exec.go

package exec

import (
	"bytes"
	"context"
	"fmt"

	"github.com/pkg/errors"
	corev1 "k8s.io/api/core/v1"
	"k8s.io/apimachinery/pkg/runtime"
	"k8s.io/client-go/kubernetes"
	"k8s.io/client-go/rest"
	"k8s.io/client-go/tools/remotecommand"
)

func InPod(
	scheme *runtime.Scheme,
	config *rest.Config,
	namespace, name, container string,
	cmd []string,
) (string, string, error) {
	clientset, err := kubernetes.NewForConfig(config)
	if err != nil {
		return "", "", errors.Wrapf(err, "failed to create kubernetes clientset")
	}

	req := clientset.CoreV1().RESTClient().Post().
		Resource("pods").
		Name(name).
		Namespace(namespace).
		SubResource("exec")

	parameterCodec := runtime.NewParameterCodec(scheme)
	req.VersionedParams(&corev1.PodExecOptions{
		Command:   cmd,
		Container: container,
		Stdin:     false,
		Stdout:    true,
		Stderr:    true,
		TTY:       false,
	}, parameterCodec)

	exec, err := remotecommand.NewSPDYExecutor(config, "POST", req.URL())
	if err != nil {
		return "", "", errors.Wrapf(err, "failed to initialize SPDY executor")
	}

	var stdout, stderr bytes.Buffer
	err = exec.StreamWithContext(
		context.TODO(),
		remotecommand.StreamOptions{
			Stdin:  nil,
			Stdout: &stdout,
			Stderr: &stderr,
			Tty:    false,
		},
	)
	if err != nil {
		return stdout.String(), stderr.String(), errors.Wrapf(
			err,
			fmt.Sprintf("failed to stream execution results back, stdout:\n\"%s\"stderr:\n\"%s\"", stdout.String(), stderr.String()),
		)
	}

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