[Breaking Change] Move GameServerAllocation to an API Extension Server.

This moves the implementation of GameServerAllocation (GSA) to a
[Kubernetes API Extension](https://kubernetes.io/docs/concepts/extend-kubernetes/api-extension/apiserver-aggregation/)
instead of using CRDs. This was essentially done for performance reasons, but to break it down:

1. GSA is now create only. Since we had no need for GSA storage, and don't want the performance hit.
1. This removes the mutation and validation webhooks, which have 30s timeout and are run in serial
    1. API Server still does cut off a response after 60s, but the api can
       continue processing (60s gives us enough time, I think for a SDK.Ack() on Allocate, which I don't think
       we had before)
    1. Validation now happens in the request.
1. We can now do batching of requests for higher throughput (googleforgames#536), since we control the entire http request.
1. Sets us up if we decide we also want to have an alternative (http and/or gRPC) endpoint for allocation, based
   on feedback from this implementation.

The breaking changes are:
1. GameServerAllocation's group is now `allocation.agones.dev` rather than `stable.agones.dev`,
because a CRD group can't overlap with a api server.
1. Since there is only the `create` verb for GSA, there is no get/list/watch options for GameServerAllocations - so no
   informers/listers either. But this could be added at a later date, if needed.

This also includes some libraries for building further api server extension points.

Gopkg.toml

@@ -100,6 +100,14 @@
   name = "contrib.go.opencensus.io/exporter/stackdriver"
   version = "v0.8.0"
 
+[[constraint]]
+  name = "github.com/go-openapi/spec"
+  version = "0.18.0"
+
+[[constraint]]
+  branch = "master"
+  name = "github.com/munnerz/goautoneg"
+
 [[constraint]]
   name = "fortio.org/fortio"
   version = "1.3.1"

build/build-image/Dockerfile

@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-# ForceUpdate 6 -- change here if you need to force a rebuild
+# ForceUpdate 7 -- change here if you need to force a rebuild
 
 # compiling proto + grpc takes an exceptionally long time
 # so we'll use a base from `base` - which is manually built using the below tag.

build/build-image/gen-crd-client.sh

@@ -14,9 +14,12 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+set -x
+
+rm -r $GOPATH/src/agones.dev/agones/pkg/client
 rsync -r /go/src/agones.dev/agones/vendor/k8s.io/ /go/src/k8s.io/
 cd /go/src/k8s.io/code-generator
 ./generate-groups.sh "all" \
     agones.dev/agones/pkg/client \
-    agones.dev/agones/pkg/apis stable:v1alpha1 \
+    agones.dev/agones/pkg/apis "allocation:v1alpha1 stable:v1alpha1" \
     --go-header-file=/go/src/agones.dev/agones/build/boilerplate.go.txt

cmd/controller/main.go

@@ -33,6 +33,8 @@ import (
 	"agones.dev/agones/pkg/gameservers"
 	"agones.dev/agones/pkg/gameserversets"
 	"agones.dev/agones/pkg/metrics"
+	"agones.dev/agones/pkg/util/apiserver"
+	"agones.dev/agones/pkg/util/https"
 	"agones.dev/agones/pkg/util/runtime"
 	"agones.dev/agones/pkg/util/signals"
 	"agones.dev/agones/pkg/util/webhooks"
@@ -105,7 +107,11 @@ func main() {
 		logger.WithError(err).Fatal("Could not create the agones api clientset")
 	}
 
-	wh := webhooks.NewWebHook(ctlConf.CertFile, ctlConf.KeyFile)
+	// https server and the items that share the Mux for routing
+	httpsServer := https.NewServer(ctlConf.CertFile, ctlConf.KeyFile)
+	wh := webhooks.NewWebHook(httpsServer.Mux)
+	api := apiserver.NewAPIServer(httpsServer.Mux)
+
 	agonesInformerFactory := externalversions.NewSharedInformerFactory(agonesClient, defaultResync)
 	kubeInformerFactory := informers.NewSharedInformerFactory(kubeClient, defaultResync)
 
@@ -159,13 +165,13 @@ func main() {
 	fleetController := fleets.NewController(wh, health, kubeClient, extClient, agonesClient, agonesInformerFactory)
 	faController := fleetallocation.NewController(wh, allocationMutex,
 		kubeClient, extClient, agonesClient, agonesInformerFactory)
-	gasController := gameserverallocations.NewController(wh, health, allocationMutex, kubeClient,
-		kubeInformerFactory, extClient, agonesClient, agonesInformerFactory)
+	gasController := gameserverallocations.NewController(api, allocationMutex, kubeClient,
+		kubeInformerFactory, agonesClient, agonesInformerFactory)
 	fasController := fleetautoscalers.NewController(wh, health,
 		kubeClient, extClient, agonesClient, agonesInformerFactory)
 
 	rs = append(rs,
-		wh, gsController, gsSetController, fleetController, faController, fasController, gasController, server)
+		httpsServer, gsController, gsSetController, fleetController, faController, fasController, gasController, server)
 
 	stop := signals.NewStopChannel()
 

examples/gameserverallocation.yaml

@@ -20,7 +20,7 @@
 # multiple Fleets, or a self managed group of GameServers.
 #
 
-apiVersion: "stable.agones.dev/v1alpha1"
+apiVersion: "allocation.agones.dev/v1alpha1"
 kind: GameServerAllocation
 metadata:
   # We recommend using the following to generate a unique name when creating Allocations

examples/simple-udp/gameserverallocation.yaml

@@ -12,14 +12,13 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+#
+# A GameServerAllocation against a Fleet named 'simple-udp'
 # (GameServerAllocation is currently experimental, and likely to change in upcoming releases)
+#
 
-apiVersion: "stable.agones.dev/v1alpha1"
+apiVersion: "allocation.agones.dev/v1alpha1"
 kind: GameServerAllocation
-metadata:
-  # We recommend using the following to generate a unique name when creating Allocations
-  # This will need to be created with `kubectl create` if using the command line tooling
-  generateName: simple-udp-
 spec:
   # GameServer selector from which to choose GameServers from.
   # GameServers still have the hard requirement to be `Ready` to be allocated from

examples/xonotic/gameserverallocation.yaml

@@ -14,7 +14,7 @@
 
 # (GameServerAllocation is currently experimental, and likely to change in upcoming releases)
 
-apiVersion: "stable.agones.dev/v1alpha1"
+apiVersion: "allocation.agones.dev/v1alpha1"
 kind: GameServerAllocation
 metadata:
   # We recommend using the following to generate a unique name when creating Allocations

install/helm/agones/scripts/delete_agones_resources.sh

@@ -32,7 +32,6 @@ for ns in $namespaces; do
   kubectl -n $ns delete gameserversets --all
   kubectl -n $ns delete gameservers --all
   kubectl -n $ns delete fleetallocations --all
-  kubectl -n $ns delete gameserverallocations --all
 
   # Since we don't have the nifty kubectl wait yet, hack one in the meantime
   for p in $pods; do