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https://github.com/kubernetes-sigs/external-dns.git
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feat(services): implement Kubernetes services source
This commit is contained in:
Martin Linkhorst
parent
786055f3b3
commit
84910c4844
6
endpoint/endpoint.go
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6
endpoint/endpoint.go
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package endpoint
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type Endpoint struct {
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DNSName string
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Target string
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}
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63
source/service.go
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63
source/service.go
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package source
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import (
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"k8s.io/client-go/kubernetes"
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"k8s.io/client-go/pkg/api/v1"
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"github.com/kubernetes-incubator/external-dns/endpoint"
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)
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const (
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// The annotation used for figuring out which controller is responsible
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controllerAnnotationKey = "external-dns.kubernetes.io/controller"
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// The annotation used for defining the desired hostname
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hostnameAnnotationKey = "external-dns.kubernetes.io/hostname"
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// The value of the controller annotation so that we feel resposible
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controllerAnnotationValue = "dns-controller"
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)
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// ServiceSource is an implementation of Source for Kubernetes service objects.
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// It will find all services that are under our jurisdiction, i.e. annotated
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// desired hostname and matching or no controller annotation. For each of the
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// matches services' external entrypoints it will return a corresponding
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// Endpoint object.
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type ServiceSource struct {
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Client kubernetes.Interface
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}
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// Endpoints returns endpoint objects for each service that should be processed.
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func (sc *ServiceSource) Endpoints() ([]endpoint.Endpoint, error) {
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services, err := sc.Client.Core().Services(v1.NamespaceAll).List(v1.ListOptions{})
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if err != nil {
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return nil, err
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}
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endpoints := []endpoint.Endpoint{}
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for _, svc := range services.Items {
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// Check controller annotation to see if we are responsible.
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controller, exists := svc.Annotations[controllerAnnotationKey]
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if exists && controller != controllerAnnotationValue {
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continue
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}
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// Get the desired hostname of the service from the annotation.
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hostname, exists := svc.Annotations[hostnameAnnotationKey]
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if !exists {
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continue
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}
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// Create an endpoint matching the desired hostname.
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endpoint := endpoint.Endpoint{
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DNSName: hostname,
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}
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// Create a corresponding endpoint for each configured external entrypoint.
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for _, lb := range svc.Status.LoadBalancer.Ingress {
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endpoint.Target = lb.IP
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endpoints = append(endpoints, endpoint)
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}
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}
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return endpoints, nil
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}
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201
source/service_test.go
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201
source/service_test.go
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package source
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import (
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"testing"
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"k8s.io/client-go/kubernetes/fake"
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"k8s.io/client-go/pkg/api/v1"
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"github.com/kubernetes-incubator/external-dns/endpoint"
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)
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// TestEndpoints tests that various services generate the correct endpoints.
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func TestEndpoints(t *testing.T) {
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for _, tc := range []struct {
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namespace string
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name string
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annotations map[string]string
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lbs []string
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expected []endpoint.Endpoint
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}{
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// Completely opted-out: no endpoints returned.
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{
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"testing",
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"foo",
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map[string]string{},
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[]string{"1.2.3.4"},
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[]endpoint.Endpoint{},
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},
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// Opt-in by setting desired hostname.
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{
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"testing",
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"foo",
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map[string]string{
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"external-dns.kubernetes.io/hostname": "foo.example.org",
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},
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[]string{"1.2.3.4"},
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[]endpoint.Endpoint{
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{DNSName: "foo.example.org", Target: "1.2.3.4"},
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},
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},
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// Opt-in by setting desired hostname and this controller.
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{
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"testing",
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"foo",
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map[string]string{
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"external-dns.kubernetes.io/controller": "dns-controller",
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"external-dns.kubernetes.io/hostname": "foo.example.org",
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},
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[]string{"1.2.3.4"},
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[]endpoint.Endpoint{
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{DNSName: "foo.example.org", Target: "1.2.3.4"},
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},
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},
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// Opt-out by setting a different controller.
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{
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"testing",
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"foo",
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map[string]string{
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"external-dns.kubernetes.io/controller": "some-other-tool",
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"external-dns.kubernetes.io/hostname": "foo.example.org",
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},
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[]string{"1.2.3.4"},
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[]endpoint.Endpoint{},
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},
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// Make sure services are found in all namespaces.
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{
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"other-testing",
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"foo",
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map[string]string{
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"external-dns.kubernetes.io/hostname": "foo.example.org",
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},
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[]string{"1.2.3.4"},
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[]endpoint.Endpoint{
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{DNSName: "foo.example.org", Target: "1.2.3.4"},
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},
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},
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// No external entrypoints lead to no endpoints.
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{
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"testing",
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"foo",
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map[string]string{
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"external-dns.kubernetes.io/hostname": "foo.example.org",
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},
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[]string{},
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[]endpoint.Endpoint{},
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},
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// Multiple external entrypoints lead to multiple endpoints.
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{
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"testing",
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"foo",
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map[string]string{
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"external-dns.kubernetes.io/hostname": "foo.example.org",
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},
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[]string{"1.2.3.4", "8.8.8.8"},
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[]endpoint.Endpoint{
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{DNSName: "foo.example.org", Target: "1.2.3.4"},
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{DNSName: "foo.example.org", Target: "8.8.8.8"},
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},
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},
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} {
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// Create a Kubernetes testing client
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kubernetes := fake.NewSimpleClientset()
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// Create a service to test against
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ingresses := []v1.LoadBalancerIngress{}
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for _, lb := range tc.lbs {
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ingresses = append(ingresses, v1.LoadBalancerIngress{IP: lb})
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}
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service := &v1.Service{
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ObjectMeta: v1.ObjectMeta{
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Namespace: tc.namespace,
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Name: tc.name,
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Annotations: tc.annotations,
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},
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Status: v1.ServiceStatus{
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LoadBalancer: v1.LoadBalancerStatus{
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Ingress: ingresses,
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},
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},
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}
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_, err := kubernetes.Core().Services(service.Namespace).Create(service)
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if err != nil {
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t.Fatal(err)
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}
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// Create our object under test and get the endpoints.
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client := &ServiceSource{
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Client: kubernetes,
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}
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endpoints, err := client.Endpoints()
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if err != nil {
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t.Fatal(err)
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}
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// Validate returned endpoints against desired endpoints.
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validateEndpoints(t, endpoints, tc.expected)
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}
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}
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func BenchmarkEndpoints(b *testing.B) {
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kubernetes := fake.NewSimpleClientset()
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service := &v1.Service{
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ObjectMeta: v1.ObjectMeta{
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Namespace: "testing",
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Name: "foo",
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Annotations: map[string]string{
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"external-dns.kubernetes.io/hostname": "foo.example.org",
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},
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},
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Status: v1.ServiceStatus{
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LoadBalancer: v1.LoadBalancerStatus{
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Ingress: []v1.LoadBalancerIngress{
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{IP: "1.2.3.4"},
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{IP: "8.8.8.8"},
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},
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},
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},
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}
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_, err := kubernetes.Core().Services(service.Namespace).Create(service)
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if err != nil {
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b.Fatal(err)
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}
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client := &ServiceSource{
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Client: kubernetes,
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}
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for i := 0; i < b.N; i++ {
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_, err := client.Endpoints()
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if err != nil {
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b.Fatal(err)
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}
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}
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}
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// test helper functions
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func validateEndpoints(t *testing.T, endpoints, expected []endpoint.Endpoint) {
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if len(endpoints) != len(expected) {
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t.Fatalf("expected %d endpoints, got %d", len(expected), len(endpoints))
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}
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for i := range endpoints {
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validateEndpoint(t, endpoints[i], expected[i])
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}
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}
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func validateEndpoint(t *testing.T, endpoint, expected endpoint.Endpoint) {
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if endpoint.DNSName != expected.DNSName {
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t.Errorf("expected %s, got %s", expected.DNSName, endpoint.DNSName)
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}
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if endpoint.Target != expected.Target {
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t.Errorf("expected %s, got %s", expected.Target, endpoint.Target)
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}
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}
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