Merge pull request #53442 from deads2k/server-02-nesteddecoding

Automatic merge from submit-queue (batch tested with PRs 53916, 53442). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

add nested encoder and decoder to admission config

Fixes https://github.com/kubernetes/kubernetes/issues/54159

Adds the required nested object encoder/decoder pairs for admission config extensions.

@sttts

staging/src/k8s.io/apiserver/pkg/apis/apiserver/v1alpha1/BUILD

@@ -8,6 +8,7 @@ load(
 go_library(
     name = "go_default_library",
     srcs = [
+        "conversion.go",
         "doc.go",
         "register.go",
         "types.go",

staging/src/k8s.io/apiserver/pkg/apis/apiserver/v1alpha1/conversion.go

@@ -0,0 +1,88 @@
+/*
+Copyright 2017 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 v1alpha1
+
+import (
+	runtime "k8s.io/apimachinery/pkg/runtime"
+)
+
+var _ runtime.NestedObjectDecoder = &AdmissionConfiguration{}
+
+// DecodeNestedObjects handles encoding RawExtensions on the AdmissionConfiguration, ensuring the
+// objects are decoded with the provided decoder.
+func (c *AdmissionConfiguration) DecodeNestedObjects(d runtime.Decoder) error {
+	// decoding failures result in a runtime.Unknown object being created in Object and passed
+	// to conversion
+	for k, v := range c.Plugins {
+		decodeNestedRawExtensionOrUnknown(d, &v.Configuration)
+		c.Plugins[k] = v
+	}
+	return nil
+}
+
+var _ runtime.NestedObjectEncoder = &AdmissionConfiguration{}
+
+// EncodeNestedObjects handles encoding RawExtensions on the AdmissionConfiguration, ensuring the
+// objects are encoded with the provided encoder.
+func (c *AdmissionConfiguration) EncodeNestedObjects(e runtime.Encoder) error {
+	for k, v := range c.Plugins {
+		if err := encodeNestedRawExtension(e, &v.Configuration); err != nil {
+			return err
+		}
+		c.Plugins[k] = v
+	}
+	return nil
+}
+
+// decodeNestedRawExtensionOrUnknown decodes the raw extension into an object once.  If called
+// On a RawExtension that has already been decoded (has an object), it will not run again.
+func decodeNestedRawExtensionOrUnknown(d runtime.Decoder, ext *runtime.RawExtension) {
+	if ext.Raw == nil || ext.Object != nil {
+		return
+	}
+	obj, gvk, err := d.Decode(ext.Raw, nil, nil)
+	if err != nil {
+		unk := &runtime.Unknown{Raw: ext.Raw}
+		if runtime.IsNotRegisteredError(err) {
+			if _, gvk, err := d.Decode(ext.Raw, nil, unk); err == nil {
+				unk.APIVersion = gvk.GroupVersion().String()
+				unk.Kind = gvk.Kind
+				ext.Object = unk
+				return
+			}
+		}
+		// TODO: record mime-type with the object
+		if gvk != nil {
+			unk.APIVersion = gvk.GroupVersion().String()
+			unk.Kind = gvk.Kind
+		}
+		obj = unk
+	}
+	ext.Object = obj
+}
+
+func encodeNestedRawExtension(e runtime.Encoder, ext *runtime.RawExtension) error {
+	if ext.Raw != nil || ext.Object == nil {
+		return nil
+	}
+	data, err := runtime.Encode(e, ext.Object)
+	if err != nil {
+		return err
+	}
+	ext.Raw = data
+	return nil
+}