-import EventEmitter from 'events'
-import type { MessageValue } from '../utility-types'
-import type { IPool } from './pool'
+import type {
+ MessageValue,
+ PromiseWorkerResponseWrapper
+} from '../utility-types'
+import { EMPTY_FUNCTION } from '../utils'
+import { isKillBehavior, KillBehaviors } from '../worker/worker-options'
+import type { PoolOptions } from './pool'
+import { PoolEmitter } from './pool'
+import type { IPoolInternal, TasksUsage } from './pool-internal'
+import { PoolType } from './pool-internal'
+import type { IPoolWorker } from './pool-worker'
+import {
+ WorkerChoiceStrategies,
+ WorkerChoiceStrategy
+} from './selection-strategies/selection-strategies-types'
+import { WorkerChoiceStrategyContext } from './selection-strategies/worker-choice-strategy-context'
/**
- * Callback invoked if the worker raised an error.
- */
-export type ErrorHandler<Worker> = (this: Worker, e: Error) => void
-
-/**
- * Callback invoked when the worker has started successfully.
- */
-export type OnlineHandler<Worker> = (this: Worker) => void
-
-/**
- * Callback invoked when the worker exits successfully.
- */
-export type ExitHandler<Worker> = (this: Worker, code: number) => void
-
-/**
- * Basic interface that describes the minimum required implementation of listener events for a pool-worker.
- */
-export interface IWorker {
- on(event: 'error', handler: ErrorHandler<this>): void
- on(event: 'online', handler: OnlineHandler<this>): void
- on(event: 'exit', handler: ExitHandler<this>): void
- once(event: 'exit', handler: ExitHandler<this>): void
-}
-
-/**
- * Options for a poolifier pool.
- */
-export interface PoolOptions<Worker> {
- /**
- * A function that will listen for error event on each worker.
- */
- 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.
- */
- exitHandler?: ExitHandler<Worker>
- /**
- * This is just to avoid non-useful warning messages.
- *
- * Will be used to set `maxListeners` on event emitters (workers are event emitters).
- *
- * @default 1000
- * @see [Node events emitter.setMaxListeners(n)](https://nodejs.org/api/events.html#events_emitter_setmaxlisteners_n)
- */
- maxTasks?: number
-}
-
-/**
- * Internal poolifier pool emitter.
- */
-class PoolEmitter extends EventEmitter {}
-
-/**
- * Base class containing some shared logic for all poolifier pools.
+ * Base class that implements some shared logic for all poolifier pools.
*
* @template Worker Type of worker which manages this pool.
- * @template Data Type of data sent to the worker.
- * @template Response Type of response of execution.
+ * @template Data Type of data sent to the worker. This can only be serializable data.
+ * @template Response Type of response of execution. This can only be serializable data.
*/
export abstract class AbstractPool<
- Worker extends IWorker,
+ Worker extends IPoolWorker,
Data = unknown,
Response = unknown
-> implements IPool<Data, Response> {
- /**
- * List of currently available workers.
- */
+> implements IPoolInternal<Worker, Data, Response> {
+ /** @inheritDoc */
public readonly workers: Worker[] = []
- /**
- * Index for the next worker.
- */
- public nextWorkerIndex: number = 0
+ /** @inheritDoc */
+ public readonly workersTasksUsage: Map<Worker, TasksUsage> = new Map<
+ Worker,
+ TasksUsage
+ >()
- /**
- * - `key`: The `Worker`
- * - `value`: Number of tasks that has been assigned to that worker since it started
- */
- public readonly tasks: Map<Worker, number> = new Map<Worker, number>()
+ /** @inheritDoc */
+ public readonly emitter?: PoolEmitter
/**
- * Emitter on which events can be listened to.
+ * The promise map.
*
- * Events that can currently be listened to:
+ * - `key`: This is the message Id of each submitted task.
+ * - `value`: An object that contains the worker, the resolve function and the reject function.
*
- * - `'FullPool'`
+ * When we receive a message from the worker we get a map entry and resolve/reject the promise based on the message.
*/
- public readonly emitter: PoolEmitter
+ protected promiseMap: Map<
+ number,
+ PromiseWorkerResponseWrapper<Worker, Response>
+ > = new Map<number, PromiseWorkerResponseWrapper<Worker, Response>>()
/**
- * ID of the next message.
+ * Id of the next message.
*/
protected nextMessageId: number = 0
+ /**
+ * Worker choice strategy instance implementing the worker choice algorithm.
+ *
+ * Default to a strategy implementing a round robin algorithm.
+ */
+ protected workerChoiceStrategyContext: WorkerChoiceStrategyContext<
+ Worker,
+ Data,
+ Response
+ >
+
/**
* Constructs a new poolifier pool.
*
* @param numberOfWorkers Number of workers that this pool should manage.
* @param filePath Path to the worker-file.
- * @param opts Options for the pool. Default: `{ maxTasks: 1000 }`
+ * @param opts Options for the pool.
*/
public constructor (
public readonly numberOfWorkers: number,
public readonly filePath: string,
- public readonly opts: PoolOptions<Worker> = { maxTasks: 1000 }
+ public readonly opts: PoolOptions<Worker>
) {
- if (!this.isMain()) {
+ if (this.isMain() === false) {
throw new Error('Cannot start a pool from a worker!')
}
- // TODO christopher 2021-02-07: Improve this check e.g. with a pattern or blank check
- if (!this.filePath) {
- throw new Error('Please specify a file with a worker implementation')
- }
-
+ this.checkNumberOfWorkers(this.numberOfWorkers)
+ this.checkFilePath(this.filePath)
+ this.checkPoolOptions(this.opts)
this.setupHook()
for (let i = 1; i <= this.numberOfWorkers; i++) {
this.createAndSetupWorker()
}
- this.emitter = new PoolEmitter()
+ if (this.opts.enableEvents === true) {
+ this.emitter = new PoolEmitter()
+ }
+ this.workerChoiceStrategyContext = new WorkerChoiceStrategyContext(
+ this,
+ () => {
+ const workerCreated = this.createAndSetupWorker()
+ this.registerWorkerMessageListener(workerCreated, message => {
+ if (
+ isKillBehavior(KillBehaviors.HARD, message.kill) ||
+ this.getWorkerRunningTasks(workerCreated) === 0
+ ) {
+ // Kill received from the worker, means that no new tasks are submitted to that worker for a while ( > maxInactiveTime)
+ this.destroyWorker(workerCreated) as void
+ }
+ })
+ return workerCreated
+ },
+ this.opts.workerChoiceStrategy
+ )
}
- /**
- * Number of workers that this pool should manage.
- *
- * @returns Number of workers that this pool manages.
- * @deprecated Only here for backward compatibility.
- */
- // eslint-disable-next-line spellcheck/spell-checker
- public get numWorkers (): number {
- return this.numberOfWorkers
+ private checkFilePath (filePath: string): void {
+ if (!filePath) {
+ throw new Error('Please specify a file with a worker implementation')
+ }
}
- /**
- * Index for the next worker.
- *
- * @returns Index for the next worker.
- * @deprecated Only here for backward compatibility.
- */
- public get nextWorker (): number {
- return this.nextWorkerIndex
+ private checkNumberOfWorkers (numberOfWorkers: number): void {
+ if (numberOfWorkers == null) {
+ throw new Error(
+ 'Cannot instantiate a pool without specifying the number of workers'
+ )
+ } else if (Number.isSafeInteger(numberOfWorkers) === false) {
+ throw new TypeError(
+ 'Cannot instantiate a pool with a non integer number of workers'
+ )
+ } else if (numberOfWorkers < 0) {
+ throw new RangeError(
+ 'Cannot instantiate a pool with a negative number of workers'
+ )
+ } else if (this.type === PoolType.FIXED && numberOfWorkers === 0) {
+ throw new Error('Cannot instantiate a fixed pool with no worker')
+ }
+ }
+
+ private checkPoolOptions (opts: PoolOptions<Worker>): void {
+ this.opts.workerChoiceStrategy =
+ opts.workerChoiceStrategy ?? WorkerChoiceStrategies.ROUND_ROBIN
+ this.opts.enableEvents = opts.enableEvents ?? true
+ }
+
+ /** @inheritDoc */
+ public abstract get type (): PoolType
+
+ /** @inheritDoc */
+ public get numberOfRunningTasks (): number {
+ return this.promiseMap.size
+ }
+
+ /** @inheritDoc */
+ public getWorkerIndex (worker: Worker): number {
+ return this.workers.indexOf(worker)
+ }
+
+ /** @inheritDoc */
+ public getWorkerRunningTasks (worker: Worker): number | undefined {
+ return this.workersTasksUsage.get(worker)?.running
+ }
+
+ /** @inheritDoc */
+ public getWorkerAverageTasksRunTime (worker: Worker): number | undefined {
+ return this.workersTasksUsage.get(worker)?.avgRunTime
+ }
+
+ /** @inheritDoc */
+ public setWorkerChoiceStrategy (
+ workerChoiceStrategy: WorkerChoiceStrategy
+ ): void {
+ this.opts.workerChoiceStrategy = workerChoiceStrategy
+ for (const worker of this.workers) {
+ this.resetWorkerTasksUsage(worker)
+ }
+ this.workerChoiceStrategyContext.setWorkerChoiceStrategy(
+ workerChoiceStrategy
+ )
}
+ /** @inheritDoc */
+ public abstract get busy (): boolean
+
+ protected internalGetBusyStatus (): boolean {
+ return (
+ this.numberOfRunningTasks >= this.numberOfWorkers &&
+ this.findFreeWorker() === false
+ )
+ }
+
+ /** @inheritDoc */
+ public findFreeWorker (): Worker | false {
+ for (const worker of this.workers) {
+ if (this.getWorkerRunningTasks(worker) === 0) {
+ // A worker is free, return the matching worker
+ return worker
+ }
+ }
+ return false
+ }
+
+ /** @inheritDoc */
public execute (data: Data): Promise<Response> {
// Configure worker to handle message with the specified task
const worker = this.chooseWorker()
- this.increaseWorkersTask(worker)
- const messageId = ++this.nextMessageId
- const res = this.internalExecute(worker, messageId)
- this.sendToWorker(worker, { data: data || ({} as Data), id: messageId })
+ const res = this.internalExecute(worker, this.nextMessageId)
+ this.checkAndEmitBusy()
+ this.sendToWorker(worker, {
+ data: data ?? ({} as Data),
+ id: this.nextMessageId
+ })
+ ++this.nextMessageId
return res
}
+ /** @inheritDoc */
public async destroy (): Promise<void> {
await Promise.all(this.workers.map(worker => this.destroyWorker(worker)))
}
/**
- * Shut down given worker.
+ * Shutdowns given worker.
*
* @param worker A worker within `workers`.
*/
protected abstract isMain (): boolean
/**
- * Increase the number of tasks that the given workers has done.
+ * Hook executed before the worker task promise resolution.
+ * Can be overridden.
*
- * @param worker Workers whose tasks are increased.
+ * @param worker The worker.
*/
- protected increaseWorkersTask (worker: Worker): void {
- const numberOfTasksTheWorkerHas = this.tasks.get(worker)
- if (numberOfTasksTheWorkerHas !== undefined) {
- this.tasks.set(worker, numberOfTasksTheWorkerHas + 1)
- } else {
- throw Error('Worker could not be found in tasks map')
- }
+ protected beforePromiseWorkerResponseHook (worker: Worker): void {
+ this.increaseWorkerRunningTasks(worker)
+ }
+
+ /**
+ * Hook executed after the worker task promise resolution.
+ * Can be overridden.
+ *
+ * @param message The received message.
+ * @param promise The Promise response.
+ */
+ protected afterPromiseWorkerResponseHook (
+ message: MessageValue<Response>,
+ promise: PromiseWorkerResponseWrapper<Worker, Response>
+ ): void {
+ this.decreaseWorkerRunningTasks(promise.worker)
+ this.stepWorkerRunTasks(promise.worker, 1)
+ this.updateWorkerTasksRunTime(promise.worker, message.taskRunTime)
}
/**
* Removes the given worker from the pool.
*
- * @param worker Worker that will be removed.
+ * @param worker The worker that will be removed.
*/
protected removeWorker (worker: Worker): void {
// Clean worker from data structure
- const workerIndex = this.workers.indexOf(worker)
- this.workers.splice(workerIndex, 1)
- this.tasks.delete(worker)
+ this.workers.splice(this.getWorkerIndex(worker), 1)
+ this.removeWorkerTasksUsage(worker)
}
/**
- * Choose a worker for the next task.
+ * Chooses a worker for the next task.
*
* The default implementation uses a round robin algorithm to distribute the load.
*
* @returns Worker.
*/
protected chooseWorker (): Worker {
- const chosenWorker = this.workers[this.nextWorkerIndex]
- this.nextWorkerIndex++
- this.nextWorkerIndex %= this.workers.length
- return chosenWorker
+ return this.workerChoiceStrategyContext.execute()
}
/**
- * Send a message to the given worker.
+ * Sends a message to the given worker.
*
* @param worker The worker which should receive the message.
* @param message The message.
message: MessageValue<Data>
): void
- protected abstract registerWorkerMessageListener (
- port: Worker,
- listener: (message: MessageValue<Response>) => void
- ): void
-
- protected abstract unregisterWorkerMessageListener (
- port: Worker,
- listener: (message: MessageValue<Response>) => void
- ): void
+ /**
+ * Registers a listener callback on a given worker.
+ *
+ * @param worker The worker which should register a listener.
+ * @param listener The message listener callback.
+ */
+ protected abstract registerWorkerMessageListener<
+ Message extends Data | Response
+ > (worker: Worker, listener: (message: MessageValue<Message>) => void): void
protected internalExecute (
worker: Worker,
messageId: number
): Promise<Response> {
- return new Promise((resolve, reject) => {
- const listener: (message: MessageValue<Response>) => void = message => {
- if (message.id === messageId) {
- this.unregisterWorkerMessageListener(worker, listener)
- this.increaseWorkersTask(worker)
- if (message.error) reject(message.error)
- else resolve(message.data as Response)
- }
- }
- this.registerWorkerMessageListener(worker, listener)
+ this.beforePromiseWorkerResponseHook(worker)
+ return new Promise<Response>((resolve, reject) => {
+ this.promiseMap.set(messageId, { resolve, reject, worker })
})
}
* @returns New, completely set up worker.
*/
protected createAndSetupWorker (): Worker {
- const worker: Worker = this.createWorker()
+ const worker = this.createWorker()
- worker.on('error', this.opts.errorHandler ?? (() => {}))
- worker.on('online', this.opts.onlineHandler ?? (() => {}))
- worker.on('exit', this.opts.exitHandler ?? (() => {}))
+ worker.on('message', this.opts.messageHandler ?? EMPTY_FUNCTION)
+ worker.on('error', this.opts.errorHandler ?? EMPTY_FUNCTION)
+ worker.on('online', this.opts.onlineHandler ?? EMPTY_FUNCTION)
+ worker.on('exit', this.opts.exitHandler ?? EMPTY_FUNCTION)
worker.once('exit', () => this.removeWorker(worker))
this.workers.push(worker)
- // Init tasks map
- this.tasks.set(worker, 0)
+ // Init worker tasks usage map
+ this.initWorkerTasksUsage(worker)
this.afterWorkerSetup(worker)
return worker
}
+
+ /**
+ * This function is the listener registered for each worker.
+ *
+ * @returns The listener function to execute when a message is received from a worker.
+ */
+ protected workerListener (): (message: MessageValue<Response>) => void {
+ return message => {
+ if (message.id !== undefined) {
+ const promise = this.promiseMap.get(message.id)
+ if (promise !== undefined) {
+ if (message.error) {
+ promise.reject(message.error)
+ } else {
+ promise.resolve(message.data as Response)
+ }
+ this.afterPromiseWorkerResponseHook(message, promise)
+ this.promiseMap.delete(message.id)
+ }
+ }
+ }
+ }
+
+ private checkAndEmitBusy (): void {
+ if (this.opts.enableEvents === true && this.busy === true) {
+ this.emitter?.emit('busy')
+ }
+ }
+
+ /**
+ * Increases the number of tasks that the given worker has applied.
+ *
+ * @param worker Worker which running tasks is increased.
+ */
+ private increaseWorkerRunningTasks (worker: Worker): void {
+ this.stepWorkerRunningTasks(worker, 1)
+ }
+
+ /**
+ * Decreases the number of tasks that the given worker has applied.
+ *
+ * @param worker Worker which running tasks is decreased.
+ */
+ private decreaseWorkerRunningTasks (worker: Worker): void {
+ this.stepWorkerRunningTasks(worker, -1)
+ }
+
+ /**
+ * Steps the number of tasks that the given worker has applied.
+ *
+ * @param worker Worker which running tasks are stepped.
+ * @param step Number of running tasks step.
+ */
+ private stepWorkerRunningTasks (worker: Worker, step: number): void {
+ if (this.checkWorkerTasksUsage(worker) === true) {
+ const tasksUsage = this.workersTasksUsage.get(worker) as TasksUsage
+ tasksUsage.running = tasksUsage.running + step
+ this.workersTasksUsage.set(worker, tasksUsage)
+ }
+ }
+
+ /**
+ * Steps the number of tasks that the given worker has run.
+ *
+ * @param worker Worker which has run tasks.
+ * @param step Number of run tasks step.
+ */
+ private stepWorkerRunTasks (worker: Worker, step: number): void {
+ if (this.checkWorkerTasksUsage(worker) === true) {
+ const tasksUsage = this.workersTasksUsage.get(worker) as TasksUsage
+ tasksUsage.run = tasksUsage.run + step
+ this.workersTasksUsage.set(worker, tasksUsage)
+ }
+ }
+
+ /**
+ * Updates tasks runtime for the given worker.
+ *
+ * @param worker Worker which run the task.
+ * @param taskRunTime Worker task runtime.
+ */
+ private updateWorkerTasksRunTime (
+ worker: Worker,
+ taskRunTime: number | undefined
+ ): void {
+ if (
+ this.workerChoiceStrategyContext.getWorkerChoiceStrategy()
+ .requiredStatistics.runTime === true &&
+ this.checkWorkerTasksUsage(worker) === true
+ ) {
+ const tasksUsage = this.workersTasksUsage.get(worker) as TasksUsage
+ tasksUsage.runTime += taskRunTime ?? 0
+ if (tasksUsage.run !== 0) {
+ tasksUsage.avgRunTime = tasksUsage.runTime / tasksUsage.run
+ }
+ this.workersTasksUsage.set(worker, tasksUsage)
+ }
+ }
+
+ /**
+ * Checks if the given worker is registered in the workers tasks usage map.
+ *
+ * @param worker Worker to check.
+ * @returns `true` if the worker is registered in the workers tasks usage map. `false` otherwise.
+ */
+ private checkWorkerTasksUsage (worker: Worker): boolean {
+ const hasTasksUsage = this.workersTasksUsage.has(worker)
+ if (hasTasksUsage === false) {
+ throw new Error('Worker could not be found in workers tasks usage map')
+ }
+ return hasTasksUsage
+ }
+
+ /**
+ * Initializes tasks usage statistics.
+ *
+ * @param worker The worker.
+ */
+ private initWorkerTasksUsage (worker: Worker): void {
+ this.workersTasksUsage.set(worker, {
+ run: 0,
+ running: 0,
+ runTime: 0,
+ avgRunTime: 0
+ })
+ }
+
+ /**
+ * Removes worker tasks usage statistics.
+ *
+ * @param worker The worker.
+ */
+ private removeWorkerTasksUsage (worker: Worker): void {
+ this.workersTasksUsage.delete(worker)
+ }
+
+ /**
+ * Resets worker tasks usage statistics.
+ *
+ * @param worker The worker.
+ */
+ private resetWorkerTasksUsage (worker: Worker): void {
+ this.removeWorkerTasksUsage(worker)
+ this.initWorkerTasksUsage(worker)
+ }
}
repositories / poolifier.git / blobdiff