Alpha SDK.SetPlayerCapacity & GetPlayerCapacity

This PR doesn't complete this functionality, but was enough to warrant
review.

It does two things:
1. The refactoring to move alpha and beta SDK Server implementations
into the same file as the main SDK Server, as being able to reuse the
current logic made sense on review.
2. Initial Implementation of SDK GetPlayerCapacity & SetPlayerCapacity
methods with unit tests. E2E tests can be implemented once googleforgames#1397 is
resolved.

Next steps will be to implement the local SDK functionality, and
conformance tests for Go for these two functions.

Work on googleforgames#1033

cmd/sdk-server/main.go

@@ -30,8 +30,6 @@ import (
 	sdkalpha "agones.dev/agones/pkg/sdk/alpha"
 	sdkbeta "agones.dev/agones/pkg/sdk/beta"
 	"agones.dev/agones/pkg/sdkserver"
-	serveralpha "agones.dev/agones/pkg/sdkserver/alpha"
-	serverbeta "agones.dev/agones/pkg/sdkserver/beta"
 	"agones.dev/agones/pkg/util/runtime"
 	"agones.dev/agones/pkg/util/signals"
 	gwruntime "github.com/grpc-ecosystem/grpc-gateway/runtime"
@@ -154,8 +152,8 @@ func main() {
 			}
 		}()
 		sdk.RegisterSDKServer(grpcServer, s)
-		sdkalpha.RegisterSDKServer(grpcServer, serveralpha.NewSDKServer())
-		sdkbeta.RegisterSDKServer(grpcServer, serverbeta.NewSDKServer())
+		sdkalpha.RegisterSDKServer(grpcServer, s)
+		sdkbeta.RegisterSDKServer(grpcServer, s)
 	}
 
 	grpcEndpoint := fmt.Sprintf("%s:%d", ctlConf.Address, ctlConf.GRPCPort)
@@ -185,45 +183,37 @@ func registerLocal(grpcServer *grpc.Server, ctlConf config) (func(), error) {
 		}
 	}
 
-	stableSDK, err := sdkserver.NewLocalSDKServer(filePath)
+	s, err := sdkserver.NewLocalSDKServer(filePath)
 	if err != nil {
 		return nil, err
 	}
-	alphaSDK := serveralpha.NewLocalSDKServer()
-	betaSDK := serverbeta.NewLocalSDKServer()
 
-	sdk.RegisterSDKServer(grpcServer, stableSDK)
-	sdkalpha.RegisterSDKServer(grpcServer, alphaSDK)
-	sdkbeta.RegisterSDKServer(grpcServer, betaSDK)
+	sdk.RegisterSDKServer(grpcServer, s)
+	sdkalpha.RegisterSDKServer(grpcServer, s)
+	sdkbeta.RegisterSDKServer(grpcServer, s)
 	return func() {
-		alphaSDK.Close()
-		betaSDK.Close()
-		stableSDK.Close()
+		s.Close()
 	}, err
 }
 
 // registerLocal registers the local test SDK servers, and returns a cancel func that
 // closes all the SDK implementations
 func registerTestSdkServer(grpcServer *grpc.Server, ctlConf config) (func(), error) {
-	stableSDK, err := sdkserver.NewLocalSDKServer("")
+	s, err := sdkserver.NewLocalSDKServer("")
 	if err != nil {
 		return nil, err
 	}
-	alphaSDK := serveralpha.NewLocalSDKServer()
-	betaSDK := serverbeta.NewLocalSDKServer()
 
-	stableSDK.SetTestMode(true)
-	stableSDK.GenerateUID()
+	s.SetTestMode(true)
+	s.GenerateUID()
 	expectedFuncs := strings.Split(ctlConf.Test, ",")
-	stableSDK.SetExpectedSequence(expectedFuncs)
+	s.SetExpectedSequence(expectedFuncs)
 
-	sdk.RegisterSDKServer(grpcServer, stableSDK)
-	sdkalpha.RegisterSDKServer(grpcServer, alphaSDK)
-	sdkbeta.RegisterSDKServer(grpcServer, betaSDK)
+	sdk.RegisterSDKServer(grpcServer, s)
+	sdkalpha.RegisterSDKServer(grpcServer, s)
+	sdkbeta.RegisterSDKServer(grpcServer, s)
 	return func() {
-		alphaSDK.Close()
-		betaSDK.Close()
-		stableSDK.Close()
+		s.Close()
 	}, err
 }
 
@@ -281,7 +271,7 @@ func parseEnvFlags() config {
 	pflag.Int(httpPortFlag, viper.GetInt(httpPortFlag), fmt.Sprintf("Port on which to bind the HTTP server. Defaults to %d", defaultHTTPPort))
 	pflag.Int(delayFlag, viper.GetInt(delayFlag), "Time to delay (in seconds) before starting to execute main. Useful for tests")
 	pflag.Int(timeoutFlag, viper.GetInt(timeoutFlag), "Time of execution (in seconds) before close. Useful for tests")
-	pflag.String(testFlag, viper.GetString(testFlag), "List functions which shoud be called during the SDK Conformance test run.")
+	pflag.String(testFlag, viper.GetString(testFlag), "List functions which should be called during the SDK Conformance test run.")
 	runtime.FeaturesBindFlags()
 	pflag.Parse()
 

pkg/apis/agones/v1/gameserver.go

@@ -313,10 +313,12 @@ func (gs *GameServer) applyStatusDefaults() {
 	}
 
 	if runtime.FeatureEnabled(runtime.FeaturePlayerTracking) {
+		// set value if enabled, otherwise very easy to accidentally panic
+		// when gs.Status.Players is nil
+		if gs.Status.Players == nil {
+			gs.Status.Players = &PlayerStatus{}
+		}
 		if gs.Spec.Players != nil {
-			if gs.Status.Players == nil {
-				gs.Status.Players = &PlayerStatus{}
-			}
 			gs.Status.Players.Capacity = gs.Spec.Players.InitialCapacity
 		}
 	}

pkg/sdkserver/localsdk.go

@@ -25,6 +25,8 @@ import (
 
 	agonesv1 "agones.dev/agones/pkg/apis/agones/v1"
 	"agones.dev/agones/pkg/sdk"
+	"agones.dev/agones/pkg/sdk/alpha"
+	"agones.dev/agones/pkg/sdk/beta"
 	"github.com/fsnotify/fsnotify"
 	"github.com/pkg/errors"
 	"github.com/sirupsen/logrus"
@@ -33,7 +35,9 @@ import (
 )
 
 var (
-	_ sdk.SDKServer = &LocalSDKServer{}
+	_ sdk.SDKServer   = &LocalSDKServer{}
+	_ alpha.SDKServer = &LocalSDKServer{}
+	_ beta.SDKServer  = &LocalSDKServer{}
 
 	defaultGs = &sdk.GameServer{
 		ObjectMeta: &sdk.GameServer_ObjectMeta{
@@ -425,3 +429,30 @@ func (l *LocalSDKServer) setGameServerFromFilePath(filePath string) error {
 	l.gs = convert(&gs)
 	return nil
 }
+
+/* Alpha Functionality */
+
+// PlayerConnect should be called when a player connects.
+func (l *LocalSDKServer) PlayerConnect(ctx context.Context, id *alpha.PlayerId) (*alpha.Empty, error) {
+	panic("implement me")
+}
+
+// PlayerDisconnect should be called when a player disconnects.
+func (l *LocalSDKServer) PlayerDisconnect(ctx context.Context, id *alpha.PlayerId) (*alpha.Empty, error) {
+	panic("implement me")
+}
+
+// SetPlayerCapacity to change the game server's player capacity.
+func (l *LocalSDKServer) SetPlayerCapacity(ctx context.Context, count *alpha.Count) (*alpha.Empty, error) {
+	panic("implement me")
+}
+
+// GetPlayerCapacity returns the current player capacity.
+func (l *LocalSDKServer) GetPlayerCapacity(ctx context.Context, _ *alpha.Empty) (*alpha.Count, error) {
+	panic("implement me")
+}
+
+// GetPlayerCount returns the current player count.
+func (l *LocalSDKServer) GetPlayerCount(ctx context.Context, _ *alpha.Empty) (*alpha.Count, error) {
+	panic("implement me")
+}