Reset and close the Stream Deck on panic or termination signal (#57)

deck.go

@@ -253,7 +253,7 @@ func (d *Deck) updateWidgets() {
 
 		// fmt.Println("Repaint", w.Key())
 		if err := w.Update(); err != nil {
-			fatalf("error: %v\n", err)
+			fatalf("error: %v", err)
 		}
 	}
 }

fonts.go

@@ -1,9 +1,11 @@
 package main
 
 import (
+	"fmt"
 	"image"
 	"image/color"
 	"io/ioutil"
+	"os"
 
 	"github.com/flopp/go-findfont"
 	"github.com/golang/freetype"
@@ -86,16 +88,19 @@ func init() {
 	var err error
 	ttfFont, err = loadFont("Roboto-Regular.ttf")
 	if err != nil {
-		fatal(err)
+		fmt.Fprintln(os.Stderr, "Error loading font:", err)
+		os.Exit(1)
 	}
 
 	ttfThinFont, err = loadFont("Roboto-Thin.ttf")
 	if err != nil {
-		fatal(err)
+		fmt.Fprintln(os.Stderr, "Error loading font:", err)
+		os.Exit(1)
 	}
 
 	ttfBoldFont, err = loadFont("Roboto-Bold.ttf")
 	if err != nil {
-		fatal(err)
+		fmt.Fprintln(os.Stderr, "Error loading font:", err)
+		os.Exit(1)
 	}
 }

main.go

@@ -1,11 +1,14 @@
 package main
 
 import (
+	"errors"
 	"flag"
 	"fmt"
 	"os"
+	"os/signal"
 	"path/filepath"
 	"sync"
+	"syscall"
 	"time"
 
 	"github.com/bendahl/uinput"
@@ -19,6 +22,7 @@ var (
 
 	dbusConn *dbus.Conn
 	keyboard uinput.Keyboard
+	shutdown = make(chan error)
 
 	xorg          *Xorg
 	recentWindows []Window
@@ -33,13 +37,11 @@ const (
 )
 
 func fatal(v ...interface{}) {
-	fmt.Fprintln(os.Stderr, v...)
-	os.Exit(1)
+	go func() { shutdown <- errors.New(fmt.Sprint(v...)) }()
 }
 
 func fatalf(format string, a ...interface{}) {
-	fmt.Fprintf(os.Stderr, format, a...)
-	os.Exit(1)
+	go func() { shutdown <- fmt.Errorf(format, a...) }()
 }
 
 func expandPath(base, path string) (string, error) {
@@ -59,13 +61,16 @@ func expandPath(base, path string) (string, error) {
 	return filepath.Abs(path)
 }
 
-func eventLoop(dev *streamdeck.Device, tch chan interface{}) {
+func eventLoop(dev *streamdeck.Device, tch chan interface{}) error {
+	sigs := make(chan os.Signal, 1)
+	signal.Notify(sigs, syscall.SIGINT, syscall.SIGTERM)
+
 	var keyStates sync.Map
 	keyTimestamps := make(map[uint8]time.Time)
 
 	kch, err := dev.ReadKeys()
 	if err != nil {
-		fatal(err)
+		return err
 	}
 	for {
 		select {
@@ -74,9 +79,8 @@ func eventLoop(dev *streamdeck.Device, tch chan interface{}) {
 
 		case k, ok := <-kch:
 			if !ok {
-				err = dev.Open()
-				if err != nil {
-					fatal(err)
+				if err = dev.Open(); err != nil {
+					return err
 				}
 				continue
 			}
@@ -117,14 +121,30 @@ func eventLoop(dev *streamdeck.Device, tch chan interface{}) {
 			case ActiveWindowChangedEvent:
 				handleActiveWindowChanged(dev, event)
 			}
+
+		case err := <-shutdown:
+			return err
+
+		case <-sigs:
+			fmt.Println("Shutting down...")
+			return nil
 		}
 	}
 }
 
+func closeDevice(dev *streamdeck.Device) {
+	if err := dev.Reset(); err != nil {
+		fmt.Fprintln(os.Stderr, "unable to reset Stream Deck")
+	}
+	if err := dev.Close(); err != nil {
+		fmt.Fprintln(os.Stderr, "unable to close Stream Deck")
+	}
+}
+
 func initDevice() (*streamdeck.Device, error) {
 	d, err := streamdeck.Devices()
 	if err != nil {
-		fatal(err)
+		return nil, err
 	}
 	if len(d) == 0 {
 		return nil, fmt.Errorf("no Stream Deck devices found")
@@ -154,38 +174,39 @@ func initDevice() (*streamdeck.Device, error) {
 	}
 	ver, err := dev.FirmwareVersion()
 	if err != nil {
-		return nil, err
+		return &dev, err
 	}
 	fmt.Printf("Found device with serial %s (%d buttons, firmware %s)\n",
 		dev.Serial, dev.Keys, ver)
 
 	if err := dev.Reset(); err != nil {
-		return nil, err
+		return &dev, err
 	}
 
 	if *brightness > 100 {
 		*brightness = 100
 	}
 	if err = dev.SetBrightness(uint8(*brightness)); err != nil {
-		return nil, err
+		return &dev, err
 	}
 
 	return &dev, nil
 }
 
-func main() {
-	flag.Parse()
-
+func run() error {
 	// initialize device
 	dev, err := initDevice()
+	if dev != nil {
+		defer closeDevice(dev)
+	}
 	if err != nil {
-		fatal(err)
+		return fmt.Errorf("Unable to initialize Stream Deck: %s", err)
 	}
 
 	// initialize dbus connection
 	dbusConn, err = dbus.SessionBus()
 	if err != nil {
-		fatal(err)
+		return fmt.Errorf("Unable to connect to dbus: %s", err)
 	}
 
 	// initialize xorg connection and track window focus
@@ -211,9 +232,18 @@ func main() {
 	// load deck
 	deck, err = LoadDeck(dev, ".", *deckFile)
 	if err != nil {
-		fatal(err)
+		return fmt.Errorf("Can't load deck: %s", err)
 	}
 	deck.updateWidgets()
 
-	eventLoop(dev, tch)
+	return eventLoop(dev, tch)
+}
+
+func main() {
+	flag.Parse()
+
+	if err := run(); err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(1)
+	}
 }