From c88790d91cafd4fd8211fc414620dccbd2f82c78 Mon Sep 17 00:00:00 2001
From: Dimitrios Karagiannis <dhkarag@gmail.com>
Date: Fri, 24 Nov 2017 15:37:59 +0000
Subject: [PATCH] ignore hostname deletes when used by other ingresses

---
 ingress.go     | 16 +++++++++++++++-
 registrator.go |  5 +++++
 2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/ingress.go b/ingress.go
index 4364eac..35182c6 100644
--- a/ingress.go
+++ b/ingress.go
@@ -20,6 +20,7 @@ type ingressWatcher struct {
 	resyncPeriod  time.Duration
 	labelSelector string
 	stopChannel   chan struct{}
+	store         cache.Store
 }
 
 func newIngressWatcher(client kubernetes.Interface, eventHandler eventHandlerFunc, labelSelector string, resyncPeriod time.Duration) *ingressWatcher {
@@ -54,7 +55,8 @@ func (iw *ingressWatcher) Start() {
 			iw.eventHandler(watch.Deleted, obj.(*v1beta1.Ingress), nil)
 		},
 	}
-	_, controller := cache.NewInformer(lw, &v1beta1.Ingress{}, iw.resyncPeriod, eh)
+	store, controller := cache.NewInformer(lw, &v1beta1.Ingress{}, iw.resyncPeriod, eh)
+	iw.store = store
 	log.Println("[INFO] starting ingress watcher")
 	controller.Run(iw.stopChannel)
 	log.Println("[INFO] ingress watcher stopped")
@@ -65,6 +67,18 @@ func (iw *ingressWatcher) Stop() {
 	close(iw.stopChannel)
 }
 
+func (iw *ingressWatcher) HostnameOwners(hostname string) []string {
+	owners := []string{}
+	for _, i := range iw.store.List() {
+		for _, h := range getHostnamesFromIngress(i.(*v1beta1.Ingress)) {
+			if hostname == h {
+				owners = append(owners, i.(*v1beta1.Ingress).Name)
+			}
+		}
+	}
+	return owners
+}
+
 func getHostnamesFromIngress(ingress *v1beta1.Ingress) []string {
 	hostnames := []string{}
 	for _, rule := range ingress.Spec.Rules {
diff --git a/registrator.go b/registrator.go
index 5b026d5..752b51e 100644
--- a/registrator.go
+++ b/registrator.go
@@ -290,6 +290,11 @@ func (r *registrator) pruneBatch(action string, records []cnameRecord) []cnameRe
 		t, err := resolveCname(fmt.Sprintf("%s.", strings.Trim(u.Hostname, ".")), r.ListNameservers())
 		switch action {
 		case route53.ChangeActionDelete:
+			o := r.ingressWatcher.HostnameOwners(u.Hostname)
+			if len(o) > 0 {
+				log.Printf("[DEBUG] will not delete record %s because it's still claimed by: %s", u.Hostname, strings.Join(o, ","))
+				break
+			}
 			if err == nil {
 				pruned = append(pruned, u)
 			} else if err != errDNSEmptyAnswer {