About using golang to encapsulate ssh to execute commands on the remote host and upload or download files

                                                       

The following tutorial column of golang will introduce to you how to use golang to encapsulate ssh to execute commands on the remote host and upload or download files. I hope it will be helpful to friends who need it. Helped!

In python, paramiko can be used to execute commands, upload and download files on the remote host. You can also encapsulate one with go. In go, you can use ssh and sftp packages to achieve this. The following functions are implemented

• Execute the command on the remote host to return the result, return value
• Upload and download files on the remote host, and how many bytes are transferred

Authentication method

• If a password is specified, the user password is used for authentication, otherwise the user secret key is used for authentication
  • If not specified User, the current user will be used by default
• If no password is specified, the user key method will be used, and the ~/.ssh/id_rsa file private key file will be obtained by default to obtain the secret key
  Similar to paramik

Directly upload the code

package mainimport (
    "errors"
    "fmt"
    "github.com/pkg/sftp"
    "golang.org/x/crypto/ssh"
    "io"
    "io/ioutil"
    "log"
    "os"
    "os/user"
    "time")var (
    DefaultSShTcpTimeout = 15 * time.Second   // 与ssh建立连接的默认时间，自己设置一个就行)// 错误定义var (
    InvalidHostName = errors.New("invalid parameters: hostname is empty")
    InvalidPort     = errors.New("invalid parameters: port must be range 0 ~ 65535"))// 返回当前用户名func getCurrentUser() string {
    user, _ := user.Current()
    return user.Username}// 存放上传或下载的信息type TransferInfo struct {
    Kind         string   // upload或download
    Local        string   // 本地路径
    Dst          string   // 目标路径
    TransferByte int64    // 传输的字节数(byte)}func (t *TransferInfo) String()  string {
    return fmt.Sprintf(`TransforInfo(Kind:"%s", Local: "%s", Dst: "%s", TransferByte: %d)`,
        t.Kind, t.Local, t.Dst, t.TransferByte)}// 存放执行结果的结构体信息type ExecInfo struct {
    Cmd         string
    Output     []byte
    ExitCode int}func (e *ExecInfo) OutputString() string {
    return string(e.Output)}func (e *ExecInfo) String() string {
    return fmt.Sprintf(`ExecInfo(cmd: "%s", exitcode: %d)`,
        e.Cmd, e.ExitCode)}type AuthConfig struct {
    *ssh.ClientConfig
    User     string
    Password string
    KeyFile  string
    Timeout  time.Duration}func (a *AuthConfig) setDefault()  {
    if a.User == "" {
        a.User = getCurrentUser()
    }

    if a.KeyFile == "" {
        userHome, _ := os.UserHomeDir()
        a.KeyFile = fmt.Sprintf("%s/.ssh/id_rsa", userHome)
    }

    if a.Timeout == 0 {
        a.Timeout = DefaultSShTcpTimeout    }}func (a *AuthConfig) SetAuthMethod() (ssh.AuthMethod, error) {
    a.setDefault()
    if a.Password != "" {
        return ssh.Password(a.Password), nil    }
    data, err := ioutil.ReadFile(a.KeyFile)
    if err != nil {
        return nil, err    }
    singer, err := ssh.ParsePrivateKey(data)
    if err != nil {
        return nil, err    }
    return ssh.PublicKeys(singer), nil}func (a *AuthConfig) ApplyConfig() error {
    authMethod, err := a.SetAuthMethod()
    if err != nil {
        return err    }
    a.ClientConfig = &ssh.ClientConfig{
        User: a.User,
        Auth: []ssh.AuthMethod{authMethod},
        HostKeyCallback: ssh.InsecureIgnoreHostKey(),
        Timeout: a.Timeout,
    }
    return nil}// 存放连接的结构体type conn struct {
    client     *ssh.Client
    sftpClient *sftp.Client}func (c *conn) Close()  {
    if c.sftpClient != nil {
        c.sftpClient.Close()
        c.sftpClient = nil    }
    if c.client != nil {
        c.client.Close()
        c.client = nil    }}// SSHClient结构体type SSHClient struct {
    conn
    HostName   string
    Port        int
    AuthConfig AuthConfig}// 设置默认端口信息func (s *SSHClient) setDefaultValue()  {
    if s.Port == 0 {
        s.Port = 22
    }}// 与远程主机连接func (s *SSHClient) Connect() error {
    if s.client != nil {
        log.Println("Already Login")
        return nil    }
    if err := s.AuthConfig.ApplyConfig(); err != nil {
        return err    }
    s.setDefaultValue()
    addr := fmt.Sprintf("%s:%d", s.HostName, s.Port)
    var err error
    s.client, err = ssh.Dial("tcp", addr, s.AuthConfig.ClientConfig)
    if err != nil {
        return err    }
    return nil}// 一个session只能执行一次命令，也就是说不能在同一个session执行多次s.session.CombinedOutput// 如果想执行多次，需要每条为每个命令创建一个session(这里是这样做)func (s *SSHClient) Exec(cmd string) (*ExecInfo, error) {
    session, err := s.client.NewSession()
    if err != nil {
        return nil, err    }
    defer session.Close()
    output, err := session.CombinedOutput(cmd)
    var exitcode int    if err != nil {
        // 断言转成具体实现类型，获取返回值
        exitcode = err.(*ssh.ExitError).ExitStatus()
    }
    return &ExecInfo{
        Cmd: cmd,
        Output: output,
        ExitCode: exitcode,
    }, nil}// 将本地文件上传到远程主机上func (s *SSHClient) Upload(localPath string, dstPath string) (*TransferInfo, error) {
    transferInfo := &TransferInfo{Kind: "upload", Local: localPath, Dst: dstPath, TransferByte: 0}
    var err error    // 如果sftp客户端没有打开，就打开，为了复用
    if s.sftpClient == nil {
        if s.sftpClient, err = sftp.NewClient(s.client); err != nil {
            return transferInfo, err        }
    }
    localFileObj, err := os.Open(localPath)
    if err != nil {
        return transferInfo, err    }
    defer localFileObj.Close()

    dstFileObj, err := s.sftpClient.Create(dstPath)
    if err != nil {
        return transferInfo, err    }
    defer dstFileObj.Close()

    written, err := io.Copy(dstFileObj, localFileObj)
    if err != nil {
        return transferInfo, err    }
    transferInfo.TransferByte = written    return transferInfo, nil}// 从远程主机上下载文件到本地func (s *SSHClient) Download(dstPath string, localPath string)  (*TransferInfo, error) {
    transferInfo := &TransferInfo{Kind: "download", Local: localPath, Dst: dstPath, TransferByte: 0}
    var err error    if s.sftpClient == nil {
        if s.sftpClient, err = sftp.NewClient(s.client); err != nil {
            return transferInfo, err        }
    }
    //defer s.sftpClient.Close()
    localFileObj, err := os.Create(localPath)
    if err != nil {
        return transferInfo, err    }
    defer localFileObj.Close()

    dstFileObj, err := s.sftpClient.Open(dstPath)
    if err != nil {
        return transferInfo, err    }
    defer dstFileObj.Close()

    written, err := io.Copy(localFileObj, dstFileObj)
    if err != nil {
        return transferInfo, err    }
    transferInfo.TransferByte = written    return transferInfo, nil}// SSHclient的构造方法func NewSSHClient(hostname string, port int, authConfig AuthConfig) (*SSHClient, error) {
    switch {
    case hostname == "":
        return nil, InvalidHostName    case port > 65535 || port < 0:
        return nil, InvalidPort    }
    sshClient := &SSHClient{HostName: hostname, Port: port, AuthConfig: authConfig}
    err := sshClient.Connect()
    if err != nil {
        return nil, err    }
    return sshClient, nil}func main()  {// 测试
    sshClient, err := NewSSHClient("172.16.0.178", 22, AuthConfig{User: "root"})
    if err != nil {
        fmt.Println(err)
        return
    }
    defer sshClient.Close()
    //第一次 执行命令
    execinfo, err := sshClient.Exec("ls -l")
    fmt.Println(execinfo.OutputString(), err)
    //第二次执行命令
    out1, exitcode2 := sshClient.Exec("ifconfig -a")
     fmt.Println(string(out1), exitcode2)
     // 上传文件
    transInfoUpload, err := sshClient.Upload("/tmp/passwd", "/tmp/password_upload")
    fmt.Println(transInfoUpload, err)
    // 下载文件
    transInfoDownload, err := sshClient.Download("/etc/passwd", "/tmp/passwd_download")
    fmt.Println(transInfoDownload, err)}

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