Add more metrics (#176)

middleware/metrics/README.md

@@ -7,13 +7,16 @@ The following metrics are exported:
 
 * coredns_dns_request_count_total
 * coredns_dns_request_duration_seconds
+* coredns_dns_request_size_bytes
+* coredns_dns_request_do_count_total
 * coredns_dns_response_size_bytes
 * coredns_dns_response_rcode_count_total
 
 Each counter has a label `zone` which is the zonename used for the request/response. and a label
-`qtype` which old the query type. The `dns_request_count_total` has an extra label `proto` which
-holds the transport of the response ("udp" or "tcp"). The `response_rcode_count_total` has an extra
-label `rcode` which holds the rcode of the response.
+`qtype` which old the query type. The `dns_request_count_total` has extra labels: `proto` which
+holds the transport of the response ("udp" or "tcp") and the address family of the transport (1
+= IP (IP version 4), 2 = IP6 (IP version 6)).
+The `response_rcode_count_total` has an extra label `rcode` which holds the rcode of the response.
 
 If monitoring is enabled queries that do not enter the middleware chain are exported under the fake
 domain "dropped" (without a closing dot).

middleware/metrics/handler.go

@@ -11,8 +11,8 @@ import (
 
 func (m Metrics) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (int, error) {
 	state := middleware.State{W: w, Req: r}
-	qname := state.Name()
-	net := state.Proto()
+
+	qname := state.QName()
 	zone := middleware.Zones(m.ZoneNames).Matches(qname)
 	if zone == "" {
 		zone = "."
@@ -22,21 +22,33 @@ func (m Metrics) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg)
 	rw := middleware.NewResponseRecorder(w)
 	status, err := m.Next.ServeDNS(ctx, rw, r)
 
-	Report(zone, net, rw.Rcode(), rw.Size(), rw.Start())
+	Report(state, zone, rw.Rcode(), rw.Size(), rw.Start())
 
 	return status, err
 }
 
 // Report is a plain reporting function that the server can use for REFUSED and other
 // queries that are turned down because they don't match any middleware.
-func Report(zone, net, rcode string, size int, start time.Time) {
+func Report(state middleware.State, zone, rcode string, size int, start time.Time) {
 	if requestCount == nil {
 		// no metrics are enabled
 		return
 	}
 
-	requestCount.WithLabelValues(zone, net).Inc()
+	// Proto and Family
+	net := state.Proto()
+	fam := "1"
+	if state.Family() == 2 {
+		fam = "2"
+	}
+
+	requestCount.WithLabelValues(zone, net, fam).Inc()
 	requestDuration.WithLabelValues(zone).Observe(float64(time.Since(start) / time.Second))
+	requestSize.WithLabelValues(zone).Observe(float64(state.Size()))
+	if state.Do() {
+		requestDo.WithLabelValues(zone).Inc()
+	}
+
 	responseSize.WithLabelValues(zone).Observe(float64(size))
 	responseRcode.WithLabelValues(zone, rcode).Inc()
 }

middleware/metrics/metrics.go

@@ -14,8 +14,11 @@ import (
 var (
 	requestCount    *prometheus.CounterVec
 	requestDuration *prometheus.HistogramVec
-	responseSize    *prometheus.HistogramVec
-	responseRcode   *prometheus.CounterVec
+	requestSize     *prometheus.HistogramVec
+	requestDo       *prometheus.CounterVec
+
+	responseSize  *prometheus.HistogramVec
+	responseRcode *prometheus.CounterVec
 )
 
 // Metrics holds the prometheus configuration. The metrics' path is fixed to be /metrics
@@ -42,6 +45,8 @@ func (m *Metrics) Start() error {
 
 		prometheus.MustRegister(requestCount)
 		prometheus.MustRegister(requestDuration)
+		prometheus.MustRegister(requestSize)
+		prometheus.MustRegister(requestDo)
 		prometheus.MustRegister(responseSize)
 		prometheus.MustRegister(responseRcode)
 
@@ -66,8 +71,8 @@ func define() {
 		Namespace: middleware.Namespace,
 		Subsystem: subsystem,
 		Name:      "request_count_total",
-		Help:      "Counter of DNS requests made per zone and protocol.",
-	}, []string{"zone", "proto"})
+		Help:      "Counter of DNS requests made per zone, protocol and family.",
+	}, []string{"zone", "proto", "family"})
 
 	requestDuration = prometheus.NewHistogramVec(prometheus.HistogramOpts{
 		Namespace: middleware.Namespace,
@@ -77,6 +82,21 @@ func define() {
 		Help:      "Histogram of the time (in seconds) each request took.",
 	}, []string{"zone"})
 
+	requestSize = prometheus.NewHistogramVec(prometheus.HistogramOpts{
+		Namespace: middleware.Namespace,
+		Subsystem: subsystem,
+		Name:      "request_buffer_size_bytes",
+		Help:      "Size of the EDNS0 UDP buffer in bytes (64K for TCP).",
+		Buckets:   []float64{0, 100, 200, 300, 400, 511, 1023, 2047, 4095, 8291, 16e3, 32e3, 48e3, 64e3},
+	}, []string{"zone"})
+
+	requestDo = prometheus.NewCounterVec(prometheus.CounterOpts{
+		Namespace: middleware.Namespace,
+		Subsystem: subsystem,
+		Name:      "request_do_count_total",
+		Help:      "Counter of DNS requests with DO bit set per zone.",
+	}, []string{"zone"})
+
 	responseSize = prometheus.NewHistogramVec(prometheus.HistogramOpts{
 		Namespace: middleware.Namespace,
 		Subsystem: subsystem,