> **Experimental**
>
> `@aws-cdk/aws-gamelift-alpha` is an [**experimental**](/stability) (alpha) package: its API may change in any release, without a major version bump.
# Alias

A Amazon GameLift alias is used to abstract a fleet designation.

Fleet designations tell GameLift where to search for available resources when creating new game sessions for players.
Use aliases instead of specific fleet IDs to seamlessly switch player traffic from one fleet to another by changing the alias's target location.

Aliases are useful in games that don't use queues.
Switching fleets in a queue is a simple matter of creating a new fleet, adding it to the queue, and removing the old fleet, none of which is visible to players.
In contrast, game clients that don't use queues must specify which fleet to use when communicating with the GameLift service.
Without aliases, a fleet switch requires updates to your game code and possibly distribution of an updated game clients to players.

When updating the fleet-id an alias points to, there is a transition period of up to 2 minutes where game sessions on the alias may end up on the old fleet.

Extends: Construct › Resource › AliasBase › Alias
Implements: IAlias, IGameSessionQueueDestination, IResource, IEnvironmentAware, IConstruct, IDependable

- Stability: [Experimental](/cdk/api/stability.html)
- CloudFormation: [`AWS::GameLift::Alias`](https://docs.aws.amazon.com/AWSCloudFormation/latest/TemplateReference/aws-resource-gamelift-alias.html)
- L1 type: [`CfnAlias`](/cdk/api/v2/docs/aws-cdk-lib.aws_gamelift.CfnAlias.html)
- Source: [`lib/alias.ts`](https://github.com/aws/aws-cdk/blob/v2.277.0-alpha.0/packages/@aws-cdk/aws-gamelift-alpha/lib/alias.ts#L138)

## Example

```ts
declare const fleet: gamelift.BuildFleet;

// Add an alias to an existing fleet using a dedicated fleet method
const liveAlias = fleet.addAlias('live');

// You can also create a standalone alias
new gamelift.Alias(this, 'TerminalAlias', {
  aliasName: 'terminal-alias',
  terminalMessage: 'A terminal message',
});
```

## Initializer

```ts
new Alias(scope: Construct, id: string, props: AliasProps)
```

## Construct Props

- `aliasName`: string (required) — Name of this alias.

- `description`: string — A human-readable description of the alias.

  **Default:** no description

- `fleet`: [IFleet](/cdk/api/v2/docs/@aws-cdk_aws-gamelift-alpha.IFleet.html) — A fleet that the alias points to. If specified, the alias resolves to one specific fleet.

  **Default:** no fleet that the alias points to.

  At least one of `fleet` and `terminalMessage` must be provided.

- `terminalMessage`: string — The message text to be used with a terminal routing strategy.

  **Default:** no terminal message

  At least one of `fleet` and `terminalMessage` must be provided.

## Properties

- `aliasArn`: string — The ARN of the alias.

- `aliasId`: string — The Identifier of the alias.

- `env`: [ResourceEnvironment](/cdk/api/v2/docs/aws-cdk-lib.interfaces.ResourceEnvironment.html) — The environment this resource belongs to.

  For resources that are created and managed in a Stack (those created by
  creating new class instances like `new Role()`, `new Bucket()`, etc.), this
  is always the same as the environment of the stack they belong to.

  For referenced resources (those obtained from referencing methods like
  `Role.fromRoleArn()`, `Bucket.fromBucketName()`, etc.), they might be
  different than the stack they were imported into.

- `fleet`: [IFleet](/cdk/api/v2/docs/@aws-cdk_aws-gamelift-alpha.IFleet.html) — A fleet that the alias points to.

- `node`: [Node](/cdk/api/v2/docs/constructs.Node.html) — The tree node.

- `PROPERTY_INJECTION_ID`: string (static) — Uniquely identifies this class.

- `resourceArnForDestination`: string — The ARN to put into the destination field of a game session queue.

- `stack`: [Stack](/cdk/api/v2/docs/aws-cdk-lib.Stack.html) — The stack in which this resource is defined.

## Methods

- `applyCrossStackReferenceStrength(strength: ReferenceStrength): void` — Override the cross-stack reference strength for this resource.

  When set, any cross-stack reference to this resource will use the specified
  mechanism instead of the global default determined by the
  `@aws-cdk/core:defaultCrossStackReferences` context key. This is useful for
  selectively weakening specific references to avoid the "deadly embrace" problem
  without changing the app-wide default.

  **Parameters**

  - `strength` — - The reference strength to use for this resource.

- `applyRemovalPolicy(policy: RemovalPolicy): void` — Apply the given removal policy to this resource.

  The Removal Policy controls what happens to this resource when it stops
  being managed by CloudFormation, either because you've removed it from the
  CDK application or because you've made a change that requires the resource
  to be replaced.

  The resource can be deleted (`RemovalPolicy.DESTROY`), or left in your AWS
  account for data recovery and cleanup later (`RemovalPolicy.RETAIN`).

- `fromAliasArn(scope: Construct, id: string, aliasArn: string): IAlias` (static) — Import an existing alias from its ARN.

- `fromAliasAttributes(scope: Construct, id: string, attrs: AliasAttributes): IAlias` (static) — Import an existing alias from its attributes.

- `fromAliasId(scope: Construct, id: string, aliasId: string): IAlias` (static) — Import an existing alias from its identifier.

- `isConstruct(x: any): boolean` (static) — Checks if `x` is a construct.

  Use this method instead of `instanceof` to properly detect `Construct`
  instances, even when the construct library is symlinked.

  Explanation: in JavaScript, multiple copies of the `constructs` library on
  disk are seen as independent, completely different libraries. As a
  consequence, the class `Construct` in each copy of the `constructs` library
  is seen as a different class, and an instance of one class will not test as
  `instanceof` the other class. `npm install` will not create installations
  like this, but users may manually symlink construct libraries together or
  use a monorepo tool: in those cases, multiple copies of the `constructs`
  library can be accidentally installed, and `instanceof` will behave
  unpredictably. It is safest to avoid using `instanceof`, and using
  this type-testing method instead.

  **Parameters**

  - `x` — Any object.

  **Returns:** true if `x` is an object created from a class which extends `Construct`.

- `isOwnedResource(construct: IConstruct): boolean` (static) — Returns true if the construct was created by CDK, and false otherwise.

- `isResource(construct: IConstruct): boolean` (static) — Check whether the given construct is a Resource.

- `toString(): string` — Returns a string representation of this construct.

- `with(...mixins: IMixin[]): IConstruct` — Applies one or more mixins to this construct.

  Mixins are applied in order. The list of constructs is captured at the
  start of the call, so constructs added by a mixin will not be visited.
  Use multiple `with()` calls if subsequent mixins should apply to added
  constructs.