diff --git a/pkg/util/apply.go b/pkg/util/apply.go new file mode 100644 index 00000000..77ea5938 --- /dev/null +++ b/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) +}