runTask method

Future<RunTaskResponse> runTask({
  1. required String taskDefinition,
  2. List<CapacityProviderStrategyItem>? capacityProviderStrategy,
  3. String? cluster,
  4. int? count,
  5. bool? enableECSManagedTags,
  6. String? group,
  7. LaunchType? launchType,
  8. NetworkConfiguration? networkConfiguration,
  9. TaskOverride? overrides,
  10. List<PlacementConstraint>? placementConstraints,
  11. List<PlacementStrategy>? placementStrategy,
  12. String? platformVersion,
  13. PropagateTags? propagateTags,
  14. String? referenceId,
  15. String? startedBy,
  16. List<Tag>? tags,
})

Starts a new task using the specified task definition.

You can allow Amazon ECS to place tasks for you, or you can customize how Amazon ECS places tasks using placement constraints and placement strategies. For more information, see Scheduling Tasks in the Amazon Elastic Container Service Developer Guide.

Alternatively, you can use StartTask to use your own scheduler or place tasks manually on specific container instances.

The Amazon ECS API follows an eventual consistency model, due to the distributed nature of the system supporting the API. This means that the result of an API command you run that affects your Amazon ECS resources might not be immediately visible to all subsequent commands you run. Keep this in mind when you carry out an API command that immediately follows a previous API command.

To manage eventual consistency, you can do the following:

  • Confirm the state of the resource before you run a command to modify it. Run the DescribeTasks command using an exponential backoff algorithm to ensure that you allow enough time for the previous command to propagate through the system. To do this, run the DescribeTasks command repeatedly, starting with a couple of seconds of wait time and increasing gradually up to five minutes of wait time.
  • Add wait time between subsequent commands, even if the DescribeTasks command returns an accurate response. Apply an exponential backoff algorithm starting with a couple of seconds of wait time, and increase gradually up to about five minutes of wait time.

May throw ServerException. May throw ClientException. May throw InvalidParameterException. May throw ClusterNotFoundException. May throw UnsupportedFeatureException. May throw PlatformUnknownException. May throw PlatformTaskDefinitionIncompatibilityException. May throw AccessDeniedException. May throw BlockedException.

Parameter taskDefinition : The family and revision (family:revision) or full ARN of the task definition to run. If a revision is not specified, the latest ACTIVE revision is used.

Parameter capacityProviderStrategy : The capacity provider strategy to use for the task.

A capacity provider strategy consists of one or more capacity providers along with the base and weight to assign to them. A capacity provider must be associated with the cluster to be used in a capacity provider strategy. The PutClusterCapacityProviders API is used to associate a capacity provider with a cluster. Only capacity providers with an ACTIVE or UPDATING status can be used.

If a capacityProviderStrategy is specified, the launchType parameter must be omitted. If no capacityProviderStrategy or launchType is specified, the defaultCapacityProviderStrategy for the cluster is used.

If specifying a capacity provider that uses an Auto Scaling group, the capacity provider must already be created. New capacity providers can be created with the CreateCapacityProvider API operation.

To use a AWS Fargate capacity provider, specify either the FARGATE or FARGATE_SPOT capacity providers. The AWS Fargate capacity providers are available to all accounts and only need to be associated with a cluster to be used.

The PutClusterCapacityProviders API operation is used to update the list of available capacity providers for a cluster after the cluster is created.

Parameter cluster : The short name or full Amazon Resource Name (ARN) of the cluster on which to run your task. If you do not specify a cluster, the default cluster is assumed.

Parameter count : The number of instantiations of the specified task to place on your cluster. You can specify up to 10 tasks per call.

Parameter enableECSManagedTags : Specifies whether to enable Amazon ECS managed tags for the task. For more information, see Tagging Your Amazon ECS Resources in the Amazon Elastic Container Service Developer Guide.

Parameter group : The name of the task group to associate with the task. The default value is the family name of the task definition (for example, family:my-family-name).

Parameter launchType : The launch type on which to run your task. For more information, see Amazon ECS Launch Types in the Amazon Elastic Container Service Developer Guide.

If a launchType is specified, the capacityProviderStrategy parameter must be omitted.

Parameter networkConfiguration : The network configuration for the task. This parameter is required for task definitions that use the awsvpc network mode to receive their own elastic network interface, and it is not supported for other network modes. For more information, see Task Networking in the Amazon Elastic Container Service Developer Guide.

Parameter overrides : A list of container overrides in JSON format that specify the name of a container in the specified task definition and the overrides it should receive. You can override the default command for a container (that is specified in the task definition or Docker image) with a command override. You can also override existing environment variables (that are specified in the task definition or Docker image) on a container or add new environment variables to it with an environment override.

Parameter placementConstraints : An array of placement constraint objects to use for the task. You can specify up to 10 constraints per task (including constraints in the task definition and those specified at runtime).

Parameter placementStrategy : The placement strategy objects to use for the task. You can specify a maximum of five strategy rules per task.

Parameter platformVersion : The platform version the task should run. A platform version is only specified for tasks using the Fargate launch type. If one is not specified, the LATEST platform version is used by default. For more information, see AWS Fargate Platform Versions in the Amazon Elastic Container Service Developer Guide.

Parameter propagateTags : Specifies whether to propagate the tags from the task definition to the task. If no value is specified, the tags are not propagated. Tags can only be propagated to the task during task creation. To add tags to a task after task creation, use the TagResource API action.

Parameter referenceId : The reference ID to use for the task.

Parameter startedBy : An optional tag specified when a task is started. For example, if you automatically trigger a task to run a batch process job, you could apply a unique identifier for that job to your task with the startedBy parameter. You can then identify which tasks belong to that job by filtering the results of a ListTasks call with the startedBy value. Up to 36 letters (uppercase and lowercase), numbers, hyphens, and underscores are allowed.

If a task is started by an Amazon ECS service, then the startedBy parameter contains the deployment ID of the service that starts it.

Parameter tags : The metadata that you apply to the task to help you categorize and organize them. Each tag consists of a key and an optional value, both of which you define.

The following basic restrictions apply to tags:

  • Maximum number of tags per resource - 50
  • For each resource, each tag key must be unique, and each tag key can have only one value.
  • Maximum key length - 128 Unicode characters in UTF-8
  • Maximum value length - 256 Unicode characters in UTF-8
  • If your tagging schema is used across multiple services and resources, remember that other services may have restrictions on allowed characters. Generally allowed characters are: letters, numbers, and spaces representable in UTF-8, and the following characters: + - = . _ : / @.
  • Tag keys and values are case-sensitive.
  • Do not use aws:, AWS:, or any upper or lowercase combination of such as a prefix for either keys or values as it is reserved for AWS use. You cannot edit or delete tag keys or values with this prefix. Tags with this prefix do not count against your tags per resource limit.

Implementation

Future<RunTaskResponse> runTask({
  required String taskDefinition,
  List<CapacityProviderStrategyItem>? capacityProviderStrategy,
  String? cluster,
  int? count,
  bool? enableECSManagedTags,
  String? group,
  LaunchType? launchType,
  NetworkConfiguration? networkConfiguration,
  TaskOverride? overrides,
  List<PlacementConstraint>? placementConstraints,
  List<PlacementStrategy>? placementStrategy,
  String? platformVersion,
  PropagateTags? propagateTags,
  String? referenceId,
  String? startedBy,
  List<Tag>? tags,
}) async {
  ArgumentError.checkNotNull(taskDefinition, 'taskDefinition');
  final headers = <String, String>{
    'Content-Type': 'application/x-amz-json-1.1',
    'X-Amz-Target': 'AmazonEC2ContainerServiceV20141113.RunTask'
  };
  final jsonResponse = await _protocol.send(
    method: 'POST',
    requestUri: '/',
    exceptionFnMap: _exceptionFns,
    // TODO queryParams
    headers: headers,
    payload: {
      'taskDefinition': taskDefinition,
      if (capacityProviderStrategy != null)
        'capacityProviderStrategy': capacityProviderStrategy,
      if (cluster != null) 'cluster': cluster,
      if (count != null) 'count': count,
      if (enableECSManagedTags != null)
        'enableECSManagedTags': enableECSManagedTags,
      if (group != null) 'group': group,
      if (launchType != null) 'launchType': launchType.toValue(),
      if (networkConfiguration != null)
        'networkConfiguration': networkConfiguration,
      if (overrides != null) 'overrides': overrides,
      if (placementConstraints != null)
        'placementConstraints': placementConstraints,
      if (placementStrategy != null) 'placementStrategy': placementStrategy,
      if (platformVersion != null) 'platformVersion': platformVersion,
      if (propagateTags != null) 'propagateTags': propagateTags.toValue(),
      if (referenceId != null) 'referenceId': referenceId,
      if (startedBy != null) 'startedBy': startedBy,
      if (tags != null) 'tags': tags,
    },
  );

  return RunTaskResponse.fromJson(jsonResponse.body);
}