mirror of
https://github.com/kubernetes-sigs/external-dns.git
synced 2025-10-31 18:50:59 +01:00
334 lines
11 KiB
Go
334 lines
11 KiB
Go
/*
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Copyright 2017 The Kubernetes Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package source
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import (
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"bytes"
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"context"
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"fmt"
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"math"
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"net"
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"reflect"
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"strconv"
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"strings"
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"text/template"
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"time"
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"unicode"
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metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
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"k8s.io/apimachinery/pkg/labels"
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"k8s.io/apimachinery/pkg/runtime"
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"k8s.io/apimachinery/pkg/runtime/schema"
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"sigs.k8s.io/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.alpha.kubernetes.io/controller"
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// The annotation used for defining the desired hostname
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hostnameAnnotationKey = "external-dns.alpha.kubernetes.io/hostname"
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// The annotation used for specifying whether the public or private interface address is used
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accessAnnotationKey = "external-dns.alpha.kubernetes.io/access"
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// The annotation used for defining the desired ingress target
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targetAnnotationKey = "external-dns.alpha.kubernetes.io/target"
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// The annotation used for defining the desired DNS record TTL
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ttlAnnotationKey = "external-dns.alpha.kubernetes.io/ttl"
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// The annotation used for switching to the alias record types e. g. AWS Alias records instead of a normal CNAME
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aliasAnnotationKey = "external-dns.alpha.kubernetes.io/alias"
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// The annotation used to determine the source of hostnames for ingresses. This is an optional field - all
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// available hostname sources are used if not specified.
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ingressHostnameSourceKey = "external-dns.alpha.kubernetes.io/ingress-hostname-source"
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// The value of the controller annotation so that we feel responsible
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controllerAnnotationValue = "dns-controller"
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// The annotation used for defining the desired hostname
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internalHostnameAnnotationKey = "external-dns.alpha.kubernetes.io/internal-hostname"
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)
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// Provider-specific annotations
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const (
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// The annotation used for determining if traffic will go through Cloudflare
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CloudflareProxiedKey = "external-dns.alpha.kubernetes.io/cloudflare-proxied"
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SetIdentifierKey = "external-dns.alpha.kubernetes.io/set-identifier"
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)
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const (
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ttlMinimum = 1
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ttlMaximum = math.MaxInt32
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)
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// Source defines the interface Endpoint sources should implement.
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type Source interface {
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Endpoints(ctx context.Context) ([]*endpoint.Endpoint, error)
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// AddEventHandler adds an event handler that should be triggered if something in source changes
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AddEventHandler(context.Context, func())
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}
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func getTTLFromAnnotations(annotations map[string]string) (endpoint.TTL, error) {
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ttlNotConfigured := endpoint.TTL(0)
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ttlAnnotation, exists := annotations[ttlAnnotationKey]
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if !exists {
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return ttlNotConfigured, nil
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}
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ttlValue, err := parseTTL(ttlAnnotation)
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if err != nil {
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return ttlNotConfigured, fmt.Errorf("\"%v\" is not a valid TTL value", ttlAnnotation)
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}
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if ttlValue < ttlMinimum || ttlValue > ttlMaximum {
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return ttlNotConfigured, fmt.Errorf("TTL value must be between [%d, %d]", ttlMinimum, ttlMaximum)
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}
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return endpoint.TTL(ttlValue), nil
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}
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// parseTTL parses TTL from string, returning duration in seconds.
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// parseTTL supports both integers like "600" and durations based
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// on Go Duration like "10m", hence "600" and "10m" represent the same value.
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//
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// Note: for durations like "1.5s" the fraction is omitted (resulting in 1 second
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// for the example).
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func parseTTL(s string) (ttlSeconds int64, err error) {
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ttlDuration, err := time.ParseDuration(s)
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if err != nil {
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return strconv.ParseInt(s, 10, 64)
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}
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return int64(ttlDuration.Seconds()), nil
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}
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type kubeObject interface {
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runtime.Object
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metav1.Object
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}
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func execTemplate(tmpl *template.Template, obj kubeObject) (hostnames []string, err error) {
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var buf bytes.Buffer
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if err := tmpl.Execute(&buf, obj); err != nil {
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kind := obj.GetObjectKind().GroupVersionKind().Kind
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return nil, fmt.Errorf("failed to apply template on %s %s/%s: %w", kind, obj.GetNamespace(), obj.GetName(), err)
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}
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for _, name := range strings.Split(buf.String(), ",") {
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name = strings.TrimFunc(name, unicode.IsSpace)
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name = strings.TrimSuffix(name, ".")
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hostnames = append(hostnames, name)
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}
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return hostnames, nil
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}
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func parseTemplate(fqdnTemplate string) (tmpl *template.Template, err error) {
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if fqdnTemplate == "" {
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return nil, nil
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}
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funcs := template.FuncMap{
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"trimPrefix": strings.TrimPrefix,
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}
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return template.New("endpoint").Funcs(funcs).Parse(fqdnTemplate)
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}
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func getHostnamesFromAnnotations(annotations map[string]string) []string {
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hostnameAnnotation, exists := annotations[hostnameAnnotationKey]
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if !exists {
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return nil
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}
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return strings.Split(strings.Replace(hostnameAnnotation, " ", "", -1), ",")
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}
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func getAccessFromAnnotations(annotations map[string]string) string {
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return annotations[accessAnnotationKey]
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}
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func getInternalHostnamesFromAnnotations(annotations map[string]string) []string {
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internalHostnameAnnotation, exists := annotations[internalHostnameAnnotationKey]
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if !exists {
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return nil
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}
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return strings.Split(strings.Replace(internalHostnameAnnotation, " ", "", -1), ",")
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}
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func getAliasFromAnnotations(annotations map[string]string) bool {
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aliasAnnotation, exists := annotations[aliasAnnotationKey]
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return exists && aliasAnnotation == "true"
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}
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func getProviderSpecificAnnotations(annotations map[string]string) (endpoint.ProviderSpecific, string) {
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providerSpecificAnnotations := endpoint.ProviderSpecific{}
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v, exists := annotations[CloudflareProxiedKey]
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if exists {
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providerSpecificAnnotations = append(providerSpecificAnnotations, endpoint.ProviderSpecificProperty{
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Name: CloudflareProxiedKey,
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Value: v,
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})
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}
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if getAliasFromAnnotations(annotations) {
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providerSpecificAnnotations = append(providerSpecificAnnotations, endpoint.ProviderSpecificProperty{
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Name: "alias",
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Value: "true",
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})
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}
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setIdentifier := ""
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for k, v := range annotations {
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if k == SetIdentifierKey {
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setIdentifier = v
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} else if strings.HasPrefix(k, "external-dns.alpha.kubernetes.io/aws-") {
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attr := strings.TrimPrefix(k, "external-dns.alpha.kubernetes.io/aws-")
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providerSpecificAnnotations = append(providerSpecificAnnotations, endpoint.ProviderSpecificProperty{
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Name: fmt.Sprintf("aws/%s", attr),
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Value: v,
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})
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} else if strings.HasPrefix(k, "external-dns.alpha.kubernetes.io/scw-") {
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attr := strings.TrimPrefix(k, "external-dns.alpha.kubernetes.io/scw-")
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providerSpecificAnnotations = append(providerSpecificAnnotations, endpoint.ProviderSpecificProperty{
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Name: fmt.Sprintf("scw/%s", attr),
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Value: v,
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})
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}
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}
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return providerSpecificAnnotations, setIdentifier
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}
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// getTargetsFromTargetAnnotation gets endpoints from optional "target" annotation.
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// Returns empty endpoints array if none are found.
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func getTargetsFromTargetAnnotation(annotations map[string]string) endpoint.Targets {
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var targets endpoint.Targets
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// Get the desired hostname of the ingress from the annotation.
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targetAnnotation, exists := annotations[targetAnnotationKey]
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if exists && targetAnnotation != "" {
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// splits the hostname annotation and removes the trailing periods
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targetsList := strings.Split(strings.Replace(targetAnnotation, " ", "", -1), ",")
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for _, targetHostname := range targetsList {
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targetHostname = strings.TrimSuffix(targetHostname, ".")
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targets = append(targets, targetHostname)
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}
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}
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return targets
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}
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// suitableType returns the DNS resource record type suitable for the target.
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// In this case type A for IPs and type CNAME for everything else.
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func suitableType(target string) string {
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if net.ParseIP(target) != nil {
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return endpoint.RecordTypeA
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}
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return endpoint.RecordTypeCNAME
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}
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// endpointsForHostname returns the endpoint objects for each host-target combination.
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func endpointsForHostname(hostname string, targets endpoint.Targets, ttl endpoint.TTL, providerSpecific endpoint.ProviderSpecific, setIdentifier string) []*endpoint.Endpoint {
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var endpoints []*endpoint.Endpoint
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var aTargets endpoint.Targets
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var cnameTargets endpoint.Targets
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for _, t := range targets {
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switch suitableType(t) {
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case endpoint.RecordTypeA:
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aTargets = append(aTargets, t)
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default:
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cnameTargets = append(cnameTargets, t)
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}
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}
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if len(aTargets) > 0 {
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epA := &endpoint.Endpoint{
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DNSName: strings.TrimSuffix(hostname, "."),
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Targets: aTargets,
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RecordTTL: ttl,
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RecordType: endpoint.RecordTypeA,
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Labels: endpoint.NewLabels(),
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ProviderSpecific: providerSpecific,
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SetIdentifier: setIdentifier,
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}
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endpoints = append(endpoints, epA)
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}
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if len(cnameTargets) > 0 {
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epCNAME := &endpoint.Endpoint{
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DNSName: strings.TrimSuffix(hostname, "."),
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Targets: cnameTargets,
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RecordTTL: ttl,
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RecordType: endpoint.RecordTypeCNAME,
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Labels: endpoint.NewLabels(),
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ProviderSpecific: providerSpecific,
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SetIdentifier: setIdentifier,
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}
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endpoints = append(endpoints, epCNAME)
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}
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return endpoints
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}
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func getLabelSelector(annotationFilter string) (labels.Selector, error) {
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labelSelector, err := metav1.ParseToLabelSelector(annotationFilter)
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if err != nil {
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return nil, err
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}
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return metav1.LabelSelectorAsSelector(labelSelector)
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}
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func matchLabelSelector(selector labels.Selector, srcAnnotations map[string]string) bool {
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annotations := labels.Set(srcAnnotations)
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return selector.Matches(annotations)
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}
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type eventHandlerFunc func()
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func (fn eventHandlerFunc) OnAdd(obj interface{}) { fn() }
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func (fn eventHandlerFunc) OnUpdate(oldObj, newObj interface{}) { fn() }
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func (fn eventHandlerFunc) OnDelete(obj interface{}) { fn() }
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type informerFactory interface {
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WaitForCacheSync(stopCh <-chan struct{}) map[reflect.Type]bool
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}
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func waitForCacheSync(ctx context.Context, factory informerFactory) error {
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ctx, cancel := context.WithTimeout(ctx, 60*time.Second)
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defer cancel()
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for typ, done := range factory.WaitForCacheSync(ctx.Done()) {
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if !done {
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select {
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case <-ctx.Done():
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return fmt.Errorf("failed to sync %v: %v", typ, ctx.Err())
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default:
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return fmt.Errorf("failed to sync %v", typ)
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}
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}
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}
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return nil
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}
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type dynamicInformerFactory interface {
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WaitForCacheSync(stopCh <-chan struct{}) map[schema.GroupVersionResource]bool
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}
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func waitForDynamicCacheSync(ctx context.Context, factory dynamicInformerFactory) error {
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ctx, cancel := context.WithTimeout(ctx, 60*time.Second)
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defer cancel()
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for typ, done := range factory.WaitForCacheSync(ctx.Done()) {
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if !done {
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select {
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case <-ctx.Done():
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return fmt.Errorf("failed to sync %v: %v", typ, ctx.Err())
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default:
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return fmt.Errorf("failed to sync %v", typ)
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}
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}
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}
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return nil
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}
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