Golang Execute Command via ssh on the remote-server

execute-command-on-remote.go

package main

// link: http://blog.ralch.com/tutorial/golang-ssh-connection/
import (
	"fmt"
	"golang.org/x/crypto/ssh"
	"io/ioutil"
	"log"
	"net"
	"time"
)

const (
	CertPassword      = 1
	CertPublicKeyFile = 2
	DefaultTimeout    = 3 // second
)

type SSH struct {
	Ip      string
	User    string
	Cert    string //password or key file path
	Port    int
	session *ssh.Session
	client  *ssh.Client
}

func (s *SSH) readPublicKeyFile(file string) ssh.AuthMethod {
	buffer, err := ioutil.ReadFile(file)
	if err != nil {
		return nil
	}

	key, err := ssh.ParsePrivateKey(buffer)
	if err != nil {
		return nil
	}
	return ssh.PublicKeys(key)
}

func (s *SSH) Connect(mode int) {

	var config *ssh.ClientConfig
	var auth []ssh.AuthMethod
	if mode == CertPassword {
		auth = []ssh.AuthMethod{ssh.Password(s.Cert)}
	} else if mode == CertPublicKeyFile {
		auth = []ssh.AuthMethod{s.readPublicKeyFile(s.Cert)}
	} else {
		log.Println("does not support mode: ", mode)
		return
	}

	config = &ssh.ClientConfig{
		User: s.User,
		Auth: auth,
		//需要验证服务端，不做验证返回nil就可以，点击HostKeyCallback看源码就知道了
		HostKeyCallback: func(hostname string, remote net.Addr, key ssh.PublicKey) error {
			return nil
		},
		Timeout: time.Second * DefaultTimeout,
	}

	client, err := ssh.Dial("tcp", fmt.Sprintf("%s:%d", s.Ip, s.Port), config)
	if err != nil {
		fmt.Println(err)
		return
	}

	session, err := client.NewSession()
	if err != nil {
		fmt.Println(err)
		client.Close()
		return
	}

	s.session = session
	s.client = client
}

func (s *SSH) RunCmd(cmd string) {
	out, err := s.session.CombinedOutput(cmd)
	if err != nil {
		fmt.Println(err)
	}
	fmt.Println(string(out))
}

func (s *SSH) Close() {
	s.session.Close()
	s.client.Close()
}

//demo
func main() {
	client := &SSH{
		Ip:   "192.168.33.10",
		User: "vagrant",
		Port: 22,
		Cert: "./remote-server/id_rsa",
	}
	client.Connect(CertPublicKeyFile)
	client.RunCmd("cat /etc/os-release")
	client.Close()
}

$ mkdir -p remote-server-command-execute/remote-server
$  remote-server-command-execute/remote-server
$ ssh-keygen -t rsa -b 4096 -C "[email protected]" -f $PWD/id_rsa
$ vagrant up 
$ cd ..
$ go run main.go

helpful links down below:

• https://github.com/jilieryuyi/ssh-simple-client/blob/master/main.go
• https://stackoverflow.com/questions/30075461/how-do-i-add-my-own-public-key-to-vagrant-vm
• https://blog.makingdevs.com/2017/07/04/add-public-key-to-vagrant/