coredns/plugin/etcd/handler.go
cedar-gao a6338e924e
optimize the performance for high qps (#6767)
Signed-off-by: gaoxuesong <gaoxuesong@jd.com>
2024-07-02 08:08:56 -04:00

82 lines
2.2 KiB
Go

package etcd
import (
"context"
"github.com/coredns/coredns/plugin"
"github.com/coredns/coredns/request"
"github.com/miekg/dns"
)
// ServeDNS implements the plugin.Handler interface.
func (e *Etcd) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (int, error) {
opt := plugin.Options{}
state := request.Request{W: w, Req: r}
zone := plugin.Zones(e.Zones).Matches(state.Name())
if zone == "" {
return plugin.NextOrFailure(e.Name(), e.Next, ctx, w, r)
}
var (
records, extra []dns.RR
truncated bool
err error
)
switch state.QType() {
case dns.TypeA:
records, truncated, err = plugin.A(ctx, e, zone, state, nil, opt)
case dns.TypeAAAA:
records, truncated, err = plugin.AAAA(ctx, e, zone, state, nil, opt)
case dns.TypeTXT:
records, truncated, err = plugin.TXT(ctx, e, zone, state, nil, opt)
case dns.TypeCNAME:
records, err = plugin.CNAME(ctx, e, zone, state, opt)
case dns.TypePTR:
records, err = plugin.PTR(ctx, e, zone, state, opt)
case dns.TypeMX:
records, extra, err = plugin.MX(ctx, e, zone, state, opt)
case dns.TypeSRV:
records, extra, err = plugin.SRV(ctx, e, zone, state, opt)
case dns.TypeSOA:
records, err = plugin.SOA(ctx, e, zone, state, opt)
case dns.TypeNS:
if state.Name() == zone {
records, extra, err = plugin.NS(ctx, e, zone, state, opt)
break
}
fallthrough
default:
// Do a fake A lookup, so we can distinguish between NODATA and NXDOMAIN
_, _, err = plugin.A(ctx, e, zone, state, nil, opt)
}
if err != nil && e.IsNameError(err) {
if e.Fall.Through(state.Name()) {
return plugin.NextOrFailure(e.Name(), e.Next, ctx, w, r)
}
// Make err nil when returning here, so we don't log spam for NXDOMAIN.
return plugin.BackendError(ctx, e, zone, dns.RcodeNameError, state, nil /* err */, opt)
}
if err != nil {
return plugin.BackendError(ctx, e, zone, dns.RcodeServerFailure, state, err, opt)
}
if len(records) == 0 {
return plugin.BackendError(ctx, e, zone, dns.RcodeSuccess, state, err, opt)
}
m := new(dns.Msg)
m.SetReply(r)
m.Truncated = truncated
m.Authoritative = true
m.Answer = records
m.Extra = extra
w.WriteMsg(m)
return dns.RcodeSuccess, nil
}
// Name implements the Handler interface.
func (e *Etcd) Name() string { return "etcd" }