115 lines
3.3 KiB
Go
115 lines
3.3 KiB
Go
/*
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Copyright 2022.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package patch
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import (
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"reflect"
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jsonpatch "github.com/evanphx/json-patch"
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"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
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"k8s.io/apimachinery/pkg/runtime"
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"k8s.io/apimachinery/pkg/util/json"
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)
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func MergePatch(source interface{}, target interface{}) ([]byte, error) {
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sourceJSON, err := json.Marshal(source)
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if err != nil {
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return nil, err
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}
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targetJSON, err := json.Marshal(target)
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if err != nil {
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return nil, err
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}
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mergePatch, err := jsonpatch.CreateMergePatch(sourceJSON, targetJSON)
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if err != nil {
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return nil, err
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}
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switch target.(type) {
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case *unstructured.Unstructured:
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// Take the JSON merge patch as is for unstructured objects
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return mergePatch, nil
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default:
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// Otherwise, for typed objects, remove null fields from the JSON merge patch,
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// so that values managed by controllers server-side are not deleted.
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var positivePatch map[string]interface{}
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err = json.Unmarshal(mergePatch, &positivePatch)
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if err != nil {
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return nil, err
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}
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removeNilValues(reflect.ValueOf(positivePatch), reflect.Value{})
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// Return an empty patch if no keys remain
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if len(positivePatch) == 0 {
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return make([]byte, 0), nil
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}
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return json.Marshal(positivePatch)
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}
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}
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func ApplyPatch(source runtime.Object) (*unstructured.Unstructured, error) {
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switch s := source.(type) {
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case *unstructured.Unstructured:
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// Directly take the unstructured object as apply patch
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return s, nil
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default:
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// Otherwise, for typed objects, remove null fields from the apply patch,
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// so that ownership is not taken for non-managed fields.
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// See https://github.com/kubernetes/enhancements/tree/master/keps/sig-api-machinery/2155-clientgo-apply
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sourceJSON, err := json.Marshal(source)
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if err != nil {
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return nil, err
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}
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var positivePatch map[string]interface{}
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err = json.Unmarshal(sourceJSON, &positivePatch)
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if err != nil {
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return nil, err
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}
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removeNilValues(reflect.ValueOf(positivePatch), reflect.Value{})
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return &unstructured.Unstructured{Object: positivePatch}, nil
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}
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}
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func removeNilValues(v reflect.Value, parent reflect.Value) {
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for v.Kind() == reflect.Ptr || v.Kind() == reflect.Interface {
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v = v.Elem()
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}
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switch v.Kind() {
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case reflect.Array, reflect.Slice:
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for i := 0; i < v.Len(); i++ {
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removeNilValues(v.Index(i), v)
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}
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case reflect.Map:
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for _, k := range v.MapKeys() {
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switch c := v.MapIndex(k); {
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case !c.IsValid():
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// Skip keys previously deleted
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continue
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case c.IsNil(), c.Elem().Kind() == reflect.Map && len(c.Elem().MapKeys()) == 0:
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v.SetMapIndex(k, reflect.Value{})
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default:
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removeNilValues(c, v)
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}
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}
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// Back process the parent map in case it has been emptied so that it's deleted as well
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if len(v.MapKeys()) == 0 && parent.Kind() == reflect.Map {
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removeNilValues(parent, reflect.Value{})
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}
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}
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}
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