rebase: bump k8s.io/kubernetes from 1.26.2 to 1.27.2

Bumps [k8s.io/kubernetes](https://github.com/kubernetes/kubernetes) from 1.26.2 to 1.27.2.
- [Release notes](https://github.com/kubernetes/kubernetes/releases)
- [Commits](https://github.com/kubernetes/kubernetes/compare/v1.26.2...v1.27.2)

---
updated-dependencies:
- dependency-name: k8s.io/kubernetes
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

vendor/k8s.io/apiserver/pkg/endpoints/discovery/aggregated/etag.go

@@ -0,0 +1,84 @@
+/*
+Copyright 2022 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package aggregated
+
+import (
+	"crypto/sha512"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"strconv"
+
+	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/apiserver/pkg/endpoints/handlers/responsewriters"
+)
+
+// This file exposes helper functions used for calculating the E-Tag header
+// used in discovery endpoint responses
+
+// Attaches Cache-Busting functionality to an endpoint
+//   - Sets ETag header to provided hash
+//   - Replies with 304 Not Modified, if If-None-Match header matches hash
+//
+// hash should be the value of calculateETag on object. If hash is empty, then
+//
+//	the object is simply serialized without E-Tag functionality
+func ServeHTTPWithETag(
+	object runtime.Object,
+	hash string,
+	serializer runtime.NegotiatedSerializer,
+	w http.ResponseWriter,
+	req *http.Request,
+) {
+	// ETag must be enclosed in double quotes:
+	// https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/ETag
+	quotedHash := strconv.Quote(hash)
+	w.Header().Set("ETag", quotedHash)
+	w.Header().Set("Vary", "Accept")
+	w.Header().Set("Cache-Control", "public")
+
+	// If Request includes If-None-Match and matches hash, reply with 304
+	// Otherwise, we delegate to the handler for actual content
+	//
+	// According to documentation, An Etag within an If-None-Match
+	// header will be enclosed within doule quotes:
+	// https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/If-None-Match#directives
+	if clientCachedHash := req.Header.Get("If-None-Match"); quotedHash == clientCachedHash {
+		w.WriteHeader(http.StatusNotModified)
+		return
+	}
+
+	responsewriters.WriteObjectNegotiated(
+		serializer,
+		DiscoveryEndpointRestrictions,
+		AggregatedDiscoveryGV,
+		w,
+		req,
+		http.StatusOK,
+		object,
+		true,
+	)
+}
+
+func calculateETag(resources interface{}) (string, error) {
+	serialized, err := json.Marshal(resources)
+	if err != nil {
+		return "", err
+	}
+
+	return fmt.Sprintf("%X", sha512.Sum512(serialized)), nil
+}

vendor/k8s.io/apiserver/pkg/endpoints/discovery/aggregated/fake.go

@@ -0,0 +1,171 @@
+/*
+Copyright 2022 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package aggregated
+
+import (
+	"context"
+	"errors"
+	"net/http"
+	"reflect"
+	"sync"
+	"time"
+
+	"github.com/emicklei/go-restful/v3"
+	"github.com/google/go-cmp/cmp"
+	apidiscoveryv2beta1 "k8s.io/api/apidiscovery/v2beta1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/util/wait"
+)
+
+type FakeResourceManager interface {
+	ResourceManager
+	Expect() ResourceManager
+
+	HasExpectedNumberActions() bool
+	Validate() error
+	WaitForActions(ctx context.Context, timeout time.Duration) error
+}
+
+func NewFakeResourceManager() FakeResourceManager {
+	return &fakeResourceManager{}
+}
+
+// a resource manager with helper functions for checking the actions
+// match expected. For Use in tests
+type fakeResourceManager struct {
+	recorderResourceManager
+	expect recorderResourceManager
+}
+
+// a resource manager which instead of managing a discovery document,
+// simply records the calls to its interface functoins for testing
+type recorderResourceManager struct {
+	lock    sync.RWMutex
+	Actions []recorderResourceManagerAction
+}
+
+var _ ResourceManager = &fakeResourceManager{}
+var _ ResourceManager = &recorderResourceManager{}
+
+// Storage type for a call to the resource manager
+type recorderResourceManagerAction struct {
+	Type    string
+	Group   string
+	Version string
+	Value   interface{}
+}
+
+func (f *fakeResourceManager) Expect() ResourceManager {
+	return &f.expect
+}
+
+func (f *fakeResourceManager) HasExpectedNumberActions() bool {
+	f.lock.RLock()
+	defer f.lock.RUnlock()
+
+	f.expect.lock.RLock()
+	defer f.expect.lock.RUnlock()
+
+	return len(f.Actions) >= len(f.expect.Actions)
+}
+
+func (f *fakeResourceManager) Validate() error {
+	f.lock.RLock()
+	defer f.lock.RUnlock()
+
+	f.expect.lock.RLock()
+	defer f.expect.lock.RUnlock()
+
+	if !reflect.DeepEqual(f.expect.Actions, f.Actions) {
+		return errors.New(cmp.Diff(f.expect.Actions, f.Actions))
+	}
+	return nil
+}
+
+func (f *fakeResourceManager) WaitForActions(ctx context.Context, timeout time.Duration) error {
+	err := wait.PollImmediateWithContext(
+		ctx,
+		100*time.Millisecond, // try every 100ms
+		timeout,              // timeout after timeout
+		func(ctx context.Context) (done bool, err error) {
+			if f.HasExpectedNumberActions() {
+				return true, f.Validate()
+			}
+			return false, nil
+		})
+	return err
+}
+
+func (f *recorderResourceManager) SetGroupVersionPriority(gv metav1.GroupVersion, grouppriority, versionpriority int) {
+	f.lock.Lock()
+	defer f.lock.Unlock()
+
+	f.Actions = append(f.Actions, recorderResourceManagerAction{
+		Type:    "SetGroupVersionPriority",
+		Group:   gv.Group,
+		Version: gv.Version,
+		Value:   versionpriority,
+	})
+}
+
+func (f *recorderResourceManager) AddGroupVersion(groupName string, value apidiscoveryv2beta1.APIVersionDiscovery) {
+	f.lock.Lock()
+	defer f.lock.Unlock()
+
+	f.Actions = append(f.Actions, recorderResourceManagerAction{
+		Type:  "AddGroupVersion",
+		Group: groupName,
+		Value: value,
+	})
+}
+func (f *recorderResourceManager) RemoveGroup(groupName string) {
+	f.lock.Lock()
+	defer f.lock.Unlock()
+
+	f.Actions = append(f.Actions, recorderResourceManagerAction{
+		Type:  "RemoveGroup",
+		Group: groupName,
+	})
+
+}
+func (f *recorderResourceManager) RemoveGroupVersion(gv metav1.GroupVersion) {
+	f.lock.Lock()
+	defer f.lock.Unlock()
+
+	f.Actions = append(f.Actions, recorderResourceManagerAction{
+		Type:    "RemoveGroupVersion",
+		Group:   gv.Group,
+		Version: gv.Version,
+	})
+
+}
+func (f *recorderResourceManager) SetGroups(values []apidiscoveryv2beta1.APIGroupDiscovery) {
+	f.lock.Lock()
+	defer f.lock.Unlock()
+
+	f.Actions = append(f.Actions, recorderResourceManagerAction{
+		Type:  "SetGroups",
+		Value: values,
+	})
+}
+func (f *recorderResourceManager) WebService() *restful.WebService {
+	panic("unimplemented")
+}
+
+func (f *recorderResourceManager) ServeHTTP(http.ResponseWriter, *http.Request) {
+	panic("unimplemented")
+}

vendor/k8s.io/apiserver/pkg/endpoints/discovery/aggregated/handler.go

@@ -0,0 +1,368 @@
+/*
+Copyright 2022 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package aggregated
+
+import (
+	"net/http"
+	"reflect"
+	"sort"
+	"sync"
+
+	apidiscoveryv2beta1 "k8s.io/api/apidiscovery/v2beta1"
+	"k8s.io/apimachinery/pkg/runtime/serializer"
+	"k8s.io/apimachinery/pkg/version"
+	"k8s.io/apiserver/pkg/endpoints/handlers/responsewriters"
+
+	"sync/atomic"
+
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/runtime"
+	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
+	"k8s.io/klog/v2"
+)
+
+// This handler serves the /apis endpoint for an aggregated list of
+// api resources indexed by their group version.
+type ResourceManager interface {
+	// Adds knowledge of the given groupversion to the discovery document
+	// If it was already being tracked, updates the stored APIVersionDiscovery
+	// Thread-safe
+	AddGroupVersion(groupName string, value apidiscoveryv2beta1.APIVersionDiscovery)
+
+	// Sets a priority to be used while sorting a specific group and
+	// group-version. If two versions report different priorities for
+	// the group, the higher one will be used. If the group is not
+	// known, the priority is ignored. The priority for this version
+	// is forgotten once the group-version is forgotten
+	SetGroupVersionPriority(gv metav1.GroupVersion, grouppriority, versionpriority int)
+
+	// Removes all group versions for a given group
+	// Thread-safe
+	RemoveGroup(groupName string)
+
+	// Removes a specific groupversion. If all versions of a group have been
+	// removed, then the entire group is unlisted.
+	// Thread-safe
+	RemoveGroupVersion(gv metav1.GroupVersion)
+
+	// Resets the manager's known list of group-versions and replaces them
+	// with the given groups
+	// Thread-Safe
+	SetGroups([]apidiscoveryv2beta1.APIGroupDiscovery)
+
+	http.Handler
+}
+
+type resourceDiscoveryManager struct {
+	serializer runtime.NegotiatedSerializer
+	// cache is an atomic pointer to avoid the use of locks
+	cache atomic.Pointer[cachedGroupList]
+
+	// Writes protected by the lock.
+	// List of all apigroups & resources indexed by the resource manager
+	lock              sync.RWMutex
+	apiGroups         map[string]*apidiscoveryv2beta1.APIGroupDiscovery
+	versionPriorities map[metav1.GroupVersion]priorityInfo
+}
+
+type priorityInfo struct {
+	GroupPriorityMinimum int
+	VersionPriority      int
+}
+
+func NewResourceManager() ResourceManager {
+	scheme := runtime.NewScheme()
+	codecs := serializer.NewCodecFactory(scheme)
+	utilruntime.Must(apidiscoveryv2beta1.AddToScheme(scheme))
+	return &resourceDiscoveryManager{serializer: codecs, versionPriorities: make(map[metav1.GroupVersion]priorityInfo)}
+}
+
+func (rdm *resourceDiscoveryManager) SetGroupVersionPriority(gv metav1.GroupVersion, groupPriorityMinimum, versionPriority int) {
+	rdm.lock.Lock()
+	defer rdm.lock.Unlock()
+
+	rdm.versionPriorities[gv] = priorityInfo{
+		GroupPriorityMinimum: groupPriorityMinimum,
+		VersionPriority:      versionPriority,
+	}
+	rdm.cache.Store(nil)
+}
+
+func (rdm *resourceDiscoveryManager) SetGroups(groups []apidiscoveryv2beta1.APIGroupDiscovery) {
+	rdm.lock.Lock()
+	defer rdm.lock.Unlock()
+
+	rdm.apiGroups = nil
+	rdm.cache.Store(nil)
+
+	for _, group := range groups {
+		for _, version := range group.Versions {
+			rdm.addGroupVersionLocked(group.Name, version)
+		}
+	}
+
+	// Filter unused out priority entries
+	for gv := range rdm.versionPriorities {
+		entry, exists := rdm.apiGroups[gv.Group]
+		if !exists {
+			delete(rdm.versionPriorities, gv)
+			continue
+		}
+
+		containsVersion := false
+
+		for _, v := range entry.Versions {
+			if v.Version == gv.Version {
+				containsVersion = true
+				break
+			}
+		}
+
+		if !containsVersion {
+			delete(rdm.versionPriorities, gv)
+		}
+	}
+}
+
+func (rdm *resourceDiscoveryManager) AddGroupVersion(groupName string, value apidiscoveryv2beta1.APIVersionDiscovery) {
+	rdm.lock.Lock()
+	defer rdm.lock.Unlock()
+
+	rdm.addGroupVersionLocked(groupName, value)
+}
+
+func (rdm *resourceDiscoveryManager) addGroupVersionLocked(groupName string, value apidiscoveryv2beta1.APIVersionDiscovery) {
+	klog.Infof("Adding GroupVersion %s %s to ResourceManager", groupName, value.Version)
+
+	if rdm.apiGroups == nil {
+		rdm.apiGroups = make(map[string]*apidiscoveryv2beta1.APIGroupDiscovery)
+	}
+
+	if existing, groupExists := rdm.apiGroups[groupName]; groupExists {
+		// If this version already exists, replace it
+		versionExists := false
+
+		// Not very efficient, but in practice there are generally not many versions
+		for i := range existing.Versions {
+			if existing.Versions[i].Version == value.Version {
+				// The new gv is the exact same as what is already in
+				// the map. This is a noop and cache should not be
+				// invalidated.
+				if reflect.DeepEqual(existing.Versions[i], value) {
+					return
+				}
+				existing.Versions[i] = value
+				versionExists = true
+				break
+			}
+		}
+
+		if !versionExists {
+			existing.Versions = append(existing.Versions, value)
+		}
+
+	} else {
+		group := &apidiscoveryv2beta1.APIGroupDiscovery{
+			ObjectMeta: metav1.ObjectMeta{
+				Name: groupName,
+			},
+			Versions: []apidiscoveryv2beta1.APIVersionDiscovery{value},
+		}
+		rdm.apiGroups[groupName] = group
+	}
+
+	gv := metav1.GroupVersion{Group: groupName, Version: value.Version}
+	if _, ok := rdm.versionPriorities[gv]; !ok {
+		rdm.versionPriorities[gv] = priorityInfo{
+			GroupPriorityMinimum: 1000,
+			VersionPriority:      15,
+		}
+	}
+
+	// Reset response document so it is recreated lazily
+	rdm.cache.Store(nil)
+}
+
+func (rdm *resourceDiscoveryManager) RemoveGroupVersion(apiGroup metav1.GroupVersion) {
+	rdm.lock.Lock()
+	defer rdm.lock.Unlock()
+	group, exists := rdm.apiGroups[apiGroup.Group]
+	if !exists {
+		return
+	}
+
+	modified := false
+	for i := range group.Versions {
+		if group.Versions[i].Version == apiGroup.Version {
+			group.Versions = append(group.Versions[:i], group.Versions[i+1:]...)
+			modified = true
+			break
+		}
+	}
+	// If no modification was done, cache does not need to be cleared
+	if !modified {
+		return
+	}
+
+	delete(rdm.versionPriorities, apiGroup)
+	if len(group.Versions) == 0 {
+		delete(rdm.apiGroups, group.Name)
+	}
+
+	// Reset response document so it is recreated lazily
+	rdm.cache.Store(nil)
+}
+
+func (rdm *resourceDiscoveryManager) RemoveGroup(groupName string) {
+	rdm.lock.Lock()
+	defer rdm.lock.Unlock()
+
+	delete(rdm.apiGroups, groupName)
+
+	for k := range rdm.versionPriorities {
+		if k.Group == groupName {
+			delete(rdm.versionPriorities, k)
+		}
+	}
+
+	// Reset response document so it is recreated lazily
+	rdm.cache.Store(nil)
+}
+
+// Prepares the api group list for serving by converting them from map into
+// list and sorting them according to insertion order
+func (rdm *resourceDiscoveryManager) calculateAPIGroupsLocked() []apidiscoveryv2beta1.APIGroupDiscovery {
+	// Re-order the apiGroups by their priority.
+	groups := []apidiscoveryv2beta1.APIGroupDiscovery{}
+	for _, group := range rdm.apiGroups {
+		copied := *group.DeepCopy()
+
+		// Re-order versions based on their priority. Use kube-aware string
+		// comparison as a tie breaker
+		sort.SliceStable(copied.Versions, func(i, j int) bool {
+			iVersion := copied.Versions[i].Version
+			jVersion := copied.Versions[j].Version
+
+			iPriority := rdm.versionPriorities[metav1.GroupVersion{Group: group.Name, Version: iVersion}].VersionPriority
+			jPriority := rdm.versionPriorities[metav1.GroupVersion{Group: group.Name, Version: jVersion}].VersionPriority
+
+			// Sort by version string comparator if priority is equal
+			if iPriority == jPriority {
+				return version.CompareKubeAwareVersionStrings(iVersion, jVersion) > 0
+			}
+
+			// i sorts before j if it has a higher priority
+			return iPriority > jPriority
+		})
+
+		groups = append(groups, *copied.DeepCopy())
+
+	}
+
+	// For each group, determine the highest minimum group priority and use that
+	priorities := map[string]int{}
+	for gv, info := range rdm.versionPriorities {
+		if existing, exists := priorities[gv.Group]; exists {
+			if existing < info.GroupPriorityMinimum {
+				priorities[gv.Group] = info.GroupPriorityMinimum
+			}
+		} else {
+			priorities[gv.Group] = info.GroupPriorityMinimum
+		}
+	}
+
+	sort.SliceStable(groups, func(i, j int) bool {
+		iName := groups[i].Name
+		jName := groups[j].Name
+
+		// Default to 0 priority by default
+		iPriority := priorities[iName]
+		jPriority := priorities[jName]
+
+		// Sort discovery based on apiservice priority.
+		// Duplicated from staging/src/k8s.io/kube-aggregator/pkg/apis/apiregistration/v1/helpers.go
+		if iPriority == jPriority {
+			// Equal priority uses name to break ties
+			return iName < jName
+		}
+
+		// i sorts before j if it has a higher priority
+		return iPriority > jPriority
+	})
+
+	return groups
+}
+
+// Fetches from cache if it exists. If cache is empty, create it.
+func (rdm *resourceDiscoveryManager) fetchFromCache() *cachedGroupList {
+	rdm.lock.RLock()
+	defer rdm.lock.RUnlock()
+
+	cacheLoad := rdm.cache.Load()
+	if cacheLoad != nil {
+		return cacheLoad
+	}
+	response := apidiscoveryv2beta1.APIGroupDiscoveryList{
+		Items: rdm.calculateAPIGroupsLocked(),
+	}
+	etag, err := calculateETag(response)
+	if err != nil {
+		klog.Errorf("failed to calculate etag for discovery document: %s", etag)
+		etag = ""
+	}
+	cached := &cachedGroupList{
+		cachedResponse:     response,
+		cachedResponseETag: etag,
+	}
+	rdm.cache.Store(cached)
+	return cached
+}
+
+type cachedGroupList struct {
+	cachedResponse     apidiscoveryv2beta1.APIGroupDiscoveryList
+	cachedResponseETag string
+}
+
+func (rdm *resourceDiscoveryManager) ServeHTTP(resp http.ResponseWriter, req *http.Request) {
+	cache := rdm.fetchFromCache()
+	response := cache.cachedResponse
+	etag := cache.cachedResponseETag
+
+	if len(etag) > 0 {
+		// Use proper e-tag headers if one is available
+		ServeHTTPWithETag(
+			&response,
+			etag,
+			rdm.serializer,
+			resp,
+			req,
+		)
+	} else {
+		// Default to normal response in rare case etag is
+		// not cached with the object for some reason.
+		responsewriters.WriteObjectNegotiated(
+			rdm.serializer,
+			DiscoveryEndpointRestrictions,
+			AggregatedDiscoveryGV,
+			resp,
+			req,
+			http.StatusOK,
+			&response,
+			true,
+		)
+	}
+}

vendor/k8s.io/apiserver/pkg/endpoints/discovery/aggregated/negotiation.go

@@ -0,0 +1,45 @@
+/*
+Copyright 2022 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package aggregated
+
+import (
+	"k8s.io/apimachinery/pkg/runtime/schema"
+)
+
+var AggregatedDiscoveryGV = schema.GroupVersion{Group: "apidiscovery.k8s.io", Version: "v2beta1"}
+
+// Interface is from "k8s.io/apiserver/pkg/endpoints/handlers/negotiation"
+
+// DiscoveryEndpointRestrictions allows requests to /apis to provide a Content Negotiation GVK for aggregated discovery.
+var DiscoveryEndpointRestrictions = discoveryEndpointRestrictions{}
+
+type discoveryEndpointRestrictions struct{}
+
+func (discoveryEndpointRestrictions) AllowsMediaTypeTransform(mimeType string, mimeSubType string, gvk *schema.GroupVersionKind) bool {
+	return IsAggregatedDiscoveryGVK(gvk)
+}
+
+func (discoveryEndpointRestrictions) AllowsServerVersion(string) bool  { return false }
+func (discoveryEndpointRestrictions) AllowsStreamSchema(s string) bool { return s == "watch" }
+
+// IsAggregatedDiscoveryGVK checks if a provided GVK is the GVK for serving aggregated discovery.
+func IsAggregatedDiscoveryGVK(gvk *schema.GroupVersionKind) bool {
+	if gvk != nil {
+		return gvk.Group == "apidiscovery.k8s.io" && gvk.Version == "v2beta1" && gvk.Kind == "APIGroupDiscoveryList"
+	}
+	return false
+}

vendor/k8s.io/apiserver/pkg/endpoints/discovery/aggregated/wrapper.go

@@ -0,0 +1,78 @@
+/*
+Copyright 2022 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package aggregated
+
+import (
+	"net/http"
+
+	apidiscoveryv2beta1 "k8s.io/api/apidiscovery/v2beta1"
+	"k8s.io/apimachinery/pkg/runtime/serializer"
+
+	"github.com/emicklei/go-restful/v3"
+	"k8s.io/apimachinery/pkg/runtime"
+
+	"k8s.io/apiserver/pkg/endpoints/handlers/negotiation"
+	genericfeatures "k8s.io/apiserver/pkg/features"
+	utilfeature "k8s.io/apiserver/pkg/util/feature"
+)
+
+type WrappedHandler struct {
+	s          runtime.NegotiatedSerializer
+	handler    http.Handler
+	aggHandler http.Handler
+}
+
+func (wrapped *WrappedHandler) ServeHTTP(resp http.ResponseWriter, req *http.Request) {
+	if utilfeature.DefaultFeatureGate.Enabled(genericfeatures.AggregatedDiscoveryEndpoint) {
+		mediaType, _ := negotiation.NegotiateMediaTypeOptions(req.Header.Get("Accept"), wrapped.s.SupportedMediaTypes(), DiscoveryEndpointRestrictions)
+		// mediaType.Convert looks at the request accept headers and is used to control whether the discovery document will be aggregated.
+		if IsAggregatedDiscoveryGVK(mediaType.Convert) {
+			wrapped.aggHandler.ServeHTTP(resp, req)
+			return
+		}
+	}
+	wrapped.handler.ServeHTTP(resp, req)
+}
+
+func (wrapped *WrappedHandler) restfulHandle(req *restful.Request, resp *restful.Response) {
+	wrapped.ServeHTTP(resp.ResponseWriter, req.Request)
+}
+
+func (wrapped *WrappedHandler) GenerateWebService(prefix string, returnType interface{}) *restful.WebService {
+	mediaTypes, _ := negotiation.MediaTypesForSerializer(wrapped.s)
+	ws := new(restful.WebService)
+	ws.Path(prefix)
+	ws.Doc("get available API versions")
+	ws.Route(ws.GET("/").To(wrapped.restfulHandle).
+		Doc("get available API versions").
+		Operation("getAPIVersions").
+		Produces(mediaTypes...).
+		Consumes(mediaTypes...).
+		Writes(returnType))
+	return ws
+}
+
+// WrapAggregatedDiscoveryToHandler wraps a handler with an option to
+// emit the aggregated discovery by passing in the aggregated
+// discovery type in content negotiation headers: eg: (Accept:
+// application/json;v=v2beta1;g=apidiscovery.k8s.io;as=APIGroupDiscoveryList)
+func WrapAggregatedDiscoveryToHandler(handler http.Handler, aggHandler http.Handler) *WrappedHandler {
+	scheme := runtime.NewScheme()
+	apidiscoveryv2beta1.AddToScheme(scheme)
+	codecs := serializer.NewCodecFactory(scheme)
+	return &WrappedHandler{codecs, handler, aggHandler}
+}