Implementation of SDK.Allocate()

Now GameServers can self Allocate!

This is just the implementation of the GO SDK at this stage (although
the gRPC libraries have been regenerated). Other languages can come in
later PRs.

This is the first part of 1st Party MatchMaking support (#660)

build/Makefile

@@ -57,7 +57,7 @@ KIND_PROFILE ?= agones
 KIND_CONTAINER_NAME=kind-$(KIND_PROFILE)-control-plane
 
 # Game Server image to use while doing end-to-end tests
-GS_TEST_IMAGE ?= gcr.io/agones-images/udp-server:0.7
+GS_TEST_IMAGE ?= gcr.io/agones-images/udp-server:0.8
 
 # Directory that this Makefile is in.
 mkfile_path := $(abspath $(lastword $(MAKEFILE_LIST)))

examples/fleet.yaml

@@ -67,4 +67,4 @@ spec:
         spec:
           containers:
           - name: simple-udp
-            image: gcr.io/agones-images/udp-server:0.7
+            image: gcr.io/agones-images/udp-server:0.8

examples/simple-udp/Makefile

@@ -27,7 +27,7 @@ REPOSITORY = gcr.io/agones-images
 
 mkfile_path := $(abspath $(lastword $(MAKEFILE_LIST)))
 project_path := $(dir $(mkfile_path))
-server_tag = $(REPOSITORY)/udp-server:0.7
+server_tag = $(REPOSITORY)/udp-server:0.8
 root_path = $(realpath $(project_path)/../..)
 
 #   _____                    _

examples/simple-udp/fleet-distributed.yaml

@@ -32,7 +32,7 @@ spec:
         spec:
           containers:
           - name: simple-udp
-            image: gcr.io/agones-images/udp-server:0.7
+            image: gcr.io/agones-images/udp-server:0.8
             resources:
               requests:
                 memory: "32Mi"

examples/simple-udp/fleet.yaml

@@ -27,7 +27,7 @@ spec:
         spec:
           containers:
           - name: simple-udp
-            image: gcr.io/agones-images/udp-server:0.7
+            image: gcr.io/agones-images/udp-server:0.8
             resources:
               requests:
                 memory: "64Mi"

examples/simple-udp/gameserver.yaml

@@ -25,7 +25,7 @@ spec:
     spec:
       containers:
       - name: simple-udp
-        image: gcr.io/agones-images/udp-server:0.7
+        image: gcr.io/agones-images/udp-server:0.8
         resources:
           requests:
             memory: "32Mi"

examples/simple-udp/gameserverset.yaml

@@ -31,4 +31,4 @@ spec:
         spec:
           containers:
           - name: simple-udp
-            image: gcr.io/agones-images/udp-server:0.7
+            image: gcr.io/agones-images/udp-server:0.8

examples/simple-udp/main.go

@@ -94,6 +94,9 @@ func readWriteLoop(conn net.PacketConn, stop chan struct{}, s *sdk.SDK) {
 		case "GAMESERVER":
 			writeGameServerName(s, conn, sender)
 
+		case "ALLOCATE":
+			allocate(s)
+
 		case "WATCH":
 			watchGameServerEvents(s)
 
@@ -126,6 +129,14 @@ func readWriteLoop(conn net.PacketConn, stop chan struct{}, s *sdk.SDK) {
 	}
 }
 
+// allocate attemps to allocate this gameserver
+func allocate(s *sdk.SDK) {
+	err := s.Allocate()
+	if err != nil {
+		log.Fatalf("could not allocate gameserver: %v", err)
+	}
+}
+
 // readPacket reads a string from the connection
 func readPacket(conn net.PacketConn, b []byte) (net.Addr, string) {
 	n, sender, err := conn.ReadFrom(b)

install/helm/agones/templates/NOTES.txt

@@ -19,7 +19,7 @@ spec:
     spec:
       containers:
       - name: simple-udp
-        image: gcr.io/agones-images/udp-server:0.7
+        image: gcr.io/agones-images/udp-server:0.8
 
 Finally don't forget to explore our documentation and usage guides on how to develop and host dedicated game servers on top of Agones. :
 

pkg/sdkserver/localsdk.go

@@ -121,6 +121,12 @@ func (l *LocalSDKServer) Ready(context.Context, *sdk.Empty) (*sdk.Empty, error)
 	return &sdk.Empty{}, nil
 }
 
+// Allocate logs that an allocate request has been received
+func (l *LocalSDKServer) Allocate(context.Context, *sdk.Empty) (*sdk.Empty, error) {
+	logrus.Info("Allocate request has been received!")
+	return &sdk.Empty{}, nil
+}
+
 // Shutdown logs that the shutdown request has been received
 func (l *LocalSDKServer) Shutdown(context.Context, *sdk.Empty) (*sdk.Empty, error) {
 	logrus.Info("Shutdown request has been received!")

pkg/sdkserver/sdkserver.go

@@ -35,6 +35,7 @@ import (
 	"github.com/sirupsen/logrus"
 	"golang.org/x/net/context"
 	corev1 "k8s.io/api/core/v1"
+	k8serrors "k8s.io/apimachinery/pkg/api/errors"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/fields"
 	"k8s.io/apimachinery/pkg/util/clock"
@@ -55,7 +56,17 @@ const (
 	updateAnnotation Operation = "updateAnnotation"
 )
 
-var _ sdk.SDKServer = &SDKServer{}
+var (
+	_ sdk.SDKServer = &SDKServer{}
+
+	defaultTimeout = 30 * time.Second
+	defaultBackoff = wait.Backoff{
+		Duration: 100 * time.Millisecond,
+		Factor:   1,
+		Jitter:   0.1,
+		Steps:    5,
+	}
+)
 
 // SDKServer is a gRPC server, that is meant to be a sidecar
 // for a GameServer that will update the game server status on SDK requests
@@ -330,6 +341,51 @@ func (s *SDKServer) Ready(ctx context.Context, e *sdk.Empty) (*sdk.Empty, error)
 	return e, nil
 }
 
+// Allocate set the GameServer to Allocate, as longs as it's not in UnHealthy,
+// Shutdown or has a DeletionTimeStamp(). Times out after 30 seconds if it cannot
+// complete the operation due to contention issues.
+func (s *SDKServer) Allocate(context.Context, *sdk.Empty) (*sdk.Empty, error) {
+	s.logger.Info("Received self Allocate request")
+
+	now := s.clock.Now()
+	err := wait.ExponentialBackoff(defaultBackoff, func() (done bool, err error) {
+		gs, err := s.gameServer()
+		if err != nil {
+			return true, err
+		}
+
+		if !gs.ObjectMeta.DeletionTimestamp.IsZero() {
+			return true, nil
+		}
+
+		switch gs.Status.State {
+		case stablev1alpha1.GameServerStateUnhealthy:
+			return true, errors.New("cannot Allocate an Unhealthy GameServer")
+
+		case stablev1alpha1.GameServerStateShutdown:
+			return true, errors.New("cannot Allocate a Shutdown GameServer")
+		}
+
+		gsCopy := gs.DeepCopy()
+		gsCopy.Status.State = stablev1alpha1.GameServerStateAllocated
+		_, err = s.gameServerGetter.GameServers(s.namespace).Update(gsCopy)
+
+		// if a contention, and we are under the timeout period.
+		if k8serrors.IsConflict(err) {
+			// TODO: write a test for this
+			if s.clock.Since(now) > defaultTimeout {
+				return true, errors.New("Allocation request timed out")
+			}
+
+			return false, nil
+		}
+
+		return true, errors.Wrap(err, "could not update gameserver to Allocated")
+	})
+
+	return &sdk.Empty{}, errors.WithStack(err)
+}
+
 // Shutdown enters the Shutdown state change for this GameServer into
 // the workqueue so it can be updated
 func (s *SDKServer) Shutdown(ctx context.Context, e *sdk.Empty) (*sdk.Empty, error) {