Add zone serial numbers as metrics

bind/bind.go

@@ -93,6 +93,7 @@ const (
 type Statistics struct {
 	Server      Server
 	Views       []View
+	ZoneViews   []ZoneView
 	TaskManager TaskManager
 }
 
@@ -114,6 +115,12 @@ type View struct {
 	ResolverQueries []Counter
 }
 
+// View represents statistics for a single BIND zone view.
+type ZoneView struct {
+	Name     string
+	ZoneData []ZoneCounter
+}
+
 // TaskManager contains information about all running tasks.
 type TaskManager struct {
 	Tasks       []Task      `xml:"tasks>task"`
@@ -126,6 +133,12 @@ type Counter struct {
 	Counter uint64 `xml:",chardata"`
 }
 
+// Counter represents a single zone counter value.
+type ZoneCounter struct {
+	Name   string
+	Serial uint64
+}
+
 // Gauge represents a single gauge value.
 type Gauge struct {
 	Name  string `xml:"name"`

bind/v2/v2.go

@@ -53,13 +53,13 @@ type View struct {
 	Cache   []bind.Gauge `xml:"cache>rrset"`
 	Rdtype  []Counter    `xml:"rdtype"`
 	Resstat []Counter    `xml:"resstat"`
-	Zones   []Counter    `xml:"zones>zone"`
+	Zones   []Zone       `xml:"zones>zone"`
 }
 
 type Zone struct {
 	Name       string `xml:"name"`
 	Rdataclass string `xml:"rdataclass"`
-	Serial     string `xml:"serial"`
+	Serial     uint64 `xml:"serial"`
 }
 
 type Counter struct {
@@ -107,12 +107,26 @@ func (c *Client) Stats(...bind.StatisticGroup) (bind.Statistics, error) {
 			Name:  view.Name,
 			Cache: view.Cache,
 		}
+		zv := bind.ZoneView{
+			Name: view.Name,
+		}
 		for _, t := range view.Rdtype {
 			v.ResolverQueries = append(v.ResolverQueries, bind.Counter(t))
 		}
 		for _, t := range view.Resstat {
 			v.ResolverStats = append(v.ResolverStats, bind.Counter(t))
 		}
+		for _, zone := range view.Zones {
+			if zone.Rdataclass != "IN" {
+				continue
+			}
+			z := bind.ZoneCounter{
+				Name:   zone.Name,
+				Serial: zone.Serial,
+			}
+			zv.ZoneData = append(zv.ZoneData, z)
+		}
+		s.ZoneViews = append(s.ZoneViews, zv)
 		s.Views = append(s.Views, v)
 	}
 	s.TaskManager = stats.Taskmgr

bind/v3/v3.go

@@ -27,6 +27,8 @@ const (
 	StatusPath = "/xml/v3/status"
 	// TasksPath is the HTTP path of the v3 tasks resource.
 	TasksPath = "/xml/v3/tasks"
+	// ZonesPath is the HTTP path of the v3 zones resource.
+	ZonesPath = "/xml/v3/zones"
 
 	nsstat   = "nsstat"
 	opcode   = "opcode"
@@ -44,6 +46,10 @@ type Statistics struct {
 	Views     []View           `xml:"views>view"`
 }
 
+type ZoneStatistics struct {
+	ZoneViews []ZoneView `xml:"views>view"`
+}
+
 type Server struct {
 	BootTime   time.Time  `xml:"boot-time"`
 	ConfigTime time.Time  `xml:"config-time"`
@@ -54,7 +60,11 @@ type View struct {
 	Name     string       `xml:"name,attr"`
 	Cache    []bind.Gauge `xml:"cache>rrset"`
 	Counters []Counters   `xml:"counters"`
-	Zones    struct{}     `xml:"zones>zone"`
+}
+
+type ZoneView struct {
+	Name  string        `xml:"name,attr"`
+	Zones []ZoneCounter `xml:"zones>zone"`
 }
 
 type Counters struct {
@@ -67,6 +77,12 @@ type Counter struct {
 	Counter uint64 `xml:"counter"`
 }
 
+type ZoneCounter struct {
+	Name       string `xml:"name,attr"`
+	Rdataclass string `xml:"rdataclass,attr"`
+	Serial     uint64 `xml:"serial"`
+}
+
 // Client implements bind.Client and can be used to query a BIND v3 API.
 type Client struct {
 	*bind.XMLClient
@@ -86,6 +102,7 @@ func (c *Client) Stats(groups ...bind.StatisticGroup) (bind.Statistics, error) {
 	}
 
 	var stats Statistics
+	var zonestats ZoneStatistics
 	if m[bind.ServerStats] || m[bind.ViewStats] {
 		if err := c.Get(ServerPath, &stats); err != nil {
 			return s, err
@@ -122,6 +139,28 @@ func (c *Client) Stats(groups ...bind.StatisticGroup) (bind.Statistics, error) {
 			s.Views = append(s.Views, v)
 		}
 	}
+
+	if err := c.Get(ZonesPath, &zonestats); err != nil {
+		return s, err
+	}
+
+	for _, view := range zonestats.ZoneViews {
+		v := bind.ZoneView{
+			Name: view.Name,
+		}
+		for _, zone := range view.Zones {
+			if zone.Rdataclass != "IN" {
+				continue
+			}
+			z := bind.ZoneCounter{
+				Name:   zone.Name,
+				Serial: zone.Serial,
+			}
+			v.ZoneData = append(v.ZoneData, z)
+		}
+		s.ZoneViews = append(s.ZoneViews, v)
+	}
+
 	if m[bind.TaskStats] {
 		if err := c.Get(TasksPath, &stats); err != nil {
 			return s, err

bind_exporter.go

@@ -205,6 +205,11 @@ var (
 		"Total number of available worker threads.",
 		nil, nil,
 	)
+	zoneSerial = prometheus.NewDesc(
+		prometheus.BuildFQName(namespace, "", "zone_serial"),
+		"Zone serial number.",
+		[]string{"view", "zone_name"}, nil,
+	)
 )
 
 type collectorConstructor func(*bind.Statistics) prometheus.Collector
@@ -327,6 +332,14 @@ func (c *viewCollector) Collect(ch chan<- prometheus.Metric) {
 			level.Warn(logger).Log("msg", "Error parsing RTT", "err", err)
 		}
 	}
+
+	for _, v := range c.stats.ZoneViews {
+		for _, z := range v.ZoneData {
+			ch <- prometheus.MustNewConstMetric(
+				zoneSerial, prometheus.CounterValue, float64(z.Serial), v.Name, z.Name,
+			)
+		}
+	}
 }
 
 type taskCollector struct {

bind_exporter_test.go

@@ -61,6 +61,7 @@ var (
 		`bind_resolver_query_duration_seconds_bucket{view="_default",le="0.8"} 187375`,
 		`bind_resolver_query_duration_seconds_bucket{view="_default",le="1.6"} 188409`,
 		`bind_resolver_query_duration_seconds_bucket{view="_default",le="+Inf"} 227755`,
+		`bind_zone_serial{view="_default",zone_name="TEST_ZONE"} 123`,
 	}
 	taskStats = []string{
 		`bind_tasks_running 8`,
@@ -195,6 +196,7 @@ func newV3Server() *httptest.Server {
 		"/xml/v3/server": "fixtures/v3/server",
 		"/xml/v3/status": "fixtures/v3/status",
 		"/xml/v3/tasks":  "fixtures/v3/tasks",
+		"/xml/v3/zones":  "fixtures/v3/zones",
 	}
 	return httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		if f, ok := m[r.RequestURI]; ok {

fixtures/v2.xml

@@ -7,6 +7,11 @@
         <view>
           <name>_default</name>
           <zones>
+            <zone>
+              <name>TEST_ZONE</name>
+              <rdataclass>IN</rdataclass>
+              <serial>123</serial>
+            </zone>
             <zone>
               <name>0.in-addr.arpa/IN</name>
               <rdataclass>IN</rdataclass>

fixtures/v3/zones

@@ -0,0 +1,14 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<?xml-stylesheet type="text/xsl" href="/bind9.xsl"?>
+<statistics version="3.6">
+  <views>
+    <view name="_default">
+      <zones>
+        <zone name="TEST_ZONE" rdataclass="IN">
+          <type>builtin</type>
+          <serial>123</serial>
+        </zone>
+      </zones>
+    </view>
+  </views>
+</statistics>