Add OpenAPI v3 publishing under feature gate OpenAPIV3

Kubernetes-commit: 5bf3ed7a98e1e5247fe3fc2f6f948e6ed9a23521

pkg/server/genericapiserver.go

@@ -49,9 +49,10 @@ import (
 	utilopenapi "k8s.io/apiserver/pkg/util/openapi"
 	restclient "k8s.io/client-go/rest"
 	"k8s.io/klog/v2"
-	openapibuilder "k8s.io/kube-openapi/pkg/builder"
+	openapibuilder2 "k8s.io/kube-openapi/pkg/builder"
 	openapicommon "k8s.io/kube-openapi/pkg/common"
 	"k8s.io/kube-openapi/pkg/handler"
+	"k8s.io/kube-openapi/pkg/handler3"
 	openapiutil "k8s.io/kube-openapi/pkg/util"
 	openapiproto "k8s.io/kube-openapi/pkg/util/proto"
 	"k8s.io/kube-openapi/pkg/validation/spec"
@@ -144,6 +145,10 @@ type GenericAPIServer struct {
 	// It is set during PrepareRun if `openAPIConfig` is non-nil unless `skipOpenAPIInstallation` is true.
 	OpenAPIVersionedService *handler.OpenAPIService
 
+	// OpenAPIV3VersionedService controls the /openapi/v3 endpoint and can be used to update the served spec.
+	// It is set during PrepareRun if `openAPIConfig` is non-nil unless `skipOpenAPIInstallation` is true.
+	OpenAPIV3VersionedService *handler3.OpenAPIService
+
 	// StaticOpenAPISpec is the spec derived from the restful container endpoints.
 	// It is set during PrepareRun.
 	StaticOpenAPISpec *spec.Swagger
@@ -345,7 +350,12 @@ func (s *GenericAPIServer) PrepareRun() preparedGenericAPIServer {
 	if s.openAPIConfig != nil && !s.skipOpenAPIInstallation {
 		s.OpenAPIVersionedService, s.StaticOpenAPISpec = routes.OpenAPI{
 			Config: s.openAPIConfig,
-		}.Install(s.Handler.GoRestfulContainer, s.Handler.NonGoRestfulMux)
+		}.InstallV2(s.Handler.GoRestfulContainer, s.Handler.NonGoRestfulMux)
+		if utilfeature.DefaultFeatureGate.Enabled(features.OpenAPIV3) {
+			s.OpenAPIV3VersionedService = routes.OpenAPI{
+				Config: s.openAPIConfig,
+			}.InstallV3(s.Handler.GoRestfulContainer, s.Handler.NonGoRestfulMux)
+		}
 	}
 
 	s.installHealthz()
@@ -706,7 +716,7 @@ func (s *GenericAPIServer) getOpenAPIModels(apiPrefix string, apiGroupInfos ...*
 	}
 
 	// Build the openapi definitions for those resources and convert it to proto models
-	openAPISpec, err := openapibuilder.BuildOpenAPIDefinitionsForResources(s.openAPIConfig, resourceNames...)
+	openAPISpec, err := openapibuilder2.BuildOpenAPIDefinitionsForResources(s.openAPIConfig, resourceNames...)
 	if err != nil {
 		return nil, err
 	}

pkg/server/routes/openapi.go

@@ -21,9 +21,11 @@ import (
 	"k8s.io/klog/v2"
 
 	"k8s.io/apiserver/pkg/server/mux"
-	"k8s.io/kube-openapi/pkg/builder"
+	builder2 "k8s.io/kube-openapi/pkg/builder"
+	"k8s.io/kube-openapi/pkg/builder3"
 	"k8s.io/kube-openapi/pkg/common"
 	"k8s.io/kube-openapi/pkg/handler"
+	"k8s.io/kube-openapi/pkg/handler3"
 	"k8s.io/kube-openapi/pkg/validation/spec"
 )
 
@@ -33,8 +35,8 @@ type OpenAPI struct {
 }
 
 // Install adds the SwaggerUI webservice to the given mux.
-func (oa OpenAPI) Install(c *restful.Container, mux *mux.PathRecorderMux) (*handler.OpenAPIService, *spec.Swagger) {
-	spec, err := builder.BuildOpenAPISpec(c.RegisteredWebServices(), oa.Config)
+func (oa OpenAPI) InstallV2(c *restful.Container, mux *mux.PathRecorderMux) (*handler.OpenAPIService, *spec.Swagger) {
+	spec, err := builder2.BuildOpenAPISpec(c.RegisteredWebServices(), oa.Config)
 	if err != nil {
 		klog.Fatalf("Failed to build open api spec for root: %v", err)
 	}
@@ -51,3 +53,34 @@ func (oa OpenAPI) Install(c *restful.Container, mux *mux.PathRecorderMux) (*hand
 
 	return openAPIVersionedService, spec
 }
+
+// InstallV3 adds the static group/versions defined in the RegisteredWebServices to the OpenAPI v3 spec
+func (oa OpenAPI) InstallV3(c *restful.Container, mux *mux.PathRecorderMux) *handler3.OpenAPIService {
+	openAPIVersionedService, err := handler3.NewOpenAPIService(nil)
+	if err != nil {
+		klog.Fatalf("Failed to create OpenAPIService: %v", err)
+	}
+
+	err = openAPIVersionedService.RegisterOpenAPIV3VersionedService("/openapi/v3", mux)
+	if err != nil {
+		klog.Fatalf("Failed to register versioned open api spec for root: %v", err)
+	}
+
+	grouped := make(map[string][]*restful.WebService)
+
+	for _, t := range c.RegisteredWebServices() {
+		// Strip the "/" prefix from the name
+		gvName := t.RootPath()[1:]
+		grouped[gvName] = []*restful.WebService{t}
+	}
+
+	for gv, ws := range grouped {
+		spec, err := builder3.BuildOpenAPISpec(ws, oa.Config)
+		if err != nil {
+			klog.Errorf("Failed to build OpenAPI v3 for group %s, %q", gv, err)
+
+		}
+		openAPIVersionedService.UpdateGroupVersion(gv, spec)
+	}
+	return openAPIVersionedService
+}