Function execCommandOnce

pkg/utils/exec.go:188–241

execCommandOnce performs a single kubectl exec operation without retries

(
	ctx context.Context,
	client kubernetes.Interface,
	config *rest.Config,
	pod corev1.Pod,
	targetContainer int,
	timeout *time.Duration,
	command ...string,
)

// execCommandOnce performs a single kubectl exec operation without retries
func execCommandOnce(
	ctx context.Context,
	client kubernetes.Interface,
	config *rest.Config,
	pod corev1.Pod,
	targetContainer int,
	timeout *time.Duration,
	command ...string,
) (string, string, error) {
	req := client.CoreV1().RESTClient().Post().
		Resource("pods").
		Name(pod.Name).
		Namespace(pod.Namespace).
		SubResource("exec").
		Param("container", pod.Spec.Containers[targetContainer].Name)

	newConfig := *config // local copy avoids modifying the passed config arg
	if timeout != nil {
		req.Timeout(*timeout)
		newConfig.Timeout = *timeout
	}

	req.VersionedParams(&corev1.PodExecOptions{
		Container: pod.Spec.Containers[targetContainer].Name,
		Command:   command,
		Stdout:    true,
		Stderr:    true,
	}, scheme.ParameterCodec)

	wsExecutor, err := remotecommand.NewWebSocketExecutor(&newConfig, "POST", req.URL().String())
	if err != nil {
		return "", "", err
	}
	spdyExecutor, err := remotecommand.NewSPDYExecutor(&newConfig, "POST", req.URL())
	if err != nil {
		return "", "", err
	}
	executor, err := remotecommand.NewFallbackExecutor(wsExecutor, spdyExecutor, shouldFallbackToSPDY)
	if err != nil {
		return "", "", err
	}

	var stdout, stderr bytes.Buffer
	err = executor.StreamWithContext(ctx, remotecommand.StreamOptions{
		Stdout: &stdout,
		Stderr: &stderr,
	})
	if err != nil {
		retErr := fmt.Errorf("cmd: %s\nerror: %w\nstdErr: %v", command, err, stderr.String())
		return stdout.String(), stderr.String(), retErr
	}

	return stdout.String(), stderr.String(), nil
}