decode kubernetes internal etcd encoding to YAMLs

k8sint.go

package main

import (
	"fmt"
	"io/ioutil"
	"os"

	"k8s.io/apimachinery/pkg/runtime"
	"k8s.io/apimachinery/pkg/runtime/serializer"
	"k8s.io/apimachinery/pkg/runtime/serializer/json"
	"k8s.io/client-go/kubernetes/scheme"
)

func decode(data []byte) (runtime.Object, error) {
	codec := serializer.NewCodecFactory(scheme.Scheme)
	decoder := codec.UniversalDeserializer()
	object, err := runtime.Decode(decoder, data)
	if err != nil {
		return nil, err
	}
	return object, nil
}

func encode(object runtime.Object) ([]byte, error) {
	encoder := json.NewYAMLSerializer(json.DefaultMetaFactory, scheme.Scheme, scheme.Scheme)
	data, err := runtime.Encode(encoder, object)
	if err != nil {
		return nil, err
	}
	return data, nil
}

func main() {
	data, err := ioutil.ReadAll(os.Stdin)
	if err != nil {
		fmt.Fprintf(os.Stderr, "ERR: cant read stdin: %v\n", err)
		os.Exit(1)
	}

	obj, err := decode(data)
	if err != nil {
		fmt.Fprintf(os.Stderr, "ERR: cant decode: %v\n", err)
		os.Exit(1)
	}

	fmt.Printf("GVK: %v\n", obj.GetObjectKind().GroupVersionKind())
	fmt.Printf("%+v\n", obj)

	fmt.Printf("as yaml:\n---\n")
	enc, err := encode(obj)
	if err != nil {
		fmt.Fprintf(os.Stderr, "ERR: cant encode: %v\n", err)
		os.Exit(1)
	}
	fmt.Println(string(enc))
}

or just use https://github.com/jpbetz/auger