-import EventEmitterAsyncResource from 'node:events'
+import { EventEmitter } from 'node:events'
+import { type TransferListItem } from 'node:worker_threads'
+import type { TaskFunction } from '../worker/task-functions'
import type {
ErrorHandler,
ExitHandler,
IWorker,
+ IWorkerNode,
MessageHandler,
OnlineHandler,
- WorkerNode
+ WorkerType
} from './worker'
import type {
WorkerChoiceStrategy,
} from './selection-strategies/selection-strategies-types'
/**
- * Pool types.
- *
- * @enum
- * @internal
+ * Enumeration of pool types.
*/
-export enum PoolType {
+export const PoolTypes = Object.freeze({
/**
* Fixed pool type.
*/
- FIXED = 'fixed',
+ fixed: 'fixed',
/**
* Dynamic pool type.
*/
- DYNAMIC = 'dynamic'
-}
+ dynamic: 'dynamic'
+} as const)
+
+/**
+ * Pool type.
+ */
+export type PoolType = keyof typeof PoolTypes
/**
* Pool events emitter.
*/
-export class PoolEmitter extends EventEmitterAsyncResource {}
+export class PoolEmitter extends EventEmitter {}
/**
* Enumeration of pool events.
*/
export const PoolEvents = Object.freeze({
- full: 'full',
+ ready: 'ready',
busy: 'busy',
+ full: 'full',
+ destroy: 'destroy',
error: 'error',
- taskError: 'taskError'
+ taskError: 'taskError',
+ backPressure: 'backPressure'
} as const)
/**
export type PoolEvent = keyof typeof PoolEvents
/**
- * Worker tasks queue options.
+ * Pool information.
+ */
+export interface PoolInfo {
+ readonly version: string
+ readonly type: PoolType
+ readonly worker: WorkerType
+ readonly started: boolean
+ readonly ready: boolean
+ readonly strategy: WorkerChoiceStrategy
+ readonly minSize: number
+ readonly maxSize: number
+ /** Pool utilization. */
+ readonly utilization?: number
+ /** Pool total worker nodes. */
+ readonly workerNodes: number
+ /** Pool idle worker nodes. */
+ readonly idleWorkerNodes: number
+ /** Pool busy worker nodes. */
+ readonly busyWorkerNodes: number
+ readonly executedTasks: number
+ readonly executingTasks: number
+ readonly queuedTasks?: number
+ readonly maxQueuedTasks?: number
+ readonly backPressure?: boolean
+ readonly stolenTasks?: number
+ readonly failedTasks: number
+ readonly runTime?: {
+ readonly minimum: number
+ readonly maximum: number
+ readonly average?: number
+ readonly median?: number
+ }
+ readonly waitTime?: {
+ readonly minimum: number
+ readonly maximum: number
+ readonly average?: number
+ readonly median?: number
+ }
+}
+
+/**
+ * Worker node tasks queue options.
*/
export interface TasksQueueOptions {
/**
- * Maximum number of tasks that can be executed concurrently on a worker.
+ * Maximum tasks queue size per worker node flagging it as back pressured.
+ *
+ * @defaultValue (pool maximum size)^2
+ */
+ readonly size?: number
+ /**
+ * Maximum number of tasks that can be executed concurrently on a worker node.
*
* @defaultValue 1
*/
- concurrency?: number
+ readonly concurrency?: number
+ /**
+ * Whether to enable task stealing.
+ *
+ * @defaultValue true
+ */
+ readonly taskStealing?: boolean
+ /**
+ * Whether to enable tasks stealing on back pressure.
+ *
+ * @defaultValue true
+ */
+ readonly tasksStealingOnBackPressure?: boolean
}
/**
* @typeParam Worker - Type of worker.
*/
export interface PoolOptions<Worker extends IWorker> {
+ /**
+ * A function that will listen for online event on each worker.
+ *
+ * @defaultValue `() => {}`
+ */
+ onlineHandler?: OnlineHandler<Worker>
/**
* A function that will listen for message event on each worker.
+ *
+ * @defaultValue `() => {}`
*/
messageHandler?: MessageHandler<Worker>
/**
* A function that will listen for error event on each worker.
+ *
+ * @defaultValue `() => {}`
*/
errorHandler?: ErrorHandler<Worker>
- /**
- * A function that will listen for online event on each worker.
- */
- onlineHandler?: OnlineHandler<Worker>
/**
* A function that will listen for exit event on each worker.
+ *
+ * @defaultValue `() => {}`
*/
exitHandler?: ExitHandler<Worker>
+ /**
+ * Whether to start the minimum number of workers at pool initialization.
+ *
+ * @defaultValue true
+ */
+ startWorkers?: boolean
/**
* The worker choice strategy to use in this pool.
*
*/
enableEvents?: boolean
/**
- * Pool worker tasks queue.
+ * Pool worker node tasks queue.
*
* @defaultValue false
*/
enableTasksQueue?: boolean
/**
- * Pool worker tasks queue options.
+ * Pool worker node tasks queue options.
*/
tasksQueueOptions?: TasksQueueOptions
}
* Contract definition for a poolifier pool.
*
* @typeParam Worker - Type of worker which manages this pool.
- * @typeParam Data - Type of data sent to the worker. This can only be serializable data.
- * @typeParam Response - Type of execution response. This can only be serializable data.
+ * @typeParam Data - Type of data sent to the worker. This can only be structured-cloneable data.
+ * @typeParam Response - Type of execution response. This can only be structured-cloneable data.
*/
export interface IPool<
Worker extends IWorker,
Response = unknown
> {
/**
- * Pool type.
- *
- * If it is `'dynamic'`, it provides the `max` property.
+ * Pool information.
*/
- readonly type: PoolType
+ readonly info: PoolInfo
/**
- * Pool maximum size.
+ * Pool worker nodes.
+ *
+ * @internal
*/
- readonly size: number
+ readonly workerNodes: Array<IWorkerNode<Worker, Data>>
/**
- * Pool worker nodes.
+ * Whether the worker node has back pressure (i.e. its tasks queue is full).
+ *
+ * @param workerNodeKey - The worker node key.
+ * @returns `true` if the worker node has back pressure, `false` otherwise.
+ * @internal
*/
- readonly workerNodes: Array<WorkerNode<Worker, Data>>
+ readonly hasWorkerNodeBackPressure: (workerNodeKey: number) => boolean
/**
* Emitter on which events can be listened to.
*
* Events that can currently be listened to:
*
- * - `'full'`: Emitted when the pool is dynamic and full.
- * - `'busy'`: Emitted when the pool is busy.
+ * - `'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).
*/
readonly emitter?: PoolEmitter
/**
* Executes the specified function in the worker constructor with the task data input parameter.
*
- * @param data - The task input data for the specified worker function. This can only be serializable data.
- * @param name - The name of the worker function to execute. If not specified, the default worker function will be executed.
+ * @param data - The optional task input data for the specified task function. This can only be structured-cloneable data.
+ * @param name - The optional name of the task function to execute. If not specified, the default task function will be executed.
+ * @param transferList - An optional array of transferable objects to transfer ownership of. Ownership of the transferred objects is given to the pool's worker_threads worker and they should not be used in the main thread afterwards.
* @returns Promise that will be fulfilled when the task is completed.
*/
- execute: (data?: Data, name?: string) => Promise<Response>
+ readonly execute: (
+ data?: Data,
+ name?: string,
+ transferList?: TransferListItem[]
+ ) => Promise<Response>
+ /**
+ * Starts the minimum number of workers in this pool.
+ */
+ readonly start: () => void
/**
- * Shutdowns every current worker in this pool.
+ * Terminates all workers in this pool.
+ */
+ readonly destroy: () => Promise<void>
+ /**
+ * Whether the specified task function exists in this pool.
+ *
+ * @param name - The name of the task function.
+ * @returns `true` if the task function exists, `false` otherwise.
+ */
+ readonly hasTaskFunction: (name: string) => boolean
+ /**
+ * Adds a task function to this pool.
+ * If a task function with the same name already exists, it will be overwritten.
+ *
+ * @param name - The name of the task function.
+ * @param taskFunction - The task function.
+ * @returns `true` if the task function was added, `false` otherwise.
+ */
+ readonly addTaskFunction: (
+ name: string,
+ taskFunction: TaskFunction<Data, Response>
+ ) => Promise<boolean>
+ /**
+ * Removes a task function from this pool.
+ *
+ * @param name - The name of the task function.
+ * @returns `true` if the task function was removed, `false` otherwise.
+ */
+ readonly removeTaskFunction: (name: string) => Promise<boolean>
+ /**
+ * Lists the names of task function available in this pool.
+ *
+ * @returns The names of task function available in this pool.
+ */
+ readonly listTaskFunctionNames: () => string[]
+ /**
+ * Sets the default task function in this pool.
+ *
+ * @param name - The name of the task function.
+ * @returns `true` if the default task function was set, `false` otherwise.
*/
- destroy: () => Promise<void>
+ readonly setDefaultTaskFunction: (name: string) => Promise<boolean>
/**
* Sets the worker choice strategy in this pool.
*
* @param workerChoiceStrategy - The worker choice strategy.
* @param workerChoiceStrategyOptions - The worker choice strategy options.
*/
- setWorkerChoiceStrategy: (
+ readonly setWorkerChoiceStrategy: (
workerChoiceStrategy: WorkerChoiceStrategy,
workerChoiceStrategyOptions?: WorkerChoiceStrategyOptions
) => void
*
* @param workerChoiceStrategyOptions - The worker choice strategy options.
*/
- setWorkerChoiceStrategyOptions: (
+ readonly setWorkerChoiceStrategyOptions: (
workerChoiceStrategyOptions: WorkerChoiceStrategyOptions
) => void
/**
- * Enables/disables the worker tasks queue in this pool.
+ * Enables/disables the worker node tasks queue in this pool.
*
- * @param enable - Whether to enable or disable the worker tasks queue.
- * @param tasksQueueOptions - The worker tasks queue options.
+ * @param enable - Whether to enable or disable the worker node tasks queue.
+ * @param tasksQueueOptions - The worker node tasks queue options.
*/
- enableTasksQueue: (
+ readonly enableTasksQueue: (
enable: boolean,
tasksQueueOptions?: TasksQueueOptions
) => void
/**
- * Sets the worker tasks queue options in this pool.
+ * Sets the worker node tasks queue options in this pool.
*
- * @param tasksQueueOptions - The worker tasks queue options.
+ * @param tasksQueueOptions - The worker node tasks queue options.
*/
- setTasksQueueOptions: (tasksQueueOptions: TasksQueueOptions) => void
+ readonly setTasksQueueOptions: (tasksQueueOptions: TasksQueueOptions) => void
}