --input-base "$(cd "${in_dir}" && pwd -P)" `# must be absolute path or Go import path"` \
         --plural-exceptions "${plural_exceptions}" \
+        --prefers-protobuf="${prefers_protobuf}" \
         "${inputs[@]}"
 
     if [ "${watchable}" == "true" ]; then

staging/src/k8s.io/kube-aggregator/hack/update-codegen.sh

@@ -51,4 +51,5 @@ kube::codegen::gen_client \
     --clientset-name "clientset_generated" \
     --versioned-name "clientset" \
     --boilerplate "${SCRIPT_ROOT}/hack/boilerplate.go.txt" \
+    --prefers-protobuf \
     "${SCRIPT_ROOT}/pkg/apis"

staging/src/k8s.io/metrics/hack/update-codegen.sh

@@ -36,4 +36,5 @@ kube::codegen::gen_client \
     --output-dir "${SCRIPT_ROOT}/pkg/client" \
     --output-pkg "${THIS_PKG}/pkg/client" \
     --boilerplate "${SCRIPT_ROOT}/hack/boilerplate.go.txt" \
+    --prefers-protobuf \
     "${SCRIPT_ROOT}/pkg/apis"