kubectl/pkg/kinflate/util/util.go

/*
Copyright 2018 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 (
	"bytes"
	"fmt"
	"io"
	"sort"

	"github.com/ghodss/yaml"

	"k8s.io/apimachinery/pkg/api/meta"
	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
	"k8s.io/apimachinery/pkg/runtime/schema"
	k8syaml "k8s.io/apimachinery/pkg/util/yaml"
)

type GroupVersionKindName struct {
	gvk schema.GroupVersionKind
	// name of the resource.
	name string
}

func Decode(in []byte) (map[GroupVersionKindName]*unstructured.Unstructured, error) {
	decoder := k8syaml.NewYAMLOrJSONDecoder(bytes.NewReader(in), 1024)
	objs := []*unstructured.Unstructured{}

	var err error
	for {
		var out unstructured.Unstructured
		err = decoder.Decode(&out)
		if err != nil {
			break
		}
		objs = append(objs, &out)
	}
	if err != io.EOF {
		return nil, err
	}

	m := map[GroupVersionKindName]*unstructured.Unstructured{}
	for i := range objs {
		metaAccessor, err := meta.Accessor(objs[i])
		if err != nil {
			return nil, err
		}
		name := metaAccessor.GetName()
		typeAccessor, err := meta.TypeAccessor(objs[i])
		if err != nil {
			return nil, err
		}
		apiVersion := typeAccessor.GetAPIVersion()
		kind := typeAccessor.GetKind()
		gv, err := schema.ParseGroupVersion(apiVersion)
		if err != nil {
			return nil, err
		}
		gvk := gv.WithKind(kind)
		gvkn := GroupVersionKindName{
			gvk:  gvk,
			name: name,
		}
		m[gvkn] = objs[i]
	}
	return m, nil
}

func Encode(in map[GroupVersionKindName]*unstructured.Unstructured) ([]byte, error) {
	gvknList := []GroupVersionKindName{}
	for gvkn := range in {
		gvknList = append(gvknList, gvkn)
	}
	sort.Sort(ByGVKN(gvknList))

	firstObj := true
	var b []byte
	buf := bytes.NewBuffer(b)
	for _, gvkn := range gvknList {
		obj := in[gvkn]
		out, err := yaml.Marshal(obj)
		if err != nil {
			return nil, err
		}
		if !firstObj {
			_, err = buf.WriteString("---\n")
			if err != nil {
				return nil, err
			}
		}
		_, err = buf.Write(out)
		if err != nil {
			return nil, err
		}
		firstObj = false
	}
	return buf.Bytes(), nil
}

type mutateFunc func(interface{}) (interface{}, error)

func mutateField(m map[string]interface{}, pathToField []string, createIfNotPresent bool, fns ...mutateFunc) error {
	if len(pathToField) == 0 {
		return nil
	}

	_, found := m[pathToField[0]]
	if !found {
		if !createIfNotPresent {
			return nil
		}
		m[pathToField[0]] = map[string]interface{}{}
	}

	if len(pathToField) == 1 {
		var err error
		for _, fn := range fns {
			m[pathToField[0]], err = fn(m[pathToField[0]])
			if err != nil {
				return err
			}
		}
		return nil
	}

	v := m[pathToField[0]]
	newPathToField := pathToField[1:]
	switch typedV := v.(type) {
	case map[string]interface{}:
		return mutateField(typedV, newPathToField, createIfNotPresent, fns...)
	case []interface{}:
		for i := range typedV {
			item := typedV[i]
			typedItem, ok := item.(map[string]interface{})
			if !ok {
				return fmt.Errorf("%#v is expectd to be %T", item, typedItem)
			}
			err := mutateField(typedItem, newPathToField, createIfNotPresent, fns...)
			if err != nil {
				return err
			}
		}
		return nil
	default:
		return fmt.Errorf("%#v is not expected to be a primitive type", typedV)
	}
}