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Support Ambassador Host resources as sources
Ambassador can be configured with `Host` resources (based on the `Host` CRD) for defining the external DNS host name. This code adds a new source, `ambassador-host`, that looks for the `ambassador/ambassador` Service and and uses the `hostname` from the `Host` resource. Signed-off-by: Alvaro Saurin <alvaro.saurin@gmail.com>
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,241 @@ | ||
| /* | ||
| Copyright 2017 The Kubernetes Authors. | ||
| Licensed under the Apache License, Version 2.0 (the "License"); | ||
| you may not use this file except in compliance with the License. | ||
| You may obtain a copy of the License at | ||
| http://www.apache.org/licenses/LICENSE-2.0 | ||
| Unless required by applicable law or agreed to in writing, software | ||
| distributed under the License is distributed on an "AS IS" BASIS, | ||
| WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | ||
| See the License for the specific language governing permissions and | ||
| limitations under the License. | ||
| */ | ||
|
|
||
| package source | ||
|
|
||
| import ( | ||
| "context" | ||
| "fmt" | ||
| "sort" | ||
| "strings" | ||
| "time" | ||
|
|
||
| "github.com/pkg/errors" | ||
| log "github.com/sirupsen/logrus" | ||
| metav1 "k8s.io/apimachinery/pkg/apis/meta/v1" | ||
| "k8s.io/apimachinery/pkg/apis/meta/v1/unstructured" | ||
| "k8s.io/apimachinery/pkg/labels" | ||
| "k8s.io/apimachinery/pkg/runtime/schema" | ||
| "k8s.io/apimachinery/pkg/util/wait" | ||
| "k8s.io/client-go/dynamic" | ||
| "k8s.io/client-go/dynamic/dynamicinformer" | ||
| "k8s.io/client-go/informers" | ||
| "k8s.io/client-go/kubernetes" | ||
| "k8s.io/client-go/tools/cache" | ||
|
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||
| "sigs.k8s.io/external-dns/endpoint" | ||
| ) | ||
|
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| // ambHostAnnotation is the annotation in the Host that maps to a Service | ||
| const ambHostAnnotation = "external-dns.ambassador-service" | ||
|
|
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| // groupName is the group name for the Ambassador API | ||
| const groupName = "getambassador.io" | ||
|
|
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| var schemeGroupVersion = schema.GroupVersion{Group: groupName, Version: "v2"} | ||
|
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| var ambHostGVR = schemeGroupVersion.WithResource("hosts") | ||
|
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| // ambassadorHostSource is an implementation of Source for Ambassador Host objects. | ||
| // The IngressRoute implementation uses the spec.virtualHost.fqdn value for the hostname. | ||
| // Use targetAnnotationKey to explicitly set Endpoint. | ||
| type ambassadorHostSource struct { | ||
| dynamicKubeClient dynamic.Interface | ||
| kubeClient kubernetes.Interface | ||
| namespace string | ||
| ambassadorHostInformer informers.GenericInformer | ||
| } | ||
|
|
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| // NewAmbassadorHostSource creates a new ambassadorHostSource with the given config. | ||
| func NewAmbassadorHostSource( | ||
| dynamicKubeClient dynamic.Interface, | ||
| kubeClient kubernetes.Interface, | ||
| namespace string) (Source, error) { | ||
| var err error | ||
|
|
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| // Use shared informer to listen for add/update/delete of Host in the specified namespace. | ||
| // Set resync period to 0, to prevent processing when nothing has changed. | ||
| informerFactory := dynamicinformer.NewFilteredDynamicSharedInformerFactory(dynamicKubeClient, 0, namespace, nil) | ||
| ambassadorHostInformer := informerFactory.ForResource(ambHostGVR) | ||
|
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| // Add default resource event handlers to properly initialize informer. | ||
| ambassadorHostInformer.Informer().AddEventHandler( | ||
| cache.ResourceEventHandlerFuncs{ | ||
| AddFunc: func(obj interface{}) { | ||
| }, | ||
| }, | ||
| ) | ||
|
|
||
| // TODO informer is not explicitly stopped since controller is not passing in its channel. | ||
| informerFactory.Start(wait.NeverStop) | ||
|
|
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| // wait for the local cache to be populated. | ||
| err = poll(time.Second, 60*time.Second, func() (bool, error) { | ||
| return ambassadorHostInformer.Informer().HasSynced(), nil | ||
| }) | ||
| if err != nil { | ||
| return nil, fmt.Errorf("failed to sync cache: %v", err) | ||
| } | ||
|
|
||
| return &ambassadorHostSource{ | ||
| dynamicKubeClient: dynamicKubeClient, | ||
| kubeClient: kubeClient, | ||
| namespace: namespace, | ||
| ambassadorHostInformer: ambassadorHostInformer, | ||
| }, nil | ||
| } | ||
|
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| // Endpoints returns endpoint objects for each host-target combination that should be processed. | ||
| // Retrieves all Hosts in the source's namespace(s). | ||
| func (sc *ambassadorHostSource) Endpoints(ctx context.Context) ([]*endpoint.Endpoint, error) { | ||
| hosts, err := sc.ambassadorHostInformer.Lister().ByNamespace(sc.namespace).List(labels.Everything()) | ||
| if err != nil { | ||
| return nil, err | ||
| } | ||
|
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| endpoints := []*endpoint.Endpoint{} | ||
|
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| for _, host := range hosts { | ||
| unstructuredHost, ok := host.(*unstructured.Unstructured) | ||
| if !ok { | ||
| return nil, errors.New("could not convert") | ||
| } | ||
|
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| fullname := fmt.Sprintf("%s/%s", unstructuredHost.GetNamespace(), unstructuredHost.GetName()) | ||
|
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| annotations, found, err := parseAmbHostAnnotations(unstructuredHost) | ||
| if err != nil { | ||
| log.Warn(err) | ||
| continue | ||
| } | ||
| if !found { | ||
| log.Debugf("Host %s ignored: no annotations found", fullname) | ||
| continue | ||
| } | ||
|
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| // look for the "exernal-dns.ambassador-service" annotation. If it is not there then just ignore this `Host` | ||
| service, found := annotations[ambHostAnnotation] | ||
| if !found { | ||
| log.Debugf("Host %s ignored: no annotation %q found", fullname, ambHostAnnotation) | ||
| continue | ||
| } | ||
|
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| targets, err := sc.targetsFromAmbassadorLoadBalancer(ctx, service) | ||
| if err != nil { | ||
| return nil, err | ||
| } | ||
|
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| hostEndpoints, err := sc.endpointsFromHost(ctx, unstructuredHost, targets) | ||
| if err != nil { | ||
| return nil, err | ||
| } | ||
| if len(hostEndpoints) == 0 { | ||
| log.Debugf("No endpoints could be generated from Host %s", fullname) | ||
| continue | ||
| } | ||
|
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| log.Debugf("Endpoints generated from Host: %s: %v", fullname, hostEndpoints) | ||
| endpoints = append(endpoints, hostEndpoints...) | ||
| } | ||
|
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| for _, ep := range endpoints { | ||
| sort.Sort(ep.Targets) | ||
| } | ||
|
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| return endpoints, nil | ||
| } | ||
|
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| // endpointsFromHost extracts the endpoints from a Host object | ||
| func (sc *ambassadorHostSource) endpointsFromHost(ctx context.Context, host *unstructured.Unstructured, targets endpoint.Targets) ([]*endpoint.Endpoint, error) { | ||
| var endpoints []*endpoint.Endpoint | ||
|
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| providerSpecific := endpoint.ProviderSpecific{} | ||
| setIdentifier := "" | ||
|
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| annotations, found, err := parseAmbHostAnnotations(host) | ||
| if err != nil { | ||
| log.Warn(err) | ||
| } | ||
| if found { | ||
| providerSpecific, setIdentifier = getProviderSpecificAnnotations(annotations) | ||
| } | ||
|
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| ttl, err := getTTLFromAnnotations(annotations) | ||
| if err != nil { | ||
| log.Warn(err) | ||
| } | ||
|
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| hostname, found, err := parseAmbHostHostname(host) | ||
| if err != nil { | ||
| return nil, err | ||
| } | ||
| if found { | ||
| endpoints = append(endpoints, endpointsForHostname(hostname, targets, ttl, providerSpecific, setIdentifier)...) | ||
| } | ||
|
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| return endpoints, nil | ||
| } | ||
|
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| func (sc *ambassadorHostSource) targetsFromAmbassadorLoadBalancer(ctx context.Context, service string) (targets endpoint.Targets, err error) { | ||
| lbNamespace, lbName, err := parseAmbLoadBalancerService(service) | ||
| if err != nil { | ||
| return nil, err | ||
| } | ||
| if svc, err := sc.kubeClient.CoreV1().Services(lbNamespace).Get(ctx, lbName, metav1.GetOptions{}); err != nil { | ||
| log.Warn(err) | ||
| } else { | ||
| for _, lb := range svc.Status.LoadBalancer.Ingress { | ||
| if lb.IP != "" { | ||
| targets = append(targets, lb.IP) | ||
| } | ||
| if lb.Hostname != "" { | ||
| targets = append(targets, lb.Hostname) | ||
| } | ||
| } | ||
| } | ||
|
|
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| return | ||
| } | ||
|
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| // parseAmbHostHostname returns the hostname in a `Host` | ||
| func parseAmbHostHostname(host *unstructured.Unstructured) (string, bool, error) { | ||
| return unstructured.NestedString(host.Object, "spec", "hostname") | ||
| } | ||
|
|
||
| // parseAmbHostAnnotations returns the annotations in a `Host` | ||
| func parseAmbHostAnnotations(host *unstructured.Unstructured) (map[string]string, bool, error) { | ||
| return unstructured.NestedStringMap(host.Object, "metadata", "annotations") | ||
| } | ||
|
|
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| // parseAmbLoadBalancerService returns a name/namespace tuple from the annotation in a `Host` | ||
| func parseAmbLoadBalancerService(service string) (namespace, name string, err error) { | ||
| parts := strings.Split(service, "/") | ||
| if len(parts) == 2 { | ||
| namespace, name = parts[0], parts[1] | ||
| } else { | ||
| parts = strings.Split(service, ".") | ||
| if len(parts) == 2 { | ||
| name, namespace = parts[0], parts[1] | ||
| } else { | ||
| err = fmt.Errorf("invalid Ambassador load balancer service (namespace/name or name.namespace) found '%v'", service) | ||
| } | ||
| } | ||
|
|
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| return | ||
| } | ||
|
|
||
| func (sc *ambassadorHostSource) AddEventHandler(ctx context.Context, handler func()) { | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,38 @@ | ||
| /* | ||
| Copyright 2019 The Kubernetes Authors. | ||
| Licensed under the Apache License, Version 2.0 (the "License"); | ||
| you may not use this file except in compliance with the License. | ||
| You may obtain a copy of the License at | ||
| http://www.apache.org/licenses/LICENSE-2.0 | ||
| Unless required by applicable law or agreed to in writing, software | ||
| distributed under the License is distributed on an "AS IS" BASIS, | ||
| WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | ||
| See the License for the specific language governing permissions and | ||
| limitations under the License. | ||
| */ | ||
|
|
||
| package source | ||
|
|
||
| import ( | ||
| "testing" | ||
|
|
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| "github.com/stretchr/testify/require" | ||
| "github.com/stretchr/testify/suite" | ||
| ) | ||
|
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| type AmbassadorSuite struct { | ||
| suite.Suite | ||
| } | ||
|
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| func TestAmbassadorSource(t *testing.T) { | ||
| suite.Run(t, new(AmbassadorSuite)) | ||
| t.Run("Interface", testAmbassadorSourceImplementsSource) | ||
| } | ||
|
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| // testAmbassadorSourceImplementsSource tests that ambassadorHostSource is a valid Source. | ||
| func testAmbassadorSourceImplementsSource(t *testing.T) { | ||
| require.Implements(t, (*Source)(nil), new(ambassadorHostSource)) | ||
| } |
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