TUN-528: Move cloudflared into a separate repo

tunneldns/metrics.go

@@ -0,0 +1,45 @@
+package tunneldns
+
+import (
+	"github.com/coredns/coredns/plugin"
+	"github.com/coredns/coredns/plugin/metrics/vars"
+	"github.com/coredns/coredns/plugin/pkg/dnstest"
+	"github.com/coredns/coredns/plugin/pkg/rcode"
+	"github.com/coredns/coredns/request"
+	"github.com/miekg/dns"
+	"github.com/prometheus/client_golang/prometheus"
+	"golang.org/x/net/context"
+)
+
+// MetricsPlugin is an adapter for CoreDNS and built-in metrics
+type MetricsPlugin struct {
+	Next plugin.Handler
+}
+
+// NewMetricsPlugin creates a plugin with configured metrics
+func NewMetricsPlugin(next plugin.Handler) *MetricsPlugin {
+	prometheus.MustRegister(vars.RequestCount)
+	prometheus.MustRegister(vars.RequestDuration)
+	prometheus.MustRegister(vars.RequestSize)
+	prometheus.MustRegister(vars.RequestDo)
+	prometheus.MustRegister(vars.RequestType)
+	prometheus.MustRegister(vars.ResponseSize)
+	prometheus.MustRegister(vars.ResponseRcode)
+	return &MetricsPlugin{Next: next}
+}
+
+// ServeDNS implements the CoreDNS plugin interface
+func (p MetricsPlugin) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (int, error) {
+	state := request.Request{W: w, Req: r}
+
+	rw := dnstest.NewRecorder(w)
+	status, err := plugin.NextOrFailure(p.Name(), p.Next, ctx, rw, r)
+
+	// Update built-in metrics
+	vars.Report(ctx, state, ".", rcode.ToString(rw.Rcode), rw.Len, rw.Start)
+
+	return status, err
+}
+
+// Name implements the CoreDNS plugin interface
+func (p MetricsPlugin) Name() string { return "metrics" }