cmd/tailscale/cli: add a hidden configure subcommand

Also make `tailscale configure-host` an alias to `tailscale configure synology`

Updates #7220

Signed-off-by: Maisem Ali <maisem@tailscale.com>

cmd/tailscale/cli/cli.go

@@ -150,6 +150,8 @@ func Run(args []string) (err error) {
 		rootCmd.Subcommands = append(rootCmd.Subcommands, serveCmd)
 	case slices.Contains(args, "update"):
 		rootCmd.Subcommands = append(rootCmd.Subcommands, updateCmd)
+	case slices.Contains(args, "configure"):
+		rootCmd.Subcommands = append(rootCmd.Subcommands, configureCmd)
 	}
 	if runtime.GOOS == "linux" && distro.Get() == distro.Synology {
 		rootCmd.Subcommands = append(rootCmd.Subcommands, configureHostCmd)

cmd/tailscale/cli/configure-synology.go

@@ -18,9 +18,23 @@
 	"tailscale.com/version/distro"
 )
 
+// configureHostCmd is the "tailscale configure-host" command which
+// was once used to configure Synology devices, but is now a redirect
+// to "tailscale configure synology".
 var configureHostCmd = &ffcli.Command{
 	Name:      "configure-host",
-	Exec:      runConfigureHost,
+	Exec:      runConfigureSynology,
+	ShortHelp: synologyConfigureCmd.ShortHelp,
+	LongHelp:  synologyConfigureCmd.LongHelp,
+	FlagSet: (func() *flag.FlagSet {
+		fs := newFlagSet("configure-host")
+		return fs
+	})(),
+}
+
+var synologyConfigureCmd = &ffcli.Command{
+	Name:      "synology",
+	Exec:      runConfigureSynology,
 	ShortHelp: "Configure Synology to enable more Tailscale features",
 	LongHelp: strings.TrimSpace(`
 The 'configure-host' command is intended to run at boot as root
@@ -30,14 +44,12 @@
 See: https://tailscale.com/kb/1152/synology-outbound/
 `),
 	FlagSet: (func() *flag.FlagSet {
-		fs := newFlagSet("configure-host")
+		fs := newFlagSet("synology")
 		return fs
 	})(),
 }
 
-var configureHostArgs struct{}
-
-func runConfigureHost(ctx context.Context, args []string) error {
+func runConfigureSynology(ctx context.Context, args []string) error {
 	if len(args) > 0 {
 		return errors.New("unknown arguments")
 	}

cmd/tailscale/cli/configure.go

@@ -0,0 +1,32 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+package cli
+
+import (
+	"context"
+	"flag"
+	"runtime"
+
+	"github.com/peterbourgon/ff/v3/ffcli"
+	"tailscale.com/version/distro"
+)
+
+var configureCmd = &ffcli.Command{
+	Name: "configure",
+	FlagSet: (func() *flag.FlagSet {
+		fs := newFlagSet("configure")
+		return fs
+	})(),
+	Subcommands: configureSubcommands(),
+	Exec: func(ctx context.Context, args []string) error {
+		return flag.ErrHelp
+	},
+}
+
+func configureSubcommands() (out []*ffcli.Command) {
+	if runtime.GOOS == "linux" && distro.Get() == distro.Synology {
+		out = append(out, synologyConfigureCmd)
+	}
+	return out
+}