exec command in K8S Pod

pod.go

func ExecPod(namespace string, name string, command ...string) error {
	config, err := clientcmd.BuildConfigFromKubeconfigGetter("", clientcmd.NewDefaultClientConfigLoadingRules().Load)
	if err != nil {
		return nil, err
	}

	k, err := kubernetes.NewForConfig(config)
	if err != nil {
		return nil, err
	}
	
	
	config, err := clientcmd.BuildConfigFromFlags("<master url>", "<path to kube config>")
	if err != nil {
		return err
	}
	fmt.Printf("executing command %q", strings.Join(command, " "))

	var (
		execOut bytes.Buffer
		execErr bytes.Buffer
	)

	pod, err := k.CoreV1().Pods(namespace).Get(name, metav1.GetOptions{})
	if err != nil {
		return fmt.Errorf("could not get pod info: %v", err)
	}
	// iterate through all containers looking for the one running PostgreSQL.
	if len(pod.Spec.Containers) <= 0 {
		return fmt.Errorf("no container found on Pod %s", pod.Name)
	}

	req := k.CoreV1().RESTClient().Post().
		Resource("pods").
		Name(name).
		Namespace(namespace).
		SubResource("exec")
	req.VersionedParams(&v1.PodExecOptions{
		Container: pod.Spec.Containers[0].Name,
		Command:   command,
		Stdout:    true,
		Stderr:    true,
	}, scheme.ParameterCodec)

	// restConfig, err := rest.InClusterConfig()
	// if err != nil {
	// 	return fmt.Errorf("failed to get in cluster config: %v", err)
	// }
	exec, err := remotecommand.NewSPDYExecutor(config, "POST", req.URL())
	if err != nil {
		return fmt.Errorf("failed to init executor: %v", err)
	}

	err = exec.Stream(remotecommand.StreamOptions{
		Stdout: &execOut,
		Stderr: &execErr,
		Tty:    false,
	})

	if err != nil {
		return fmt.Errorf("could not execute: %v", err)
	}

	if execErr.Len() > 0 {
		return fmt.Errorf("stderr: %v", execErr.String())
	}

	fmt.Println("---------------")
	fmt.Println(execOut.String())
	fmt.Println("---------------")
	return nil
}