MessageValue,
PromiseWorkerResponseWrapper
} from '../utility-types'
+import { EMPTY_FUNCTION } from '../utils'
+import { isKillBehavior, KillBehaviors } from '../worker/worker-options'
import type { IPoolInternal } from './pool-internal'
-import { PoolEmitter } from './pool-internal'
+import { PoolEmitter, PoolType } from './pool-internal'
import type { WorkerChoiceStrategy } from './selection-strategies'
import {
WorkerChoiceStrategies,
} from './selection-strategies'
/**
- * An intentional empty function.
+ * Callback invoked if the worker has received a message.
*/
-const EMPTY_FUNCTION: () => void = () => {
- /* Intentionally empty */
-}
+export type MessageHandler<Worker> = (this: Worker, m: unknown) => void
/**
* Callback invoked if the worker raised an error.
* Basic interface that describes the minimum required implementation of listener events for a pool-worker.
*/
export interface IWorker {
+ /**
+ * Register a listener to the message event.
+ *
+ * @param event `'message'`.
+ * @param handler The message handler.
+ */
+ on(event: 'message', handler: MessageHandler<this>): void
/**
* Register a listener to the error event.
*
* Options for a poolifier pool.
*/
export interface PoolOptions<Worker> {
+ /**
+ * A function that will listen for message event on each worker.
+ */
+ messageHandler?: MessageHandler<Worker>
/**
* A function that will listen for error event on each 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
/**
* The work choice strategy to use in this pool.
*/
workerChoiceStrategy?: WorkerChoiceStrategy
+ /**
+ * Pool events emission.
+ *
+ * @default true
+ */
+ enableEvents?: boolean
}
/**
Data = unknown,
Response = unknown
> implements IPoolInternal<Worker, Data, Response> {
+ /** @inheritdoc */
+ public readonly workers: Worker[] = []
+
+ /** @inheritdoc */
+ public readonly tasks: Map<Worker, number> = new Map<Worker, number>()
+
+ /** @inheritdoc */
+ public readonly emitter?: PoolEmitter
+
+ /** @inheritdoc */
+ public readonly max?: number
+
/**
* The promise map.
*
- * - `key`: This is the message ID of each submitted task.
+ * - `key`: This is the message Id of each submitted task.
* - `value`: An object that contains the worker, the resolve function and the reject function.
*
* When we receive a message from the worker we get a map entry and resolve/reject the promise based on the message.
PromiseWorkerResponseWrapper<Worker, Response>
> = new Map<number, PromiseWorkerResponseWrapper<Worker, Response>>()
- /** @inheritdoc */
- public readonly workers: Worker[] = []
-
- /** @inheritdoc */
- public readonly tasks: Map<Worker, number> = new Map<Worker, number>()
-
- /** @inheritdoc */
- public readonly emitter: PoolEmitter
-
/**
- * ID of the next message.
+ * Id of the next message.
*/
protected nextMessageId: number = 0
*
* @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()) {
throw new Error('Cannot start a pool from a worker!')
}
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) {
+ this.emitter = new PoolEmitter()
+ }
this.workerChoiceStrategyContext = new WorkerChoiceStrategyContext(
this,
- opts.workerChoiceStrategy ?? WorkerChoiceStrategies.ROUND_ROBIN
+ () => {
+ const workerCreated = this.createAndSetupWorker()
+ this.registerWorkerMessageListener(workerCreated, async message => {
+ const tasksInProgress = this.tasks.get(workerCreated)
+ if (
+ isKillBehavior(KillBehaviors.HARD, message.kill) ||
+ tasksInProgress === 0
+ ) {
+ // Kill received from the worker, means that no new tasks are submitted to that worker for a while ( > maxInactiveTime)
+ await this.destroyWorker(workerCreated)
+ }
+ })
+ return workerCreated
+ },
+ this.opts.workerChoiceStrategy
)
}
throw new Error(
'Cannot instantiate a pool with a negative number of workers'
)
- } else if (!this.isDynamic() && numberOfWorkers === 0) {
+ } 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 isDynamic (): boolean {
- return false
+ public abstract get type (): PoolType
+
+ /** @inheritdoc */
+ public get numberOfRunningTasks (): number {
+ return this.promiseMap.size
}
/** @inheritdoc */
public setWorkerChoiceStrategy (
workerChoiceStrategy: WorkerChoiceStrategy
): void {
+ this.opts.workerChoiceStrategy = workerChoiceStrategy
this.workerChoiceStrategyContext.setWorkerChoiceStrategy(
workerChoiceStrategy
)
}
+ /** @inheritdoc */
+ public abstract get busy (): boolean
+
+ protected internalGetBusyStatus (): boolean {
+ return (
+ this.numberOfRunningTasks >= this.numberOfWorkers &&
+ this.findFreeTasksMapEntry() === false
+ )
+ }
+
+ /** @inheritdoc */
+ public findFreeTasksMapEntry (): [Worker, number] | false {
+ for (const [worker, numberOfTasks] of this.tasks) {
+ if (numberOfTasks === 0) {
+ // A worker is free, return the matching tasks map entry
+ return [worker, numberOfTasks]
+ }
+ }
+ 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.checkAndEmitBusy()
this.sendToWorker(worker, { data: data || ({} as Data), id: messageId })
return res
}
await Promise.all(this.workers.map(worker => this.destroyWorker(worker)))
}
- /** @inheritdoc */
- public abstract destroyWorker (worker: Worker): void | Promise<void>
+ /**
+ * Shut down given worker.
+ *
+ * @param worker A worker within `workers`.
+ */
+ protected abstract destroyWorker (worker: Worker): void | Promise<void>
/**
* Setup hook that can be overridden by a Poolifier pool implementation
protected abstract isMain (): boolean
/**
- * Increase the number of tasks that the given workers has done.
+ * Increase the number of tasks that the given worker has applied.
*
* @param worker Worker whose tasks are increased.
*/
}
/**
- * Decrease the number of tasks that the given workers has done.
+ * Decrease the number of tasks that the given worker has applied.
*
* @param worker Worker whose tasks are decreased.
*/
}
/**
- * Step the number of tasks that the given workers has done.
+ * Step the number of tasks that the given worker has applied.
*
* @param worker Worker whose tasks are set.
* @param step Worker number of tasks step.
message: MessageValue<Data>
): void
- /** @inheritdoc */
- public abstract registerWorkerMessageListener<
+ /**
+ * Register a listener callback on a given worker.
+ *
+ * @param worker A worker.
+ * @param listener A message listener callback.
+ */
+ protected abstract registerWorkerMessageListener<
Message extends Data | Response
> (worker: Worker, listener: (message: MessageValue<Message>) => void): void
worker: Worker,
messageId: number
): Promise<Response> {
+ this.increaseWorkersTask(worker)
return new Promise<Response>((resolve, reject) => {
this.promiseMap.set(messageId, { resolve, reject, worker })
})
*/
protected abstract afterWorkerSetup (worker: Worker): void
- /** @inheritdoc */
- public createAndSetupWorker (): Worker {
+ /**
+ * Creates a new worker for this pool and sets it up completely.
+ *
+ * @returns New, completely set up worker.
+ */
+ protected createAndSetupWorker (): Worker {
const worker: Worker = this.createWorker()
+ 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)
* @returns The listener function to execute when a message is sent from a worker.
*/
protected workerListener (): (message: MessageValue<Response>) => void {
- const listener: (message: MessageValue<Response>) => void = message => {
+ return message => {
if (message.id) {
const value = this.promiseMap.get(message.id)
if (value) {
}
}
}
- return listener
+ }
+
+ private checkAndEmitBusy (): void {
+ if (this.opts.enableEvents && this.busy) {
+ this.emitter?.emit('busy')
+ }
}
}
repositories / poolifier.git / blobdiff