fix: handle non integer values for zone serial

bind/bind.go

@@ -136,7 +136,7 @@ type Counter struct {
 // Counter represents a single zone counter value.
 type ZoneCounter struct {
 	Name   string
-	Serial uint64
+	Serial string
 }
 
 // Gauge represents a single gauge value.

bind/v2/v2.go

@@ -59,7 +59,7 @@ type View struct {
 type Zone struct {
 	Name       string `xml:"name"`
 	Rdataclass string `xml:"rdataclass"`
-	Serial     uint64 `xml:"serial"`
+	Serial     string `xml:"serial"`
 }
 
 type Counter struct {

bind/v3/v3.go

@@ -80,7 +80,7 @@ type Counter struct {
 type ZoneCounter struct {
 	Name       string `xml:"name,attr"`
 	Rdataclass string `xml:"rdataclass,attr"`
-	Serial     uint64 `xml:"serial"`
+	Serial     string `xml:"serial"`
 }
 
 // Client implements bind.Client and can be used to query a BIND v3 API.

bind_exporter.go

@@ -337,9 +337,11 @@ func (c *viewCollector) Collect(ch chan<- prometheus.Metric) {
 
 	for _, v := range c.stats.ZoneViews {
 		for _, z := range v.ZoneData {
-			ch <- prometheus.MustNewConstMetric(
-				zoneSerial, prometheus.CounterValue, float64(z.Serial), v.Name, z.Name,
-			)
+			if suint, err := strconv.ParseUint(z.Serial, 10, 64); err == nil {
+				ch <- prometheus.MustNewConstMetric(
+					zoneSerial, prometheus.CounterValue, float64(suint), v.Name, z.Name,
+				)
+			}
 		}
 	}
 }