plugin/forward: fast-path string comparison in isAllowedDomain (#8385)

* 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(forward): fast-path string comparison in isAllowedDomain

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

---------

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

plugin/kubernetes/kubernetes_test.go

@@ -493,3 +493,33 @@ func TestServicesAuthority(t *testing.T) {
 		}
 	}
 }
+
+func BenchmarkServices(b *testing.B) {
+	k := New([]string{"inter.webs.tests."})
+	k.APIConn = APIConnServiceTest{}
+	ctx := context.TODO()
+
+	m := new(dns.Msg)
+	m.SetQuestion("svc1.testns.svc.inter.webs.tests.", dns.TypeA)
+	state := request.Request{Zone: k.Zones[0], Req: m}
+
+	b.ReportAllocs()
+	for b.Loop() {
+		_, _ = k.Services(ctx, state, false, plugin.Options{})
+	}
+}
+
+func BenchmarkServicesHeadless(b *testing.B) {
+	k := New([]string{"inter.webs.tests."})
+	k.APIConn = APIConnServiceTest{}
+	ctx := context.TODO()
+
+	m := new(dns.Msg)
+	m.SetQuestion("hdls1.testns.svc.inter.webs.tests.", dns.TypeA)
+	state := request.Request{Zone: k.Zones[0], Req: m}
+
+	b.ReportAllocs()
+	for b.Loop() {
+		_, _ = k.Services(ctx, state, false, plugin.Options{})
+	}
+}

plugin/kubernetes/parse_test.go

@@ -63,3 +63,10 @@ func TestParseInvalidRequest(t *testing.T) {
 }
 
 const zone = "inter.webs.tests."
+
+func BenchmarkParseRequest(b *testing.B) {
+	b.ReportAllocs()
+	for b.Loop() {
+		_, _ = parseRequest("1-2-3-4.webs.mynamespace.svc.inter.webs.tests.", zone, false)
+	}
+}

request/request_test.go

@@ -381,3 +381,23 @@ func TestRequestClear(t *testing.T) {
 		t.Errorf("Expected st.port to be cleared after Clear")
 	}
 }
+
+func BenchmarkRequestIP(b *testing.B) {
+	st := testRequest()
+	b.ReportAllocs()
+
+	for b.Loop() {
+		st.Clear()
+		_ = st.IP()
+	}
+}
+
+func BenchmarkRequestPort(b *testing.B) {
+	st := testRequest()
+	b.ReportAllocs()
+
+	for b.Loop() {
+		st.Clear()
+		_ = st.Port()
+	}
+}