extend SchemaResolver for more types of schemas.

staging/src/k8s.io/apiserver/pkg/cel/openapi/resolver/combined.go

@@ -0,0 +1,45 @@
+/*
+Copyright 2023 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 resolver
+
+import (
+	"k8s.io/apimachinery/pkg/runtime/schema"
+	"k8s.io/kube-openapi/pkg/validation/spec"
+)
+
+// Combine combines the DefinitionsSchemaResolver with a secondary schema resolver.
+// The resulting schema resolver uses the DefinitionsSchemaResolver for a GVK that DefinitionsSchemaResolver knows,
+// and the secondary otherwise.
+func (d *DefinitionsSchemaResolver) Combine(secondary SchemaResolver) SchemaResolver {
+	return &combinedSchemaResolver{definitions: d, secondary: secondary}
+}
+
+type combinedSchemaResolver struct {
+	definitions *DefinitionsSchemaResolver
+	secondary   SchemaResolver
+}
+
+// ResolveSchema takes a GroupVersionKind (GVK) and returns the OpenAPI schema
+// identified by the GVK.
+// If the DefinitionsSchemaResolver knows the gvk, the DefinitionsSchemaResolver handles the resolution,
+// otherwise, the secondary does.
+func (r *combinedSchemaResolver) ResolveSchema(gvk schema.GroupVersionKind) (*spec.Schema, error) {
+	if _, ok := r.definitions.gvkToSchema[gvk]; ok {
+		return r.definitions.ResolveSchema(gvk)
+	}
+	return r.secondary.ResolveSchema(gvk)
+}

staging/src/k8s.io/apiserver/pkg/cel/openapi/resolver/definitions.go

@@ -35,11 +35,11 @@ type DefinitionsSchemaResolver struct {
 
 // NewDefinitionsSchemaResolver creates a new DefinitionsSchemaResolver.
 // An example working setup:
-// scheme         = "k8s.io/client-go/kubernetes/scheme".Scheme
 // getDefinitions = "k8s.io/kubernetes/pkg/generated/openapi".GetOpenAPIDefinitions
-func NewDefinitionsSchemaResolver(scheme *runtime.Scheme, getDefinitions common.GetOpenAPIDefinitions) *DefinitionsSchemaResolver {
+// scheme         = "k8s.io/client-go/kubernetes/scheme".Scheme
+func NewDefinitionsSchemaResolver(getDefinitions common.GetOpenAPIDefinitions, schemes ...*runtime.Scheme) *DefinitionsSchemaResolver {
 	gvkToSchema := make(map[schema.GroupVersionKind]*spec.Schema)
-	namer := openapi.NewDefinitionNamer(scheme)
+	namer := openapi.NewDefinitionNamer(schemes...)
 	defs := getDefinitions(func(path string) spec.Ref {
 		return spec.MustCreateRef(path)
 	})

test/integration/apiserver/cel/typeresolution_test.go

@@ -79,7 +79,7 @@ func TestTypeResolver(t *testing.T) {
 		}
 	}(crd)
 	discoveryResolver := &resolver.ClientDiscoveryResolver{Discovery: client.Discovery()}
-	definitionsResolver := resolver.NewDefinitionsSchemaResolver(k8sscheme.Scheme, openapi.GetOpenAPIDefinitions)
+	definitionsResolver := resolver.NewDefinitionsSchemaResolver(openapi.GetOpenAPIDefinitions, k8sscheme.Scheme)
 	// wait until the CRD schema is published at the OpenAPI v3 endpoint
 	err = wait.PollImmediate(time.Second, time.Minute, func() (done bool, err error) {
 		p, err := client.OpenAPIV3().Paths()
@@ -330,7 +330,7 @@ func TestBuiltinResolution(t *testing.T) {
 	}{
 		{
 			name:     "definitions",
-			resolver: resolver.NewDefinitionsSchemaResolver(k8sscheme.Scheme, openapi.GetOpenAPIDefinitions),
+			resolver: resolver.NewDefinitionsSchemaResolver(openapi.GetOpenAPIDefinitions, k8sscheme.Scheme),
 			scheme:   buildTestScheme(),
 		},
 		{