initial commit of the implementation

.gitignore

@@ -10,3 +10,9 @@
 
 # Output of the go coverage tool, specifically when used with LiteIDE
 *.out
+
+# Development
+*.swp
+*.swo
+*.bak*
+vendor

Dockerfile

@@ -0,0 +1,13 @@
+FROM golang:1.13.1-buster as builder
+WORKDIR /app
+COPY . .
+
+ENV GOARCH arm
+ENV GOARM 7
+ENV GOOS linux
+RUN ["go", "build", "-o", "trafficlights", "."]
+
+FROM raspbian/jessie:latest
+WORKDIR /app
+COPY --from=builder /app/trafficlights /app
+CMD ["/app/trafficlights"]

go.mod

@@ -0,0 +1,5 @@
+module tamarakaufler/traffic-lights
+
+go 1.12
+
+require github.com/stianeikeland/go-rpio v4.2.0+incompatible

go.sum

@@ -0,0 +1,2 @@
+github.com/stianeikeland/go-rpio v4.2.0+incompatible h1:CUOlIxdJdT+H1obJPsmg8byu7jMSECLfAN9zynm5QGo=
+github.com/stianeikeland/go-rpio v4.2.0+incompatible/go.mod h1:Sh81rdJwD96E2wja2Gd7rrKM+XZ9LrwvN2w4IXrqLR8=

main.go

@@ -0,0 +1,80 @@
+package main
+
+import (
+	"fmt"
+	"os"
+	"os/signal"
+	"syscall"
+	"time"
+
+	"github.com/stianeikeland/go-rpio"
+)
+
+func main() {
+	fmt.Printf("Starting traffic lights at %s\n", time.Now())
+
+	if err := rpio.Open(); err != nil {
+		fmt.Println(err)
+		os.Exit(1)
+	}
+
+	// Get the pin for each of the lights
+	redPin := rpio.Pin(2)
+	yellowPin := rpio.Pin(3)
+	greenPin := rpio.Pin(4)
+
+	// Set the pins to output mode
+	redPin.Output()
+	yellowPin.Output()
+	greenPin.Output()
+
+	// Clean up on ctrl-c and turn lights out
+	c := make(chan os.Signal, 1)
+	signal.Notify(c, os.Interrupt, syscall.SIGTERM)
+	go func() {
+		<-c
+
+		fmt.Printf("Switching off traffic lights at %s\n", time.Now())
+
+		redPin.Low()
+		yellowPin.Low()
+		greenPin.Low()
+
+		os.Exit(0)
+	}()
+
+	defer rpio.Close()
+
+	// Turn lights off to start.
+	redPin.Low()
+	yellowPin.Low()
+	greenPin.Low()
+
+	fmt.Printf("All traffic lights switched off at %s\n\n", time.Now())
+
+	// A while true loop.
+	for {
+		// Red
+		redPin.High()
+		time.Sleep(time.Second * 2)
+
+		// Yellow
+		redPin.Low()
+		yellowPin.High()
+		time.Sleep(time.Second)
+
+		// Green
+		yellowPin.Low()
+		greenPin.High()
+		time.Sleep(time.Second * 2)
+
+		// Yellow
+		greenPin.Low()
+		yellowPin.High()
+		time.Sleep(time.Second * 2)
+
+		// Yellow off
+		yellowPin.Low()
+	}
+
+}