Class DynamicClusterPool<Data, Response>

A cluster pool with a dynamic number of workers, but a guaranteed minimum number of workers.

This cluster pool creates new workers when the others are busy, up to the maximum number of workers. When the maximum number of workers is reached and workers are busy, an event is emitted. If you want to listen to this event, use the pool's emitter.

Christopher Quadflieg

2.0.0

Type Parameters

  • Data = unknown

    Type of data sent to the worker. This can only be structured-cloneable data.

  • Response = unknown

    Type of execution response. This can only be structured-cloneable data.

Hierarchy (view full)

Constructors

Properties

emitter?: EventEmitterAsyncResource

Pool event emitter integrated with async resource. The async tracking tooling identifier is poolifier:<PoolType>-<WorkerType>-pool.

Events that can currently be listened to:

  • 'ready': Emitted when the number of workers created in the pool has reached the minimum size expected and are ready. If the pool is dynamic with a minimum number of workers is set to zero, this event is emitted when at least one dynamic worker is ready.
  • 'busy': Emitted when the number of workers created in the pool has reached the maximum size expected and are executing concurrently their tasks quota.
  • 'full': Emitted when the pool is dynamic and the number of workers created has reached the maximum size expected.
  • 'empty': Emitted when the pool is dynamic with a minimum number of workers set to zero and the number of workers has reached the minimum size expected.
  • 'destroy': Emitted when the pool is destroyed.
  • 'error': Emitted when an uncaught error occurs.
  • 'taskError': Emitted when an error occurs while executing a task.
  • 'backPressure': Emitted when all worker nodes have back pressure (i.e. their tasks queue is full: queue size >= maximum queue size).
filePath: string

Path to the worker file.

maximumNumberOfWorkers?: number

Maximum number of workers that this pool manages.

minimumNumberOfWorkers: number

Minimum number of workers that this pool manages.

opts: PoolOptions<Worker>

Options for the pool.

promiseResponseMap: Map<`${string}-${string}-${string}-${string}-${string}`, PromiseResponseWrapper<Response>> = ...

The task execution response promise map:

  • key: The message id of each submitted task.
  • value: An object that contains task's worker node key, execution response promise resolve and reject callbacks, async resource.

When we receive a message from the worker, we get a map entry with the promise resolve/reject bound to the message id.

workerChoiceStrategiesContext?: WorkerChoiceStrategiesContext<Worker, Data, Response>

Worker choice strategies context referencing worker choice algorithms implementation.

workerNodes: IWorkerNode<Worker, Data>[] = []

Pool worker nodes.

Accessors

  • get busy(): boolean
  • Whether the pool is busy or not.

    Returns boolean

    The pool busyness boolean status.

  • get empty(): boolean
  • Whether the pool is empty or not.

    Returns boolean

    The pool emptiness boolean status.

  • get full(): boolean
  • Whether the pool is full or not.

    Returns boolean

    The pool fullness boolean status.

  • get type(): "fixed" | "dynamic"
  • The pool type.

    If it is 'dynamic', it provides the max property.

    Returns "fixed" | "dynamic"

  • get worker(): "thread" | "cluster"
  • The worker type.

    Returns "thread" | "cluster"

Methods

  • Parameters

    • Optionaldata: Data

      The optional task input data for the specified task function. This can only be structured-cloneable data.

    • Optionalname: string

      The optional name of the task function to execute. If not specified, the default task function will be executed.

    • OptionaltransferList: readonly TransferListItem[]

      An optional array of transferable objects to transfer ownership of. Ownership of the transferred objects is given to the chosen pool's worker_threads worker and they should not be used in the main thread afterwards.

    Returns Promise<Response>

    Promise with a task function response that will be fulfilled when the task is completed.

  • Parameters

    • data: Iterable<Data>

      The tasks iterable input data for the specified task function. This can only be an iterable of structured-cloneable data.

    • Optionalname: string

      The optional name of the task function to execute. If not specified, the default task function will be executed.

    • OptionaltransferList: readonly TransferListItem[]

      An optional array of transferable objects to transfer ownership of. Ownership of the transferred objects is given to the chosen pool's worker_threads worker and they should not be used in the main thread afterwards.

    Returns Promise<Response[]>

    Promise with an array of task function responses that will be fulfilled when the tasks are completed.

  • Parameters

    • workerChoiceStrategy:
          | "ROUND_ROBIN"
          | "LEAST_USED"
          | "LEAST_BUSY"
          | "LEAST_ELU"
          | "FAIR_SHARE"
          | "WEIGHTED_ROUND_ROBIN"
          | "INTERLEAVED_WEIGHTED_ROUND_ROBIN"
    • OptionalworkerChoiceStrategyOptions: WorkerChoiceStrategyOptions

    Returns void