exec.go

package kubeapi

/*
 Copyright 2017-2018 Crunchy Data Solutions, Inc.
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
 You may obtain a copy of the License at

      http://www.apache.org/licenses/LICENSE-2.0

 Unless required by applicable law or agreed to in writing, software
 distributed under the License is distributed on an "AS IS" BASIS,
 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.
*/

import (
	"bytes"
	log "github.com/Sirupsen/logrus"
	"io"
	"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"
)

// ExecToPodThroughAPI uninterractively exec to the pod with the command specified.
// :param string command: list of the str which specify the command.
// :param string pod_name: Pod name
// :param string namespace: namespace of the Pod.
// :param io.Reader stdin: Standerd Input if necessary, otherwise `nil`
// :return: string: Output of the command. (STDOUT)
//          string: Errors. (STDERR)
//           error: If any error has occurred otherwise `nil`
func ExecToPodThroughAPI(config *rest.Config, clientset *kubernetes.Clientset, command []string, containerName, podName, namespace string, stdin io.Reader) (string, string, error) {
	req := clientset.Core().RESTClient().Post().
		Resource("pods").
		Name(podName).
		Namespace(namespace).
		SubResource("exec")
	scheme := runtime.NewScheme()
	if err := v1.AddToScheme(scheme); err != nil {
		log.Error(err)
		return "", "", err
	}

	parameterCodec := runtime.NewParameterCodec(scheme)
	req.VersionedParams(&v1.PodExecOptions{
		Command:   command,
		Container: containerName,
		Stdin:     stdin != nil,
		Stdout:    true,
		Stderr:    true,
		TTY:       false,
	}, parameterCodec)

	log.Debug("Request URL:", req.URL().String())

	exec, err := remotecommand.NewSPDYExecutor(config, "POST", req.URL())
	if err != nil {
		log.Error(err)
		return "", "", err
	}

	var stdout, stderr bytes.Buffer
	err = exec.Stream(remotecommand.StreamOptions{
		Stdin:  stdin,
		Stdout: &stdout,
		Stderr: &stderr,
		Tty:    false,
	})
	if err != nil {
		log.Error(err)
		return "", "", err
	}

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