plugin/k8s_external: implement zone transfers (#4977)

Implement transfer for k8s_external. Notifies not supported.

Signed-off-by: Chris O'Haver <cohaver@infoblox.com>

1 files changed, 9 insertions, 3 deletions

diff --git a/plugin/k8s_external/external.go b/plugin/k8s_external/external.go
index 720556969..c584b3414 100644
--- a/plugin/k8s_external/external.go
+++ b/plugin/k8s_external/external.go
@@ -29,9 +29,13 @@ type Externaler interface {
 	External(request.Request) ([]msg.Service, int)
 	// ExternalAddress should return a string slice of addresses for the nameserving endpoint.
 	ExternalAddress(state request.Request) []dns.RR
+	// ExternalServices returns all services in the given zone as a slice of msg.Service.
+	ExternalServices(zone string) []msg.Service
+	// ExternalSerial gets the current serial.
+	ExternalSerial(string) uint32
 }
 
-// External resolves Ingress and Loadbalance IPs from kubernetes clusters.
+// External serves records for External IPs and Loadbalance IPs of Services in Kubernetes clusters.
 type External struct {
 	Next  plugin.Handler
 	Zones []string
@@ -42,8 +46,10 @@ type External struct {
 
 	upstream *upstream.Upstream
 
-	externalFunc     func(request.Request) ([]msg.Service, int)
-	externalAddrFunc func(request.Request) []dns.RR
+	externalFunc         func(request.Request) ([]msg.Service, int)
+	externalAddrFunc     func(request.Request) []dns.RR
+	externalSerialFunc   func(string) uint32
+	externalServicesFunc func(string) []msg.Service
 }
 
 // New returns a new and initialized *External.