cmd/systray: WIP of a linux systray app

This adds a systray app for linux, similar to the apps for macOS and
windows. There are already a number of community-developed systray apps,
but most of them are either long abandoned, are built for a specific
desktop environment, or simply wrap the tailscale CLI.

This uses fyne.io/systray (a fork of github.com/getlantern/systray)
which uses newer D-Bus specifications to render the tray icon and menu.
This results in a pretty broad support for modern Desktop Environments.

---

This is a work in progress. Some things are still half-built, this is
just where I stopped to take a break.

 - fast user switching works
 - connect and disconnecting work, and show correct icon (including the
   animated loading icon while connecting)
 - devices menu works, but seems to have issues with really large menus,
   either crashing or rending off-screen with no scroll option.
 - clipboard and notification integration works to copy device IPs
 - exit node menu is built, but currently non-functional (this is where I
   stopped). Exit nodes are not re-rendered when switching profiles.

The code is currently "okay", but certainly needs cleanup, docs, etc.

Signed-off-by: Will Norris <will@tailscale.com>

cmd/systray/systray.go

@@ -0,0 +1,502 @@
+package main
+
+import (
+	"context"
+	"embed"
+	"fmt"
+	"io"
+	"io/fs"
+	"log"
+	"net/http"
+	"os"
+	"sort"
+	"strings"
+	"sync"
+	"time"
+
+	"fyne.io/systray"
+	"github.com/atotto/clipboard"
+	dbus "github.com/godbus/dbus/v5"
+	"tailscale.com/client/tailscale"
+	"tailscale.com/ipn"
+	"tailscale.com/ipn/ipnstate"
+	"tailscale.com/tailcfg"
+	"tailscale.com/util/set"
+)
+
+var (
+	localClient tailscale.LocalClient
+	chState     chan ipn.State
+	menu        Menu
+
+	mu     sync.Mutex // mu protects status
+	status *ipnstate.Status
+
+	appIcon     *os.File
+	loadingDone chan struct{}
+)
+
+//go:embed icons/*
+var iconFS embed.FS
+
+func main() {
+	systray.Run(onReady, onExit)
+}
+
+type Menu struct {
+	connect    *systray.MenuItem
+	disconnect *systray.MenuItem
+
+	profile     *systray.MenuItem
+	profileSub  []*systray.MenuItem
+	profileDone chan struct{}
+
+	self        *systray.MenuItem
+	devices     *systray.MenuItem
+	devicesSub  []*systray.MenuItem
+	devicesDone chan struct{}
+
+	exitNodes        *systray.MenuItem
+	noExitNode       *systray.MenuItem
+	tailnetExitNodes []*systray.MenuItem
+	mullvadExitNodes []*systray.MenuItem
+	runExitNode      *systray.MenuItem
+	currentExitNode  *systray.MenuItem
+
+	quit *systray.MenuItem
+}
+
+func onReady() {
+	log.Printf("starting")
+	ctx := context.Background()
+
+	disconnected, _ := fs.ReadFile(iconFS, "icons/disconnected.png")
+	systray.SetIcon(disconnected)
+
+	appIcon, _ = os.CreateTemp("", "tailscale-systray.png")
+	connected, _ := iconFS.Open("icons/connected.png")
+	io.Copy(appIcon, connected)
+	connected.Close()
+
+	var err error
+	mu.Lock()
+	status, err = localClient.Status(ctx)
+	mu.Unlock()
+	if err != nil {
+		log.Print(err)
+	}
+
+	chState = make(chan ipn.State)
+
+	menu.connect = systray.AddMenuItem("Connect", "")
+	menu.disconnect = systray.AddMenuItem("Disconnect", "")
+	menu.disconnect.Hide()
+	systray.AddSeparator()
+	menu.profile = systray.AddMenuItem("", "")
+	systray.AddSeparator()
+
+	if status != nil && status.Self != nil {
+		title := fmt.Sprintf("This Device: %s (%s)", status.Self.HostName, status.Self.TailscaleIPs[0])
+		menu.self = systray.AddMenuItem(title, "")
+	}
+	menu.devices = systray.AddMenuItem("Network Devices", "")
+	systray.AddSeparator()
+
+	menu.exitNodes = systray.AddMenuItem("Exit Nodes", "")
+
+	menu.quit = systray.AddMenuItem("Quit", "Quit the app")
+	menu.quit.Enable()
+
+	go watchIPNBus(ctx)
+
+	for {
+		select {
+		case st := <-chState:
+			switch st {
+			case ipn.Running:
+				go loadingIcon()
+				mu.Lock()
+				status, err = localClient.Status(ctx)
+				mu.Unlock()
+				if err != nil {
+					log.Print(err)
+				}
+				updateProfilesMenu(ctx)
+				updateDevicesMenu()
+				updateExitNodeMenu()
+				if loadingDone != nil {
+					close(loadingDone)
+				}
+				icon, _ := fs.ReadFile(iconFS, "icons/connected.png")
+				systray.SetIcon(icon)
+				menu.connect.SetTitle("Connected")
+				menu.connect.Disable()
+				menu.disconnect.Show()
+				menu.disconnect.Enable()
+			case ipn.NoState, ipn.Stopped:
+				menu.connect.SetTitle("Connect")
+				menu.connect.Enable()
+				menu.disconnect.Hide()
+				icon, _ := fs.ReadFile(iconFS, "icons/disconnected.png")
+				systray.SetIcon(icon)
+			case ipn.Starting:
+				go loadingIcon()
+			}
+		case <-menu.connect.ClickedCh:
+			_, err = localClient.EditPrefs(ctx, &ipn.MaskedPrefs{
+				Prefs: ipn.Prefs{
+					WantRunning: true,
+				},
+				WantRunningSet: true,
+			})
+			if err != nil {
+				log.Print(err)
+				continue
+			}
+
+		case <-menu.disconnect.ClickedCh:
+			_, err = localClient.EditPrefs(ctx, &ipn.MaskedPrefs{
+				Prefs: ipn.Prefs{
+					WantRunning: false,
+				},
+				WantRunningSet: true,
+			})
+			if err != nil {
+				log.Print(err)
+				continue
+			}
+
+		case <-menu.self.ClickedCh:
+			copyTailscaleIP(status.Self)
+
+		case <-menu.quit.ClickedCh:
+			systray.Quit()
+		}
+	}
+}
+
+func watchIPNBus(ctx context.Context) {
+	watcher, err := localClient.WatchIPNBus(ctx, ipn.NotifyWatchEngineUpdates|ipn.NotifyInitialState|
+		ipn.NotifyInitialPrefs|ipn.NotifyInitialNetMap)
+	if err != nil {
+		log.Printf("watching ipn bus: %v", err)
+	}
+	defer watcher.Close()
+	for {
+		n, err := watcher.Next()
+		if err != nil {
+			log.Printf("ipnbus error: %v", err)
+		}
+		if n.State != nil {
+			chState <- *n.State
+			log.Printf("new state: %v", n.State)
+		}
+	}
+}
+
+func updateProfilesMenu(ctx context.Context) {
+	current, all, err := localClient.ProfileStatus(ctx)
+	if err != nil {
+		log.Print(err)
+		return
+	}
+
+	// include tailnet in profile name if any two profiles have the same name
+	var includeTailnet bool
+	names := make(map[string]bool)
+	for _, pr := range all {
+		if _, ok := names[pr.Name]; ok {
+			includeTailnet = true
+			break
+		}
+		names[pr.Name] = true
+	}
+
+	title := current.Name
+	if includeTailnet {
+		title = fmt.Sprintf("%s\n(%s)", current.Name, current.NetworkProfile.DomainName)
+	}
+	menu.profile.SetTitle(title)
+	if resp, err := http.Get(current.UserProfile.ProfilePicURL); err == nil {
+		b, _ := io.ReadAll(resp.Body)
+		resp.Body.Close()
+		menu.profile.SetIcon(b)
+	}
+
+	if menu.profileDone != nil {
+		close(menu.profileDone)
+	}
+	for _, sm := range menu.profileSub {
+		sm.Remove()
+	}
+	menu.profileSub = nil
+	menu.profileDone = make(chan struct{})
+
+	for _, pr := range all {
+		title := pr.Name
+		if includeTailnet {
+			title = fmt.Sprintf("%s\n(%s)", pr.Name, pr.NetworkProfile.DomainName)
+		}
+		sm := menu.profile.AddSubMenuItem(title, "")
+		setIcon(sm, pr.UserProfile.ProfilePicURL)
+		if resp, err := http.Get(pr.UserProfile.ProfilePicURL); err == nil {
+			b, _ := io.ReadAll(resp.Body)
+			resp.Body.Close()
+			sm.SetIcon(b)
+		}
+		menu.profileSub = append(menu.profileSub, sm)
+		go func() {
+			for {
+				select {
+				case <-menu.profileDone:
+					return
+				case <-sm.ClickedCh:
+					localClient.SwitchProfile(ctx, pr.ID)
+				}
+			}
+		}()
+	}
+}
+
+var httpCache = map[string][]byte{}
+
+func setIcon(menu *systray.MenuItem, urlStr string) {
+	if menu == nil || urlStr == "" {
+		return
+	}
+
+	b, ok := httpCache[urlStr]
+	if !ok {
+		if resp, err := http.Get(urlStr); err == nil {
+			b, _ = io.ReadAll(resp.Body)
+			httpCache[urlStr] = b
+			resp.Body.Close()
+		}
+	}
+
+	if len(b) > 0 {
+		menu.SetIcon(b)
+	}
+}
+
+func updateDevicesMenu() {
+	var ownerSet set.Set[tailcfg.UserProfile]
+	ownerSet.Make()
+
+	tagOwner := tailcfg.UserProfile{
+		ID:          -1,
+		DisplayName: "Tagged Devices",
+		LoginName:   "tagged-devices",
+	}
+	ownedDevices := make(map[tailcfg.UserID][]*ipnstate.PeerStatus)
+
+	for _, peer := range status.Peer {
+		if peer.ShareeNode {
+			continue
+		}
+		if peer.Tags != nil && peer.Tags.Len() > 0 {
+			ownerSet.Add(tagOwner)
+			ownedDevices[tagOwner.ID] = append(ownedDevices[tagOwner.ID], peer)
+			continue
+		}
+		if peer.UserID != status.Self.UserID {
+			ownerSet.Add(status.User[peer.UserID])
+		}
+		ownedDevices[peer.UserID] = append(ownedDevices[peer.UserID], peer)
+	}
+
+	owners := ownerSet.Slice()
+	sort.SliceStable(owners, func(i, j int) bool {
+		return strings.ToLower(owners[i].DisplayName) < strings.ToLower(owners[j].DisplayName)
+	})
+
+	myDevices := tailcfg.UserProfile{
+		ID:          status.Self.UserID,
+		DisplayName: "My Devices",
+		LoginName:   status.User[status.Self.UserID].LoginName,
+	}
+	owners = append([]tailcfg.UserProfile{myDevices}, owners...)
+
+	if menu.devicesDone != nil {
+		close(menu.devicesDone)
+	}
+	for _, sm := range menu.devicesSub {
+		sm.Remove()
+	}
+	menu.devicesSub = nil
+	menu.devicesDone = make(chan struct{})
+
+	var i int
+	for _, u := range owners {
+		i++
+		if i > 50 {
+			// FIXME: systray crashes on even moderately large menus
+			more := menu.devices.AddSubMenuItem("too many items to show", "")
+			more.Disable()
+			menu.devicesSub = append(menu.devicesSub, more)
+			break
+		}
+		if i == 2 {
+			menu.devices.AddSeparator()
+		}
+		ownerMenu := menu.devices.AddSubMenuItem(u.DisplayName, "")
+		loginMenu := ownerMenu.AddSubMenuItem(u.LoginName, "")
+		loginMenu.Disable()
+		menu.devicesSub = append(menu.devicesSub, ownerMenu)
+		menu.devicesSub = append(menu.devicesSub, loginMenu)
+		ownerMenu.AddSeparator()
+		for _, device := range ownedDevices[u.ID] {
+			name := strings.Split(device.DNSName, ".")[0]
+			if name != device.HostName {
+				name += " (" + device.HostName + ")"
+			}
+			sm := ownerMenu.AddSubMenuItem(name, "")
+			menu.devicesSub = append(menu.devicesSub, sm)
+			// TODO: add click handler
+			go func() {
+				for {
+					select {
+					case <-menu.devicesDone:
+						return
+					case <-sm.ClickedCh:
+						copyTailscaleIP(device)
+					}
+				}
+			}()
+		}
+	}
+}
+
+func loadingIcon() {
+	loadingDone = make(chan struct{})
+	var icons [][]byte
+	for i := 1; i <= 16; i++ {
+		b, err := fs.ReadFile(iconFS, fmt.Sprintf("icons/connecting-%d.png", i))
+		if err == nil {
+			icons = append(icons, b)
+		}
+	}
+
+	t := time.NewTicker(300 * time.Millisecond)
+	var i int
+	for {
+		select {
+		case <-loadingDone:
+			return
+		case <-t.C:
+			systray.SetIcon(icons[i])
+			i++
+			if i >= len(icons) {
+				i = 0
+			}
+		}
+	}
+}
+
+func copyTailscaleIP(device *ipnstate.PeerStatus) {
+	if device == nil || len(device.TailscaleIPs) == 0 {
+		return
+	}
+	name := strings.Split(device.DNSName, ".")[0]
+	ip := device.TailscaleIPs[0].String()
+	err := clipboard.WriteAll(ip)
+	if err != nil {
+		log.Printf("clipboard error: %v", err)
+	}
+
+	sendNotification(fmt.Sprintf("Copied Address for %v", name), ip)
+}
+
+func sendNotification(title, content string) {
+	conn, err := dbus.SessionBus()
+	if err != nil {
+		log.Printf("dbus: %v", err)
+		return
+	}
+	timeout := 3 * time.Second
+	obj := conn.Object("org.freedesktop.Notifications", "/org/freedesktop/Notifications")
+	call := obj.Call("org.freedesktop.Notifications.Notify", 0, "Tailscale", uint32(0),
+		appIcon.Name(), title, content, []string{}, map[string]dbus.Variant{}, int32(timeout.Milliseconds()))
+	if call.Err != nil {
+		log.Printf("dbus: %v", call.Err)
+	}
+}
+
+func updateExitNodeMenu() {
+	msg := menu.exitNodes.AddSubMenuItem("Nothing in this menu currently works", "")
+	msg.Disable()
+	menu.exitNodes.AddSeparator()
+
+	menu.noExitNode = menu.exitNodes.AddSubMenuItemCheckbox("None", "", true)
+	menu.exitNodes.AddSeparator()
+	tailnetNodes := menu.exitNodes.AddSubMenuItem("Tailnet Exit Nodes", "")
+	tailnetNodes.Disable()
+	for _, ps := range status.Peer {
+		if !ps.ExitNodeOption || ps.Location != nil {
+			continue
+		}
+		name := strings.Split(ps.DNSName, ".")[0]
+		if !ps.Online {
+			name += " (offline)"
+		}
+		sm := menu.exitNodes.AddSubMenuItemCheckbox(name, "", false)
+		menu.tailnetExitNodes = append(menu.tailnetExitNodes, sm)
+		if !ps.Online {
+			sm.Disable()
+		}
+	}
+	menu.exitNodes.AddSeparator()
+	locationNodes := menu.exitNodes.AddSubMenuItem("Location-based Exit Nodes", "")
+	locationNodes.Disable()
+	mullvadNodes := menu.exitNodes.AddSubMenuItem("Mullvad VPN", "")
+	menu.exitNodes.AddSeparator()
+	menu.runExitNode = menu.exitNodes.AddSubMenuItemCheckbox("Run Exit Node", "", false)
+
+	for _, country := range mullvadExitNodes() {
+		cm := mullvadNodes.AddSubMenuItem(country.name, "")
+		for _, city := range country.cities {
+			cm.AddSubMenuItem(city.name, "")
+		}
+	}
+}
+
+type country struct {
+	name   string
+	cities map[string]*city
+}
+
+type city struct {
+	name  string
+	peers []*ipnstate.PeerStatus
+}
+
+func mullvadExitNodes() (nodes map[string]*country) {
+	for _, ps := range status.Peer {
+		if !ps.ExitNodeOption || ps.Location == nil {
+			continue
+		}
+		if nodes == nil {
+			nodes = make(map[string]*country)
+		}
+		loc := ps.Location
+		if _, ok := nodes[loc.CountryCode]; !ok {
+			nodes[loc.CountryCode] = &country{
+				name:   loc.Country,
+				cities: make(map[string]*city),
+			}
+		}
+		if _, ok := nodes[loc.CountryCode].cities[loc.CityCode]; !ok {
+			nodes[loc.CountryCode].cities[loc.CityCode] = &city{
+				name: loc.City,
+			}
+		}
+		c := nodes[loc.CountryCode].cities[loc.CityCode]
+		c.peers = append(c.peers, ps)
+	}
+	return nodes
+}
+
+func onExit() {
+	log.Printf("exiting")
+	os.Remove(appIcon.Name())
+}

go.mod

@@ -120,7 +120,9 @@ require (
 )
 
 require (
+	fyne.io/systray v1.11.0 // indirect
 	github.com/Microsoft/go-winio v0.6.1 // indirect
+	github.com/atotto/clipboard v0.1.4 // indirect
 	github.com/bits-and-blooms/bitset v1.13.0 // indirect
 	github.com/cyphar/filepath-securejoin v0.2.4 // indirect
 	github.com/dave/astrid v0.0.0-20170323122508-8c2895878b14 // indirect

go.sum

@@ -48,6 +48,8 @@ filippo.io/mkcert v1.4.4 h1:8eVbbwfVlaqUM7OwuftKc2nuYOoTDQWqsoXmzoXZdbc=
 filippo.io/mkcert v1.4.4/go.mod h1:VyvOchVuAye3BoUsPUOOofKygVwLV2KQMVFJNRq+1dA=
 fybrik.io/crdoc v0.6.3 h1:jNNAVINu8up5vrLa0jrV7z7HSlyHF/6lNOrAtrXwYlI=
 fybrik.io/crdoc v0.6.3/go.mod h1:kvZRt7VAzOyrmDpIqREtcKAVFSJYEBoAyniYebsJGtQ=
+fyne.io/systray v1.11.0 h1:D9HISlxSkx+jHSniMBR6fCFOUjk1x/OOOJLa9lJYAKg=
+fyne.io/systray v1.11.0/go.mod h1:RVwqP9nYMo7h5zViCBHri2FgjXF7H2cub7MAq4NSoLs=
 github.com/Abirdcfly/dupword v0.0.11 h1:z6v8rMETchZXUIuHxYNmlUAuKuB21PeaSymTed16wgU=
 github.com/Abirdcfly/dupword v0.0.11/go.mod h1:wH8mVGuf3CP5fsBTkfWwwwKTjDnVVCxtU8d8rgeVYXA=
 github.com/AlekSi/pointer v1.2.0 h1:glcy/gc4h8HnG2Z3ZECSzZ1IX1x2JxRVuDzaJwQE0+w=
@@ -112,6 +114,8 @@ github.com/ashanbrown/forbidigo v1.5.1 h1:WXhzLjOlnuDYPYQo/eFlcFMi8X/kLfvWLYu6CS
 github.com/ashanbrown/forbidigo v1.5.1/go.mod h1:Y8j9jy9ZYAEHXdu723cUlraTqbzjKF1MUyfOKL+AjcU=
 github.com/ashanbrown/makezero v1.1.1 h1:iCQ87C0V0vSyO+M9E/FZYbu65auqH0lnsOkf5FcB28s=
 github.com/ashanbrown/makezero v1.1.1/go.mod h1:i1bJLCRSCHOcOa9Y6MyF2FTfMZMFdHvxKHxgO5Z1axI=
+github.com/atotto/clipboard v0.1.4 h1:EH0zSVneZPSuFR11BlR9YppQTVDbh5+16AmcJi4g1z4=
+github.com/atotto/clipboard v0.1.4/go.mod h1:ZY9tmq7sm5xIbd9bOK4onWV4S6X0u6GY7Vn0Yu86PYI=
 github.com/aws/aws-sdk-go-v2 v1.18.0/go.mod h1:uzbQtefpm44goOPmdKyAlXSNcwlRgF3ePWVW6EtJvvw=
 github.com/aws/aws-sdk-go-v2 v1.24.1 h1:xAojnj+ktS95YZlDf0zxWBkbFtymPeDP+rvUQIH3uAU=
 github.com/aws/aws-sdk-go-v2 v1.24.1/go.mod h1:LNh45Br1YAkEKaAqvmE1m8FUx6a5b/V0oAKV7of29b4=