Added comments and example.

Test program done ;)

misc/devices_counter.go

 package main
 
+/*
+This simple program counts the number of devices with a given prefix and outputs the result on stdout in JSON format.
+The output use nerdfonts icons and outputs looks like this: {"text": "󰌶 1  󰶑 0  󰠚 0"}
+
+This can be used with waybar to provide a nice display. You can find a sample configuration below:
+
+  "custom/devices": {
+    "exec": "~/.config/waybar/devices_counter",
+    "format": "{}",
+    "return-type": "json"
+  },
+
+*/
+
 import (
 	"fmt"
 	"log/slog"
@@ -25,7 +39,7 @@ type CounterDevice struct {
 
 var (
 	deviceIcons = map[string]string{
-		"lamp":    " ",
+		"lamp":    "󰌶 ",
 		"motion":  "󰶑 ",
 		"contact": "󰠚 ",
 	}
@@ -84,6 +98,7 @@ func (d *CounterDevice) updateCounter(msg *xaal.Message, prefix string) {
 	}
 }
 
+// update Alive counters
 func (d *CounterDevice) updateAlive(msg *xaal.Message) {
 	cnt := d.getCounter(msg)
 
@@ -92,6 +107,7 @@ func (d *CounterDevice) updateAlive(msg *xaal.Message) {
 	}
 }
 
+// handle xAAL incomming messages
 func (d *CounterDevice) handleMessage(msg *xaal.Message) {
 	// let's filter the messages we are interested in
 	prefix := getPrefix(msg)
@@ -139,25 +155,22 @@ func (d *CounterDevice) sendGetAttritube(addr uuid.UUID) {
 	d.engine.Send(msg)
 }
 
-// display outputs the result on stdout and flush
+// display outputs the result on stdout w/ nerdfonts icons
 func (d *CounterDevice) display() {
-	// slog.Info("Devices", "count", len(devices))
 	prefixs := []string{"lamp", "motion", "contact"}
+	values := ""
 	for _, prefix := range prefixs {
-		fmt.Print(d.displayPrefix(prefix))
-		fmt.Print("  ")
+		values += fmt.Sprintf("%s%d  ", deviceIcons[prefix], d.countPrefix(prefix))
 	}
-	fmt.Print("\n")
-}
-
-func (d *CounterDevice) displayPrefix(prefix string) string {
-	return fmt.Sprintf("%s%d", deviceIcons[prefix], d.countPrefix(prefix))
+	text := fmt.Sprintf(`{"text": "%s"}`, strings.TrimRight(values, " "))
+	fmt.Println(text)
 }
 
 // ----------------------------------------------------------------------------
 // Message handling functions
 // -----------------------------------------------------------------------------
 
+// getPrefix returns the prefix associated for an xAAL Message
 func getPrefix(msg *xaal.Message) string {
 	// let's split the msg.DevType on points and keep the first part
 	tmp := strings.Split(msg.DevType, ".")
@@ -169,6 +182,7 @@ func getPrefix(msg *xaal.Message) string {
 	return prefix
 }
 
+// getAttribute exacts a given attribute from an xAAL Message
 func getAttribute(msg *xaal.Message, attr string) bool {
 	if value, ok := msg.Body[attr].(bool); ok {
 		return value
@@ -176,15 +190,11 @@ func getAttribute(msg *xaal.Message, attr string) bool {
 	return false
 }
 
-func init() {
-	xaal.SetupLogger(slog.LevelDebug)
-}
-
 func main() {
+	xaal.SetupLogger(slog.LevelWarn)
 	eng := xaal.NewEngine()
 	eng.DisableMessageFilter()
 	dev := NewCounterDevice(eng)
-
 	eng.Subscribe(dev.handleMessage)
 	dev.sendIsAlive()
 	eng.Run()