Move pkg/kubectl/apply.go to staging

Kubernetes-commit: 309de42878f25c8a09b13c4b4ec0488a88da4de3

pkg/util/apply.go

@@ -0,0 +1,146 @@
+/*
+Copyright 2014 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 util
+
+import (
+	"k8s.io/api/core/v1"
+	"k8s.io/apimachinery/pkg/api/meta"
+	"k8s.io/apimachinery/pkg/runtime"
+)
+
+var metadataAccessor = meta.NewAccessor()
+
+// GetOriginalConfiguration retrieves the original configuration of the object
+// from the annotation, or nil if no annotation was found.
+func GetOriginalConfiguration(obj runtime.Object) ([]byte, error) {
+	annots, err := metadataAccessor.Annotations(obj)
+	if err != nil {
+		return nil, err
+	}
+
+	if annots == nil {
+		return nil, nil
+	}
+
+	original, ok := annots[v1.LastAppliedConfigAnnotation]
+	if !ok {
+		return nil, nil
+	}
+
+	return []byte(original), nil
+}
+
+// SetOriginalConfiguration sets the original configuration of the object
+// as the annotation on the object for later use in computing a three way patch.
+func setOriginalConfiguration(obj runtime.Object, original []byte) error {
+	if len(original) < 1 {
+		return nil
+	}
+
+	annots, err := metadataAccessor.Annotations(obj)
+	if err != nil {
+		return err
+	}
+
+	if annots == nil {
+		annots = map[string]string{}
+	}
+
+	annots[v1.LastAppliedConfigAnnotation] = string(original)
+	return metadataAccessor.SetAnnotations(obj, annots)
+}
+
+// GetModifiedConfiguration retrieves the modified configuration of the object.
+// If annotate is true, it embeds the result as an annotation in the modified
+// configuration. If an object was read from the command input, it will use that
+// version of the object. Otherwise, it will use the version from the server.
+func GetModifiedConfiguration(obj runtime.Object, annotate bool, codec runtime.Encoder) ([]byte, error) {
+	// First serialize the object without the annotation to prevent recursion,
+	// then add that serialization to it as the annotation and serialize it again.
+	var modified []byte
+
+	// Otherwise, use the server side version of the object.
+	// Get the current annotations from the object.
+	annots, err := metadataAccessor.Annotations(obj)
+	if err != nil {
+		return nil, err
+	}
+
+	if annots == nil {
+		annots = map[string]string{}
+	}
+
+	original := annots[v1.LastAppliedConfigAnnotation]
+	delete(annots, v1.LastAppliedConfigAnnotation)
+	if err := metadataAccessor.SetAnnotations(obj, annots); err != nil {
+		return nil, err
+	}
+
+	modified, err = runtime.Encode(codec, obj)
+	if err != nil {
+		return nil, err
+	}
+
+	if annotate {
+		annots[v1.LastAppliedConfigAnnotation] = string(modified)
+		if err := metadataAccessor.SetAnnotations(obj, annots); err != nil {
+			return nil, err
+		}
+
+		modified, err = runtime.Encode(codec, obj)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	// Restore the object to its original condition.
+	annots[v1.LastAppliedConfigAnnotation] = original
+	if err := metadataAccessor.SetAnnotations(obj, annots); err != nil {
+		return nil, err
+	}
+
+	return modified, nil
+}
+
+// updateApplyAnnotation calls CreateApplyAnnotation if the last applied
+// configuration annotation is already present. Otherwise, it does nothing.
+func updateApplyAnnotation(obj runtime.Object, codec runtime.Encoder) error {
+	if original, err := GetOriginalConfiguration(obj); err != nil || len(original) <= 0 {
+		return err
+	}
+	return CreateApplyAnnotation(obj, codec)
+}
+
+// CreateApplyAnnotation gets the modified configuration of the object,
+// without embedding it again, and then sets it on the object as the annotation.
+func CreateApplyAnnotation(obj runtime.Object, codec runtime.Encoder) error {
+	modified, err := GetModifiedConfiguration(obj, false, codec)
+	if err != nil {
+		return err
+	}
+	return setOriginalConfiguration(obj, modified)
+}
+
+// CreateOrUpdateAnnotation creates the annotation used by
+// kubectl apply only when createAnnotation is true
+// Otherwise, only update the annotation when it already exists
+func CreateOrUpdateAnnotation(createAnnotation bool, obj runtime.Object, codec runtime.Encoder) error {
+	if createAnnotation {
+		return CreateApplyAnnotation(obj, codec)
+	}
+	return updateApplyAnnotation(obj, codec)
+}