Merge pull request #75570 from smarterclayton/fix_performance

Fix a regression in watch performance and reduce allocations in the GET path

staging/src/k8s.io/apiextensions-apiserver/pkg/apiserver/customresource_handler.go

@@ -644,6 +644,8 @@ func (s unstructuredNegotiatedSerializer) SupportedMediaTypes() []runtime.Serial
 	return []runtime.SerializerInfo{
 		{
 			MediaType:        "application/json",
+			MediaTypeType:    "application",
+			MediaTypeSubType: "json",
 			EncodesAsText:    true,
 			Serializer:       json.NewSerializer(json.DefaultMetaFactory, s.creator, s.typer, false),
 			PrettySerializer: json.NewSerializer(json.DefaultMetaFactory, s.creator, s.typer, true),
@@ -654,9 +656,11 @@ func (s unstructuredNegotiatedSerializer) SupportedMediaTypes() []runtime.Serial
 			},
 		},
 		{
-			MediaType:     "application/yaml",
+			MediaType:        "application/yaml",
-			EncodesAsText: true,
+			MediaTypeType:    "application",
-			Serializer:    json.NewYAMLSerializer(json.DefaultMetaFactory, s.creator, s.typer),
+			MediaTypeSubType: "yaml",
+			EncodesAsText:    true,
+			Serializer:       json.NewYAMLSerializer(json.DefaultMetaFactory, s.creator, s.typer),
 		},
 	}
 }

staging/src/k8s.io/apimachinery/pkg/api/meta/help.go

@@ -17,30 +17,76 @@ limitations under the License.
 package meta
 
 import (
+	"errors"
 	"fmt"
 	"reflect"
+	"sync"
 
 	"k8s.io/apimachinery/pkg/conversion"
 	"k8s.io/apimachinery/pkg/runtime"
 )
 
-// IsListType returns true if the provided Object has a slice called Items
+var (
+	// isListCache maintains a cache of types that are checked for lists
+	// which is used by IsListType.
+	// TODO: remove and replace with an interface check
+	isListCache = struct {
+		lock   sync.RWMutex
+		byType map[reflect.Type]bool
+	}{
+		byType: make(map[reflect.Type]bool, 1024),
+	}
+)
+
+// IsListType returns true if the provided Object has a slice called Items.
+// TODO: Replace the code in this check with an interface comparison by
+//   creating and enforcing that lists implement a list accessor.
 func IsListType(obj runtime.Object) bool {
-	// if we're a runtime.Unstructured, check whether this is a list.
+	switch t := obj.(type) {
-	// TODO: refactor GetItemsPtr to use an interface that returns []runtime.Object
+	case runtime.Unstructured:
-	if unstructured, ok := obj.(runtime.Unstructured); ok {
+		return t.IsList()
-		return unstructured.IsList()
+	}
+	t := reflect.TypeOf(obj)
+
+	isListCache.lock.RLock()
+	ok, exists := isListCache.byType[t]
+	isListCache.lock.RUnlock()
+
+	if !exists {
+		_, err := getItemsPtr(obj)
+		ok = err == nil
+
+		// cache only the first 1024 types
+		isListCache.lock.Lock()
+		if len(isListCache.byType) < 1024 {
+			isListCache.byType[t] = ok
+		}
+		isListCache.lock.Unlock()
 	}
 
-	_, err := GetItemsPtr(obj)
+	return ok
-	return err == nil
 }
 
+var (
+	errExpectFieldItems = errors.New("no Items field in this object")
+	errExpectSliceItems = errors.New("Items field must be a slice of objects")
+)
+
 // GetItemsPtr returns a pointer to the list object's Items member.
 // If 'list' doesn't have an Items member, it's not really a list type
 // and an error will be returned.
 // This function will either return a pointer to a slice, or an error, but not both.
+// TODO: this will be replaced with an interface in the future
 func GetItemsPtr(list runtime.Object) (interface{}, error) {
+	obj, err := getItemsPtr(list)
+	if err != nil {
+		return nil, fmt.Errorf("%T is not a list: %v", err)
+	}
+	return obj, nil
+}
+
+// getItemsPtr returns a pointer to the list object's Items member or an error.
+func getItemsPtr(list runtime.Object) (interface{}, error) {
 	v, err := conversion.EnforcePtr(list)
 	if err != nil {
 		return nil, err
@@ -48,19 +94,19 @@ func GetItemsPtr(list runtime.Object) (interface{}, error) {
 
 	items := v.FieldByName("Items")
 	if !items.IsValid() {
-		return nil, fmt.Errorf("no Items field in %#v", list)
+		return nil, errExpectFieldItems
 	}
 	switch items.Kind() {
 	case reflect.Interface, reflect.Ptr:
 		target := reflect.TypeOf(items.Interface()).Elem()
 		if target.Kind() != reflect.Slice {
-			return nil, fmt.Errorf("items: Expected slice, got %s", target.Kind())
+			return nil, errExpectSliceItems
 		}
 		return items.Interface(), nil
 	case reflect.Slice:
 		return items.Addr().Interface(), nil
 	default:
-		return nil, fmt.Errorf("items: Expected slice, got %s", items.Kind())
+		return nil, errExpectSliceItems
 	}
 }
 

staging/src/k8s.io/apimachinery/pkg/apis/meta/v1/unstructured/unstructuredscheme/scheme.go

@@ -51,6 +51,8 @@ func (s unstructuredNegotiatedSerializer) SupportedMediaTypes() []runtime.Serial
 	return []runtime.SerializerInfo{
 		{
 			MediaType:        "application/json",
+			MediaTypeType:    "application",
+			MediaTypeSubType: "json",
 			EncodesAsText:    true,
 			Serializer:       json.NewSerializer(json.DefaultMetaFactory, s.creator, s.typer, false),
 			PrettySerializer: json.NewSerializer(json.DefaultMetaFactory, s.creator, s.typer, true),
@@ -61,9 +63,11 @@ func (s unstructuredNegotiatedSerializer) SupportedMediaTypes() []runtime.Serial
 			},
 		},
 		{
-			MediaType:     "application/yaml",
+			MediaType:        "application/yaml",
-			EncodesAsText: true,
+			MediaTypeType:    "application",
-			Serializer:    json.NewYAMLSerializer(json.DefaultMetaFactory, s.creator, s.typer),
+			MediaTypeSubType: "yaml",
+			EncodesAsText:    true,
+			Serializer:       json.NewYAMLSerializer(json.DefaultMetaFactory, s.creator, s.typer),
 		},
 	}
 }

staging/src/k8s.io/apimachinery/pkg/runtime/interfaces.go

@@ -91,6 +91,10 @@ type Framer interface {
 type SerializerInfo struct {
 	// MediaType is the value that represents this serializer over the wire.
 	MediaType string
+	// MediaTypeType is the first part of the MediaType ("application" in "application/json").
+	MediaTypeType string
+	// MediaTypeSubType is the second part of the MediaType ("json" in "application/json").
+	MediaTypeSubType string
 	// EncodesAsText indicates this serializer can be encoded to UTF-8 safely.
 	EncodesAsText bool
 	// Serializer is the individual object serializer for this media type.

staging/src/k8s.io/apimachinery/pkg/runtime/serializer/codec_factory.go

@@ -17,6 +17,9 @@ limitations under the License.
 package serializer
 
 import (
+	"mime"
+	"strings"
+
 	"k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/apimachinery/pkg/runtime/schema"
 	"k8s.io/apimachinery/pkg/runtime/serializer/json"
@@ -120,6 +123,15 @@ func newCodecFactory(scheme *runtime.Scheme, serializers []serializerType) Codec
 				Serializer:       d.Serializer,
 				PrettySerializer: d.PrettySerializer,
 			}
+
+			mediaType, _, err := mime.ParseMediaType(info.MediaType)
+			if err != nil {
+				panic(err)
+			}
+			parts := strings.SplitN(mediaType, "/", 2)
+			info.MediaTypeType = parts[0]
+			info.MediaTypeSubType = parts[1]
+
 			if d.StreamSerializer != nil {
 				info.StreamSerializer = &runtime.StreamSerializerInfo{
 					Serializer:    d.StreamSerializer,

staging/src/k8s.io/apiserver/pkg/endpoints/apiserver_test.go

@@ -1616,6 +1616,41 @@ func TestGet(t *testing.T) {
 	}
 }
 
+func BenchmarkGet(b *testing.B) {
+	storage := map[string]rest.Storage{}
+	simpleStorage := SimpleRESTStorage{
+		item: genericapitesting.Simple{
+			Other: "foo",
+		},
+	}
+	selfLinker := &setTestSelfLinker{
+		expectedSet: "/" + prefix + "/" + testGroupVersion.Group + "/" + testGroupVersion.Version + "/namespaces/default/simple/id",
+		name:        "id",
+		namespace:   "default",
+	}
+	storage["simple"] = &simpleStorage
+	handler := handleLinker(storage, selfLinker)
+	server := httptest.NewServer(handler)
+	defer server.Close()
+
+	u := server.URL + "/" + prefix + "/" + testGroupVersion.Group + "/" + testGroupVersion.Version + "/namespaces/default/simple/id"
+
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		resp, err := http.Get(u)
+		if err != nil {
+			b.Fatalf("unexpected error: %v", err)
+		}
+		if resp.StatusCode != http.StatusOK {
+			b.Fatalf("unexpected response: %#v", resp)
+		}
+		if _, err := io.Copy(ioutil.Discard, resp.Body); err != nil {
+			b.Fatalf("unable to read body")
+		}
+	}
+	b.StopTimer()
+}
+
 func TestGetCompression(t *testing.T) {
 	storage := map[string]rest.Storage{}
 	simpleStorage := SimpleRESTStorage{

staging/src/k8s.io/apiserver/pkg/endpoints/handlers/negotiation/negotiate.go

@@ -43,13 +43,13 @@ func MediaTypesForSerializer(ns runtime.NegotiatedSerializer) (mediaTypes, strea
 // NegotiateOutputMediaType negotiates the output structured media type and a serializer, or
 // returns an error.
 func NegotiateOutputMediaType(req *http.Request, ns runtime.NegotiatedSerializer, restrictions EndpointRestrictions) (MediaTypeOptions, runtime.SerializerInfo, error) {
-	mediaType, ok := NegotiateMediaTypeOptions(req.Header.Get("Accept"), AcceptedMediaTypesForEndpoint(ns), restrictions)
+	mediaType, ok := NegotiateMediaTypeOptions(req.Header.Get("Accept"), ns.SupportedMediaTypes(), restrictions)
 	if !ok {
 		supported, _ := MediaTypesForSerializer(ns)
 		return mediaType, runtime.SerializerInfo{}, NewNotAcceptableError(supported)
 	}
 	// TODO: move into resthandler
-	info := mediaType.Accepted.Serializer
+	info := mediaType.Accepted
 	if (mediaType.Pretty || isPrettyPrint(req)) && info.PrettySerializer != nil {
 		info.Serializer = info.PrettySerializer
 	}
@@ -58,12 +58,12 @@ func NegotiateOutputMediaType(req *http.Request, ns runtime.NegotiatedSerializer
 
 // NegotiateOutputMediaTypeStream returns a stream serializer for the given request.
 func NegotiateOutputMediaTypeStream(req *http.Request, ns runtime.NegotiatedSerializer, restrictions EndpointRestrictions) (runtime.SerializerInfo, error) {
-	mediaType, ok := NegotiateMediaTypeOptions(req.Header.Get("Accept"), AcceptedMediaTypesForEndpoint(ns), restrictions)
+	mediaType, ok := NegotiateMediaTypeOptions(req.Header.Get("Accept"), ns.SupportedMediaTypes(), restrictions)
-	if !ok || mediaType.Accepted.Serializer.StreamSerializer == nil {
+	if !ok || mediaType.Accepted.StreamSerializer == nil {
 		_, supported := MediaTypesForSerializer(ns)
 		return runtime.SerializerInfo{}, NewNotAcceptableError(supported)
 	}
-	return mediaType.Accepted.Serializer, nil
+	return mediaType.Accepted, nil
 }
 
 // NegotiateInputSerializer returns the input serializer for the provided request.
@@ -99,10 +99,13 @@ func NegotiateInputSerializerForMediaType(mediaType string, streaming bool, ns r
 func isPrettyPrint(req *http.Request) bool {
 	// DEPRECATED: should be part of the content type
 	if req.URL != nil {
-		pp := req.URL.Query().Get("pretty")
+		// avoid an allocation caused by parsing the URL query
-		if len(pp) > 0 {
+		if strings.Contains(req.URL.RawQuery, "pretty") {
-			pretty, _ := strconv.ParseBool(pp)
+			pp := req.URL.Query().Get("pretty")
-			return pretty
+			if len(pp) > 0 {
+				pretty, _ := strconv.ParseBool(pp)
+				return pretty
+			}
 		}
 	}
 	userAgent := req.UserAgent()
@@ -139,17 +142,6 @@ func (emptyEndpointRestrictions) AllowsConversion(schema.GroupVersionKind, strin
 func (emptyEndpointRestrictions) AllowsServerVersion(string) bool  { return false }
 func (emptyEndpointRestrictions) AllowsStreamSchema(s string) bool { return s == "watch" }
 
-// AcceptedMediaType contains information about a valid media type that the
-// server can serialize.
-type AcceptedMediaType struct {
-	// Type is the first part of the media type ("application")
-	Type string
-	// SubType is the second part of the media type ("json")
-	SubType string
-	// Serializer is the serialization info this object accepts
-	Serializer runtime.SerializerInfo
-}
-
 // MediaTypeOptions describes information for a given media type that may alter
 // the server response
 type MediaTypeOptions struct {
@@ -176,13 +168,13 @@ type MediaTypeOptions struct {
 	Unrecognized []string
 
 	// the accepted media type from the client
-	Accepted *AcceptedMediaType
+	Accepted runtime.SerializerInfo
 }
 
 // acceptMediaTypeOptions returns an options object that matches the provided media type params. If
 // it returns false, the provided options are not allowed and the media type must be skipped.  These
 // parameters are unversioned and may not be changed.
-func acceptMediaTypeOptions(params map[string]string, accepts *AcceptedMediaType, endpoint EndpointRestrictions) (MediaTypeOptions, bool) {
+func acceptMediaTypeOptions(params map[string]string, accepts *runtime.SerializerInfo, endpoint EndpointRestrictions) (MediaTypeOptions, bool) {
 	var options MediaTypeOptions
 
 	// extract all known parameters
@@ -208,7 +200,7 @@ func acceptMediaTypeOptions(params map[string]string, accepts *AcceptedMediaType
 
 		// controls the streaming schema
 		case "stream":
-			if len(v) > 0 && (accepts.Serializer.StreamSerializer == nil || !endpoint.AllowsStreamSchema(v)) {
+			if len(v) > 0 && (accepts.StreamSerializer == nil || !endpoint.AllowsStreamSchema(v)) {
 				return MediaTypeOptions{}, false
 			}
 			options.Stream = v
@@ -236,16 +228,16 @@ func acceptMediaTypeOptions(params map[string]string, accepts *AcceptedMediaType
 		}
 	}
 
-	if options.Convert != nil && !endpoint.AllowsConversion(*options.Convert, accepts.Type, accepts.SubType) {
+	if options.Convert != nil && !endpoint.AllowsConversion(*options.Convert, accepts.MediaTypeType, accepts.MediaTypeSubType) {
 		return MediaTypeOptions{}, false
 	}
 
-	options.Accepted = accepts
+	options.Accepted = *accepts
 	return options, true
 }
 
 type candidateMediaType struct {
-	accepted *AcceptedMediaType
+	accepted *runtime.SerializerInfo
 	clauses  goautoneg.Accept
 }
 
@@ -253,10 +245,10 @@ type candidateMediaTypeSlice []candidateMediaType
 
 // NegotiateMediaTypeOptions returns the most appropriate content type given the accept header and
 // a list of alternatives along with the accepted media type parameters.
-func NegotiateMediaTypeOptions(header string, accepted []AcceptedMediaType, endpoint EndpointRestrictions) (MediaTypeOptions, bool) {
+func NegotiateMediaTypeOptions(header string, accepted []runtime.SerializerInfo, endpoint EndpointRestrictions) (MediaTypeOptions, bool) {
 	if len(header) == 0 && len(accepted) > 0 {
 		return MediaTypeOptions{
-			Accepted: &accepted[0],
+			Accepted: accepted[0],
 		}, true
 	}
 
@@ -266,8 +258,8 @@ func NegotiateMediaTypeOptions(header string, accepted []AcceptedMediaType, endp
 		for i := range accepted {
 			accepts := &accepted[i]
 			switch {
-			case clause.Type == accepts.Type && clause.SubType == accepts.SubType,
+			case clause.Type == accepts.MediaTypeType && clause.SubType == accepts.MediaTypeSubType,
-				clause.Type == accepts.Type && clause.SubType == "*",
+				clause.Type == accepts.MediaTypeType && clause.SubType == "*",
 				clause.Type == "*" && clause.SubType == "*":
 				candidates = append(candidates, candidateMediaType{accepted: accepts, clauses: clause})
 			}
@@ -282,22 +274,3 @@ func NegotiateMediaTypeOptions(header string, accepted []AcceptedMediaType, endp
 
 	return MediaTypeOptions{}, false
 }
-
-// AcceptedMediaTypesForEndpoint returns an array of structs that are used to efficiently check which
-// allowed media types the server exposes.
-func AcceptedMediaTypesForEndpoint(ns runtime.NegotiatedSerializer) []AcceptedMediaType {
-	var acceptedMediaTypes []AcceptedMediaType
-	for _, info := range ns.SupportedMediaTypes() {
-		segments := strings.SplitN(info.MediaType, "/", 2)
-		if len(segments) == 1 {
-			segments = append(segments, "*")
-		}
-		t := AcceptedMediaType{
-			Type:       segments[0],
-			SubType:    segments[1],
-			Serializer: info,
-		}
-		acceptedMediaTypes = append(acceptedMediaTypes, t)
-	}
-	return acceptedMediaTypes
-}

staging/src/k8s.io/apiserver/pkg/endpoints/handlers/negotiation/negotiate_test.go

@@ -17,8 +17,10 @@ limitations under the License.
 package negotiation
 
 import (
+	"mime"
 	"net/http"
 	"net/url"
+	"strings"
 	"testing"
 
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
@@ -39,7 +41,23 @@ type fakeNegotiater struct {
 func (n *fakeNegotiater) SupportedMediaTypes() []runtime.SerializerInfo {
 	var out []runtime.SerializerInfo
 	for _, s := range n.types {
-		info := runtime.SerializerInfo{Serializer: n.serializer, MediaType: s, EncodesAsText: true}
+		mediaType, _, err := mime.ParseMediaType(s)
+		if err != nil {
+			panic(err)
+		}
+		parts := strings.SplitN(mediaType, "/", 2)
+		if len(parts) == 1 {
+			// this is an error on the server side
+			parts = append(parts, "")
+		}
+
+		info := runtime.SerializerInfo{
+			Serializer:       n.serializer,
+			MediaType:        s,
+			MediaTypeType:    parts[0],
+			MediaTypeSubType: parts[1],
+			EncodesAsText:    true,
+		}
 		for _, t := range n.streamTypes {
 			if t == s {
 				info.StreamSerializer = &runtime.StreamSerializerInfo{

staging/src/k8s.io/apiserver/pkg/endpoints/handlers/rest.go

@@ -292,7 +292,12 @@ func checkName(obj runtime.Object, name, namespace string, namer ScopeNamer) err
 }
 
 // setObjectSelfLink sets the self link of an object as needed.
+// TODO: remove the need for the namer LinkSetters by requiring objects implement either Object or List
+//   interfaces
 func setObjectSelfLink(ctx context.Context, obj runtime.Object, req *http.Request, namer ScopeNamer) error {
+	// We only generate list links on objects that implement ListInterface - historically we duck typed this
+	// check via reflection, but as we move away from reflection we require that you not only carry Items but
+	// ListMeta into order to be identified as a list.
 	if !meta.IsListType(obj) {
 		requestInfo, ok := request.RequestInfoFrom(ctx)
 		if !ok {

staging/src/k8s.io/apiserver/pkg/endpoints/installer.go

@@ -512,6 +512,11 @@ func (a *APIInstaller) registerResourceHandlers(path string, storage rest.Storag
 	//
 	// test/integration/auth_test.go is currently the most comprehensive status code test
 
+	for _, s := range a.group.Serializer.SupportedMediaTypes() {
+		if len(s.MediaTypeSubType) == 0 || len(s.MediaTypeType) == 0 {
+			return nil, fmt.Errorf("all serializers in the group Serializer must have MediaTypeType and MediaTypeSubType set: %s", s.MediaType)
+		}
+	}
 	mediaTypes, streamMediaTypes := negotiation.MediaTypesForSerializer(a.group.Serializer)
 	allMediaTypes := append(mediaTypes, streamMediaTypes...)
 	ws.Produces(allMediaTypes...)

staging/src/k8s.io/apiserver/pkg/endpoints/metrics/metrics.go

@@ -20,6 +20,7 @@ import (
 	"bufio"
 	"net"
 	"net/http"
+	"net/url"
 	"regexp"
 	"strconv"
 	"strings"
@@ -34,7 +35,7 @@ import (
 	"k8s.io/apiserver/pkg/features"
 	utilfeature "k8s.io/apiserver/pkg/util/feature"
 
-	"github.com/emicklei/go-restful"
+	restful "github.com/emicklei/go-restful"
 	"github.com/prometheus/client_golang/prometheus"
 )
 
@@ -234,7 +235,7 @@ func RecordLongRunning(req *http.Request, requestInfo *request.RequestInfo, comp
 // a request. verb must be uppercase to be backwards compatible with existing monitoring tooling.
 func MonitorRequest(req *http.Request, verb, group, version, resource, subresource, scope, component, contentType string, httpCode, respSize int, elapsed time.Duration) {
 	reportedVerb := cleanVerb(verb, req)
-	dryRun := cleanDryRun(req.URL.Query()["dryRun"])
+	dryRun := cleanDryRun(req.URL)
 	client := cleanUserAgent(utilnet.GetHTTPClient(req))
 	elapsedMicroseconds := float64(elapsed / time.Microsecond)
 	elapsedSeconds := elapsed.Seconds()
@@ -331,12 +332,19 @@ func cleanVerb(verb string, request *http.Request) string {
 	return reportedVerb
 }
 
-func cleanDryRun(dryRun []string) string {
+func cleanDryRun(u *url.URL) string {
+	// avoid allocating when we don't see dryRun in the query
+	if !strings.Contains(u.RawQuery, "dryRun") {
+		return ""
+	}
+	dryRun := u.Query()["dryRun"]
 	if errs := validation.ValidateDryRun(nil, dryRun); len(errs) > 0 {
 		return "invalid"
 	}
 	// Since dryRun could be valid with any arbitrarily long length
 	// we have to dedup and sort the elements before joining them together
+	// TODO: this is a fairly large allocation for what it does, consider
+	//   a sort and dedup in a single pass
 	return strings.Join(utilsets.NewString(dryRun...).List(), ",")
 }
 
@@ -346,7 +354,10 @@ func cleanUserAgent(ua string) string {
 		return "Browser"
 	}
 	// If an old "kubectl.exe" has passed us its full path, we discard the path portion.
-	ua = kubectlExeRegexp.ReplaceAllString(ua, "$1")
+	if kubectlExeRegexp.MatchString(ua) {
+		// avoid an allocation
+		ua = kubectlExeRegexp.ReplaceAllString(ua, "$1")
+	}
 	return ua
 }
 

staging/src/k8s.io/apiserver/pkg/server/storage/storage_factory_test.go

@@ -17,7 +17,9 @@ limitations under the License.
 package storage
 
 import (
+	"mime"
 	"reflect"
+	"strings"
 	"testing"
 
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
@@ -60,7 +62,24 @@ type fakeNegotiater struct {
 func (n *fakeNegotiater) SupportedMediaTypes() []runtime.SerializerInfo {
 	var out []runtime.SerializerInfo
 	for _, s := range n.types {
-		info := runtime.SerializerInfo{Serializer: n.serializer, MediaType: s, EncodesAsText: true}
+		mediaType, _, err := mime.ParseMediaType(s)
+		if err != nil {
+			panic(err)
+		}
+		parts := strings.SplitN(mediaType, "/", 2)
+		if len(parts) == 1 {
+			// this is an error on the server side
+			parts = append(parts, "")
+		}
+
+		info := runtime.SerializerInfo{
+			Serializer:       n.serializer,
+			MediaType:        s,
+			MediaTypeType:    parts[0],
+			MediaTypeSubType: parts[1],
+			EncodesAsText:    true,
+		}
+
 		for _, t := range n.streamTypes {
 			if t == s {
 				info.StreamSerializer = &runtime.StreamSerializerInfo{

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

@@ -43,6 +43,8 @@ func init() {
 
 var watchJsonSerializerInfo = runtime.SerializerInfo{
 	MediaType:        "application/json",
+	MediaTypeType:    "application",
+	MediaTypeSubType: "json",
 	EncodesAsText:    true,
 	Serializer:       json.NewSerializer(json.DefaultMetaFactory, watchScheme, watchScheme, false),
 	PrettySerializer: json.NewSerializer(json.DefaultMetaFactory, watchScheme, watchScheme, true),
@@ -77,6 +79,8 @@ func (s basicNegotiatedSerializer) SupportedMediaTypes() []runtime.SerializerInf
 	return []runtime.SerializerInfo{
 		{
 			MediaType:        "application/json",
+			MediaTypeType:    "application",
+			MediaTypeSubType: "json",
 			EncodesAsText:    true,
 			Serializer:       json.NewSerializer(json.DefaultMetaFactory, basicScheme, basicScheme, false),
 			PrettySerializer: json.NewSerializer(json.DefaultMetaFactory, basicScheme, basicScheme, true),