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plugin/kubernetes: Add support for topology-aware headless services via "az-pinned" subdomains (#8388)
This commit is contained in:
rpb-ant
GitHub
263
plugin/kubernetes/zonal_test.go
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263
plugin/kubernetes/zonal_test.go
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@@ -0,0 +1,263 @@
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package kubernetes
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import (
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"context"
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"testing"
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"github.com/coredns/coredns/plugin/kubernetes/object"
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"github.com/coredns/coredns/plugin/pkg/dnstest"
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"github.com/coredns/coredns/plugin/test"
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"github.com/miekg/dns"
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api "k8s.io/api/core/v1"
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)
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type APIConnZonalTest struct{}
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func (APIConnZonalTest) HasSynced() bool { return true }
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func (APIConnZonalTest) Run() {}
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func (APIConnZonalTest) Stop() error { return nil }
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func (APIConnZonalTest) PodIndex(string) []*object.Pod { return nil }
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func (APIConnZonalTest) SvcIndexReverse(string) []*object.Service { return nil }
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func (APIConnZonalTest) SvcExtIndexReverse(string) []*object.Service { return nil }
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func (APIConnZonalTest) ServiceImportList() []*object.ServiceImport { return nil }
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func (APIConnZonalTest) SvcImportIndex(string) []*object.ServiceImport { return nil }
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func (APIConnZonalTest) EpIndexReverse(string) []*object.Endpoints { return nil }
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func (APIConnZonalTest) McEpIndex(string) []*object.MultiClusterEndpoints { return nil }
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func (APIConnZonalTest) Modified(ModifiedMode) int64 { return int64(1499347823) }
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func (a APIConnZonalTest) ServiceList() []*object.Service {
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return []*object.Service{
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{
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Name: "hdls",
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Namespace: "testns",
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ClusterIPs: []string{api.ClusterIPNone},
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},
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{
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Name: "clstr",
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Namespace: "testns",
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ClusterIPs: []string{"10.0.0.10"},
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Ports: []api.ServicePort{{Name: "http", Protocol: "tcp", Port: 80}},
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},
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}
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}
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func (a APIConnZonalTest) SvcIndex(idx string) []*object.Service {
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switch idx {
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case "hdls.testns":
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return a.ServiceList()[:1]
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case "clstr.testns":
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return a.ServiceList()[1:]
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}
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return nil
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}
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func (a APIConnZonalTest) EndpointsList() []*object.Endpoints {
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return []*object.Endpoints{
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{
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Subsets: []object.EndpointSubset{
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{
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Addresses: []object.EndpointAddress{
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{IP: "172.0.0.1"},
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{IP: "172.0.0.2"},
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{IP: "172.0.0.3"},
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},
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Ports: []object.EndpointPort{{Port: 80, Name: "http", Protocol: "tcp"}},
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},
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},
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Zones: map[string]string{
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"172.0.0.1": "us-west-2a",
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"172.0.0.2": "us-west-2b",
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"172.0.0.3": "us-west-2b",
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},
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Name: "hdls-slice",
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Namespace: "testns",
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Index: object.EndpointsKey("hdls", "testns"),
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},
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}
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}
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func (a APIConnZonalTest) EpIndex(idx string) []*object.Endpoints {
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if idx == "hdls.testns" {
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return a.EndpointsList()
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}
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return nil
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}
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func (APIConnZonalTest) GetNodeByName(_ context.Context, _ string) (*api.Node, error) {
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return &api.Node{}, nil
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}
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func (APIConnZonalTest) GetNamespaceByName(name string) (*object.Namespace, error) {
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return &object.Namespace{Name: name}, nil
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}
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var zonalTestCases = []test.Case{
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{ // pin: endpoints narrowed to the requested zone
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Qname: "us-west-2a.pin._zone.hdls.testns.svc.cluster.local.", Qtype: dns.TypeA,
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Rcode: dns.RcodeSuccess,
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Answer: []dns.RR{
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test.A("us-west-2a.pin._zone.hdls.testns.svc.cluster.local. 5 IN A 172.0.0.1"),
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},
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},
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{
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Qname: "us-west-2b.pin._zone.hdls.testns.svc.cluster.local.", Qtype: dns.TypeA,
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Rcode: dns.RcodeSuccess,
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Answer: []dns.RR{
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test.A("us-west-2b.pin._zone.hdls.testns.svc.cluster.local. 5 IN A 172.0.0.2"),
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test.A("us-west-2b.pin._zone.hdls.testns.svc.cluster.local. 5 IN A 172.0.0.3"),
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},
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},
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{ // pin: any zone label without matching endpoints — drained zones and
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// typos alike — is the same determinate empty answer
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Qname: "us-west-2c.pin._zone.hdls.testns.svc.cluster.local.", Qtype: dns.TypeA,
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Rcode: dns.RcodeSuccess,
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Ns: []dns.RR{
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test.SOA("cluster.local. 5 IN SOA ns.dns.cluster.local. hostmaster.cluster.local. 1499347823 7200 1800 86400 5"),
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},
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},
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{ // prefer: narrows exactly like pin when the zone is populated
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Qname: "us-west-2a.prefer._zone.hdls.testns.svc.cluster.local.", Qtype: dns.TypeA,
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Rcode: dns.RcodeSuccess,
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Answer: []dns.RR{
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test.A("us-west-2a.prefer._zone.hdls.testns.svc.cluster.local. 5 IN A 172.0.0.1"),
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},
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},
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{ // prefer: an empty zone falls back to every endpoint — the fallback
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// is chosen in the name, so it is not a silent widening of a pin
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Qname: "us-west-2c.prefer._zone.hdls.testns.svc.cluster.local.", Qtype: dns.TypeA,
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Rcode: dns.RcodeSuccess,
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Answer: []dns.RR{
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test.A("us-west-2c.prefer._zone.hdls.testns.svc.cluster.local. 5 IN A 172.0.0.1"),
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test.A("us-west-2c.prefer._zone.hdls.testns.svc.cluster.local. 5 IN A 172.0.0.2"),
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test.A("us-west-2c.prefer._zone.hdls.testns.svc.cluster.local. 5 IN A 172.0.0.3"),
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},
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},
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{ // a nonexistent service stays NXDOMAIN under any directive
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Qname: "us-west-2a.pin._zone.ghost.testns.svc.cluster.local.", Qtype: dns.TypeA,
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Rcode: dns.RcodeNameError,
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Ns: []dns.RR{
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test.SOA("cluster.local. 5 IN SOA ns.dns.cluster.local. hostmaster.cluster.local. 1499347823 7200 1800 86400 5"),
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},
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},
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{ // an unknown directive keeps the stock too-long NXDOMAIN
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Qname: "us-west-2a.florp._zone.hdls.testns.svc.cluster.local.", Qtype: dns.TypeA,
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Rcode: dns.RcodeNameError,
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Ns: []dns.RR{
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test.SOA("cluster.local. 5 IN SOA ns.dns.cluster.local. hostmaster.cluster.local. 1499347823 7200 1800 86400 5"),
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},
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},
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{ // zone-scoped names are defined for headless services only
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Qname: "us-west-2a.pin._zone.clstr.testns.svc.cluster.local.", Qtype: dns.TypeA,
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Rcode: dns.RcodeNameError,
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Ns: []dns.RR{
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test.SOA("cluster.local. 5 IN SOA ns.dns.cluster.local. hostmaster.cluster.local. 1499347823 7200 1800 86400 5"),
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},
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},
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{ // pin: exists-but-empty stays NODATA for non-address qtypes too (TXT
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// has its own lookup branch; NXDOMAIN would be negative-cached per name)
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Qname: "us-west-2c.pin._zone.hdls.testns.svc.cluster.local.", Qtype: dns.TypeTXT,
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Rcode: dns.RcodeSuccess,
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Ns: []dns.RR{
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test.SOA("cluster.local. 5 IN SOA ns.dns.cluster.local. hostmaster.cluster.local. 1499347823 7200 1800 86400 5"),
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},
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},
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{ // prefer: SRV narrows when populated and falls back when not, same as A
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Qname: "us-west-2c.prefer._zone.hdls.testns.svc.cluster.local.", Qtype: dns.TypeSRV,
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Rcode: dns.RcodeSuccess,
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Answer: []dns.RR{
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test.SRV("us-west-2c.prefer._zone.hdls.testns.svc.cluster.local. 5 IN SRV 0 33 80 172-0-0-1.hdls.testns.svc.cluster.local."),
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test.SRV("us-west-2c.prefer._zone.hdls.testns.svc.cluster.local. 5 IN SRV 0 33 80 172-0-0-2.hdls.testns.svc.cluster.local."),
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test.SRV("us-west-2c.prefer._zone.hdls.testns.svc.cluster.local. 5 IN SRV 0 33 80 172-0-0-3.hdls.testns.svc.cluster.local."),
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},
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Extra: []dns.RR{
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test.A("172-0-0-1.hdls.testns.svc.cluster.local. 5 IN A 172.0.0.1"),
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test.A("172-0-0-2.hdls.testns.svc.cluster.local. 5 IN A 172.0.0.2"),
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test.A("172-0-0-3.hdls.testns.svc.cluster.local. 5 IN A 172.0.0.3"),
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},
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},
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{ // prefer: TXT on a zonal name is NODATA like every non-address type
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Qname: "us-west-2c.prefer._zone.hdls.testns.svc.cluster.local.", Qtype: dns.TypeTXT,
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Rcode: dns.RcodeSuccess,
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Ns: []dns.RR{
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test.SOA("cluster.local. 5 IN SOA ns.dns.cluster.local. hostmaster.cluster.local. 1499347823 7200 1800 86400 5"),
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},
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},
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{ // pin: SRV comes out zone-filtered, since filtering happens at endpoint selection
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Qname: "us-west-2b.pin._zone.hdls.testns.svc.cluster.local.", Qtype: dns.TypeSRV,
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Rcode: dns.RcodeSuccess,
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Answer: []dns.RR{
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test.SRV("us-west-2b.pin._zone.hdls.testns.svc.cluster.local. 5 IN SRV 0 50 80 172-0-0-2.hdls.testns.svc.cluster.local."),
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test.SRV("us-west-2b.pin._zone.hdls.testns.svc.cluster.local. 5 IN SRV 0 50 80 172-0-0-3.hdls.testns.svc.cluster.local."),
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},
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Extra: []dns.RR{
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test.A("172-0-0-2.hdls.testns.svc.cluster.local. 5 IN A 172.0.0.2"),
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test.A("172-0-0-3.hdls.testns.svc.cluster.local. 5 IN A 172.0.0.3"),
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},
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},
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}
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// Without the option the shape is three-labels-too-long, exactly as it has
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// always been: behavior identical to before the feature existed.
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var zonalDisabledTestCases = []test.Case{
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{
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Qname: "us-west-2a.pin._zone.hdls.testns.svc.cluster.local.", Qtype: dns.TypeA,
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Rcode: dns.RcodeNameError,
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Ns: []dns.RR{
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test.SOA("cluster.local. 5 IN SOA ns.dns.cluster.local. hostmaster.cluster.local. 1499347823 7200 1800 86400 5"),
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},
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},
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}
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// A zone-only endpoint change alters zonal answers, so it must not be
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// classified as equivalent (which would skip the serial bump). Zone is
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// empty in default configurations, so this costs nothing when the option
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// is off.
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func TestEndpointsEquivalentZoneChange(t *testing.T) {
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eps := func(zone string) *object.Endpoints {
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return &object.Endpoints{
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Subsets: []object.EndpointSubset{{
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Addresses: []object.EndpointAddress{{IP: "172.0.0.1"}},
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}},
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Zones: map[string]string{"172.0.0.1": zone},
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}
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}
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if !endpointsEquivalent(eps("us-west-2a"), eps("us-west-2a")) {
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t.Fatal("identical endpoints must be equivalent")
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}
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if endpointsEquivalent(eps("us-west-2a"), eps("us-west-2b")) {
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t.Fatal("a zone-only change alters zonal answers and must not be equivalent")
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}
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}
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func TestServeDNSZonal(t *testing.T) {
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k := New([]string{"cluster.local."})
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k.APIConn = &APIConnZonalTest{}
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k.Next = test.NextHandler(dns.RcodeSuccess, nil)
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k.Namespaces = map[string]struct{}{"testns": {}}
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k.opts.zonal = true
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ctx := context.TODO()
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runZonalCases(ctx, t, k, zonalTestCases)
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k.opts.zonal = false
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runZonalCases(ctx, t, k, zonalDisabledTestCases)
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}
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func runZonalCases(ctx context.Context, t *testing.T, k *Kubernetes, cases []test.Case) {
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t.Helper()
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for i, tc := range cases {
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r := tc.Msg()
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w := dnstest.NewRecorder(&test.ResponseWriter{})
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if _, err := k.ServeDNS(ctx, w, r); err != nil {
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t.Errorf("Test %d expected no error, got %v", i, err)
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continue
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}
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if w.Msg == nil {
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t.Fatalf("Test %d, got nil message for %q", i, r.Question[0].Name)
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}
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if err := test.SortAndCheck(w.Msg, tc); err != nil {
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t.Errorf("Test %d (%s), %v", i, tc.Qname, err)
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}
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}
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}
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