main.go: Adding some documentation.

main.go

@@ -11,10 +11,13 @@ import (
 	"github.com/prometheus-community/pro-bing"
 )
 
+// printStats prints statistics from a ping.
 func printStats(pinger *probing.Pinger) {
 	stats := pinger.Statistics()
+
 	fmt.Printf("%d packets transmitted, %d packets received, %.2f%% packet loss\n",
 		stats.PacketsSent, stats.PacketsRecv, stats.PacketLoss)
+
 	fmt.Printf("round-trip min/avg/max/stddev = %v/%v/%v/%v\n",
 		stats.MinRtt, stats.AvgRtt, stats.MaxRtt, stats.StdDevRtt)
 }
@@ -22,14 +25,17 @@ func printStats(pinger *probing.Pinger) {
 func eventLoop(pinger *probing.Pinger) {
 	ticker := time.NewTicker(time.Second * 4)
 
+	// Setup signals on term and interrupt.
 	sig := make(chan os.Signal, 1)
 	signal.Notify(sig, syscall.SIGINT, syscall.SIGTERM)
 
 	for {
 		select {
+		// Got signal. stop pinger and exit goroutine
 		case <-sig:
 			pinger.Stop()
 			return
+		// Ticker ticks. print stats.
 		case <-ticker.C:
 			printStats(pinger)
 		}
@@ -42,6 +48,7 @@ func main() {
 		os.Exit(1)
 	}
 
+	// Setup pinger.
 	pinger, err := probing.NewPinger(os.Args[1])
 	if err != nil {
 		fmt.Println("Error:", err)
@@ -51,8 +58,10 @@ func main() {
 	pinger.SetPrivileged(true)
 	pinger.Interval = time.Second * 2
 
+	// Enter event loop in another goroutine.
 	go eventLoop(pinger)
 
+	// Run pinger in main thread.
 	fmt.Println("PING", pinger.Addr())
 	if err = pinger.Run(); err != nil {
 		fmt.Println("Error:", err)