initial button watcher in place

go.mod

@@ -26,6 +26,7 @@ require (
 	github.com/miekg/dns v1.1.4 // indirect
 	github.com/pkg/errors v0.9.1 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
+	github.com/stianeikeland/go-rpio/v4 v4.6.0 // indirect
 	github.com/tadglines/go-pkgs v0.0.0-20140924210655-1f86682992f1 // indirect
 	golang.org/x/crypto v0.0.0-20190621222207-cc06ce4a13d4 // indirect
 	golang.org/x/net v0.0.0-20191004110552-13f9640d40b9 // indirect

go.sum

@@ -56,6 +56,8 @@ github.com/spf13/pflag v1.0.3/go.mod h1:DYY7MBk1bdzusC3SYhjObp+wFpr4gzcvqqNjLnIn
 github.com/spf13/pflag v1.0.5 h1:iy+VFUOCP1a+8yFto/drg2CJ5u0yRoB7fZw3DKv/JXA=
 github.com/spf13/pflag v1.0.5/go.mod h1:McXfInJRrz4CZXVZOBLb0bTZqETkiAhM9Iw0y3An2Bg=
 github.com/spf13/viper v1.3.2/go.mod h1:ZiWeW+zYFKm7srdB9IoDzzZXaJaI5eL9QjNiN/DMA2s=
+github.com/stianeikeland/go-rpio/v4 v4.6.0 h1:eAJgtw3jTtvn/CqwbC82ntcS+dtzUTgo5qlZKe677EY=
+github.com/stianeikeland/go-rpio/v4 v4.6.0/go.mod h1:A3GvHxC1Om5zaId+HqB3HKqx4K/AqeckxB7qRjxMK7o=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
 github.com/stretchr/testify v1.4.0 h1:2E4SXV/wtOkTonXsotYi4li6zVWxYlZuYNCXe9XRJyk=

pkg/dashboard/button.go

@@ -0,0 +1,29 @@
+package dashboard
+
+import (
+	"fmt"
+	"time"
+
+	"github.com/stianeikeland/go-rpio/v4"
+)
+
+func (a *App) WatchButton() {
+	if err := rpio.Open(); err != nil {
+		fmt.Println(err)
+		return
+	}
+	defer rpio.Close()
+	buttonPin := rpio.Pin(a.ButtonPin)
+
+	buttonPin.Input()
+	buttonPin.PullUp()
+	buttonPin.Detect(rpio.FallEdge)     // enable falling edge event detection
+	defer buttonPin.Detect(rpio.NoEdge) // disable edge event detection
+
+	for {
+		if buttonPin.EdgeDetected() { // check if event occured
+			fmt.Println("button pressed")
+		}
+		time.Sleep(time.Second / 2)
+	}
+}

pkg/dashboard/dashboard.go

@@ -27,10 +27,11 @@ var (
 
 // App encapsulates all the config for the server
 type App struct {
-	Router *mux.Router
-	Port   int
-	Array  *neopixel.LEDArray
-	Screen *screen.Display
+	Router    *mux.Router
+	Port      int
+	Array     *neopixel.LEDArray
+	Screen    *screen.Display
+	ButtonPin int64
 }
 
 func getBaseTemplate() (*template.Template, error) {
@@ -106,13 +107,16 @@ func (a *App) Initialize() {
 		}
 	}
 
+	a.ButtonPin = 4
+
 	a.Router = router
 }
 
 // Run starts the http server
 func (a *App) Run() {
 	http.Handle("/", a.Router)
 	klog.Infof("Starting dashboard server on port %d", a.Port)
+	go a.WatchButton()
 	defer a.Array.WS.Fini()
 	klog.Fatalf("%v", http.ListenAndServe(fmt.Sprintf(":%d", a.Port), nil))
 }