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package codespace
// This file defines the 'gh cs ssh' and 'gh cs cp' subcommands.
import (
"context"
"errors"
"fmt"
"io"
"io/ioutil"
"log"
"net"
"os"
"path/filepath"
"strings"
"sync"
"text/template"
"github.com/MakeNowJust/heredoc"
"github.com/cli/cli/v2/internal/codespaces"
"github.com/cli/cli/v2/internal/codespaces/api"
"github.com/cli/cli/v2/pkg/cmdutil"
"github.com/cli/cli/v2/pkg/liveshare"
"github.com/spf13/cobra"
)
type sshOptions struct {
codespace string
profile string
serverPort int
debug bool
debugFile string
stdio bool
config bool
scpArgs []string // scp arguments, for 'cs cp' (nil for 'cs ssh')
}
func newSSHCmd(app *App) *cobra.Command {
var opts sshOptions
sshCmd := &cobra.Command{
Use: "ssh [<flags>...] [-- <ssh-flags>...] [<command>]",
Short: "SSH into a codespace",
Long: heredoc.Doc(`
The 'ssh' command is used to SSH into a codespace. In its simplest form, you can
run 'gh cs ssh', select a codespace interactively, and connect.
The 'ssh' command also supports deeper integration with OpenSSH using a
'--config' option that generates per-codespace ssh configuration in OpenSSH
format. Including this configuration in your ~/.ssh/config improves the user
experience of tools that integrate with OpenSSH, such as bash/zsh completion of
ssh hostnames, remote path completion for scp/rsync/sshfs, git ssh remotes, and
so on.
Once that is set up (see the second example below), you can ssh to codespaces as
if they were ordinary remote hosts (using 'ssh', not 'gh cs ssh').
`),
Example: heredoc.Doc(`
$ gh codespace ssh
$ gh codespace ssh --config > ~/.ssh/codespaces
$ printf 'Match all\nInclude ~/.ssh/codespaces\n' >> ~/.ssh/config
`),
PreRunE: func(c *cobra.Command, args []string) error {
if opts.stdio {
if opts.codespace == "" {
return errors.New("`--stdio` requires explicit `--codespace`")
}
if opts.config {
return errors.New("cannot use `--stdio` with `--config`")
}
if opts.serverPort != 0 {
return errors.New("cannot use `--stdio` with `--server-port`")
}
if opts.profile != "" {
return errors.New("cannot use `--stdio` with `--profile`")
}
}
if opts.config {
if opts.profile != "" {
return errors.New("cannot use `--config` with `--profile`")
}
if opts.serverPort != 0 {
return errors.New("cannot use `--config` with `--server-port`")
}
}
return nil
},
RunE: func(cmd *cobra.Command, args []string) error {
if opts.config {
return app.printOpenSSHConfig(cmd.Context(), opts)
} else {
return app.SSH(cmd.Context(), args, opts)
}
},
DisableFlagsInUseLine: true,
}
sshCmd.Flags().StringVarP(&opts.profile, "profile", "", "", "Name of the SSH profile to use")
sshCmd.Flags().IntVarP(&opts.serverPort, "server-port", "", 0, "SSH server port number (0 => pick unused)")
sshCmd.Flags().StringVarP(&opts.codespace, "codespace", "c", "", "Name of the codespace")
sshCmd.Flags().BoolVarP(&opts.debug, "debug", "d", false, "Log debug data to a file")
sshCmd.Flags().StringVarP(&opts.debugFile, "debug-file", "", "", "Path of the file log to")
sshCmd.Flags().BoolVarP(&opts.config, "config", "", false, "Write OpenSSH configuration to stdout")
sshCmd.Flags().BoolVar(&opts.stdio, "stdio", false, "Proxy sshd connection to stdio")
if err := sshCmd.Flags().MarkHidden("stdio"); err != nil {
fmt.Fprintf(os.Stderr, "%v\n", err)
}
return sshCmd
}
// SSH opens an ssh session or runs an ssh command in a codespace.
func (a *App) SSH(ctx context.Context, sshArgs []string, opts sshOptions) (err error) {
// Ensure all child tasks (e.g. port forwarding) terminate before return.
ctx, cancel := context.WithCancel(ctx)
defer cancel()
// While connecting, ensure in the background that the user has keys installed.
// That lets us report a more useful error message if they don't.
authkeys := make(chan error, 1)
go func() {
authkeys <- checkAuthorizedKeys(ctx, a.apiClient)
}()
codespace, err := getOrChooseCodespace(ctx, a.apiClient, opts.codespace)
if err != nil {
return err
}
liveshareLogger := noopLogger()
if opts.debug {
debugLogger, err := newFileLogger(opts.debugFile)
if err != nil {
return fmt.Errorf("error creating debug logger: %w", err)
}
defer safeClose(debugLogger, &err)
liveshareLogger = debugLogger.Logger
a.errLogger.Printf("Debug file located at: %s", debugLogger.Name())
}
session, err := codespaces.ConnectToLiveshare(ctx, a, liveshareLogger, a.apiClient, codespace)
if err != nil {
if authErr := <-authkeys; authErr != nil {
return authErr
}
return fmt.Errorf("error connecting to codespace: %w", err)
}
defer safeClose(session, &err)
a.StartProgressIndicatorWithLabel("Fetching SSH Details")
remoteSSHServerPort, sshUser, err := session.StartSSHServer(ctx)
a.StopProgressIndicator()
if err != nil {
return fmt.Errorf("error getting ssh server details: %w", err)
}
if opts.stdio {
fwd := liveshare.NewPortForwarder(session, "sshd", remoteSSHServerPort, true)
stdio := newReadWriteCloser(os.Stdin, os.Stdout)
err := fwd.Forward(ctx, stdio) // always non-nil
return fmt.Errorf("tunnel closed: %w", err)
}
localSSHServerPort := opts.serverPort
usingCustomPort := localSSHServerPort != 0 // suppress log of command line in Shell
// Ensure local port is listening before client (Shell) connects.
// Unless the user specifies a server port, localSSHServerPort is 0
// and thus the client will pick a random port.
listen, err := net.Listen("tcp", fmt.Sprintf("127.0.0.1:%d", localSSHServerPort))
if err != nil {
return err
}
defer listen.Close()
localSSHServerPort = listen.Addr().(*net.TCPAddr).Port
connectDestination := opts.profile
if connectDestination == "" {
connectDestination = fmt.Sprintf("%s@localhost", sshUser)
}
tunnelClosed := make(chan error, 1)
go func() {
fwd := liveshare.NewPortForwarder(session, "sshd", remoteSSHServerPort, true)
tunnelClosed <- fwd.ForwardToListener(ctx, listen) // always non-nil
}()
shellClosed := make(chan error, 1)
go func() {
var err error
if opts.scpArgs != nil {
err = codespaces.Copy(ctx, opts.scpArgs, localSSHServerPort, connectDestination)
} else {
err = codespaces.Shell(ctx, a.errLogger, sshArgs, localSSHServerPort, connectDestination, usingCustomPort)
}
shellClosed <- err
}()
select {
case err := <-tunnelClosed:
return fmt.Errorf("tunnel closed: %w", err)
case err := <-shellClosed:
if err != nil {
return fmt.Errorf("shell closed: %w", err)
}
return nil // success
}
}
func (a *App) printOpenSSHConfig(ctx context.Context, opts sshOptions) error {
ctx, cancel := context.WithCancel(ctx)
defer cancel()
var err error
var csList []*api.Codespace
if opts.codespace == "" {
a.StartProgressIndicatorWithLabel("Fetching codespaces")
csList, err = a.apiClient.ListCodespaces(ctx, -1)
a.StopProgressIndicator()
} else {
var codespace *api.Codespace
codespace, err = getOrChooseCodespace(ctx, a.apiClient, opts.codespace)
csList = []*api.Codespace{codespace}
}
if err != nil {
return fmt.Errorf("error getting codespace info: %w", err)
}
type sshResult struct {
codespace *api.Codespace
user string // on success, the remote ssh username; else nil
err error
}
sshUsers := make(chan sshResult, len(csList))
var wg sync.WaitGroup
var status error
for _, cs := range csList {
if cs.State != "Available" && opts.codespace == "" {
fmt.Fprintf(os.Stderr, "skipping unavailable codespace %s: %s\n", cs.Name, cs.State)
status = cmdutil.SilentError
continue
}
cs := cs
wg.Add(1)
go func() {
result := sshResult{}
defer wg.Done()
session, err := codespaces.ConnectToLiveshare(ctx, a, noopLogger(), a.apiClient, cs)
if err != nil {
result.err = fmt.Errorf("error connecting to codespace: %w", err)
} else {
defer session.Close()
_, result.user, err = session.StartSSHServer(ctx)
if err != nil {
result.err = fmt.Errorf("error getting ssh server details: %w", err)
} else {
result.codespace = cs
}
}
sshUsers <- result
}()
}
go func() {
wg.Wait()
close(sshUsers)
}()
// While the above fetches are running, ensure that the user has keys installed.
// That lets us report a more useful error message if they don't.
if err = checkAuthorizedKeys(ctx, a.apiClient); err != nil {
return err
}
t, err := template.New("ssh_config").Parse(heredoc.Doc(`
Host cs.{{.Name}}.{{.EscapedRef}}
User {{.SSHUser}}
ProxyCommand {{.GHExec}} cs ssh -c {{.Name}} --stdio
UserKnownHostsFile=/dev/null
StrictHostKeyChecking no
LogLevel quiet
ControlMaster auto
`))
if err != nil {
return fmt.Errorf("error formatting template: %w", err)
}
ghExec := a.executable.Executable()
for result := range sshUsers {
if result.err != nil {
fmt.Fprintf(os.Stderr, "%v\n", result.err)
status = cmdutil.SilentError
continue
}
// codespaceSSHConfig contains values needed to write an OpenSSH host
// configuration for a single codespace. For example:
//
// Host {{Name}}.{{EscapedRef}
// User {{SSHUser}
// ProxyCommand {{GHExec}} cs ssh -c {{Name}} --stdio
//
// EscapedRef is included in the name to help distinguish between codespaces
// when tab-completing ssh hostnames. '/' characters in EscapedRef are
// flattened to '-' to prevent problems with tab completion or when the
// hostname appears in ControlMaster socket paths.
type codespaceSSHConfig struct {
Name string // the codespace name, passed to `ssh -c`
EscapedRef string // the currently checked-out branch
SSHUser string // the remote ssh username
GHExec string // path used for invoking the current `gh` binary
}
conf := codespaceSSHConfig{
Name: result.codespace.Name,
EscapedRef: strings.ReplaceAll(result.codespace.GitStatus.Ref, "/", "-"),
SSHUser: result.user,
GHExec: ghExec,
}
if err := t.Execute(a.io.Out, conf); err != nil {
return err
}
}
return status
}
type cpOptions struct {
sshOptions
recursive bool // -r
expand bool // -e
}
func newCpCmd(app *App) *cobra.Command {
var opts cpOptions
cpCmd := &cobra.Command{
Use: "cp [-e] [-r] [-- [<scp flags>...]] <sources>... <dest>",
Short: "Copy files between local and remote file systems",
Long: heredoc.Docf(`
The cp command copies files between the local and remote file systems.
As with the UNIX %[1]scp%[1]s command, the first argument specifies the source and the last
specifies the destination; additional sources may be specified after the first,
if the destination is a directory.
The %[1]s--recursive%[1]s flag is required if any source is a directory.
A "remote:" prefix on any file name argument indicates that it refers to
the file system of the remote (Codespace) machine. It is resolved relative
to the home directory of the remote user.
By default, remote file names are interpreted literally. With the %[1]s--expand%[1]s flag,
each such argument is treated in the manner of %[1]sscp%[1]s, as a Bash expression to
be evaluated on the remote machine, subject to expansion of tildes, braces, globs,
environment variables, and backticks. For security, do not use this flag with arguments
provided by untrusted users; see <https://lwn.net/Articles/835962/> for discussion.
`, "`"),
Example: heredoc.Doc(`
$ gh codespace cp -e README.md 'remote:/workspaces/$RepositoryName/'
$ gh codespace cp -e 'remote:~/*.go' ./gofiles/
$ gh codespace cp -e 'remote:/workspaces/myproj/go.{mod,sum}' ./gofiles/
$ gh codespace cp -e -- -F ~/.ssh/codespaces_config 'remote:~/*.go' ./gofiles/
`),
RunE: func(cmd *cobra.Command, args []string) error {
return app.Copy(cmd.Context(), args, opts)
},
DisableFlagsInUseLine: true,
}
// We don't expose all sshOptions.
cpCmd.Flags().BoolVarP(&opts.recursive, "recursive", "r", false, "Recursively copy directories")
cpCmd.Flags().BoolVarP(&opts.expand, "expand", "e", false, "Expand remote file names on remote shell")
cpCmd.Flags().StringVarP(&opts.codespace, "codespace", "c", "", "Name of the codespace")
cpCmd.Flags().StringVarP(&opts.profile, "profile", "p", "", "Name of the SSH profile to use")
return cpCmd
}
// Copy copies files between the local and remote file systems.
// The mechanics are similar to 'ssh' but using 'scp'.
func (a *App) Copy(ctx context.Context, args []string, opts cpOptions) error {
if len(args) < 2 {
return fmt.Errorf("cp requires source and destination arguments")
}
if opts.recursive {
opts.scpArgs = append(opts.scpArgs, "-r")
}
hasRemote := false
for _, arg := range args {
if rest := strings.TrimPrefix(arg, "remote:"); rest != arg {
hasRemote = true
// scp treats each filename argument as a shell expression,
// subjecting it to expansion of environment variables, braces,
// tilde, backticks, globs and so on. Because these present a
// security risk (see https://lwn.net/Articles/835962/), we
// disable them by shell-escaping the argument unless the user
// provided the -e flag.
if !opts.expand {
arg = `remote:'` + strings.Replace(rest, `'`, `'\''`, -1) + `'`
}
} else if !filepath.IsAbs(arg) {
// scp treats a colon in the first path segment as a host identifier.
// Escape it by prepending "./".
// TODO(adonovan): test on Windows, including with a c:\\foo path.
const sep = string(os.PathSeparator)
first := strings.Split(filepath.ToSlash(arg), sep)[0]
if strings.Contains(first, ":") {
arg = "." + sep + arg
}
}
opts.scpArgs = append(opts.scpArgs, arg)
}
if !hasRemote {
return cmdutil.FlagErrorf("at least one argument must have a 'remote:' prefix")
}
return a.SSH(ctx, nil, opts.sshOptions)
}
// fileLogger is a wrapper around an log.Logger configured to write
// to a file. It exports two additional methods to get the log file name
// and close the file handle when the operation is finished.
type fileLogger struct {
*log.Logger
f *os.File
}
// newFileLogger creates a new fileLogger. It returns an error if the file
// cannot be created. The file is created on the specified path, if the path
// is empty it is created in the temporary directory.
func newFileLogger(file string) (fl *fileLogger, err error) {
var f *os.File
if file == "" {
f, err = ioutil.TempFile("", "")
if err != nil {
return nil, fmt.Errorf("failed to create tmp file: %w", err)
}
} else {
f, err = os.Create(file)
if err != nil {
return nil, err
}
}
return &fileLogger{
Logger: log.New(f, "", log.LstdFlags),
f: f,
}, nil
}
func (fl *fileLogger) Name() string {
return fl.f.Name()
}
func (fl *fileLogger) Close() error {
return fl.f.Close()
}
type combinedReadWriteCloser struct {
io.ReadCloser
io.WriteCloser
}
func newReadWriteCloser(reader io.ReadCloser, writer io.WriteCloser) io.ReadWriteCloser {
return &combinedReadWriteCloser{reader, writer}
}
func (crwc *combinedReadWriteCloser) Close() error {
werr := crwc.WriteCloser.Close()
rerr := crwc.ReadCloser.Close()
if werr != nil {
return werr
}
return rerr
}