Encoding runtime.Object

package main

import (
	"bufio"
	"bytes"
	"fmt"
	"log"

	_ "k8s.io/client-go/kubernetes"
	"k8s.io/client-go/pkg/api"
	"k8s.io/client-go/pkg/runtime"
	"k8s.io/client-go/pkg/runtime/serializer/json"
)

const depYml = `
apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: push
`

func main() {

	// Decode into obj.
	d := api.Codecs.UniversalDecoder()
	obj, gvk, err := d.Decode([]byte(depYml), nil, nil)
	if err != nil {
		log.Fatalf("could not decode depYml: %s\n%s", depYml, err)
	}

	obj.GetObjectKind().SetGroupVersionKind(*gvk)

	// Create YML encoder.
	var encoder runtime.Encoder
	mediaTypes := api.Codecs.SupportedMediaTypes()
	for _, info := range mediaTypes {
		if info.MediaType == "application/yaml" {
			encoder = info.Serializer
			break
		}
	}

	if encoder == nil {
		log.Fatal("encoder == nil")
	}

	gv := obj.GetObjectKind().GroupVersionKind().GroupVersion()
	encoder = json.NewYAMLSerializer(json.DefaultMetaFactory, api.Scheme, api.Scheme)
	encoder = api.Codecs.EncoderForVersion(encoder, gv)

	var b bytes.Buffer
	w := bufio.NewWriter(&b)

	if err := encoder.Encode(obj, w); err != nil {
		log.Fatal(err)
	}

	w.Flush()
	fmt.Println(b.String())
}