用golang封装ssh用于在远程主机上执行命令，上传或下载文件

python中可以paramiko实现在远程主机上执行命令，上传和下载文件，用go也可以封装一个，在go中用ssh就sftp包可以实现，实现了下面的功能

• 在远程主机执行命令返回结果、返回值
• 上传和下载文件远程主机上，以及传输了多少个字节

认证方式

• 如果指定了密码，那么采用用户+密码的方式认证，否则采用用户+秘钥的方式
  • 如果没有指定用户，则默认使用当前的用户
• 如果没有指定密码，将采用用户+秘钥方式，默认取~/.ssh/id_rsa文件私钥文件获取秘钥
  和paramik类似

直接上代码

package main

import (
    "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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