serve sftp: serve an rclone remote over SFTP

cmd/serve/sftp/sftp.go

@@ -0,0 +1,101 @@
+// Package sftp implements an SFTP server to serve an rclone VFS
+
+// +build !plan9
+
+package sftp
+
+import (
+	"github.com/ncw/rclone/cmd"
+	"github.com/ncw/rclone/fs/config/flags"
+	"github.com/ncw/rclone/fs/rc"
+	"github.com/ncw/rclone/vfs"
+	"github.com/ncw/rclone/vfs/vfsflags"
+	"github.com/spf13/cobra"
+	"github.com/spf13/pflag"
+)
+
+// Options contains options for the http Server
+type Options struct {
+	ListenAddr     string // Port to listen on
+	Key            string // Path to private key
+	AuthorizedKeys string // Path to authorized keys file
+	User           string // single username
+	Pass           string // password for user
+	NoAuth         bool   // allow no authentication on connections
+}
+
+// DefaultOpt is the default values used for Options
+var DefaultOpt = Options{
+	ListenAddr:     "localhost:2022",
+	AuthorizedKeys: "~/.ssh/authorized_keys",
+}
+
+// Opt is options set by command line flags
+var Opt = DefaultOpt
+
+// AddFlags adds flags for the sftp
+func AddFlags(flagSet *pflag.FlagSet, Opt *Options) {
+	rc.AddOption("sftp", &Opt)
+	flags.StringVarP(flagSet, &Opt.ListenAddr, "addr", "", Opt.ListenAddr, "IPaddress:Port or :Port to bind server to.")
+	flags.StringVarP(flagSet, &Opt.Key, "key", "", Opt.Key, "SSH private key file (leave blank to auto generate)")
+	flags.StringVarP(flagSet, &Opt.AuthorizedKeys, "authorized-keys", "", Opt.AuthorizedKeys, "Authorized keys file")
+	flags.StringVarP(flagSet, &Opt.User, "user", "", Opt.User, "User name for authentication.")
+	flags.StringVarP(flagSet, &Opt.Pass, "pass", "", Opt.Pass, "Password for authentication.")
+	flags.BoolVarP(flagSet, &Opt.NoAuth, "no-auth", "", Opt.NoAuth, "Allow connections with no authentication if set.")
+}
+
+func init() {
+	vfsflags.AddFlags(Command.Flags())
+	AddFlags(Command.Flags(), &Opt)
+}
+
+// Command definition for cobra
+var Command = &cobra.Command{
+	Use:   "sftp remote:path",
+	Short: `Serve the remote over SFTP.`,
+	Long: `rclone serve sftp implements an SFTP server to serve the remote
+over SFTP.  This can be used with an SFTP client or you can make a
+remote of type sftp to use with it.
+
+You can use the filter flags (eg --include, --exclude) to control what
+is served.
+
+The server will log errors.  Use -v to see access logs.
+
+--bwlimit will be respected for file transfers.  Use --stats to
+control the stats printing.
+
+You must provide some means of authentication, either with --user/--pass,
+an authorized keys file (specify location with --authorized-keys - the
+default is the same as ssh) or set the --no-auth flag for no
+authentication when logging in.
+
+Note that this also implements a small number of shell commands so
+that it can provide md5sum/sha1sum/df information for the rclone sftp
+backend.  This means that is can support SHA1SUMs, MD5SUMs and the
+about command when paired with the rclone sftp backend.
+
+If you don't supply a --key then rclone will generate one and cache it
+for later use.
+
+By default the server binds to localhost:2022 - if you want it to be
+reachable externally then supply "--addr :2022" for example.
+
+Note that the default of "--vfs-cache-mode off" is fine for the rclone
+sftp backend, but it may not be with other SFTP clients.
+
+` + vfs.Help,
+	Run: func(command *cobra.Command, args []string) {
+		cmd.CheckArgs(1, 1, command, args)
+		f := cmd.NewFsSrc(args)
+		cmd.Run(false, true, command, func() error {
+			s := newServer(f, &Opt)
+			err := s.Serve()
+			if err != nil {
+				return err
+			}
+			s.Wait()
+			return nil
+		})
+	},
+}