API server serves CRD per-version schema/subresources/columns

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

@@ -136,7 +136,11 @@ func (c *DiscoveryController) sync(version schema.GroupVersion) error {
 			Categories:   crd.Status.AcceptedNames.Categories,
 		})
 
-		if crd.Spec.Subresources != nil && crd.Spec.Subresources.Status != nil {
+		subresources, err := getSubresourcesForVersion(crd, version.Version)
+		if err != nil {
+			return err
+		}
+		if subresources != nil && subresources.Status != nil {
 			apiResourcesForDiscovery = append(apiResourcesForDiscovery, metav1.APIResource{
 				Name:       crd.Status.AcceptedNames.Plural + "/status",
 				Namespaced: crd.Spec.Scope == apiextensions.NamespaceScoped,
@@ -145,7 +149,7 @@ func (c *DiscoveryController) sync(version schema.GroupVersion) error {
 			})
 		}
 
-		if crd.Spec.Subresources != nil && crd.Spec.Subresources.Scale != nil {
+		if subresources != nil && subresources.Scale != nil {
 			apiResourcesForDiscovery = append(apiResourcesForDiscovery, metav1.APIResource{
 				Group:      autoscaling.GroupName,
 				Version:    "v1",

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

@@ -220,10 +220,16 @@ func (r *crdHandler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
 	}
 
 	var handler http.HandlerFunc
+	subresources, err := getSubresourcesForVersion(crd, requestInfo.APIVersion)
+	if err != nil {
+		utilruntime.HandleError(err)
+		http.Error(w, "the server could not properly serve the CR subresources", http.StatusInternalServerError)
+		return
+	}
 	switch {
-	case subresource == "status" && crd.Spec.Subresources != nil && crd.Spec.Subresources.Status != nil:
+	case subresource == "status" && subresources != nil && subresources.Status != nil:
 		handler = r.serveStatus(w, req, requestInfo, crdInfo, terminating, supportedTypes)
-	case subresource == "scale" && crd.Spec.Subresources != nil && crd.Spec.Subresources.Scale != nil:
+	case subresource == "scale" && subresources != nil && subresources.Scale != nil:
 		handler = r.serveScale(w, req, requestInfo, crdInfo, terminating, supportedTypes)
 	case len(subresource) == 0:
 		handler = r.serveResource(w, req, requestInfo, crdInfo, terminating, supportedTypes)
@@ -443,19 +449,28 @@ func (r *crdHandler) getOrCreateServingInfoFor(crd *apiextensions.CustomResource
 		typer := newUnstructuredObjectTyper(parameterScheme)
 		creator := unstructuredCreator{}
 
-		validator, _, err := apiservervalidation.NewSchemaValidator(crd.Spec.Validation)
+		validationSchema, err := getSchemaForVersion(crd, v.Name)
+		if err != nil {
+			utilruntime.HandleError(err)
+			return nil, fmt.Errorf("the server could not properly serve the CR schema")
+		}
+		validator, _, err := apiservervalidation.NewSchemaValidator(validationSchema)
 		if err != nil {
 			return nil, err
 		}
 
 		var statusSpec *apiextensions.CustomResourceSubresourceStatus
 		var statusValidator *validate.SchemaValidator
-		if utilfeature.DefaultFeatureGate.Enabled(apiextensionsfeatures.CustomResourceSubresources) && crd.Spec.Subresources != nil && crd.Spec.Subresources.Status != nil {
+		subresources, err := getSubresourcesForVersion(crd, v.Name)
-			statusSpec = crd.Spec.Subresources.Status
+		if err != nil {
-
+			utilruntime.HandleError(err)
+			return nil, fmt.Errorf("the server could not properly serve the CR subresources")
+		}
+		if utilfeature.DefaultFeatureGate.Enabled(apiextensionsfeatures.CustomResourceSubresources) && subresources != nil && subresources.Status != nil {
+			statusSpec = subresources.Status
 			// for the status subresource, validate only against the status schema
-			if crd.Spec.Validation != nil && crd.Spec.Validation.OpenAPIV3Schema != nil && crd.Spec.Validation.OpenAPIV3Schema.Properties != nil {
+			if validationSchema != nil && validationSchema.OpenAPIV3Schema != nil && validationSchema.OpenAPIV3Schema.Properties != nil {
-				if statusSchema, ok := crd.Spec.Validation.OpenAPIV3Schema.Properties["status"]; ok {
+				if statusSchema, ok := validationSchema.OpenAPIV3Schema.Properties["status"]; ok {
 					openapiSchema := &spec.Schema{}
 					if err := apiservervalidation.ConvertJSONSchemaProps(&statusSchema, openapiSchema); err != nil {
 						return nil, err
@@ -466,11 +481,16 @@ func (r *crdHandler) getOrCreateServingInfoFor(crd *apiextensions.CustomResource
 		}
 
 		var scaleSpec *apiextensions.CustomResourceSubresourceScale
-		if utilfeature.DefaultFeatureGate.Enabled(apiextensionsfeatures.CustomResourceSubresources) && crd.Spec.Subresources != nil && crd.Spec.Subresources.Scale != nil {
+		if utilfeature.DefaultFeatureGate.Enabled(apiextensionsfeatures.CustomResourceSubresources) && subresources != nil && subresources.Scale != nil {
-			scaleSpec = crd.Spec.Subresources.Scale
+			scaleSpec = subresources.Scale
 		}
 
-		table, err := tableconvertor.New(crd.Spec.AdditionalPrinterColumns)
+		columns, err := getColumnsForVersion(crd, v.Name)
+		if err != nil {
+			utilruntime.HandleError(err)
+			return nil, fmt.Errorf("the server could not properly serve the CR columns")
+		}
+		table, err := tableconvertor.New(columns)
 		if err != nil {
 			glog.V(2).Infof("The CRD for %v has an invalid printer specification, falling back to default printing: %v", kind, err)
 		}

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

@@ -0,0 +1,117 @@
+/*
+Copyright 2018 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 apiserver
+
+import (
+	"fmt"
+
+	"k8s.io/apiextensions-apiserver/pkg/apis/apiextensions"
+)
+
+// getSchemaForVersion returns the validation schema for given version in given CRD.
+func getSchemaForVersion(crd *apiextensions.CustomResourceDefinition, version string) (*apiextensions.CustomResourceValidation, error) {
+	if !hasPerVersionSchema(crd.Spec.Versions) {
+		return crd.Spec.Validation, nil
+	}
+	if crd.Spec.Validation != nil {
+		return nil, fmt.Errorf("malformed CustomResourceDefinition %s version %s: top-level and per-version schemas must be mutual exclusive", crd.Name, version)
+	}
+	for _, v := range crd.Spec.Versions {
+		if version == v.Name {
+			return v.Schema, nil
+		}
+	}
+	return nil, fmt.Errorf("version %s not found in CustomResourceDefinition: %v", version, crd.Name)
+}
+
+// getSubresourcesForVersion returns the subresources for given version in given CRD.
+func getSubresourcesForVersion(crd *apiextensions.CustomResourceDefinition, version string) (*apiextensions.CustomResourceSubresources, error) {
+	if !hasPerVersionSubresources(crd.Spec.Versions) {
+		return crd.Spec.Subresources, nil
+	}
+	if crd.Spec.Subresources != nil {
+		return nil, fmt.Errorf("malformed CustomResourceDefinition %s version %s: top-level and per-version subresources must be mutual exclusive", crd.Name, version)
+	}
+	for _, v := range crd.Spec.Versions {
+		if version == v.Name {
+			return v.Subresources, nil
+		}
+	}
+	return nil, fmt.Errorf("version %s not found in CustomResourceDefinition: %v", version, crd.Name)
+}
+
+// getColumnsForVersion returns the columns for given version in given CRD.
+// NOTE: the newly logically-defaulted columns is not pointing to the original CRD object.
+// One cannot mutate the original CRD columns using the logically-defaulted columns. Please iterate through
+// the original CRD object instead.
+func getColumnsForVersion(crd *apiextensions.CustomResourceDefinition, version string) ([]apiextensions.CustomResourceColumnDefinition, error) {
+	if !hasPerVersionColumns(crd.Spec.Versions) {
+		return serveDefaultColumnsIfEmpty(crd.Spec.AdditionalPrinterColumns), nil
+	}
+	if len(crd.Spec.AdditionalPrinterColumns) > 0 {
+		return nil, fmt.Errorf("malformed CustomResourceDefinition %s version %s: top-level and per-version additionalPrinterColumns must be mutual exclusive", crd.Name, version)
+	}
+	for _, v := range crd.Spec.Versions {
+		if version == v.Name {
+			return serveDefaultColumnsIfEmpty(v.AdditionalPrinterColumns), nil
+		}
+	}
+	return nil, fmt.Errorf("version %s not found in CustomResourceDefinition: %v", version, crd.Name)
+}
+
+// serveDefaultColumnsIfEmpty applies logically defaulting to columns, if the input columns is empty.
+// NOTE: in this way, the newly logically-defaulted columns is not pointing to the original CRD object.
+// One cannot mutate the original CRD columns using the logically-defaulted columns. Please iterate through
+// the original CRD object instead.
+func serveDefaultColumnsIfEmpty(columns []apiextensions.CustomResourceColumnDefinition) []apiextensions.CustomResourceColumnDefinition {
+	if len(columns) > 0 {
+		return columns
+	}
+	return []apiextensions.CustomResourceColumnDefinition{
+		{Name: "Age", Type: "date", Description: swaggerMetadataDescriptions["creationTimestamp"], JSONPath: ".metadata.creationTimestamp"},
+	}
+}
+
+// hasPerVersionSchema returns true if a CRD uses per-version schema.
+func hasPerVersionSchema(versions []apiextensions.CustomResourceDefinitionVersion) bool {
+	for _, v := range versions {
+		if v.Schema != nil {
+			return true
+		}
+	}
+	return false
+}
+
+// hasPerVersionSubresources returns true if a CRD uses per-version subresources.
+func hasPerVersionSubresources(versions []apiextensions.CustomResourceDefinitionVersion) bool {
+	for _, v := range versions {
+		if v.Subresources != nil {
+			return true
+		}
+	}
+	return false
+}
+
+// hasPerVersionColumns returns true if a CRD uses per-version columns.
+func hasPerVersionColumns(versions []apiextensions.CustomResourceDefinitionVersion) bool {
+	for _, v := range versions {
+		if len(v.AdditionalPrinterColumns) > 0 {
+			return true
+		}
+	}
+	return false
+}