Merge pull request #2366 from ikaven1024/feature-proxy

add proxy skeleton

cmd/karmada-search/app/options/options.go

@@ -4,13 +4,18 @@ import (
 	"context"
 	"fmt"
 	"net"
+	"net/http"
+	"path"
 
 	"github.com/spf13/pflag"
 	"k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/apimachinery/pkg/runtime/schema"
+	"k8s.io/apimachinery/pkg/util/sets"
 	"k8s.io/apiserver/pkg/endpoints/openapi"
+	"k8s.io/apiserver/pkg/endpoints/request"
 	"k8s.io/apiserver/pkg/features"
 	genericapiserver "k8s.io/apiserver/pkg/server"
+	genericfilters "k8s.io/apiserver/pkg/server/filters"
 	genericoptions "k8s.io/apiserver/pkg/server/options"
 	utilfeature "k8s.io/apiserver/pkg/util/feature"
 	"k8s.io/klog/v2"
@@ -18,9 +23,14 @@ import (
 
 	searchscheme "github.com/karmada-io/karmada/pkg/apis/search/scheme"
 	searchv1alpha1 "github.com/karmada-io/karmada/pkg/apis/search/v1alpha1"
+	karmadaclientset "github.com/karmada-io/karmada/pkg/generated/clientset/versioned"
+	informerfactory "github.com/karmada-io/karmada/pkg/generated/informers/externalversions"
 	generatedopenapi "github.com/karmada-io/karmada/pkg/generated/openapi"
 	"github.com/karmada-io/karmada/pkg/search"
+	"github.com/karmada-io/karmada/pkg/search/proxy"
 	"github.com/karmada-io/karmada/pkg/sharedcli/profileflag"
+	"github.com/karmada-io/karmada/pkg/util/fedinformer/genericmanager"
+	"github.com/karmada-io/karmada/pkg/util/lifted"
 	"github.com/karmada-io/karmada/pkg/version"
 )
 
@@ -89,12 +99,23 @@ func (o *Options) Run(ctx context.Context) error {
 		return nil
 	})
 
+	server.GenericAPIServer.AddPostStartHookOrDie("start-karmada-informers", func(context genericapiserver.PostStartHookContext) error {
+		config.KarmadaSharedInformerFactory.Start(context.StopCh)
+		return nil
+	})
+
 	server.GenericAPIServer.AddPostStartHookOrDie("start-karmada-search-controller", func(context genericapiserver.PostStartHookContext) error {
 		// start ResourceRegistry controller
 		config.Controller.Start(context.StopCh)
 		return nil
 	})
 
+	server.GenericAPIServer.AddPostStartHookOrDie("start-karmada-proxy-controller", func(context genericapiserver.PostStartHookContext) error {
+		// start ResourceRegistry controller
+		config.ProxyController.Start(context.StopCh)
+		return nil
+	})
+
 	return server.GenericAPIServer.PrepareRun().Run(ctx.Done())
 }
 
@@ -108,6 +129,9 @@ func (o *Options) Config() (*search.Config, error) {
 	o.RecommendedOptions.Features = &genericoptions.FeatureOptions{EnableProfiling: false}
 
 	serverConfig := genericapiserver.NewRecommendedConfig(searchscheme.Codecs)
+	serverConfig.LongRunningFunc = customLongRunningRequestCheck(
+		sets.NewString("watch", "proxy"),
+		sets.NewString("attach", "exec", "proxy", "log", "portforward"))
 	serverConfig.OpenAPIConfig = genericapiserver.DefaultOpenAPIConfig(generatedopenapi.GetOpenAPIDefinitions, openapi.NewDefinitionNamer(searchscheme.Scheme))
 	serverConfig.OpenAPIConfig.Info.Title = "karmada-search"
 	if err := o.RecommendedOptions.ApplyTo(serverConfig); err != nil {
@@ -121,9 +145,31 @@ func (o *Options) Config() (*search.Config, error) {
 		return nil, err
 	}
 
+	karmadaClient := karmadaclientset.NewForConfigOrDie(serverConfig.ClientConfig)
+	factory := informerfactory.NewSharedInformerFactory(karmadaClient, 0)
+
+	proxyCtl, err := proxy.NewController(serverConfig.ClientConfig, genericmanager.GetInstance(), serverConfig.SharedInformerFactory, factory)
+	if err != nil {
+		return nil, err
+	}
+
 	config := &search.Config{
-		GenericConfig: serverConfig,
-		Controller:    ctl,
+		GenericConfig:                serverConfig,
+		Controller:                   ctl,
+		ProxyController:              proxyCtl,
+		KarmadaSharedInformerFactory: factory,
 	}
 	return config, nil
 }
+
+func customLongRunningRequestCheck(longRunningVerbs, longRunningSubresources sets.String) request.LongRunningRequestCheck {
+	return func(r *http.Request, requestInfo *request.RequestInfo) bool {
+		if requestInfo.APIGroup == "search.karmada.io" && requestInfo.Resource == "proxying" {
+			reqClone := r.Clone(context.TODO())
+			// requestInfo.Parts is like [proxying foo proxy api v1 nodes]
+			reqClone.URL.Path = "/" + path.Join(requestInfo.Parts[3:]...)
+			requestInfo = lifted.NewRequestInfo(reqClone)
+		}
+		return genericfilters.BasicLongRunningRequestCheck(longRunningVerbs, longRunningSubresources)(r, requestInfo)
+	}
+}

pkg/apis/search/register.go

@@ -34,6 +34,7 @@ func addKnownTypes(scheme *runtime.Scheme) error {
 		&ResourceRegistry{},
 		&ResourceRegistryList{},
 		&Search{},
+		&Proxying{},
 	)
 	return nil
 }

pkg/apis/search/searchregistry_types.go

@@ -105,3 +105,10 @@ type ResourceRegistryList struct {
 type Search struct {
 	metav1.TypeMeta
 }
+
+// +k8s:deepcopy-gen:interfaces=k8s.io/apimachinery/pkg/runtime.Object
+
+// Proxying define a flag for resource proxying that do not have actual resources.
+type Proxying struct {
+	metav1.TypeMeta
+}

pkg/apis/search/v1alpha1/searchregistry_types.go

@@ -118,3 +118,10 @@ type ResourceRegistryList struct {
 type Search struct {
 	metav1.TypeMeta `json:",inline"`
 }
+
+// +k8s:deepcopy-gen:interfaces=k8s.io/apimachinery/pkg/runtime.Object
+
+// Proxying define a flag for resource proxying that do not have actual resources.
+type Proxying struct {
+	metav1.TypeMeta `json:",inline"`
+}

pkg/apis/search/v1alpha1/zz_generated.conversion.go

@@ -41,6 +41,16 @@ func RegisterConversions(s *runtime.Scheme) error {
 	}); err != nil {
 		return err
 	}
+	if err := s.AddGeneratedConversionFunc((*Proxying)(nil), (*search.Proxying)(nil), func(a, b interface{}, scope conversion.Scope) error {
+		return Convert_v1alpha1_Proxying_To_search_Proxying(a.(*Proxying), b.(*search.Proxying), scope)
+	}); err != nil {
+		return err
+	}
+	if err := s.AddGeneratedConversionFunc((*search.Proxying)(nil), (*Proxying)(nil), func(a, b interface{}, scope conversion.Scope) error {
+		return Convert_search_Proxying_To_v1alpha1_Proxying(a.(*search.Proxying), b.(*Proxying), scope)
+	}); err != nil {
+		return err
+	}
 	if err := s.AddGeneratedConversionFunc((*ResourceRegistry)(nil), (*search.ResourceRegistry)(nil), func(a, b interface{}, scope conversion.Scope) error {
 		return Convert_v1alpha1_ResourceRegistry_To_search_ResourceRegistry(a.(*ResourceRegistry), b.(*search.ResourceRegistry), scope)
 	}); err != nil {
@@ -146,6 +156,24 @@ func Convert_search_OpenSearchConfig_To_v1alpha1_OpenSearchConfig(in *search.Ope
 	return autoConvert_search_OpenSearchConfig_To_v1alpha1_OpenSearchConfig(in, out, s)
 }
 
+func autoConvert_v1alpha1_Proxying_To_search_Proxying(in *Proxying, out *search.Proxying, s conversion.Scope) error {
+	return nil
+}
+
+// Convert_v1alpha1_Proxying_To_search_Proxying is an autogenerated conversion function.
+func Convert_v1alpha1_Proxying_To_search_Proxying(in *Proxying, out *search.Proxying, s conversion.Scope) error {
+	return autoConvert_v1alpha1_Proxying_To_search_Proxying(in, out, s)
+}
+
+func autoConvert_search_Proxying_To_v1alpha1_Proxying(in *search.Proxying, out *Proxying, s conversion.Scope) error {
+	return nil
+}
+
+// Convert_search_Proxying_To_v1alpha1_Proxying is an autogenerated conversion function.
+func Convert_search_Proxying_To_v1alpha1_Proxying(in *search.Proxying, out *Proxying, s conversion.Scope) error {
+	return autoConvert_search_Proxying_To_v1alpha1_Proxying(in, out, s)
+}
+
 func autoConvert_v1alpha1_ResourceRegistry_To_search_ResourceRegistry(in *ResourceRegistry, out *search.ResourceRegistry, s conversion.Scope) error {
 	out.ObjectMeta = in.ObjectMeta
 	if err := Convert_v1alpha1_ResourceRegistrySpec_To_search_ResourceRegistrySpec(&in.Spec, &out.Spec, s); err != nil {

pkg/apis/search/v1alpha1/zz_generated.deepcopy.go

@@ -53,6 +53,31 @@ func (in *OpenSearchConfig) DeepCopy() *OpenSearchConfig {
 	return out
 }
 
+// DeepCopyInto is an autogenerated deepcopy function, copying the receiver, writing into out. in must be non-nil.
+func (in *Proxying) DeepCopyInto(out *Proxying) {
+	*out = *in
+	out.TypeMeta = in.TypeMeta
+	return
+}
+
+// DeepCopy is an autogenerated deepcopy function, copying the receiver, creating a new Proxying.
+func (in *Proxying) DeepCopy() *Proxying {
+	if in == nil {
+		return nil
+	}
+	out := new(Proxying)
+	in.DeepCopyInto(out)
+	return out
+}
+
+// DeepCopyObject is an autogenerated deepcopy function, copying the receiver, creating a new runtime.Object.
+func (in *Proxying) DeepCopyObject() runtime.Object {
+	if c := in.DeepCopy(); c != nil {
+		return c
+	}
+	return nil
+}
+
 // DeepCopyInto is an autogenerated deepcopy function, copying the receiver, writing into out. in must be non-nil.
 func (in *ResourceRegistry) DeepCopyInto(out *ResourceRegistry) {
 	*out = *in

pkg/apis/search/v1alpha1/zz_generated.register.go

@@ -42,6 +42,7 @@ func init() {
 // Adds the list of known types to Scheme.
 func addKnownTypes(scheme *runtime.Scheme) error {
 	scheme.AddKnownTypes(SchemeGroupVersion,
+		&Proxying{},
 		&ResourceRegistry{},
 		&ResourceRegistryList{},
 		&Search{},

pkg/apis/search/zz_generated.deepcopy.go

@@ -53,6 +53,31 @@ func (in *OpenSearchConfig) DeepCopy() *OpenSearchConfig {
 	return out
 }
 
+// DeepCopyInto is an autogenerated deepcopy function, copying the receiver, writing into out. in must be non-nil.
+func (in *Proxying) DeepCopyInto(out *Proxying) {
+	*out = *in
+	out.TypeMeta = in.TypeMeta
+	return
+}
+
+// DeepCopy is an autogenerated deepcopy function, copying the receiver, creating a new Proxying.
+func (in *Proxying) DeepCopy() *Proxying {
+	if in == nil {
+		return nil
+	}
+	out := new(Proxying)
+	in.DeepCopyInto(out)
+	return out
+}
+
+// DeepCopyObject is an autogenerated deepcopy function, copying the receiver, creating a new runtime.Object.
+func (in *Proxying) DeepCopyObject() runtime.Object {
+	if c := in.DeepCopy(); c != nil {
+		return c
+	}
+	return nil
+}
+
 // DeepCopyInto is an autogenerated deepcopy function, copying the receiver, writing into out. in must be non-nil.
 func (in *ResourceRegistry) DeepCopyInto(out *ResourceRegistry) {
 	*out = *in

pkg/generated/openapi/zz_generated.openapi.go

@@ -71,6 +71,7 @@ func GetOpenAPIDefinitions(ref common.ReferenceCallback) map[string]common.OpenA
 		"github.com/karmada-io/karmada/pkg/apis/policy/v1alpha1.StaticClusterWeight":                         schema_pkg_apis_policy_v1alpha1_StaticClusterWeight(ref),
 		"github.com/karmada-io/karmada/pkg/apis/search/v1alpha1.BackendStoreConfig":                          schema_pkg_apis_search_v1alpha1_BackendStoreConfig(ref),
 		"github.com/karmada-io/karmada/pkg/apis/search/v1alpha1.OpenSearchConfig":                            schema_pkg_apis_search_v1alpha1_OpenSearchConfig(ref),
+		"github.com/karmada-io/karmada/pkg/apis/search/v1alpha1.Proxying":                                    schema_pkg_apis_search_v1alpha1_Proxying(ref),
 		"github.com/karmada-io/karmada/pkg/apis/search/v1alpha1.ResourceRegistry":                            schema_pkg_apis_search_v1alpha1_ResourceRegistry(ref),
 		"github.com/karmada-io/karmada/pkg/apis/search/v1alpha1.ResourceRegistryList":                        schema_pkg_apis_search_v1alpha1_ResourceRegistryList(ref),
 		"github.com/karmada-io/karmada/pkg/apis/search/v1alpha1.ResourceRegistrySpec":                        schema_pkg_apis_search_v1alpha1_ResourceRegistrySpec(ref),
@@ -3063,6 +3064,33 @@ func schema_pkg_apis_search_v1alpha1_OpenSearchConfig(ref common.ReferenceCallba
 	}
 }
 
+func schema_pkg_apis_search_v1alpha1_Proxying(ref common.ReferenceCallback) common.OpenAPIDefinition {
+	return common.OpenAPIDefinition{
+		Schema: spec.Schema{
+			SchemaProps: spec.SchemaProps{
+				Description: "Proxying define a flag for resource proxying that do not have actual resources.",
+				Type:        []string{"object"},
+				Properties: map[string]spec.Schema{
+					"kind": {
+						SchemaProps: spec.SchemaProps{
+							Description: "Kind is a string value representing the REST resource this object represents. Servers may infer this from the endpoint the client submits requests to. Cannot be updated. In CamelCase. More info: https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#types-kinds",
+							Type:        []string{"string"},
+							Format:      "",
+						},
+					},
+					"apiVersion": {
+						SchemaProps: spec.SchemaProps{
+							Description: "APIVersion defines the versioned schema of this representation of an object. Servers should convert recognized schemas to the latest internal value, and may reject unrecognized values. More info: https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md#resources",
+							Type:        []string{"string"},
+							Format:      "",
+						},
+					},
+				},
+			},
+		},
+	}
+}
+
 func schema_pkg_apis_search_v1alpha1_ResourceRegistry(ref common.ReferenceCallback) common.OpenAPIDefinition {
 	return common.OpenAPIDefinition{
 		Schema: spec.Schema{

pkg/registry/search/storage/proxy.go

@@ -0,0 +1,72 @@
+package storage
+
+import (
+	"context"
+	"fmt"
+	"net/http"
+	"path"
+
+	"k8s.io/apimachinery/pkg/runtime"
+	genericrequest "k8s.io/apiserver/pkg/endpoints/request"
+	"k8s.io/apiserver/pkg/registry/rest"
+	"k8s.io/klog/v2"
+
+	searchapis "github.com/karmada-io/karmada/pkg/apis/search"
+	"github.com/karmada-io/karmada/pkg/search/proxy"
+)
+
+var proxyMethods = []string{"GET", "POST", "PUT", "PATCH", "DELETE", "HEAD", "OPTIONS"}
+
+// ProxyingREST implements a RESTStorage for proxying resource.
+type ProxyingREST struct {
+	ctl *proxy.Controller
+}
+
+var _ rest.Scoper = &ProxyingREST{}
+var _ rest.Storage = &ProxyingREST{}
+var _ rest.Connecter = &ProxyingREST{}
+
+// NewProxyingREST returns a RESTStorage object that will work against search.
+func NewProxyingREST(ctl *proxy.Controller) *ProxyingREST {
+	return &ProxyingREST{
+		ctl: ctl,
+	}
+}
+
+// New return empty Proxy object.
+func (r *ProxyingREST) New() runtime.Object {
+	return &searchapis.Proxying{}
+}
+
+// NamespaceScoped returns false because Proxy is not namespaced.
+func (r *ProxyingREST) NamespaceScoped() bool {
+	return false
+}
+
+// ConnectMethods returns the list of HTTP methods handled by Connect.
+func (r *ProxyingREST) ConnectMethods() []string {
+	return proxyMethods
+}
+
+// NewConnectOptions returns an empty options object that will be used to pass options to the Connect method.
+func (r *ProxyingREST) NewConnectOptions() (runtime.Object, bool, string) {
+	return nil, true, ""
+}
+
+// Connect returns a handler for proxy.
+func (r *ProxyingREST) Connect(ctx context.Context, _ string, _ runtime.Object, responder rest.Responder) (http.Handler, error) {
+	info, ok := genericrequest.RequestInfoFrom(ctx)
+	if !ok {
+		return nil, fmt.Errorf("no RequestInfo found in the context")
+	}
+
+	if len(info.Parts) < 2 {
+		return nil, fmt.Errorf("invalid requestInfo parts: %v", info.Parts)
+	}
+
+	// For example, the whole request URL is /apis/search.karmada.io/v1alpha1/proxying/foo/proxy/api/v1/nodes
+	// info.Parts is [proxying foo proxy api v1 nodes], so proxyPath is /api/v1/nodes
+	proxyPath := "/" + path.Join(info.Parts[3:]...)
+	klog.V(4).Infof("ProxyingREST connect %v", proxyPath)
+	return r.ctl.Connect(ctx, proxyPath, responder)
+}

pkg/search/apiserver.go

@@ -8,23 +8,28 @@ import (
 
 	searchapis "github.com/karmada-io/karmada/pkg/apis/search"
 	searchscheme "github.com/karmada-io/karmada/pkg/apis/search/scheme"
+	informerfactory "github.com/karmada-io/karmada/pkg/generated/informers/externalversions"
 	clusterlister "github.com/karmada-io/karmada/pkg/generated/listers/cluster/v1alpha1"
 	searchstorage "github.com/karmada-io/karmada/pkg/registry/search/storage"
+	"github.com/karmada-io/karmada/pkg/search/proxy"
 	"github.com/karmada-io/karmada/pkg/util/fedinformer/genericmanager"
 )
 
 // ExtraConfig holds custom apiserver config
 type ExtraConfig struct {
-	MultiClusterInformerManager genericmanager.MultiClusterInformerManager
-	ClusterLister               clusterlister.ClusterLister
-
+	MultiClusterInformerManager  genericmanager.MultiClusterInformerManager
+	ClusterLister                clusterlister.ClusterLister
+	KarmadaSharedInformerFactory informerfactory.SharedInformerFactory
+	ProxyController              *proxy.Controller
 	// Add custom config if necessary.
 }
 
 // Config defines the config for the APIServer.
 type Config struct {
-	GenericConfig *genericapiserver.RecommendedConfig
-	Controller    *Controller
+	GenericConfig                *genericapiserver.RecommendedConfig
+	Controller                   *Controller
+	ProxyController              *proxy.Controller
+	KarmadaSharedInformerFactory informerfactory.SharedInformerFactory
 }
 
 // APIServer contains state for karmada-search.
@@ -47,8 +52,10 @@ func (cfg *Config) Complete() CompletedConfig {
 	c := completedConfig{
 		cfg.GenericConfig.Complete(),
 		&ExtraConfig{
-			MultiClusterInformerManager: cfg.Controller.InformerManager,
-			ClusterLister:               cfg.Controller.clusterLister,
+			MultiClusterInformerManager:  cfg.Controller.InformerManager,
+			ClusterLister:                cfg.Controller.clusterLister,
+			KarmadaSharedInformerFactory: cfg.KarmadaSharedInformerFactory,
+			ProxyController:              cfg.ProxyController,
 		},
 	}
 
@@ -78,11 +85,13 @@ func (c completedConfig) New() (*APIServer, error) {
 		return nil, err
 	}
 	searchREST := searchstorage.NewSearchREST(c.ExtraConfig.MultiClusterInformerManager, c.ExtraConfig.ClusterLister)
+	proxyingREST := searchstorage.NewProxyingREST(c.ExtraConfig.ProxyController)
 
 	v1alpha1search := map[string]rest.Storage{}
 	v1alpha1search["resourceregistries"] = resourceRegistryStorage.ResourceRegistry
 	v1alpha1search["resourceregistries/status"] = resourceRegistryStorage.Status
 	v1alpha1search["search"] = searchREST
+	v1alpha1search["proxying"] = proxyingREST
 	apiGroupInfo.VersionedResourcesStorageMap["v1alpha1"] = v1alpha1search
 
 	if err = server.GenericAPIServer.InstallAPIGroup(&apiGroupInfo); err != nil {

pkg/search/proxy/cache_proxy.go

@@ -0,0 +1,22 @@
+package proxy
+
+import (
+	"context"
+	"net/http"
+
+	"github.com/karmada-io/karmada/pkg/search/proxy/store"
+)
+
+type cacheProxy struct {
+	store *store.MultiClusterCache
+}
+
+func (p *cacheProxy) connect(ctx context.Context) http.Handler {
+	return nil
+}
+
+func newCacheProxy(store *store.MultiClusterCache) *cacheProxy {
+	return &cacheProxy{
+		store: store,
+	}
+}

pkg/search/proxy/cluster_proxy.go

@@ -0,0 +1,42 @@
+package proxy
+
+import (
+	"context"
+	"fmt"
+	"net/http"
+	"path"
+
+	corev1 "k8s.io/api/core/v1"
+	"k8s.io/apiserver/pkg/registry/rest"
+	listcorev1 "k8s.io/client-go/listers/core/v1"
+
+	"github.com/karmada-io/karmada/pkg/apis/cluster/v1alpha1"
+	"github.com/karmada-io/karmada/pkg/util/proxy"
+)
+
+// clusterProxy proxy to member clusters
+type clusterProxy struct {
+	secretLister listcorev1.SecretLister
+}
+
+func newClusterProxy(secretLister listcorev1.SecretLister) *clusterProxy {
+	return &clusterProxy{
+		secretLister: secretLister,
+	}
+}
+
+func (c *clusterProxy) connect(ctx context.Context, cluster *v1alpha1.Cluster, proxyPath string, responder rest.Responder) (http.Handler, error) {
+	location, transport, err := proxy.Location(cluster.Name, cluster.Spec.APIEndpoint, cluster.Spec.ProxyURL)
+	if err != nil {
+		return nil, err
+	}
+	location.Path = path.Join(location.Path, proxyPath)
+
+	secretGetter := func(context.Context, string) (*corev1.Secret, error) {
+		if cluster.Spec.ImpersonatorSecretRef == nil {
+			return nil, fmt.Errorf("the impersonatorSecretRef of cluster %s is nil", cluster.Name)
+		}
+		return c.secretLister.Secrets(cluster.Spec.ImpersonatorSecretRef.Namespace).Get(cluster.Spec.ImpersonatorSecretRef.Name)
+	}
+	return proxy.ConnectCluster(ctx, cluster.Name, location, transport, responder, secretGetter)
+}

pkg/search/proxy/controller.go

@@ -0,0 +1,150 @@
+package proxy
+
+import (
+	"context"
+	"net/http"
+
+	"k8s.io/apimachinery/pkg/runtime/schema"
+	"k8s.io/apiserver/pkg/endpoints/request"
+	"k8s.io/apiserver/pkg/registry/rest"
+	"k8s.io/client-go/informers"
+	restclient "k8s.io/client-go/rest"
+	"k8s.io/client-go/tools/cache"
+
+	informerfactory "github.com/karmada-io/karmada/pkg/generated/informers/externalversions"
+	clusterlisters "github.com/karmada-io/karmada/pkg/generated/listers/cluster/v1alpha1"
+	searchlisters "github.com/karmada-io/karmada/pkg/generated/listers/search/v1alpha1"
+	"github.com/karmada-io/karmada/pkg/search/proxy/store"
+	"github.com/karmada-io/karmada/pkg/util"
+	"github.com/karmada-io/karmada/pkg/util/fedinformer/genericmanager"
+	"github.com/karmada-io/karmada/pkg/util/lifted"
+)
+
+const workKey = "key"
+
+// Controller syncs Cluster and GlobalResource.
+type Controller struct {
+	clusterLister   clusterlisters.ClusterLister
+	registryLister  searchlisters.ResourceRegistryLister
+	worker          util.AsyncWorker
+	informerManager genericmanager.MultiClusterInformerManager
+	store           *store.MultiClusterCache
+
+	// proxy
+	karmadaProxy *karmadaProxy
+	clusterProxy *clusterProxy
+	cacheProxy   *cacheProxy
+}
+
+// NewController create a controller for proxy
+func NewController(restConfig *restclient.Config, informerManager genericmanager.MultiClusterInformerManager, factory informers.SharedInformerFactory, karmadaFactory informerfactory.SharedInformerFactory) (*Controller, error) {
+	kp, err := newKarmadaProxy(restConfig)
+	if err != nil {
+		return nil, err
+	}
+
+	s := &store.MultiClusterCache{}
+
+	ctl := &Controller{
+		clusterLister:   karmadaFactory.Cluster().V1alpha1().Clusters().Lister(),
+		registryLister:  karmadaFactory.Search().V1alpha1().ResourceRegistries().Lister(),
+		informerManager: informerManager,
+		store:           s,
+		karmadaProxy:    kp,
+		clusterProxy:    newClusterProxy(factory.Core().V1().Secrets().Lister()),
+		cacheProxy:      newCacheProxy(s),
+	}
+
+	workerOptions := util.Options{
+		Name:          "proxy-controller",
+		KeyFunc:       nil,
+		ReconcileFunc: ctl.reconcile,
+	}
+	ctl.worker = util.NewAsyncWorker(workerOptions)
+
+	resourceEventHandler := cache.ResourceEventHandlerFuncs{
+		AddFunc: func(interface{}) {
+			ctl.worker.Add(workKey)
+		},
+		UpdateFunc: func(_, _ interface{}) {
+			ctl.worker.Add(workKey)
+		},
+		DeleteFunc: func(interface{}) {
+			ctl.worker.Add(workKey)
+		},
+	}
+
+	karmadaFactory.Cluster().V1alpha1().Clusters().Informer().AddEventHandler(resourceEventHandler)
+	karmadaFactory.Search().V1alpha1().ResourceRegistries().Informer().AddEventHandler(resourceEventHandler)
+
+	return ctl, nil
+}
+
+// Start run the proxy controller
+func (ctl *Controller) Start(stopCh <-chan struct{}) {
+	ctl.worker.Run(1, stopCh)
+}
+
+// reconcile cache
+func (ctl *Controller) reconcile(util.QueueKey) error {
+	return nil
+}
+
+// Connect proxy and dispatch handlers
+func (ctl *Controller) Connect(ctx context.Context, proxyPath string, responder rest.Responder) (http.Handler, error) {
+	return http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
+		newReq := req.Clone(req.Context())
+		newReq.URL.Path = proxyPath
+		requestInfo := lifted.NewRequestInfo(newReq)
+
+		newCtx := request.WithRequestInfo(ctx, requestInfo)
+		newCtx = request.WithNamespace(newCtx, requestInfo.Namespace)
+		newReq = newReq.WithContext(newCtx)
+
+		h, err := ctl.connect(newCtx, requestInfo, proxyPath, responder)
+		if err != nil {
+			responder.Error(err)
+			return
+		}
+		h.ServeHTTP(rw, newReq)
+	}), nil
+}
+
+func (ctl *Controller) connect(ctx context.Context, requestInfo *request.RequestInfo, path string, responder rest.Responder) (http.Handler, error) {
+	gvr := schema.GroupVersionResource{
+		Group:    requestInfo.APIGroup,
+		Version:  requestInfo.APIVersion,
+		Resource: requestInfo.Resource,
+	}
+
+	// requests will be redirected to:
+	// 1. karmada apiserver
+	// 2. cache
+	// 3. member clusters
+	// see more information from https://github.com/karmada-io/karmada/tree/master/docs/proposals/resource-aggregation-proxy#request-routing
+
+	// 1. For non-resource requests, or resources are not defined in ResourceRegistry,
+	// we redirect the requests to karmada apiserver.
+	// Usually the request are
+	// - api index, e.g.: `/api`, `/apis`
+	// - to workload created in karmada controller panel, such as deployments and services.
+	if !requestInfo.IsResourceRequest || !ctl.store.HasResource(gvr) {
+		return ctl.karmadaProxy.connect(path, responder)
+	}
+
+	// 2. For reading requests, we redirect them to cache.
+	// Users call these requests to read resources in member clusters, such as pods and nodes.
+	if requestInfo.Subresource == "" && (requestInfo.Verb == "get" || requestInfo.Verb == "list" || requestInfo.Verb == "watch") {
+		return ctl.cacheProxy.connect(ctx), nil
+	}
+
+	// 3. The remaining requests are:
+	// - writing resources.
+	// - or subresource requests, e.g. `pods/log`
+	// We firstly find the resource from cache, and get the located cluster. Then redirect the request to the cluster.
+	cluster, err := ctl.store.GetClusterForResource(ctx, gvr)
+	if err != nil {
+		return nil, err
+	}
+	return ctl.clusterProxy.connect(ctx, cluster, path, responder)
+}

pkg/search/proxy/karmada_proxy.go

@@ -0,0 +1,51 @@
+package proxy
+
+import (
+	"net/http"
+	"net/url"
+	"path"
+
+	"k8s.io/apiserver/pkg/registry/rest"
+	restclient "k8s.io/client-go/rest"
+
+	"github.com/karmada-io/karmada/pkg/util/proxy"
+)
+
+// karmadaProxy is proxy for karmada control panel
+type karmadaProxy struct {
+	proxyLocation  *url.URL
+	proxyTransport http.RoundTripper
+}
+
+func newKarmadaProxy(restConfig *restclient.Config) (*karmadaProxy, error) {
+	location, err := url.Parse(restConfig.Host)
+	if err != nil {
+		return nil, err
+	}
+	transport, err := restclient.TransportFor(restConfig)
+	if err != nil {
+		return nil, err
+	}
+
+	return &karmadaProxy{
+		proxyLocation:  location,
+		proxyTransport: transport,
+	}, nil
+}
+
+// connect to Karmada-ApiServer directly
+func (p *karmadaProxy) connect(proxyPath string, responder rest.Responder) (http.Handler, error) {
+	return http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
+		location, transport := p.resourceLocation()
+		location.Path = path.Join(location.Path, proxyPath)
+		location.RawQuery = req.URL.RawQuery
+
+		handler := proxy.NewThrottledUpgradeAwareProxyHandler(location, transport, true, false, responder)
+		handler.ServeHTTP(rw, req)
+	}), nil
+}
+
+func (p *karmadaProxy) resourceLocation() (*url.URL, http.RoundTripper) {
+	location := *p.proxyLocation
+	return &location, p.proxyTransport
+}

pkg/search/proxy/store/cluster_cache.go

@@ -0,0 +1,5 @@
+package store
+
+// clusterCache caches resources for single member cluster
+type clusterCache struct {
+}

pkg/search/proxy/store/multi_cluster_cache.go

@@ -0,0 +1,28 @@
+package store
+
+import (
+	"context"
+
+	"k8s.io/apimachinery/pkg/runtime/schema"
+
+	clusterv1alpha1 "github.com/karmada-io/karmada/pkg/apis/cluster/v1alpha1"
+)
+
+// temporarily suppress lint: xxx is unused
+// TODO: remove it after these structs are used
+var _ = clusterCache{}
+var _ = resourceCache{}
+
+// MultiClusterCache caches resource from multi member clusters
+type MultiClusterCache struct {
+}
+
+// HasResource return whether resource is cached.
+func (c *MultiClusterCache) HasResource(_ schema.GroupVersionResource) bool {
+	return false
+}
+
+// GetClusterForResource returns which cluster the resource belong to.
+func (c *MultiClusterCache) GetClusterForResource(ctx context.Context, gvr schema.GroupVersionResource) (*clusterv1alpha1.Cluster, error) {
+	return nil, nil
+}

pkg/search/proxy/store/resource_cache.go

@@ -0,0 +1,5 @@
+package store
+
+// resourceCache cache one kind resource for single member cluster
+type resourceCache struct {
+}

pkg/util/proxy/proxy.go

@@ -0,0 +1,130 @@
+package proxy
+
+import (
+	"context"
+	"crypto/tls"
+	"errors"
+	"fmt"
+	"net/http"
+	"net/url"
+
+	authenticationv1 "k8s.io/api/authentication/v1"
+	corev1 "k8s.io/api/core/v1"
+	utilnet "k8s.io/apimachinery/pkg/util/net"
+	"k8s.io/apimachinery/pkg/util/proxy"
+	"k8s.io/apiserver/pkg/authentication/user"
+	"k8s.io/apiserver/pkg/endpoints/handlers/responsewriters"
+	"k8s.io/apiserver/pkg/endpoints/request"
+	"k8s.io/apiserver/pkg/registry/rest"
+
+	clusterapis "github.com/karmada-io/karmada/pkg/apis/cluster"
+)
+
+// NewThrottledUpgradeAwareProxyHandler creates a new proxy handler with a default flush interval. Responder is required for returning
+// errors to the caller.
+func NewThrottledUpgradeAwareProxyHandler(location *url.URL, transport http.RoundTripper, wrapTransport, upgradeRequired bool, responder rest.Responder) *proxy.UpgradeAwareHandler {
+	return proxy.NewUpgradeAwareHandler(location, transport, wrapTransport, upgradeRequired, proxy.NewErrorResponder(responder))
+}
+
+// ConnectCluster returns a handler for proxy cluster.
+func ConnectCluster(ctx context.Context, clusterName string, location *url.URL, transport http.RoundTripper, responder rest.Responder,
+	impersonateSecretGetter func(context.Context, string) (*corev1.Secret, error)) (http.Handler, error) {
+	secret, err := impersonateSecretGetter(ctx, clusterName)
+	if err != nil {
+		return nil, err
+	}
+
+	impersonateToken, err := getImpersonateToken(clusterName, secret)
+	if err != nil {
+		return nil, fmt.Errorf("failed to get impresonateToken for cluster %s: %v", clusterName, err)
+	}
+
+	return newProxyHandler(location, transport, impersonateToken, responder)
+}
+
+// Location returns a URL to which one can send traffic for the specified cluster.
+func Location(clusterName string, apiEndpoint string, proxyURL string) (*url.URL, http.RoundTripper, error) {
+	location, err := constructLocation(clusterName, apiEndpoint)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	transport, err := createProxyTransport(proxyURL)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	return location, transport, nil
+}
+
+func constructLocation(clusterName string, apiEndpoint string) (*url.URL, error) {
+	if apiEndpoint == "" {
+		return nil, fmt.Errorf("API endpoint of cluster %s should not be empty", clusterName)
+	}
+
+	uri, err := url.Parse(apiEndpoint)
+	if err != nil {
+		return nil, fmt.Errorf("failed to parse api endpoint %s: %v", apiEndpoint, err)
+	}
+	return uri, nil
+}
+
+func createProxyTransport(proxyURL string) (*http.Transport, error) {
+	var proxyDialerFn utilnet.DialFunc
+	proxyTLSClientConfig := &tls.Config{InsecureSkipVerify: true} // #nosec
+	trans := utilnet.SetTransportDefaults(&http.Transport{
+		DialContext:     proxyDialerFn,
+		TLSClientConfig: proxyTLSClientConfig,
+	})
+
+	if proxyURL != "" {
+		u, err := url.Parse(proxyURL)
+		if err != nil {
+			return nil, fmt.Errorf("failed to parse url of proxy url %s: %v", proxyURL, err)
+		}
+		trans.Proxy = http.ProxyURL(u)
+	}
+	return trans, nil
+}
+
+func getImpersonateToken(clusterName string, secret *corev1.Secret) (string, error) {
+	token, found := secret.Data[clusterapis.SecretTokenKey]
+	if !found {
+		return "", fmt.Errorf("the impresonate token of cluster %s is empty", clusterName)
+	}
+	return string(token), nil
+}
+
+func newProxyHandler(location *url.URL, transport http.RoundTripper, impersonateToken string, responder rest.Responder) (http.Handler, error) {
+	return http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
+		requester, exist := request.UserFrom(req.Context())
+		if !exist {
+			responsewriters.InternalError(rw, req, errors.New("no user found for request"))
+			return
+		}
+		req.Header.Set(authenticationv1.ImpersonateUserHeader, requester.GetName())
+		for _, group := range requester.GetGroups() {
+			if !skipGroup(group) {
+				req.Header.Add(authenticationv1.ImpersonateGroupHeader, group)
+			}
+		}
+
+		req.Header.Set("Authorization", fmt.Sprintf("bearer %s", impersonateToken))
+
+		// Retain RawQuery in location because upgrading the request will use it.
+		// See https://github.com/karmada-io/karmada/issues/1618#issuecomment-1103793290 for more info.
+		location.RawQuery = req.URL.RawQuery
+
+		handler := NewThrottledUpgradeAwareProxyHandler(location, transport, true, false, responder)
+		handler.ServeHTTP(rw, req)
+	}), nil
+}
+
+func skipGroup(group string) bool {
+	switch group {
+	case user.AllAuthenticated, user.AllUnauthenticated:
+		return true
+	default:
+		return false
+	}
+}