mw/kubernetes: remove federation and cidr (#916)

* mw/kubernetes: remove federation and cidr

Remove both as we have a corefile syntax change that handles cidr and
remove federation because that is going to be its own middleware.

* backwards incompat changes

This PR:
* removes cidr from kubernetes (core Corefile feature now)
* removes federation from kubernets (comes back as new middleware)
* [remove autopath - which was already gone, so that already was
  backwards incompat]
* adds `fallthrough` to the *etcd* middleware and makes you enable it.
* Fail on unknown properties
* documentation
* Disable TestHealthCheck as it uses realtime and fails

middleware/etcd/README.md

@@ -23,6 +23,7 @@ If you want to `round robin` A and AAAA responses look at the `loadbalance` midd
 ~~~
 etcd [ZONES...] {
     stubzones
+    fallthrough
     path PATH
     endpoint ENDPOINT...
     upstream ADDRESS...
@@ -33,6 +34,7 @@ etcd [ZONES...] {
 
 * `stubzones` enables the stub zones feature. The stubzone is *only* done in the etcd tree located
     under the *first* zone specified.
+* `fallthrough` If zone matches but no record can be generated, pass request to the next middleware.
 * **PATH** the path inside etcd. Defaults to "/skydns".
 * **ENDPOINT** the etcd endpoints. Defaults to "http://localhost:2397".
 * `upstream` upstream resolvers to be used resolve external names found in etcd (think CNAMEs)

middleware/etcd/etcd.go

@@ -21,15 +21,16 @@ import (
 
 // Etcd is a middleware talks to an etcd cluster.
 type Etcd struct {
-	Next       middleware.Handler
-	Zones      []string
-	PathPrefix string
-	Proxy      proxy.Proxy // Proxy for looking up names during the resolution process
-	Client     etcdc.KeysAPI
-	Ctx        context.Context
-	Inflight   *singleflight.Group
-	Stubmap    *map[string]proxy.Proxy // list of proxies for stub resolving.
-	Debugging  bool                    // Do we allow debug queries.
+	Next        middleware.Handler
+	Fallthrough bool
+	Zones       []string
+	PathPrefix  string
+	Proxy       proxy.Proxy // Proxy for looking up names during the resolution process
+	Client      etcdc.KeysAPI
+	Ctx         context.Context
+	Inflight    *singleflight.Group
+	Stubmap     *map[string]proxy.Proxy // list of proxies for stub resolving.
+	Debugging   bool                    // Do we allow debug queries.
 
 	endpoints []string // Stored here as well, to aid in testing.
 }

middleware/etcd/handler.go

@@ -46,7 +46,10 @@ func (e *Etcd) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (
 		if opt.Debug != "" {
 			r.Question[0].Name = opt.Debug
 		}
-		return middleware.NextOrFailure(e.Name(), e.Next, ctx, w, r)
+		if e.Fallthrough {
+			return middleware.NextOrFailure(e.Name(), e.Next, ctx, w, r)
+		}
+		return dns.RcodeServerFailure, nil
 	}
 
 	var (

middleware/etcd/multi_test.go

@@ -16,6 +16,7 @@ import (
 func TestMultiLookup(t *testing.T) {
 	etc := newEtcdMiddleware()
 	etc.Zones = []string{"skydns.test.", "miek.nl."}
+	etc.Fallthrough = true
 	etc.Next = test.ErrorHandler()
 
 	for _, serv := range servicesMulti {

middleware/etcd/setup.go

@@ -74,6 +74,8 @@ func etcdParse(c *caddy.Controller) (*Etcd, bool, error) {
 				switch c.Val() {
 				case "stubzones":
 					stubzones = true
+				case "fallthrough":
+					etc.Fallthrough = true
 				case "debug":
 					etc.Debugging = true
 				case "path":