feat(gamelift): add GameSessionQueue L2 Construct for GameLift (aws#2…

…3266)

Following aws/aws-cdk-rfcs#436 I have written the Gamelift GameSessionQueue L2 resource which create an GameSessionQueue resource.
----

### All Submissions:

* [ ] Have you followed the guidelines in our [Contributing guide?](https://github.com/aws/aws-cdk/blob/main/CONTRIBUTING.md)

### Adding new Construct Runtime Dependencies:

* [ ] This PR adds new construct runtime dependencies following the process described [here](https://github.com/aws/aws-cdk/blob/main/CONTRIBUTING.md/#adding-construct-runtime-dependencies)

### New Features

* [x] Have you added the new feature to an [integration test](https://github.com/aws/aws-cdk/blob/main/INTEGRATION_TESTS.md)?
	* [x] Did you use `yarn integ` to deploy the infrastructure and generate the snapshot (i.e. `yarn integ` without `--dry-run`)?

*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

packages/@aws-cdk/aws-gamelift/README.md

@@ -449,6 +449,65 @@ new cloudwatch.Alarm(this, 'Alarm', {
 See: [Monitoring Using CloudWatch Metrics](https://docs.aws.amazon.com/gamelift/latest/developerguide/monitoring-cloudwatch.html)
 in the *Amazon GameLift Developer Guide*.
 
+## Game session queue
+
+The game session queue is the primary mechanism for processing new game session
+requests and locating available game servers to host them. Although it is
+possible to request a new game session be hosted on specific fleet or location.
+
+The `GameSessionQueue` resource creates a placement queue that processes requests for
+new game sessions. A queue uses FleetIQ algorithms to determine the best placement
+locations and find an available game server, then prompts the game server to start a
+new game session. Queues can have destinations (GameLift fleets or aliases), which
+determine where the queue can place new game sessions. A queue can have destinations
+with varied fleet type (Spot and On-Demand), instance type, and AWS Region.
+
+```ts
+declare const fleet: gamelift.BuildFleet;
+declare const alias: gamelift.Alias;
+
+const queue = new gamelift.GameSessionQueue(this, 'GameSessionQueue', {
+  gameSessionQueueName: 'my-queue-name',
+  destinations: [fleet]
+});
+queue.addDestination(alias);
+```
+
+A more complex configuration can also be definied to override how FleetIQ algorithms prioritize game session placement in order to favour a destination based on `Cost`, `Latency`, `Destination order`or `Location`.
+
+```ts
+declare const fleet: gamelift.BuildFleet;
+declare const topic: sns.Topic;
+
+new gamelift.GameSessionQueue(this, 'MyGameSessionQueue', {
+      gameSessionQueueName: 'test-gameSessionQueue',
+      customEventData: 'test-event-data',
+      allowedLocations: ['eu-west-1', 'eu-west-2'],
+      destinations: [fleet],
+      notificationTarget: topic,
+      playerLatencyPolicies: [{
+        maximumIndividualPlayerLatency: Duration.millis(100),
+        policyDuration: Duration.seconds(300),
+      }],
+      priorityConfiguration: {
+        locationOrder: [
+          'eu-west-1',
+          'eu-west-2',
+        ],
+        priorityOrder: [
+          gamelift.PriorityType.LATENCY,
+          gamelift.PriorityType.COST,
+          gamelift.PriorityType.DESTINATION,
+          gamelift.PriorityType.LOCATION,
+        ],
+      },
+      timeout: Duration.seconds(300),
+    });
+```
+
+See [Setting up GameLift queues for game session placement](https://docs.aws.amazon.com/gamelift/latest/developerguide/realtime-script-uploading.html)
+in the *Amazon GameLift Developer Guide*.
+
 ## GameLift FleetIQ
 
 The GameLift FleetIQ solution is a game hosting layer that supplements the full

packages/@aws-cdk/aws-gamelift/lib/alias.ts

@@ -1,12 +1,13 @@
 import * as cdk from '@aws-cdk/core';
 import { Construct } from 'constructs';
 import { IFleet } from './fleet-base';
+import { IGameSessionQueueDestination } from './game-session-queue';
 import { CfnAlias } from './gamelift.generated';
 
 /**
  * Represents a Gamelift Alias for a Gamelift fleet destination.
  */
-export interface IAlias extends cdk.IResource {
+export interface IAlias extends cdk.IResource, IGameSessionQueueDestination {
 
   /**
      * The Identifier of the alias.
@@ -106,6 +107,12 @@ export abstract class AliasBase extends cdk.Resource implements IAlias {
    * The ARN of the alias
    */
   public abstract readonly aliasArn: string;
+  /**
+   * The ARN to put into the destination field of a game session queue
+   */
+  public get resourceArnForDestination() {
+    return this.aliasArn;
+  }
 }
 
 /**

packages/@aws-cdk/aws-gamelift/lib/fleet-base.ts

@@ -4,6 +4,7 @@ import * as iam from '@aws-cdk/aws-iam';
 import * as cdk from '@aws-cdk/core';
 import { Construct } from 'constructs';
 import { Alias, AliasOptions } from './alias';
+import { IGameSessionQueueDestination } from './game-session-queue';
 import { GameLiftMetrics } from './gamelift-canned-metrics.generated';
 import { CfnFleet } from './gamelift.generated';
 
@@ -140,7 +141,7 @@ export interface ResourceCreationLimitPolicy {
 /**
  * Represents a Gamelift fleet
  */
-export interface IFleet extends cdk.IResource, iam.IGrantable {
+export interface IFleet extends cdk.IResource, iam.IGrantable, IGameSessionQueueDestination {
   /**
    * The Identifier of the fleet.
    *
@@ -535,6 +536,13 @@ export abstract class FleetBase extends cdk.Resource implements IFleet {
     }).attachTo(this);
   }
 
+  /**
+   * The ARN to put into the destination field of a game session queue
+   */
+  public get resourceArnForDestination() {
+    return this.fleetArn;
+  }
+
   /**
    * Adds a remote locations to deploy additional instances to and manage as part of the fleet.
    *