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ssh.go
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ssh.go
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package dialer
import (
"bytes"
"encoding/base64"
"errors"
"fmt"
"io"
"os"
"strconv"
"strings"
"sync"
"time"
"github.com/cnrancher/autok3s/pkg/hosts"
"github.com/cnrancher/autok3s/pkg/types"
"github.com/cnrancher/autok3s/pkg/utils"
"github.com/sirupsen/logrus"
"github.com/moby/term"
"golang.org/x/crypto/ssh"
"golang.org/x/crypto/ssh/terminal"
"k8s.io/apimachinery/pkg/util/wait"
)
var defaultBackoff = wait.Backoff{
Duration: 15 * time.Second,
Factor: 1,
Steps: 5,
}
const scriptWrapper = `#!/bin/sh
set -e
%s
`
var _ hosts.Shell = &SSHShell{}
var _ hosts.Script = &SSHDialer{}
// SSHDialer struct for ssh dialer.
type SSHDialer struct {
sshKey string
sshCert string
sshAddress string
username string
password string
passphrase string
useSSHAgentAuth bool
conn *ssh.Client
uid int
logger *logrus.Logger
shells map[hosts.Shell]hosts.Shell
}
// NewSSHDialer returns new ssh dialer.
func NewSSHDialer(n *types.Node, timeout bool, logger *logrus.Logger) (*SSHDialer, error) {
if len(n.PublicIPAddress) <= 0 && n.InstanceID == "" {
return nil, errors.New("[ssh-dialer] no node IP or node ID is specified")
}
if logger == nil {
logger = logrus.StandardLogger()
}
d := &SSHDialer{
username: n.SSHUser,
password: n.SSHPassword,
passphrase: n.SSHKeyPassphrase,
useSSHAgentAuth: n.SSHAgentAuth,
sshCert: n.SSHCert,
logger: logger,
shells: map[hosts.Shell]hosts.Shell{},
uid: -1,
}
// IP addresses are preferred.
if len(n.PublicIPAddress) > 0 {
d.sshAddress = fmt.Sprintf("%s:%s", n.PublicIPAddress[0], n.SSHPort)
} else {
d.sshAddress = n.InstanceID
}
if d.password == "" && d.sshKey == "" && !d.useSSHAgentAuth && len(n.SSHKeyPath) > 0 {
var err error
d.sshKey, err = utils.SSHPrivateKeyPath(n.SSHKeyPath)
if err != nil {
return nil, err
}
if d.sshCert == "" && len(n.SSHCertPath) > 0 {
d.sshCert, err = utils.SSHCertificatePath(n.SSHCertPath)
if err != nil {
return nil, err
}
}
}
try := 0
if err := wait.ExponentialBackoff(defaultBackoff, func() (bool, error) {
try++
logger.Infof("the %d/%d time tring to ssh to %s with user %s", try, defaultBackoff.Steps, d.sshAddress, d.username)
c, err := d.Dial(timeout)
if err != nil {
return false, nil
}
d.conn = c
return true, nil
}); err != nil {
return nil, fmt.Errorf("[ssh-dialer] init dialer [%s] error: %w", d.sshAddress, err)
}
return d, nil
}
// Dial handshake with ssh address.
func (d *SSHDialer) Dial(t bool) (*ssh.Client, error) {
timeout := defaultBackoff.Duration
if !t {
timeout = 0
}
cfg, err := utils.GetSSHConfig(d.username, d.sshKey, d.passphrase, d.sshCert, d.password, timeout, d.useSSHAgentAuth)
if err != nil {
return nil, err
}
// establish connection with SSH server.
return ssh.Dial("tcp", d.sshAddress, cfg)
}
func (d *SSHDialer) GetClient() *ssh.Client {
return d.conn
}
func (d *SSHDialer) getUserID() error {
if d.uid >= 0 {
return nil
}
session, err := d.conn.NewSession()
if err != nil {
return err
}
defer func() { _ = session.Close() }()
output, err := session.Output("id -u")
if err != nil {
return fmt.Errorf("failed to get current user id from remote host %s, %v", d.sshAddress, err)
}
// it should return a number with user id if ok
d.uid, err = strconv.Atoi(strings.TrimSpace(string(output)))
if err != nil {
return fmt.Errorf("failed to parse uid output from remote host, output: %s, %v", string(output), err)
}
return nil
}
func (d *SSHDialer) Close() error {
if d.conn != nil {
return d.conn.Close()
}
for _, shell := range d.shells {
shell.Close()
delete(d.shells, shell)
}
return nil
}
func (d *SSHDialer) wrapCommands(cmd string) string {
return base64.StdEncoding.EncodeToString([]byte(fmt.Sprintf(scriptWrapper, cmd)))
}
func (d *SSHDialer) ExecuteCommands(cmds ...string) (string, error) {
if err := d.getUserID(); err != nil {
return "", err
}
sudo := ""
if d.uid > 0 {
sudo = "sudo"
}
session, err := d.conn.NewSession()
if err != nil {
return "", err
}
defer session.Close()
encodedCMD := d.wrapCommands(strings.Join(cmds, "\n"))
cmd := fmt.Sprintf("echo \"%s\" | base64 -d | %s sh -", encodedCMD, sudo)
d.logger.Debugf("executing cmd: %s", cmd)
output := bytes.NewBuffer([]byte{})
combinedOutput := singleWriter{
b: io.MultiWriter(d.logger.Out, output),
}
session.Stderr = &combinedOutput
session.Stdout = &combinedOutput
err = session.Run(cmd)
return output.String(), err
}
func (d *SSHDialer) OpenShell() (hosts.Shell, error) {
shell := &SSHShell{
dialer: d,
}
session, err := d.conn.NewSession()
if err != nil {
return nil, err
}
shell.session = session
d.shells[shell] = shell
return shell, nil
}
type SSHShell struct {
Stdin io.ReadCloser
Stdout io.Writer
Stderr io.Writer
Writer io.Writer
Term string
Modes ssh.TerminalModes
session *ssh.Session
dialer *SSHDialer
}
func (d *SSHShell) Write(_ []byte) error {
return nil
}
// Wait waits for the remote command to exit.
func (d *SSHShell) Wait() error {
if d.session != nil {
return d.session.Wait()
}
return nil
}
// Close close the SSH connection.
func (d *SSHShell) Close() error {
defer delete(d.dialer.shells, d)
if d.session != nil {
if err := d.session.Close(); err != nil {
return err
}
}
return nil
}
// SetIO set dialer's reader and writer.
func (d *SSHShell) SetIO(stdout, stderr io.Writer, stdin io.ReadCloser) {
d.Stdout = stdout
d.Stderr = stderr
d.Stdin = stdin
}
// ChangeWindowSize change the window size for current session.
func (d *SSHShell) ChangeWindowSize(win hosts.ShellWindowSize) error {
return d.session.WindowChange(win.Height, win.Width)
}
// SetWriter set dialer's logs writer.
func (d *SSHShell) SetWriter(w io.Writer) *SSHShell {
d.Writer = w
return d
}
// Terminal starts a login shell on the remote host for CLI.
func (d *SSHShell) Terminal() error {
var win hosts.ShellWindowSize
fdInfo, _ := term.GetFdInfo(d.Stdout)
fd := int(fdInfo)
oldState, err := terminal.MakeRaw(fd)
defer func() {
_ = terminal.Restore(fd, oldState)
}()
if err != nil {
return err
}
win.Width, win.Height, err = terminal.GetSize(fd)
if err != nil {
return err
}
if err := d.OpenTerminal(win); err != nil {
return err
}
return d.session.Wait()
}
// OpenTerminal starts a login shell on the remote host.
func (d *SSHShell) OpenTerminal(win hosts.ShellWindowSize) error {
d.Term = os.Getenv("TERM")
if d.Term == "" {
d.Term = "xterm"
}
d.Modes = ssh.TerminalModes{
ssh.ECHO: 1,
ssh.TTY_OP_ISPEED: 14400,
ssh.TTY_OP_OSPEED: 14400,
}
d.session.Stdin = d.Stdin
d.session.Stdout = d.Stdout
d.session.Stderr = d.Stderr
if err := d.session.RequestPty(d.Term, win.Height, win.Width, d.Modes); err != nil {
return err
}
return d.session.Shell()
}
type singleWriter struct {
b io.Writer
mu sync.Mutex
}
func (w *singleWriter) Write(p []byte) (int, error) {
w.mu.Lock()
defer w.mu.Unlock()
return w.b.Write(p)
}