plugin/hosts: pre-convert Origins to plugin.Zones in setup (#8383)

* test: add benchmark cases for Request IP/Port and parseRequest

Signed-off-by: Manuel Rüger <manuel@rueg.eu>

* test(kubernetes): add BenchmarkServices and BenchmarkServicesHeadless

Signed-off-by: Manuel Rüger <manuel@rueg.eu>

* perf(hosts): pre-convert Origins to plugin.Zones in hosts setup

Signed-off-by: Manuel Rüger <manuel@rueg.eu>

* style: fix gofmt trailing line formatting

Signed-off-by: Manuel Rüger <manuel@rueg.eu>

---------

Signed-off-by: Manuel Rüger <manuel@rueg.eu>

plugin/hosts/hosts.go

@@ -17,6 +17,8 @@ type Hosts struct {
 	Next plugin.Handler
 	*Hostsfile
 
+	zones plugin.Zones
+
 	Fall fall.F
 
 	fallthroughUnsupported bool
@@ -27,9 +29,13 @@ func (h Hosts) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (
 	state := request.Request{W: w, Req: r}
 	qname := state.Name()
 
-	answers := []dns.RR{}
+	var answers []dns.RR
 
-	zone := plugin.Zones(h.Origins).Matches(qname)
+	zones := h.zones
+	if zones == nil {
+		zones = plugin.Zones(h.Origins)
+	}
+	zone := zones.Matches(qname)
 	if zone == "" {
 		// PTR zones don't need to be specified in Origins.
 		if state.QType() != dns.TypePTR {

plugin/hosts/hosts_test.go

@@ -5,6 +5,7 @@ import (
 	"strings"
 	"testing"
 
+	"github.com/coredns/coredns/plugin"
 	"github.com/coredns/coredns/plugin/pkg/dnstest"
 	"github.com/coredns/coredns/plugin/pkg/fall"
 	"github.com/coredns/coredns/plugin/test"
@@ -211,3 +212,50 @@ const hostsExample = `
 reload 5s
 timeout 3600
 `
+
+func BenchmarkHostsBaseline(b *testing.B) {
+	h := Hosts{
+		Next: test.NextHandler(dns.RcodeNameError, nil),
+		Hostsfile: &Hostsfile{
+			Origins: []string{"example.org."},
+			hmap:    newMap(),
+			inline:  newMap(),
+			options: newOptions(),
+		},
+	}
+	h.hmap = h.parse(strings.NewReader(hostsExample))
+
+	m := new(dns.Msg)
+	m.SetQuestion("example.org.", dns.TypeA)
+	rec := dnstest.NewRecorder(&test.ResponseWriter{})
+	ctx := context.Background()
+
+	b.ReportAllocs()
+	for b.Loop() {
+		_, _ = h.ServeDNS(ctx, rec, m)
+	}
+}
+
+func BenchmarkHostsOptimized(b *testing.B) {
+	h := Hosts{
+		Next: test.NextHandler(dns.RcodeNameError, nil),
+		Hostsfile: &Hostsfile{
+			Origins: []string{"example.org."},
+			hmap:    newMap(),
+			inline:  newMap(),
+			options: newOptions(),
+		},
+		zones: plugin.Zones([]string{"example.org."}),
+	}
+	h.hmap = h.parse(strings.NewReader(hostsExample))
+
+	m := new(dns.Msg)
+	m.SetQuestion("example.org.", dns.TypeA)
+	rec := dnstest.NewRecorder(&test.ResponseWriter{})
+	ctx := context.Background()
+
+	b.ReportAllocs()
+	for b.Loop() {
+		_, _ = h.ServeDNS(ctx, rec, m)
+	}
+}

plugin/hosts/setup.go

@@ -107,6 +107,7 @@ func hostsParse(c *caddy.Controller) (Hosts, error) {
 		}
 
 		h.Origins = plugin.OriginsFromArgsOrServerBlock(args, c.ServerBlockKeys)
+		h.zones = plugin.Zones(h.Origins)
 
 		for c.NextBlock() {
 			switch c.Val() {