run a command on a remote machine via SSH

remoteRun.go

unc remoteRun(user string, addr string, privateKey string, cmd string) (string, error) {
    // privateKey could be read from a file, or retrieved from another storage
    // source, such as the Secret Service / GNOME Keyring
    key, err := ssh.ParsePrivateKey([]byte(privateKey))
    if err != nil {
        return "", err
    }
    // Authentication
    config := &ssh.ClientConfig{
        User: user,
        // https://github.com/golang/go/issues/19767 
        // as clientConfig is non-permissive by default 
        // you can set ssh.InsercureIgnoreHostKey to allow any host 
        HostKeyCallback: ssh.InsecureIgnoreHostKey(),
        Auth: []ssh.AuthMethod{
            ssh.PublicKeys(key),
        },
        //alternatively, you could use a password
        /*
            Auth: []ssh.AuthMethod{
                ssh.Password("PASSWORD"),
            },
        */
    }
    // Connect
    client, err := ssh.Dial("tcp", net.JoinHostPort(addr, "22"), config)
    if err != nil {
        return "", err
    }
    // Create a session. It is one session per command.
    session, err := client.NewSession()
    if err != nil {
        return "", err
    }
    defer session.Close()
    var b bytes.Buffer  // import "bytes"
    session.Stdout = &b // get output
    // you can also pass what gets input to the stdin, allowing you to pipe
    // content from client to server
    //      session.Stdin = bytes.NewBufferString("My input")

    // Finally, run the command
    err = session.Run(cmd)
    return b.String(), err
}