mw/authpath: hook in kubernetees (#860)

Call out to kubernetes to get the search path - this still needs
to return something sensible, but all infrastructure has landed
to make it work.

middleware/kubernetes/autopath.go

@@ -1,11 +1,32 @@
 package kubernetes
 
-import "k8s.io/client-go/1.5/pkg/api"
+import (
+	"fmt"
 
-// TODO(miek): rename and put in autopath.go file. This will be for the
-// external middleware autopath to use. Mostly to get the namespace:
-//name, path, ok := autopath.SplitSearch(zone, state.QName(), p.Namespace)
-func (k *Kubernetes) findPodWithIP(ip string) (p *api.Pod) {
+	"github.com/coredns/coredns/request"
+
+	"k8s.io/client-go/1.5/pkg/api"
+)
+
+func (k *Kubernetes) AutoPath(state request.Request) ([]string, error) {
+	ip := state.IP()
+
+	pod := k.PodWithIP(ip)
+	if pod == nil {
+		return nil, fmt.Errorf("kubernets: no pod found for %s", ip)
+	}
+
+	// something something namespace
+	namespace := pod.Namespace
+
+	search := []string{namespace} // TODO: way more
+
+	search = append(search, "") // sentinal
+	return search, nil
+}
+
+// PodWithIP return the api.Pod for source IP ip. It return nil if nothing can be found.
+func (k *Kubernetes) PodWithIP(ip string) (p *api.Pod) {
 	objList := k.APIConn.PodIndex(ip)
 	for _, o := range objList {
 		p, ok := o.(*api.Pod)