Added an in-cluster om-agones director example (#5)

* Added an om-agones director example

go/example/om-agones-director/main.go

@@ -0,0 +1,134 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"time"
+
+	"google.golang.org/grpc"
+	"open-match.dev/open-match/pkg/pb"
+
+	agonesv1 "agones.dev/agones/pkg/apis/agones/v1"
+	allocationv1 "agones.dev/agones/pkg/apis/allocation/v1"
+	"agones.dev/agones/pkg/client/clientset/versioned"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/client-go/rest"
+
+	_ "k8s.io/client-go/plugin/pkg/client/auth/gcp"
+)
+
+func main() {
+	for {
+		if err := run(); err != nil {
+			fmt.Println(err.Error())
+		}
+	}
+}
+
+func createOMBackendClient() (pb.BackendClient, func() error) {
+	conn, err := grpc.Dial("om-backend.open-match.svc.cluster.local:50505", grpc.WithInsecure())
+	if err != nil {
+		panic(err)
+	}
+	return pb.NewBackendClient(conn), conn.Close
+}
+
+func createAgonesClient() *versioned.Clientset {
+	config, err := rest.InClusterConfig()
+	if err != nil {
+		panic(err.Error())
+	}
+	agonesClient, err := versioned.NewForConfig(config)
+	if err != nil {
+		panic(err.Error())
+	}
+	return agonesClient
+}
+
+// Customize the backend.FetchMatches request, the default one will return all tickets in the statestore
+func createOMFetchMatchesRequest() *pb.FetchMatchesRequest {
+	return &pb.FetchMatchesRequest{
+		// om-function:50502 -> the internal hostname & port number of the MMF service in our Kubernetes cluster
+		Config: &pb.FunctionConfig{
+			Host: "om-function",
+			Port: 50502,
+			Type: pb.FunctionConfig_GRPC,
+		},
+		Profiles: []*pb.MatchProfile{
+			{
+				Name:  "get-all",
+				Pools: []*pb.Pool{},
+			},
+		},
+	}
+}
+
+func createAgonesGameServerAllocation() *allocationv1.GameServerAllocation {
+	return &allocationv1.GameServerAllocation{
+		Spec: allocationv1.GameServerAllocationSpec{
+			Required: metav1.LabelSelector{
+				MatchLabels: map[string]string{agonesv1.FleetNameLabel: "simple-udp"},
+			},
+		},
+	}
+}
+
+func createOMAssignTicketRequest(match *pb.Match, gsa *allocationv1.GameServerAllocation) *pb.AssignTicketsRequest {
+	tids := []string{}
+	for _, t := range match.GetTickets() {
+		tids = append(tids, t.GetId())
+	}
+
+	return &pb.AssignTicketsRequest{
+		TicketIds: tids,
+		Assignment: &pb.Assignment{
+			Connection: fmt.Sprintf("%s:%d", gsa.Status.Address, gsa.Status.Ports[0].Port),
+		},
+	}
+}
+
+func run() error {
+	bc, closer := createOMBackendClient()
+	defer closer()
+
+	agonesClient := createAgonesClient()
+
+	stream, err := bc.FetchMatches(context.Background(), createOMFetchMatchesRequest())
+	if err != nil {
+		fmt.Printf("Director: fail to get response stream from backend.FetchMatches call, desc: %s\n", err.Error())
+		return err
+	}
+
+	// Read the FetchMatches response. Each loop fetches an available game match that satisfies the match profiles.
+	for {
+		resp, err := stream.Recv()
+		if err == io.EOF {
+			break
+		}
+		if err != nil {
+			return err
+		}
+
+		gsa, err := agonesClient.AllocationV1().GameServerAllocations("default").Create(createAgonesGameServerAllocation())
+		if err != nil {
+			return err
+		}
+		if gsa.Status.State != allocationv1.GameServerAllocationAllocated {
+			fmt.Printf("failed to allocate game server.\n")
+			continue
+		}
+
+		if _, err = bc.AssignTickets(context.Background(), createOMAssignTicketRequest(resp.GetMatch(), gsa)); err != nil {
+			// Corner case where we allocated a game server for players who left the queue after some waiting time.
+			// Note that we may still leak some game servers when tickets got assigned but players left the queue before game frontend announced the assignments.
+			if err = agonesClient.AgonesV1().GameServers("default").Delete(gsa.Status.GameServerName, &metav1.DeleteOptions{}); err != nil {
+				return err
+			}
+		}
+
+	}
+
+	time.Sleep(time.Second * 5)
+	return nil
+}

go/go.mod

@@ -17,9 +17,20 @@ module open-match.dev/open-match-ecosystem/go
 go 1.13.1
 
 require (
+	agones.dev/agones v1.0.0
+	github.com/ahmetb/gen-crd-api-reference-docs v0.1.5 // indirect
 	github.com/golang/protobuf v1.3.2
+	github.com/grpc-ecosystem/grpc-gateway v1.11.3 // indirect
 	github.com/sirupsen/logrus v1.4.2
 	github.com/stretchr/testify v1.3.0
-	golang.org/x/net v0.0.0-20190522155817-f3200d17e092
+	golang.org/x/net v0.0.0-20190620200207-3b0461eec859
+	golang.org/x/tools v0.0.0-20191016194801-f0068bd333b2 // indirect
+	google.golang.org/genproto v0.0.0-20191009194640-548a555dbc03 // indirect
+	google.golang.org/grpc v1.21.1
+	gopkg.in/yaml.v2 v2.2.4 // indirect
+	k8s.io/apimachinery v0.0.0-20190221084156-01f179d85dbc
+	k8s.io/client-go v9.0.0+incompatible
+	k8s.io/gengo v0.0.0-20191010091904-7fa3014cb28f // indirect
+	k8s.io/klog v1.0.0 // indirect
 	open-match.dev/open-match v0.4.1-0.20191015212835-2aee5d128d65
 )