Go SSH与Cisco设备通信：Pty配置优化解决长命令发送问题

package main

import (
    "fmt"
    "io"
    "log"
    "strings"
    "time"

    "golang.org/x/crypto/ssh"
)

// readUntilPrompt 从SSH输出中读取数据直到遇到指定提示符
func readUntilPrompt(reader io.Reader, prompt string) (string, error) {
    var output strings.Builder
    buf := make([]byte, 1024)
    for {
        n, err := reader.Read(buf)
        if err != nil {
            return "", fmt.Errorf("error reading from sshOut: %v", err)
        }
        output.Write(buf[:n])
        if strings.Contains(output.String(), prompt) {
            break
        }
    }
    return output.String(), nil
}

func main() {
    // 1. SSH配置
    config := &ssh.ClientConfig{
        User: "your_username",
        Auth: []ssh.AuthMethod{
            ssh.Password("your_password"),
        },
        HostKeyCallback: ssh.InsecureHostKeyCallback, // 生产环境请使用更安全的HostKeyCallback
        Timeout:         5 * time.Second,
    }

    // 2. 建立SSH连接
    client, err := ssh.Dial("tcp", "172.16.32.95:22", config)
    if err != nil {
        log.Fatalf("Failed to dial: %v", err)
    }
    defer client.Close()

    // 3. 创建新的会话
    session, err := client.NewSession()
    if err != nil {
        log.Fatalf("Failed to create session: %v", err)
    }
    defer session.Close()

    // 4. 获取标准输入输出管道
    sshOut, err := session.StdoutPipe()
    if err != nil {
        log.Fatalf("Failed to get stdout pipe: %v", err)
    }
    sshIn, err := session.StdinPipe()
    if err != nil {
        log.Fatalf("Failed to get stdin pipe: %v", err)
    }

    // 5. 请求伪终端 (PTY) - 初始配置（可能导致问题）
    modes := ssh.TerminalModes{
        ssh.ECHO:          0,     // 禁用回显
        ssh.TTY_OP_ISPEED: 14400, // input speed = 14.4kbaud
        ssh.TTY_OP_OSPEED: 14400, // output speed = 14.4kbaud
    }
    // 注意：这里的 width 参数可能过小
    if err := session.RequestPty("xterm", 80, 40, modes); err != nil { // height=80, width=40
        log.Fatalf("Request for pseudo terminal failed: %v", err)
    }

    // 6. 启动Shell
    if err := session.Shell(); err != nil {
        log.Fatalf("Failed to start shell: %v", err)
    }

    // 读取初始欢迎信息和提示符
    initialOutput, err := readUntilPrompt(sshOut, "[local]ewag#")
    if err != nil {
        log.Fatalf("Failed to read initial prompt: %v", err)
    }
    fmt.Println("--- Initial Output ---")
    fmt.Println(initialOutput)

    // 发送短命令示例
    commandShort := "show clock\r"
    fmt.Printf("--- Sending command: %s ---\n", strings.TrimSpace(commandShort))
    if _, err := sshIn.Write([]byte(commandShort)); err != nil {
        log.Fatalf("Failed to write command: %v", err)
    }
    responseShort, err := readUntilPrompt(sshOut, "[local]ewag#")
    if err != nil {
        log.Fatalf("Failed to read short command response: %v", err)
    }
    fmt.Println(responseShort)

    // ... 更多操作 ...
}

Last login: Tue Jan 14 18:09:19 -0500 2014 on pts/2 from 10.7.7.14.
Cisco Systems SSI
[local]ewag# 
show session progress ipsg
-service ipsg-gprs-svc
Unknown command - "ipsg-service", unrecognized keyword
[local]ewag# 

if err := session.RequestPty("xterm", 80, 40, modes); err != nil { // height=80, width=40
    log.Fatalf("Request for pseudo terminal failed: %v", err)
}

// 正确配置：增加宽度，将高度设置为0
if err := session.RequestPty("vt100", 0, 200, modes); err != nil { // height=0, width=200
    log.Fatalf("Request for pseudo terminal failed: %v", err)
}

// ... (之前的连接和会话建立代码) ...

// 重新配置并启动会话以应用新的PTY配置
// 注意：PTY只能请求一次，如果要在同一会话中更改，需要重新创建会话或连接
// 假设这里是为了演示，我们重新创建了一个会话
sessionFixed, err := client.NewSession() // 使用同一个client
if err != nil {
    log.Fatalf("Failed to create new session for fix: %v", err)
}
defer sessionFixed.Close()

sshOutFixed, err := sessionFixed.StdoutPipe()
if err != nil {
    log.Fatalf("Failed to get stdout pipe for fix: %v", err)
}
sshInFixed, err := sessionFixed.StdinPipe()
if err != nil {
    log.Fatalf("Failed to get stdin pipe for fix: %v", err)
}

// 优化