58 lines
1.7 KiB
Go
58 lines
1.7 KiB
Go
package metrics
|
|
|
|
import (
|
|
"context"
|
|
"path/filepath"
|
|
|
|
"github.com/coredns/coredns/plugin"
|
|
"github.com/coredns/coredns/plugin/metrics/vars"
|
|
"github.com/coredns/coredns/plugin/pkg/rcode"
|
|
"github.com/coredns/coredns/request"
|
|
|
|
"github.com/miekg/dns"
|
|
)
|
|
|
|
// ServeDNS implements the Handler interface.
|
|
func (m *Metrics) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (int, error) {
|
|
state := request.Request{W: w, Req: r}
|
|
|
|
qname := state.QName()
|
|
zone := plugin.Zones(m.ZoneNames()).Matches(qname)
|
|
if zone == "" {
|
|
zone = "."
|
|
}
|
|
|
|
// Record response to get status code and size of the reply.
|
|
rw := NewRecorder(w)
|
|
status, err := plugin.NextOrFailure(m.Name(), m.Next, ctx, rw, r)
|
|
|
|
rc := rw.Rcode
|
|
if !plugin.ClientWrite(status) {
|
|
// when no response was written, fallback to status returned from next plugin as this status
|
|
// is actually used as rcode of DNS response
|
|
// see https://github.com/coredns/coredns/blob/master/core/dnsserver/server.go#L318
|
|
rc = status
|
|
}
|
|
plugin := m.authoritativePlugin(rw.Caller)
|
|
vars.Report(WithServer(ctx), state, zone, rcode.ToString(rc), plugin, rw.Len, rw.Start)
|
|
|
|
return status, err
|
|
}
|
|
|
|
// Name implements the Handler interface.
|
|
func (m *Metrics) Name() string { return "prometheus" }
|
|
|
|
// authoritativePlugin returns which of made the write, if none is found the empty string is returned.
|
|
func (m *Metrics) authoritativePlugin(caller [3]string) string {
|
|
// a b and c contain the full path of the caller, the plugin name 2nd last elements
|
|
// .../coredns/plugin/whoami/whoami.go --> whoami
|
|
// this is likely FS specific, so use filepath.
|
|
for _, c := range caller {
|
|
plug := filepath.Base(filepath.Dir(c))
|
|
if _, ok := m.plugins[plug]; ok {
|
|
return plug
|
|
}
|
|
}
|
|
return ""
|
|
}
|