First commit

middleware/prometheus/handler.go

@@ -0,0 +1,31 @@
+package metrics
+
+import (
+	"strconv"
+	"time"
+
+	"github.com/miekg/coredns/middleware"
+	"github.com/miekg/dns"
+)
+
+func (m *Metrics) ServeDNS(w dns.ResponseWriter, r *dns.Msg) (int, error) {
+	context := middleware.Context{W: w, Req: r}
+
+	qname := context.Name()
+	qtype := context.Type()
+	zone := middleware.Zones(m.ZoneNames).Matches(qname)
+	if zone == "" {
+		zone = "."
+	}
+
+	// Record response to get status code and size of the reply.
+	rw := middleware.NewResponseRecorder(w)
+	status, err := m.Next.ServeDNS(rw, r)
+
+	requestCount.WithLabelValues(zone, qtype).Inc()
+	requestDuration.WithLabelValues(zone).Observe(float64(time.Since(rw.Start()) / time.Second))
+	responseSize.WithLabelValues(zone).Observe(float64(rw.Size()))
+	responseRcode.WithLabelValues(zone, strconv.Itoa(rw.Rcode())).Inc()
+
+	return status, err
+}