Aggregated discovery client

staging/src/k8s.io/client-go/discovery/aggregated_discovery.go

@@ -0,0 +1,108 @@
+/*
+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 discovery
+
+import (
+	"fmt"
+
+	apidiscovery "k8s.io/api/apidiscovery/v2beta1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/runtime/schema"
+)
+
+// SplitGroupsAndResources transforms "aggregated" discovery top-level structure into
+// the previous "unaggregated" discovery groups and resources.
+func SplitGroupsAndResources(aggregatedGroups apidiscovery.APIGroupDiscoveryList) (*metav1.APIGroupList, map[schema.GroupVersion]*metav1.APIResourceList) {
+	// Aggregated group list will contain the entirety of discovery, including
+	// groups, versions, and resources.
+	groups := []*metav1.APIGroup{}
+	resourcesByGV := map[schema.GroupVersion]*metav1.APIResourceList{}
+	for _, aggGroup := range aggregatedGroups.Items {
+		group, resources := convertAPIGroup(aggGroup)
+		groups = append(groups, group)
+		for gv, resourceList := range resources {
+			resourcesByGV[gv] = resourceList
+		}
+	}
+	// Transform slice of groups to group list before returning.
+	groupList := &metav1.APIGroupList{}
+	groupList.Groups = make([]metav1.APIGroup, 0, len(groups))
+	for _, group := range groups {
+		groupList.Groups = append(groupList.Groups, *group)
+	}
+	return groupList, resourcesByGV
+}
+
+// convertAPIGroup tranforms an "aggregated" APIGroupDiscovery to an "legacy" APIGroup,
+// also returning the map of APIResourceList for resources within GroupVersions.
+func convertAPIGroup(g apidiscovery.APIGroupDiscovery) (*metav1.APIGroup, map[schema.GroupVersion]*metav1.APIResourceList) {
+	// Iterate through versions to convert to group and resources.
+	group := &metav1.APIGroup{}
+	gvResources := map[schema.GroupVersion]*metav1.APIResourceList{}
+	group.Name = g.ObjectMeta.Name
+	for i, v := range g.Versions {
+		version := metav1.GroupVersionForDiscovery{}
+		gv := schema.GroupVersion{Group: g.Name, Version: v.Version}
+		version.GroupVersion = gv.String()
+		version.Version = v.Version
+		group.Versions = append(group.Versions, version)
+		if i == 0 {
+			group.PreferredVersion = version
+		}
+		resourceList := &metav1.APIResourceList{}
+		resourceList.GroupVersion = gv.String()
+		for _, r := range v.Resources {
+			resource := convertAPIResource(r)
+			resourceList.APIResources = append(resourceList.APIResources, resource)
+			// Subresources field in new format get transformed into full APIResources.
+			for _, subresource := range r.Subresources {
+				sr := convertAPISubresource(resource, subresource)
+				resourceList.APIResources = append(resourceList.APIResources, sr)
+			}
+		}
+		gvResources[gv] = resourceList
+	}
+	return group, gvResources
+}
+
+// convertAPIResource tranforms a APIResourceDiscovery to an APIResource.
+func convertAPIResource(in apidiscovery.APIResourceDiscovery) metav1.APIResource {
+	return metav1.APIResource{
+		Name:         in.Resource,
+		SingularName: in.SingularResource,
+		Namespaced:   in.Scope == apidiscovery.ScopeNamespace,
+		Group:        in.ResponseKind.Group,
+		Version:      in.ResponseKind.Version,
+		Kind:         in.ResponseKind.Kind,
+		Verbs:        in.Verbs,
+		ShortNames:   in.ShortNames,
+		Categories:   in.Categories,
+	}
+}
+
+// convertAPISubresource tranforms a APISubresourceDiscovery to an APIResource.
+func convertAPISubresource(parent metav1.APIResource, in apidiscovery.APISubresourceDiscovery) metav1.APIResource {
+	return metav1.APIResource{
+		Name:         fmt.Sprintf("%s/%s", parent.Name, in.Subresource),
+		SingularName: parent.SingularName,
+		Namespaced:   parent.Namespaced,
+		Group:        in.ResponseKind.Group,
+		Version:      in.ResponseKind.Version,
+		Kind:         in.ResponseKind.Kind,
+		Verbs:        in.Verbs,
+	}
+}