Class FixedThreadPool<Data, Response>

A thread pool with a fixed number of threads.

Author

Alessandro Pio Ardizio

Since

0.0.1

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

Constructors

  • Constructs a new poolifier fixed thread pool.

    Type Parameters

    • Data = unknown

    • Response = unknown

    Parameters

    • numberOfThreads: number

      Number of threads for this pool.

    • filePath: string

      Path to an implementation of a ThreadWorker file, which can be relative or absolute.

    • opts: ThreadPoolOptions = {}

      Options for this fixed thread pool.

    Returns FixedThreadPool<Data, Response>

Properties

emitter?: EventEmitterAsyncResource

Event emitter integrated with async resource on which events can be listened to. 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.
  • '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.
  • '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.

max?: number

Dynamic pool maximum size property placeholder.

numberOfWorkers: number

Number of workers that this pool should manage.

Options for this fixed thread pool.

promiseResponseMap: Map<string, PromiseResponseWrapper<Response>> = ...

The task execution response promise map:

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

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

workerChoiceStrategyContext: WorkerChoiceStrategyContext<Worker, Data, Response>

Worker choice strategy context referencing a worker choice algorithm implementation.

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

Pool worker nodes.

Accessors

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

    The pool busyness boolean status.

    Returns boolean

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

    The pool filling boolean status.

    Returns boolean

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

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

    Returns "fixed" | "dynamic"

  • get utilization(): number
  • The approximate pool utilization.

    Returns number

    The pool utilization.

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

    Returns "thread" | "cluster"

Methods

  • Deregisters a listener callback on the worker given its worker node key.

    Type Parameters

    • Message

    Parameters

    • workerNodeKey: number

      The worker node key.

    • listener: ((message) => void)

      The message listener callback.

        • (message): void
        • Parameters

          Returns void

    Returns void

  • Executes the specified function in the worker constructor with the task data input parameter.

    Parameters

    • Optional data: Data

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

    • Optional name: string

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

    • Optional transferList: 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 that will be fulfilled when the task is completed.

  • Whether the specified task function exists in this pool.

    Parameters

    • name: string

      The name of the task function.

    Returns boolean

    true if the task function exists, false otherwise.

  • Internal

    Whether the worker node has back pressure (i.e. its tasks queue is full).

    Parameters

    • workerNodeKey: number

      The worker node key.

    Returns boolean

    true if the worker node has back pressure, false otherwise.

  • Registers once a listener callback on the worker given its worker node key.

    Type Parameters

    • Message

    Parameters

    • workerNodeKey: number

      The worker node key.

    • listener: ((message) => void)

      The message listener callback.

        • (message): void
        • Parameters

          Returns void

    Returns void

  • Registers a listener callback on the worker given its worker node key.

    Type Parameters

    • Message

    Parameters

    • workerNodeKey: number

      The worker node key.

    • listener: ((message) => void)

      The message listener callback.

        • (message): void
        • Parameters

          Returns void

    Returns void

  • Removes a task function from this pool.

    Parameters

    • name: string

      The name of the task function.

    Returns Promise<boolean>

    true if the task function was removed, false otherwise.

  • Sends a message to worker given its worker node key.

    Parameters

    • workerNodeKey: number

      The worker node key.

    • message: MessageValue<Data, unknown>

      The message.

    • Optional transferList: TransferListItem[]

      The optional array of transferable objects.

    Returns void

  • Sets the worker choice strategy in this pool.

    Parameters

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

      The worker choice strategy.

    • Optional workerChoiceStrategyOptions: WorkerChoiceStrategyOptions

      The worker choice strategy options.

    Returns void

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