startMatchBackfill method

Future<StartMatchBackfillOutput> startMatchBackfill({ required String configurationName, required List<Player> players, String? gameSessionArn, String? ticketId, })

This API works with the following fleet types: EC2, Anywhere, Container

Finds new players to fill open slots in currently running game sessions. The backfill match process is essentially identical to the process of forming new matches. Backfill requests use the same matchmaker that was used to make the original match, and they provide matchmaking data for all players currently in the game session. FlexMatch uses this information to select new players so that backfilled match continues to meet the original match requirements.

When using FlexMatch with Amazon GameLift Servers managed hosting, you can request a backfill match from a client service by calling this operation with a GameSessions ID. You also have the option of making backfill requests directly from your game server. In response to a request, FlexMatch creates player sessions for the new players, updates the GameSession resource, and sends updated matchmaking data to the game server. You can request a backfill match at any point after a game session is started. Each game session can have only one active backfill request at a time; a subsequent request automatically replaces the earlier request.

When using FlexMatch as a standalone component, request a backfill match by calling this operation without a game session identifier. As with newly formed matches, matchmaking results are returned in a matchmaking event so that your game can update the game session that is being backfilled.

To request a backfill match, specify a unique ticket ID, the original matchmaking configuration, and matchmaking data for all current players in the game session being backfilled. Optionally, specify the GameSession ARN. If successful, a match backfill ticket is created and returned with status set to QUEUED. Track the status of backfill tickets using the same method for tracking tickets for new matches.

Only game sessions created by FlexMatch are supported for match backfill.

Learn more

Backfill existing games with FlexMatch

Matchmaking events (reference)

How Amazon GameLift Servers FlexMatch works

May throw InternalServiceException. May throw InvalidRequestException. May throw NotFoundException. May throw UnsupportedRegionException.

Parameter configurationName : Name of the matchmaker to use for this request. You can use either the configuration name or ARN value. The ARN of the matchmaker that was used with the original game session is listed in the GameSession object, MatchmakerData property.

Parameter players : Match information on all players that are currently assigned to the game session. This information is used by the matchmaker to find new players and add them to the existing game.

You can include up to 199 Players in a StartMatchBackfill request.

• PlayerID, PlayerAttributes, Team -- This information is maintained in the GameSession object, MatchmakerData property, for all players who are currently assigned to the game session. The matchmaker data is in JSON syntax, formatted as a string. For more details, see Match Data.

  The backfill request must specify the team membership for every player. Do not specify team if you are not using backfill.

• LatencyInMs -- If the matchmaker uses player latency, include a latency value, in milliseconds, for the Region that the game session is currently in. Do not include latency values for any other Region.

Parameter gameSessionArn : An identifier for the game session that is unique across all regions. The value is always a full ARN in the following format: arn:aws:gamelift:. When using FlexMatch as a standalone matchmaking solution, this parameter is not needed.

Parameter ticketId : A unique identifier for a matchmaking ticket. If no ticket ID is specified here, Amazon GameLift Servers will generate one in the form of a UUID. Use this identifier to track the match backfill ticket status and retrieve match results.

Implementation

Future<StartMatchBackfillOutput> startMatchBackfill({
  required String configurationName,
  required List<Player> players,
  String? gameSessionArn,
  String? ticketId,
}) async {
  final headers = <String, String>{
    'Content-Type': 'application/x-amz-json-1.1',
    'X-Amz-Target': 'GameLift.StartMatchBackfill'
  };
  final jsonResponse = await _protocol.send(
    method: 'POST',
    requestUri: '/',
    exceptionFnMap: _exceptionFns,
    // TODO queryParams
    headers: headers,
    payload: {
      'ConfigurationName': configurationName,
      'Players': players,
      if (gameSessionArn != null) 'GameSessionArn': gameSessionArn,
      if (ticketId != null) 'TicketId': ticketId,
    },
  );

  return StartMatchBackfillOutput.fromJson(jsonResponse.body);
}