add graceful shutdown

Signed-off-by: Nahshon Unna-Tsameret <[email protected]>

controller/controller.go

@@ -40,6 +40,8 @@ func (c *Controller) do() {
 	signals := make(chan os.Signal, 1)
 	signal.Notify(signals, os.Interrupt, syscall.SIGTERM)
 
+	defer c.stop(signals)
+
 	c.hat.Start()
 
 	msg := c.state.CreateDisplayMessage()
@@ -74,7 +76,16 @@ func (c *Controller) do() {
 
 		if changed {
 			msg := c.state.CreateDisplayMessage()
-			c.screenEvents <- msg
+			go func() {
+				c.screenEvents <- msg
+			}()
 		}
 	}
 }
+
+func (c *Controller) stop(signals chan os.Signal) {
+	c.hat.Stop()
+	<-c.joystickEvents // wait for the hat graceful shutdown
+	signal.Stop(signals)
+	close(c.done)
+}

controller/hatMock_test.go

@@ -9,6 +9,14 @@ type hatMock struct {
 	se chan hat.DisplayMessage
 }
 
+func (h *hatMock) Start() {
+	/* Implement hat.Interface */
+}
+
+func (h *hatMock) Stop() {
+	close(h.je)
+}
+
 func (h *hatMock) MoveUp() {
 	h.je <- hat.MoveUp
 }
@@ -25,10 +33,6 @@ func (h *hatMock) MoveLeft() {
 	h.je <- hat.MoveLeft
 }
 
-func (h *hatMock) Start() {
-
-}
-
 func (h *hatMock) Press() {
 	h.je <- hat.Pressed
 }

hat/hat.go

@@ -11,6 +11,7 @@ import (
 
 type Interface interface {
 	Start()
+	Stop()
 }
 
 // The format of the HAT color is 16-bit: 5 MS bits are the red color, the middle 6 bits are
@@ -52,18 +53,27 @@ func NewDisplayMessage(mat [][]common.Color, x, y uint8) DisplayMessage {
 type Hat struct {
 	events chan<- Event
 	screen <-chan DisplayMessage
+	done   chan bool
 	input  *stick.Device
 }
 
 func NewHat(joystickEvents chan<- Event, screenEvents <-chan DisplayMessage) *Hat {
-	return &Hat{events: joystickEvents, screen: screenEvents}
+	return &Hat{
+		events: joystickEvents,
+		screen: screenEvents,
+		done:   make(chan bool),
+	}
 }
 
 func (h *Hat) Start() {
 	h.init()
 	go h.do()
 }
 
+func (h *Hat) Stop() {
+	h.done <- true
+}
+
 func (h *Hat) init() {
 	var err error
 	h.input, err = stick.Open(defaultJoystickFile)
@@ -77,6 +87,8 @@ func (h *Hat) init() {
 }
 
 func (h *Hat) do() {
+	defer h.gracefulShutDown()
+
 	for {
 		select {
 		case event := <-h.input.Events:
@@ -104,6 +116,9 @@ func (h *Hat) do() {
 
 		case screenChange := <-h.screen:
 			h.drawScreen(screenChange)
+
+		case <-h.done:
+			return
 		}
 	}
 }
@@ -123,3 +138,9 @@ func (h *Hat) drawScreen(screenChange DisplayMessage) {
 		log.Println("error while printing to HAT display:", err)
 	}
 }
+
+func (h Hat) gracefulShutDown() {
+	screen.Clear()
+	// signal the controller we've done
+	close(h.events)
+}

main.go

@@ -1,8 +1,14 @@
 package main
 
-import "github.com/nunnatsa/piHatDraw/controller"
+import (
+	"fmt"
+
+	"github.com/nunnatsa/piHatDraw/controller"
+)
 
 func main() {
 	control := controller.NewController()
 	<-control.Start()
+
+	fmt.Println("\nGood Bye!")
 }