blob: 85487f8969d1be324f9e28781dc239045d8a77f1 [file] [log] [blame]
// Copyright 2017 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package main
import (
"context"
"errors"
"flag"
"fmt"
"io/ioutil"
"log"
"os"
"os/exec"
"path/filepath"
"strings"
"golang.org/x/build/internal/gomote/protos"
)
func ssh(args []string) error {
if activeGroup != nil {
return fmt.Errorf("command does not support groups")
}
fs := flag.NewFlagSet("ssh", flag.ContinueOnError)
fs.Usage = func() {
fmt.Fprintln(os.Stderr, "ssh usage: gomote ssh <instance>")
fs.PrintDefaults()
os.Exit(1)
}
fs.Parse(args)
if fs.NArg() != 1 {
fs.Usage()
}
name := fs.Arg(0)
sshKeyDir, err := sshConfigDirectory()
if err != nil {
return err
}
pubKey, priKey, err := localKeyPair(sshKeyDir)
if err != nil {
return err
}
pubKeyBytes, err := os.ReadFile(pubKey)
if err != nil {
return err
}
ctx := context.Background()
client := gomoteServerClient(ctx)
resp, err := client.SignSSHKey(ctx, &protos.SignSSHKeyRequest{
GomoteId: name,
PublicSshKey: []byte(pubKeyBytes),
})
if err != nil {
return fmt.Errorf("unable to retrieve SSH certificate: %w", err)
}
certPath, err := writeCertificateToDisk(resp.GetSignedPublicSshKey())
if err != nil {
return err
}
return sshConnect(name, priKey, certPath)
}
func sshConfigDirectory() (string, error) {
configDir, err := os.UserConfigDir()
if err != nil {
return "", fmt.Errorf("unable to retrieve user configuration directory: %w", err)
}
sshConfigDir := filepath.Join(configDir, "gomote", ".ssh")
err = os.MkdirAll(sshConfigDir, 0700)
if err != nil {
return "", fmt.Errorf("unable to create user SSH configuration directory: %w", err)
}
return sshConfigDir, nil
}
func localKeyPair(sshDir string) (string, string, error) {
priKey := filepath.Join(sshDir, "id_ed25519")
pubKey := filepath.Join(sshDir, "id_ed25519.pub")
if !fileExists(priKey) || !fileExists(pubKey) {
log.Printf("local ssh keys do not exist, attempting to create them")
if err := createLocalKeyPair(pubKey, priKey); err != nil {
return "", "", fmt.Errorf("unable to create local SSH key pair: %w", err)
}
}
return pubKey, priKey, nil
}
func createLocalKeyPair(pubKey, priKey string) error {
cmd := exec.Command("ssh-keygen", "-o", "-a", "256", "-t", "ed25519", "-f", priKey)
cmd.Stdout = os.Stdout
cmd.Stdin = os.Stdin
cmd.Stderr = os.Stderr
return cmd.Run()
}
func writeCertificateToDisk(b []byte) (string, error) {
tmpDir := filepath.Join(os.TempDir(), ".gomote")
if err := os.MkdirAll(tmpDir, 0700); err != nil {
return "", fmt.Errorf("unable to create temp directory for certficates: %w", err)
}
tf, err := ioutil.TempFile(tmpDir, "id_ed25519-*-cert.pub")
if err != nil {
return "", err
}
if err := tf.Chmod(0600); err != nil {
return "", err
}
if _, err := tf.Write(b); err != nil {
return "", err
}
return tf.Name(), tf.Close()
}
func sshConnect(name string, priKey, certPath string) error {
ssh, err := exec.LookPath("ssh")
if err != nil {
return fmt.Errorf("path to ssh not found: %w", err)
}
cli := []string{"-o", fmt.Sprintf("CertificateFile=%s", certPath), "-i", priKey, "-p", "2222", name + "@farmer.golang.org"}
fmt.Printf("$ %s %s\n", ssh, strings.Join(cli, " "))
cmd := exec.Command(ssh, cli...)
cmd.Stdout = os.Stdout
cmd.Stdin = os.Stdin
cmd.Stderr = os.Stderr
if err := cmd.Run(); err != nil {
return fmt.Errorf("unable to ssh into instance: %w", err)
}
return nil
}
func fileExists(path string) bool {
if _, err := os.Stat(path); errors.Is(err, os.ErrNotExist) {
return false
}
return true
}