Reset all counters to zero on disconnect

main.go

@@ -168,7 +168,8 @@ func runServer(c *cli.Context) {
 		}
 	}
 	opts.OnConnectionLost = func(client mqtt.Client, err error) {
-		log.Printf("Error: Connection to %s lost: %s", c.String("endpoint"), err)
+		log.Printf("Error: Connection to %s lost: %s, resetting counters", c.String("endpoint"), err)
+		resetMetrics()
 	}
 	client := mqtt.NewClient(opts)
 
@@ -194,6 +195,19 @@ func runServer(c *cli.Context) {
 	fatalfOnError(err, "Failed to bind on %s: ", c.GlobalString("bind-address"))
 }
 
+func resetMetrics() {
+	for topic, _ := range counterMetrics {
+		if counterMetrics[topic] != nil {
+			counterMetrics[topic].Set(0)
+		}
+	}
+	for topic, _ := range gaugeMetrics {
+		if counterMetrics[topic] != nil {
+			counterMetrics[topic].Set(0)
+		}
+	}
+}
+
 // $SYS/broker/bytes/received
 func processUpdate(topic, payload string) {
 	//log.Printf("Got broker update with topic %s and data %s", topic, payload)