Connect to Arista device with crypto/ssh in Go.

main.go

import (
        "bytes"
        "fmt"
        "log"
        "net"
        "os"

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

func main() {
        conn, err := net.Dial("tcp", "somehost:port")
        if err != nil {
                log.Fatal(err)
        }
        defer conn.Close()

        interactiveAuth := ssh.KeyboardInteractive(
                func(user, instruction string, questions []string, echos []bool) ([]string, error) {
                        answers := make([]string, len(questions))
                        for i := range answers {
                                answers[i] = os.Getenv("SSHPASSWORD")
                        }

                        return answers, nil
                },
        )
        config := &ssh.ClientConfig{
                HostKeyCallback: ssh.InsecureIgnoreHostKey(),
                User:os.Getenv("USER"),
                Auth: []ssh.AuthMethod{interactiveAuth},
        }

        sshConn, chans, reqs, err := ssh.NewClientConn(conn, "somehost:port", config)
        if err != nil {
                log.Fatal(err)
        }
        client := ssh.NewClient(sshConn, chans, reqs)
        session, err := client.NewSession()
        if err != nil {
                        log.Fatal("Failed to create session: ", err)
        }
        defer session.Close()

        var b bytes.Buffer
        session.Stdout = &b
        if err := session.Run("show version"); err != nil {
                        log.Fatal("Failed to run: " + err.Error())
        }
        fmt.Println(b.String())
}

Setting up the socket manually isn't necessary. Here is a simpler version:

package main

import (
        "bytes"
        "fmt"
        "log"
        "os"

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

func main() {
        interactiveAuth := ssh.KeyboardInteractive(
                func(user, instruction string, questions []string, echos []bool) ([]string, error) {
                        answers := make([]string, len(questions))
                        for i := range answers {
                                answers[i] = os.Getenv("SSHPASS")
                        }

                        return answers, nil
                },
        )
        config := &ssh.ClientConfig{
                HostKeyCallback: ssh.InsecureIgnoreHostKey(),
                User:os.Getenv("USER"),
                Auth: []ssh.AuthMethod{interactiveAuth},
        }

        client, err := ssh.Dial("tcp", "127.0.0.1:2022", config)
        if err != nil {
                        log.Fatal("Failed to create client: ", err)
        }
        defer client.Close()

        session, err := client.NewSession()
        if err != nil {
                        log.Fatal("Failed to create session: ", err)
        }
        defer session.Close()
        var stdout bytes.Buffer
        session.Stdout = &stdout
        if err := session.Run("show version"); err != nil {
                        log.Fatal("Failed to run: " + err.Error())
        }

        fmt.Println(stdout.String())
}

Hey just wanted to say thank you for sharing your code. I struggled with keyboard interactive auth. Your example really helped. Thanks again.

@twr14152 thank you so much for taking the time to leave a comment! I am thrilled that you found this useful.