feat: add lk update and lk can-update, and point unknown commands at them

cmd/lk/main.go

@@ -113,6 +113,9 @@ Docs: https://docs.livekit.io/intro/basics/cli/`,
 	app.Commands = append(app.Commands, PhoneNumberCommands...)
 	app.Commands = append(app.Commands, ReplayCommands...)
 	app.Commands = append(app.Commands, PerfCommands...)
+	app.Commands = append(app.Commands, UpdateCommands...)
+	app.CommandNotFound = commandNotFound
+	setCommandNotFound(app.Commands)
 
 	// Register cleanup hook for SIGINT, SIGTERM, SIGQUIT
 	ctx, stop := signal.NotifyContext(
@@ -282,7 +285,7 @@ var rootHelpGroups = []struct {
 	{"PROJECTS", []string{"project", "cloud", "app"}},
 	{"ROOMS AND MEDIA", []string{"room", "token", "dispatch", "egress", "ingress"}},
 	{"TELEPHONY", []string{"sip", "number"}},
-	{"TOOLS", []string{"docs", "perf"}},
+	{"TOOLS", []string{"docs", "perf", "update", "can-update"}},
 }
 
 // agentHelpSections groups a command's visible subcommands by Category, in

cmd/lk/update.go

@@ -0,0 +1,143 @@
+// Copyright 2026 LiveKit, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package main
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+
+	"github.com/Masterminds/semver/v3"
+	"github.com/urfave/cli/v3"
+
+	livekitcli "github.com/livekit/livekit-cli/v2"
+	"github.com/livekit/livekit-cli/v2/pkg/util"
+)
+
+const latestReleaseURL = "https://api.github.com/repos/livekit/livekit-cli/releases/latest"
+
+var UpdateCommands = []*cli.Command{
+	{
+		Name:  "update",
+		Usage: "Update the CLI to the latest version",
+		Description: `Detects how lk was installed (Homebrew, winget, or the Linux install script)
+and runs that installer's upgrade.`,
+		Action: updateCLI,
+	},
+	{
+		Name:   "can-update",
+		Usage:  "Check whether a newer CLI version is available",
+		Action: canUpdateCLI,
+	},
+}
+
+// commandNotFound keeps urfave/cli's default message and exit code 3, and adds
+// how to check for and install a newer lk, since the command may be newer than
+// this build.
+func commandNotFound(_ context.Context, cmd *cli.Command, name string) {
+	msg := fmt.Sprintf("No help topic for '%v'", name)
+	if cmd.Suggest {
+		if suggestion := cli.SuggestCommand(cmd.Commands, name); suggestion != "" {
+			msg += ". " + suggestion
+		}
+	}
+	msg += "\n\nIf this command is new, your lk may be out of date. Run `lk can-update` to check and `lk update` to update."
+	cli.HandleExitCoder(cli.Exit(msg, 3))
+}
+
+func setCommandNotFound(cmds []*cli.Command) {
+	for _, c := range cmds {
+		c.CommandNotFound = commandNotFound
+		setCommandNotFound(c.Commands)
+	}
+}
+
+func canUpdateCLI(ctx context.Context, cmd *cli.Command) error {
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, latestReleaseURL, nil)
+	if err != nil {
+		return err
+	}
+	resp, err := http.DefaultClient.Do(req)
+	if err != nil {
+		return err
+	}
+	defer resp.Body.Close()
+	if resp.StatusCode != http.StatusOK {
+		return fmt.Errorf("checking the latest release: %s", resp.Status)
+	}
+	var release struct {
+		TagName string `json:"tag_name"`
+	}
+	if err := json.NewDecoder(resp.Body).Decode(&release); err != nil {
+		return err
+	}
+	latest, err := semver.NewVersion(release.TagName)
+	if err != nil {
+		return err
+	}
+	current, err := semver.NewVersion(livekitcli.Version)
+	if err != nil {
+		return err
+	}
+
+	if current.LessThan(latest) {
+		out.Statusf("Yes: %s is available (you have %s). Run [%s] to update.", latest, current, util.Accented("lk update"))
+	} else {
+		out.Statusf("No: %s is the latest version.", current)
+	}
+	return nil
+}
+
+func updateCLI(ctx context.Context, cmd *cli.Command) error {
+	exe, err := os.Executable()
+	if err != nil {
+		return err
+	}
+	if resolved, err := filepath.EvalSymlinks(exe); err == nil {
+		exe = resolved
+	}
+
+	args := updateCommandFor(exe)
+	if args == nil {
+		return fmt.Errorf("can't tell how %s was installed; reinstall it with the instructions at https://docs.livekit.io/intro/basics/cli/start/", exe)
+	}
+
+	out.Statusf("Running [%s]", util.Accented(strings.Join(args, " ")))
+	c := exec.CommandContext(ctx, args[0], args[1:]...)
+	c.Stdin, c.Stdout, c.Stderr = os.Stdin, os.Stdout, os.Stderr
+	return c.Run()
+}
+
+// updateCommandFor maps the resolved path of the running binary to the
+// command that upgrades it in place, or nil when the install method is unknown.
+// The paths are the ones each installer writes to: Homebrew's Cellar, winget's
+// Packages directory, and install-cli.sh's INSTALL_PATH.
+func updateCommandFor(exe string) []string {
+	lower := strings.ToLower(strings.ReplaceAll(exe, `\`, "/"))
+	switch {
+	case strings.Contains(lower, "/cellar/livekit-cli/"):
+		return []string{"brew", "upgrade", "livekit-cli"}
+	case strings.Contains(lower, "/winget/packages/livekit.livekitcli"):
+		return []string{"winget", "upgrade", "--id", "LiveKit.LiveKitCLI", "--exact"}
+	case lower == "/usr/local/bin/lk":
+		return []string{"bash", "-c", "curl -sSL https://get.livekit.io/cli | bash"}
+	}
+	return nil
+}

cmd/lk/update_test.go

@@ -0,0 +1,38 @@
+// Copyright 2026 LiveKit, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package main
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestUpdateCommandFor(t *testing.T) {
+	cases := []struct {
+		exe  string
+		want []string
+	}{
+		{"/opt/homebrew/Cellar/livekit-cli/2.18.4/bin/lk", []string{"brew", "upgrade", "livekit-cli"}},
+		{"/home/linuxbrew/.linuxbrew/Cellar/livekit-cli/2.18.4/bin/lk", []string{"brew", "upgrade", "livekit-cli"}},
+		{`C:\Users\me\AppData\Local\Microsoft\WinGet\Packages\LiveKit.LiveKitCLI_Microsoft.Winget.Source_8wekyb3d8bbwe\lk.exe`, []string{"winget", "upgrade", "--id", "LiveKit.LiveKitCLI", "--exact"}},
+		{"/usr/local/bin/lk", []string{"bash", "-c", "curl -sSL https://get.livekit.io/cli | bash"}},
+		{"/Users/me/go/bin/lk", nil},
+		{"/Users/me/code/livekit-cli/bin/lk", nil},
+	}
+	for _, c := range cases {
+		assert.Equal(t, c.want, updateCommandFor(c.exe), c.exe)
+	}
+}