Implements SDK callback for GameServer updates

This implements the gRPC system to send messages up to a unidirectional
stream from the sdk-server to the SDK.

This has been implemented in the Go, C++ and REST SDK.

Closes #277

cmd/sdk-server/main.go

@@ -86,7 +86,7 @@ func main() {
 	defer cancel()
 
 	if ctlConf.IsLocal {
-		sdk.RegisterSDKServer(grpcServer, &gameservers.LocalSDKServer{})
+		sdk.RegisterSDKServer(grpcServer, gameservers.NewLocalSDKServer())
 	} else {
 		var config *rest.Config
 		config, err = rest.InClusterConfig()

docs/sdk_rest_api.md

@@ -102,3 +102,24 @@ Response:
     }
 }
 ```
+
+### Watch GameServer
+
+⚠️⚠️⚠️ **/watch/gameserver is currently a development feature and has not been released** ⚠️⚠️⚠️
+
+Call this when you want to get updates of when the backing `GameServer` configuration is updated.
+
+These updates will come as newline delimited JSON, send on each update. To that end, you will
+want to keep the http connection open, and read lines from the result stream and and process as they
+come in.
+
+```bash
+$ curl -H "Content-Type: application/json" -X GET http://localhost:59358/watch/gameserver
+```
+
+Response:
+```json
+{"result":{"object_meta":{"name":"local","namespace":"default","uid":"1234","resource_version":"v1","generation":"1","creation_timestamp":"1533766607","annotations":{"annotation":"true"},"labels":{"islocal":"true"}},"status":{"state":"Ready","address":"127.0.0.1","ports":[{"name":"default","port":7777}]}}}
+{"result":{"object_meta":{"name":"local","namespace":"default","uid":"1234","resource_version":"v1","generation":"1","creation_timestamp":"1533766607","annotations":{"annotation":"true"},"labels":{"islocal":"true"}},"status":{"state":"Ready","address":"127.0.0.1","ports":[{"name":"default","port":7777}]}}}
+{"result":{"object_meta":{"name":"local","namespace":"default","uid":"1234","resource_version":"v1","generation":"1","creation_timestamp":"1533766607","annotations":{"annotation":"true"},"labels":{"islocal":"true"}},"status":{"state":"Ready","address":"127.0.0.1","ports":[{"name":"default","port":7777}]}}}
+```

examples/cpp-simple/Makefile

@@ -32,7 +32,7 @@ REPOSITORY = gcr.io/agones-images
 # Directory that this Makefile is in.
 mkfile_path := $(abspath $(lastword $(MAKEFILE_LIST)))
 project_path := $(dir $(mkfile_path))
-server_tag = $(REPOSITORY)/cpp-simple-server:0.2
+server_tag = $(REPOSITORY)/cpp-simple-server:0.3
 
 #   _____                    _
 #  |_   _|_ _ _ __ __ _  ___| |_ ___

examples/cpp-simple/fleet.yaml

@@ -30,5 +30,5 @@ spec:
         spec:
           containers:
             - name: cpp-simple
-              image: gcr.io/agones-images/cpp-simple-server:0.2
+              image: gcr.io/agones-images/cpp-simple-server:0.3
               # imagePullPolicy: Always # add for development

examples/cpp-simple/gameserver.yaml

@@ -27,5 +27,5 @@ spec:
     spec:
       containers:
       - name: cpp-simple
-        image: gcr.io/agones-images/cpp-simple-server:0.2
+        image: gcr.io/agones-images/cpp-simple-server:0.3
         # imagePullPolicy: Always # add for development

examples/cpp-simple/server.cc

@@ -33,6 +33,15 @@ void doHealth(agones::SDK *sdk) {
     }
 }
 
+// watch GameServer Updates
+void watchUpdates(agones::SDK *sdk) {
+    std::cout << "Starting to watch GameServer updates..." << std::endl;
+    sdk->WatchGameServer([](stable::agones::dev::sdk::GameServer gameserver){
+        std::cout << "GameServer Update, name: " << gameserver.object_meta().name() << std::endl;
+        std::cout << "GameServer Update, state: " << gameserver.status().state() << std::endl;
+    });
+}
+
 int main() {
     std::cout << "C++ Game Server has started!" << std::endl;
 
@@ -48,6 +57,7 @@ int main() {
     std::cout << "...handshake complete." << std::endl;
 
     std::thread health (doHealth, sdk);
+    std::thread watch (watchUpdates, sdk);
 
     std::cout << "Marking server as ready..." << std::endl;
     grpc::Status status = sdk->Ready();

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:0.2
+server_tag = $(REPOSITORY)/udp-server:0.3
 package = agones.dev/agones/examples/simple-udp
 
 #   _____                    _

examples/simple-udp/server/fleet.yaml

@@ -31,4 +31,4 @@ spec:
         spec:
           containers:
           - name: simple-udp
-            image: gcr.io/agones-images/udp-server:0.2
+            image: gcr.io/agones-images/udp-server:0.3

examples/simple-udp/server/gameserver-legacy.yaml

@@ -25,4 +25,4 @@ spec:
     spec:
       containers:
       - name: simple-udp
-        image: gcr.io/agones-images/udp-server:0.2
+        image: gcr.io/agones-images/udp-server:0.3

examples/simple-udp/server/gameserver.yaml

@@ -25,4 +25,4 @@ spec:
     spec:
       containers:
       - name: simple-udp
-        image: gcr.io/agones-images/udp-server:0.2
+        image: gcr.io/agones-images/udp-server:0.3

examples/simple-udp/server/main.go

@@ -91,6 +91,9 @@ func readWriteLoop(conn net.PacketConn, stop chan struct{}, s *sdk.SDK) {
 
 		case "GAMESERVER":
 			writeGameServerName(s, conn, sender)
+
+		case "WATCH":
+			watchGameServerEvents(s)
 		}
 
 		// echo it back
@@ -120,6 +123,21 @@ func writeGameServerName(s *sdk.SDK, conn net.PacketConn, sender net.Addr) {
 	}
 }
 
+// watchGameServerEvents creates a callback to log when
+// gameserver events occur
+func watchGameServerEvents(s *sdk.SDK) {
+	err := s.WatchGameServer(func(gs *coresdk.GameServer) {
+		j, err := json.Marshal(gs)
+		if err != nil {
+			log.Fatalf("error mashalling GameServer to JSON: %v", err)
+		}
+		log.Printf("GameServer Event: %s \n", string(j))
+	})
+	if err != nil {
+		log.Fatalf("Could not watch Game Server events, %v", err)
+	}
+}
+
 // doHealth sends the regular Health Pings
 func doHealth(sdk *sdk.SDK, stop <-chan struct{}) {
 	tick := time.Tick(2 * time.Second)

pkg/gameservers/helper_test.go

@@ -26,6 +26,7 @@ import (
 	"agones.dev/agones/pkg/sdk"
 	"github.com/sirupsen/logrus"
 	"github.com/stretchr/testify/assert"
+	netcontext "golang.org/x/net/context"
 	"google.golang.org/grpc/metadata"
 	corev1 "k8s.io/api/core/v1"
 	"k8s.io/apimachinery/pkg/util/wait"
@@ -42,70 +43,110 @@ func newSingleContainerSpec() v1alpha1.GameServerSpec {
 	}
 }
 
-// mockStream is the mock of the SDK_HealthServer for streaming
-type mockStream struct {
+func testHTTPHealth(t *testing.T, url string, expectedResponse string, expectedStatus int) {
+	// do a poll, because this code could run before the health check becomes live
+	err := wait.PollImmediate(time.Second, 20*time.Second, func() (done bool, err error) {
+		resp, err := http.Get(url)
+		if err != nil {
+			logrus.WithError(err).Error("Error connecting to ", url)
+			return false, nil
+		}
+
+		assert.NotNil(t, resp)
+		if resp != nil {
+			defer resp.Body.Close() // nolint: errcheck
+			body, err := ioutil.ReadAll(resp.Body)
+			assert.Nil(t, err, "(%s) read response error should be nil: %v", url, err)
+			assert.Equal(t, expectedStatus, resp.StatusCode, "url: %s", url)
+			assert.Equal(t, []byte(expectedResponse), body, "(%s) response body should be '%s'", url, expectedResponse)
+		}
+
+		return true, nil
+	})
+	assert.Nil(t, err, "Timeout on %s health check, %v", url, err)
+}
+
+// emptyMockStream is the mock of the SDK_HealthServer for streaming
+type emptyMockStream struct {
 	msgs chan *sdk.Empty
 }
 
-func newMockStream() *mockStream {
-	return &mockStream{msgs: make(chan *sdk.Empty)}
+func newEmptyMockStream() *emptyMockStream {
+	return &emptyMockStream{msgs: make(chan *sdk.Empty)}
 }
 
-func (m *mockStream) SendAndClose(*sdk.Empty) error {
+func (m *emptyMockStream) SendAndClose(*sdk.Empty) error {
 	return nil
 }
 
-func (m *mockStream) Recv() (*sdk.Empty, error) {
+func (m *emptyMockStream) Recv() (*sdk.Empty, error) {
 	empty, ok := <-m.msgs
 	if ok {
 		return empty, nil
 	}
 	return empty, io.EOF
 }
 
-func (m *mockStream) SetHeader(metadata.MD) error {
+func (m *emptyMockStream) SetHeader(metadata.MD) error {
 	panic("implement me")
 }
 
-func (m *mockStream) SendHeader(metadata.MD) error {
+func (m *emptyMockStream) SendHeader(metadata.MD) error {
 	panic("implement me")
 }
 
-func (m *mockStream) SetTrailer(metadata.MD) {
+func (m *emptyMockStream) SetTrailer(metadata.MD) {
 	panic("implement me")
 }
 
-func (m *mockStream) Context() context.Context {
+func (m *emptyMockStream) Context() context.Context {
 	panic("implement me")
 }
 
-func (m *mockStream) SendMsg(msg interface{}) error {
+func (m *emptyMockStream) SendMsg(msg interface{}) error {
 	panic("implement me")
 }
 
-func (m *mockStream) RecvMsg(msg interface{}) error {
+func (m *emptyMockStream) RecvMsg(msg interface{}) error {
 	panic("implement me")
 }
 
-func testHTTPHealth(t *testing.T, url string, expectedResponse string, expectedStatus int) {
-	// do a poll, because this code could run before the health check becomes live
-	err := wait.PollImmediate(time.Second, 20*time.Second, func() (done bool, err error) {
-		resp, err := http.Get(url)
-		if err != nil {
-			logrus.WithError(err).Error("Error connecting to ", url)
-			return false, nil
-		}
+type gameServerMockStream struct {
+	msgs chan *sdk.GameServer
+}
 
-		assert.NotNil(t, resp)
-		if resp != nil {
-			defer resp.Body.Close() // nolint: errcheck
-			body, err := ioutil.ReadAll(resp.Body)
-			assert.Nil(t, err, "(%s) read response error should be nil: %v", url, err)
-			assert.Equal(t, expectedStatus, resp.StatusCode, "url: %s", url)
-			assert.Equal(t, []byte(expectedResponse), body, "(%s) response body should be '%s'", url, expectedResponse)
-		}
+// newGameServerMockStream implements SDK_WatchGameServerServer for testing
+func newGameServerMockStream() *gameServerMockStream {
+	return &gameServerMockStream{
+		msgs: make(chan *sdk.GameServer, 10),
+	}
+}
 
-		return true, nil
-	})
-	assert.Nil(t, err, "Timeout on %s health check, %v", url, err)
+func (m *gameServerMockStream) Send(gs *sdk.GameServer) error {
+	m.msgs <- gs
+	return nil
+}
+
+func (*gameServerMockStream) SetHeader(metadata.MD) error {
+	panic("implement me")
+}
+
+func (*gameServerMockStream) SendHeader(metadata.MD) error {
+	panic("implement me")
+}
+
+func (*gameServerMockStream) SetTrailer(metadata.MD) {
+	panic("implement me")
+}
+
+func (*gameServerMockStream) Context() netcontext.Context {
+	panic("implement me")
+}
+
+func (*gameServerMockStream) SendMsg(m interface{}) error {
+	panic("implement me")
+}
+
+func (*gameServerMockStream) RecvMsg(m interface{}) error {
+	panic("implement me")
 }

pkg/gameservers/localsdk.go

@@ -16,7 +16,6 @@ package gameservers
 
 import (
 	"io"
-
 	"time"
 
 	"agones.dev/agones/pkg/sdk"
@@ -25,12 +24,40 @@ import (
 	"golang.org/x/net/context"
 )
 
-var _ sdk.SDKServer = &LocalSDKServer{}
+var (
+	_ sdk.SDKServer = &LocalSDKServer{}
+
+	fixture = &sdk.GameServer{
+		ObjectMeta: &sdk.GameServer_ObjectMeta{
+			Name:              "local",
+			Namespace:         "default",
+			Uid:               "1234",
+			Generation:        1,
+			ResourceVersion:   "v1",
+			CreationTimestamp: time.Now().Unix(),
+			Labels:            map[string]string{"islocal": "true"},
+			Annotations:       map[string]string{"annotation": "true"},
+		},
+		Status: &sdk.GameServer_Status{
+			State:   "Ready",
+			Address: "127.0.0.1",
+			Ports:   []*sdk.GameServer_Status_Port{{Name: "default", Port: 7777}},
+		},
+	}
+)
 
 // LocalSDKServer type is the SDKServer implementation for when the sidecar
 // is being run for local development, and doesn't connect to the
 // Kubernetes cluster
 type LocalSDKServer struct {
+	watchPeriod time.Duration
+}
+
+// NewLocalSDKServer returns the default LocalSDKServer
+func NewLocalSDKServer() *LocalSDKServer {
+	return &LocalSDKServer{
+		watchPeriod: 5 * time.Second,
+	}
 }
 
 // Ready logs that the Ready request has been received
@@ -63,23 +90,24 @@ func (l *LocalSDKServer) Health(stream sdk.SDK_HealthServer) error {
 // GetGameServer returns a dummy game server.
 func (l *LocalSDKServer) GetGameServer(context.Context, *sdk.Empty) (*sdk.GameServer, error) {
 	logrus.Info("getting GameServer details")
-	gs := &sdk.GameServer{
-		ObjectMeta: &sdk.GameServer_ObjectMeta{
-			Name:              "local",
-			Namespace:         "default",
-			Uid:               "1234",
-			Generation:        1,
-			ResourceVersion:   "v1",
-			CreationTimestamp: time.Now().Unix(),
-			Labels:            map[string]string{"islocal": "true"},
-			Annotations:       map[string]string{"annotation": "true"},
-		},
-		Status: &sdk.GameServer_Status{
-			State:   "Ready",
-			Address: "127.0.0.1",
-			Ports:   []*sdk.GameServer_Status_Port{{Name: "default", Port: 7777}},
-		},
+	return fixture, nil
+}
+
+// WatchGameServer will return a dummy GameServer (with no changes), 3 times, every 5 seconds
+func (l *LocalSDKServer) WatchGameServer(_ *sdk.Empty, stream sdk.SDK_WatchGameServerServer) error {
+	logrus.Info("connected to watch GameServer...")
+	times := 3
+
+	for i := 0; i < times; i++ {
+		logrus.Info("Sending watched GameServer!")
+		err := stream.Send(fixture)
+		if err != nil {
+			logrus.WithError(err).Error("error sending gameserver")
+			return err
+		}
+
+		time.Sleep(l.watchPeriod)
 	}
 
-	return gs, nil
+	return nil
 }