Implement initial OpenAPI v3 support for virtual workspaces

Signed-off-by: Marko Mudrinić <mudrinic.mare@gmail.com>

pkg/virtual/framework/dynamic/apidefinition/types.go

@@ -24,7 +24,6 @@ import (
 	"k8s.io/apimachinery/pkg/runtime/schema"
 	"k8s.io/apiserver/pkg/endpoints/handlers"
 	"k8s.io/apiserver/pkg/registry/rest"
-	"k8s.io/kube-openapi/pkg/spec3"
 
 	dynamiccontext "github.com/kcp-dev/kcp/pkg/virtual/framework/dynamic/context"
 	apisv1alpha1 "github.com/kcp-dev/kcp/sdk/apis/apis/v1alpha1"
@@ -35,9 +34,6 @@ type APIDefinition interface {
 	// GetAPIResourceSchema returns the API schema this definition serves.
 	GetAPIResourceSchema() *apisv1alpha1.APIResourceSchema
 
-	// GetOpenAPIV3Schema fetches OpenAPI V3 Schema
-	GetOpenAPIV3Spec() *spec3.OpenAPI
-
 	// GetClusterName provides the name of the logical cluster where the resource specification comes from.
 	GetClusterName() logicalcluster.Name
 

pkg/virtual/framework/dynamic/apiserver/apiserver.go

@@ -29,7 +29,10 @@ import (
 	"k8s.io/apimachinery/pkg/runtime/serializer"
 	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
 	"k8s.io/apiserver/pkg/endpoints/discovery"
+	openapinamer "k8s.io/apiserver/pkg/endpoints/openapi"
 	genericapiserver "k8s.io/apiserver/pkg/server"
+	"k8s.io/apiserver/pkg/util/openapi"
+	generatedopenapi "k8s.io/kubernetes/pkg/generated/openapi"
 
 	virtualcontext "github.com/kcp-dev/kcp/pkg/virtual/framework/context"
 	"github.com/kcp-dev/kcp/pkg/virtual/framework/dynamic/apidefinition"
@@ -177,7 +180,12 @@ func (c completedConfig) New(virtualWorkspaceName string, delegationTarget gener
 
 	s.GenericAPIServer.Handler.GoRestfulContainer.Add(discovery.NewLegacyRootAPIHandler(c.GenericConfig.DiscoveryAddresses, s.GenericAPIServer.Serializer, "/api").WebService())
 
-	openAPIHandler := newOpenAPIHandler(s.APISetRetriever, delegateHandler)
+	getOpenAPIDefinitions := openapi.GetOpenAPIDefinitionsWithoutDisabledFeatures(generatedopenapi.GetOpenAPIDefinitions)
+	namer := openapinamer.NewDefinitionNamer(scheme)
+	openapiv3Config := genericapiserver.DefaultOpenAPIV3Config(getOpenAPIDefinitions, namer)
+	openapiv3Config.Info.Title = "Kubernetes"
+
+	openAPIHandler := newOpenAPIHandler(s.APISetRetriever, s.GenericAPIServer.Handler.GoRestfulContainer, openapiv3Config, delegateHandler)
 
 	s.GenericAPIServer.Handler.NonGoRestfulMux.Handle("/apis", crdHandler)
 	s.GenericAPIServer.Handler.NonGoRestfulMux.HandlePrefix("/apis/", crdHandler)

pkg/virtual/framework/dynamic/apiserver/discovery.go

@@ -17,7 +17,6 @@ limitations under the License.
 package apiserver
 
 import (
-	"context"
 	"fmt"
 	"net/http"
 	"sort"
@@ -34,7 +33,6 @@ import (
 	"k8s.io/apiserver/pkg/endpoints/handlers/negotiation"
 	"k8s.io/apiserver/pkg/endpoints/handlers/responsewriters"
 	"k8s.io/apiserver/pkg/registry/rest"
-	"k8s.io/kube-openapi/pkg/handler3"
 	"k8s.io/kubernetes/pkg/controlplane/apiserver/miniaggregator"
 
 	"github.com/kcp-dev/kcp/pkg/virtual/framework/dynamic/apidefinition"
@@ -332,86 +330,3 @@ func sortGroupDiscoveryByKubeAwareVersion(gd []metav1.GroupVersionForDiscovery)
 		return version.CompareKubeAwareVersionStrings(gd[i].Version, gd[j].Version) > 0
 	})
 }
-
-type openAPIHandler struct {
-	apiSetRetriever apidefinition.APIDefinitionSetGetter
-	delegate        http.Handler
-
-	openAPIV3Service *handler3.OpenAPIService
-}
-
-func newOpenAPIHandler(apiSetRetriever apidefinition.APIDefinitionSetGetter, delegate http.Handler) *openAPIHandler {
-	openAPIV3Service := handler3.NewOpenAPIService()
-
-	return &openAPIHandler{
-		apiSetRetriever: apiSetRetriever,
-		delegate:        delegate,
-
-		openAPIV3Service: openAPIV3Service,
-	}
-}
-
-func (h *openAPIHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
-	// handle /openapi 								-> do nothing
-	// handle /openapi/v2 							-> do nothing for now. TODO: Implement. Actually, let OpenAPIV2 die. Ref: https://github.com/kcp-dev/kcp/pull/3059#discussion_r1424317153
-	// handle /openapi/v3							-> discovery endpoint
-	// handle /openapi/v3/apis/<group>/<version> 	-> serve OpenAPIV3Schema for <group>/<version>
-
-	pathParts := splitPath(r.URL.Path)
-
-	// if request doesn't start with /openapi return
-	// this check is a safety measure
-	if len(pathParts) == 1 && pathParts[0] != "openapi" {
-		h.delegate.ServeHTTP(w, r)
-		return
-	}
-
-	if len(pathParts) == 1 && pathParts[0] == "openapi" {
-		return
-	}
-
-	if len(pathParts) == 2 && pathParts[1] == "v2" { // handle /openapi/v2
-		// TODO: Implement OpenAPI V2 handler. Actually, let OpenAPIV2 die. Ref: https://github.com/kcp-dev/kcp/pull/3059#discussion_r1424317153
-		return
-	} else if len(pathParts) == 2 && pathParts[1] == "v3" { // handle /openapi/v3
-		if err := h.fetchAndUpdate(r.Context(), ""); err != nil {
-			responsewriters.ErrorNegotiated(
-				apierrors.NewInternalError(fmt.Errorf("unable to  set: %w", err)),
-				errorCodecs, schema.GroupVersion{},
-				w, r)
-		}
-
-		h.openAPIV3Service.HandleDiscovery(w, r)
-		return
-	} else if len(pathParts) == 5 && pathParts[1] == "v3" && pathParts[2] == "apis" {
-		requestedGroup := pathParts[3]
-		if err := h.fetchAndUpdate(r.Context(), requestedGroup); err != nil {
-			responsewriters.ErrorNegotiated(
-				apierrors.NewInternalError(fmt.Errorf("unable to  set: %w", err)),
-				errorCodecs, schema.GroupVersion{},
-				w, r)
-		}
-
-		h.openAPIV3Service.HandleGroupVersion(w, r)
-	} else {
-		h.delegate.ServeHTTP(w, r)
-		return
-	}
-}
-
-func (h *openAPIHandler) fetchAndUpdate(ctx context.Context, group string) error {
-	apiDomainKey := dyncamiccontext.APIDomainKeyFrom(ctx)
-	apiSet, _, err := h.apiSetRetriever.GetAPIDefinitionSet(ctx, apiDomainKey)
-	if err != nil {
-		return err
-	}
-
-	for gvr, apiDefinition := range apiSet {
-		if group == "" || (group != "" && group == gvr.Group) {
-			spec := apiDefinition.GetOpenAPIV3Spec()
-			h.openAPIV3Service.UpdateGroupVersion(gvr.Group, spec)
-		}
-	}
-
-	return nil
-}

pkg/virtual/framework/dynamic/apiserver/handler_test.go

@@ -39,7 +39,6 @@ import (
 	apirequest "k8s.io/apiserver/pkg/endpoints/request"
 	"k8s.io/apiserver/pkg/registry/rest"
 	utilopenapi "k8s.io/apiserver/pkg/util/openapi"
-	"k8s.io/kube-openapi/pkg/spec3"
 	"sigs.k8s.io/yaml"
 
 	"github.com/kcp-dev/kcp/pkg/virtual/framework/dynamic/apidefinition"
@@ -59,7 +58,6 @@ type mockedAPIDefinition struct {
 	apiResourceSchema  *apisv1alpha1.APIResourceSchema
 	store              rest.Storage
 	subresourcesStores map[string]rest.Storage
-	openAPIV3Spec      *spec3.OpenAPI
 }
 
 var _ apidefinition.APIDefinition = (*mockedAPIDefinition)(nil)
@@ -73,9 +71,6 @@ func (apiDef *mockedAPIDefinition) GetClusterName() logicalcluster.Name {
 func (apiDef *mockedAPIDefinition) GetStorage() rest.Storage {
 	return apiDef.store
 }
-func (apiDef *mockedAPIDefinition) GetOpenAPIV3Spec() *spec3.OpenAPI {
-	return apiDef.openAPIV3Spec
-}
 func (apiDef *mockedAPIDefinition) GetSubResourceStorage(subresource string) rest.Storage {
 	return apiDef.subresourcesStores[subresource]
 }