go - 在golang ssh session 关闭中将EOF作为错误

Question

我正在使用“ssh”golang 模块，我想知道我是否实现了它(或尝试)。
session.Close() 中的“EOF”是否是预期的错误？在我在网上看到的示例中，没有人检查 session.Close() 错误。这是我应该忽略或处理的事情吗？
据我所知，服务器也不会出现错误。
我想知道我是否没有正确执行命令，或者没有正确读取缓冲区。

这是我的代码:

package main

import (
    "bytes"
    "fmt"
    "strings"

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

func main() {
    sshConfig := &ssh.ClientConfig{
        User: “my_username”,
        Auth: []ssh.AuthMethod{
            ssh.Password(“my password”),
        },
        HostKeyCallback: ssh.InsecureIgnoreHostKey(),
    }
    connection, err := ssh.Dial("tcp", "localhost:22", sshConfig)
    if err != nil {
        fmt.Printf("Failed to dial: %s\n", err)
        return
    }

    defer func() {
        if err := connection.Close(); err != nil {
            fmt.Println("Received an error closing the ssh connection: ", err)
        } else {
            fmt.Println("No error found closing ssh connection")
        }
    }()

    session, err := connection.NewSession()
    if err != nil {
        fmt.Printf("Failed to create session: %s\n", err)
        return
    }

    defer func() {
        if err := session.Close(); err != nil {
            fmt.Println("Received an error closing the ssh session: ", err)
        } else {
            fmt.Println("No error found closing ssh session")
        }
    }()
    fmt.Println("created session")
    var stdOut bytes.Buffer
    var stdErr bytes.Buffer

    session.Stdout = &stdOut
    session.Stderr = &stdErr
    err = session.Run("pwd")
    fmt.Println("Executed command")

    fmt.Println("Command stdOut is:", strings.TrimRight(stdOut.String(), "\n"), " --- stdError is:", strings.TrimRight(stdErr.String(), "\n"))

}

我得到的输出是:

$ go run main.go
created session
Executed command
Command stdOut is: /Users/my_username  --- stdError is: 
Received an error closing the ssh session:  EOF
No error found closing ssh connection
$ 

有什么建议吗？

Answer 1

这似乎类似于 golang/go/issue 31401 (然后指issue 32453:“x/crypto/ssh :在调用 session.Run() 之后运行 session.Wait() 的语义，当发送 EOF 消息时")

The error is returned because the session has already been closed (by Run()).
The SSH connection leaks because it is never closed — the client object returned from Dial() is discarded, but that's the object that needs to be closed to clean up the underlying TCP connection.

As an aside, this seems to be a subtle API to use correctly.
The session can be closed asynchronously at any time by the other side, and so it's always possible for correctly-written code to get an EOF from Close()

所以你可能想测试那个特定的错误，并在你的 defer 函数中忽略它。