$OUTPUT_KEYBOARD=true

src/device/output/output.go

@@ -11,5 +11,8 @@ type Output interface {
 }
 
 func New() Output {
+	if os.Getenv("OUTPUT_KEYBOARD") == "true" {
+		return NewKeyboard()
+	}
 	return NewWriter(os.Stderr)
 }

src/main.go

@@ -12,6 +12,8 @@ import (
 func Main(ctx context.Context) error {
 	reader := input.New()
 	writer := output.New()
+	defer writer.Close()
+
 	interval := time.Millisecond * 50
 	if intervalS, ok := os.LookupEnv("MAIN_INTERVAL_DURATION"); !ok {
 	} else if v, err := time.ParseDuration(intervalS); err != nil {