import type { MessageValue } from '../utility-types'
import type { IPool } from './pool'
+/**
+ * An intentional empty function.
+ */
+function emptyFunction () {
+ // intentionally left blank
+}
+
/**
* 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 error event.
+ *
+ * @param event `'error'`.
+ * @param handler The error handler.
+ */
on(event: 'error', handler: ErrorHandler<this>): void
+ /**
+ * Register a listener to the online event.
+ *
+ * @param event `'online'`.
+ * @param handler The online handler.
+ */
on(event: 'online', handler: OnlineHandler<this>): void
+ /**
+ * Register a listener to the exit event.
+ *
+ * @param event `'exit'`.
+ * @param handler The exit handler.
+ */
on(event: 'exit', handler: ExitHandler<this>): void
+ /**
+ * Register a listener to the exit event that will only performed once.
+ *
+ * @param event `'exit'`.
+ * @param handler The exit handler.
+ */
+ once(event: 'exit', handler: ExitHandler<this>): void
}
/**
* Base class containing 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,
public nextWorkerIndex: number = 0
/**
+ * The tasks map.
+ *
* - `key`: The `Worker`
- * - `value`: Number of tasks that has been assigned to that worker since it started
+ * - `value`: Number of tasks currently in progress on the worker.
*/
public readonly tasks: Map<Worker, number> = new Map<Worker, number>()
if (!this.isMain()) {
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.checkFilePath(this.filePath)
this.setupHook()
for (let i = 1; i <= this.numberOfWorkers; i++) {
this.emitter = new PoolEmitter()
}
- /**
- * 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) {
+ if (!filePath) {
+ throw new Error('Please specify a file with a worker implementation')
+ }
}
/**
- * Index for the next worker.
+ * Perform the task specified in the constructor with the data parameter.
*
- * @returns Index for the next worker.
- * @deprecated Only here for backward compatibility.
+ * @param data The input for the specified task. This can only be serializable data.
+ * @returns Promise that will be resolved when the task is successfully completed.
*/
- public get nextWorker (): number {
- return this.nextWorkerIndex
- }
-
public execute (data: Data): Promise<Response> {
// Configure worker to handle message with the specified task
const worker = this.chooseWorker()
return res
}
+ /**
+ * Shut down every current worker in this pool.
+ */
public async destroy (): Promise<void> {
- for (const worker of this.workers) {
- await this.destroyWorker(worker)
- }
+ await Promise.all(this.workers.map(worker => this.destroyWorker(worker)))
}
/**
/**
* Increase the number of tasks that the given workers has done.
*
- * @param worker Workers whose tasks are increased.
+ * @param worker Worker whose tasks are increased.
*/
protected increaseWorkersTask (worker: Worker): void {
- const numberOfTasksTheWorkerHas = this.tasks.get(worker)
- if (numberOfTasksTheWorkerHas !== undefined) {
- this.tasks.set(worker, numberOfTasksTheWorkerHas + 1)
+ this.stepWorkerNumberOfTasks(worker, 1)
+ }
+
+ /**
+ * Decrease the number of tasks that the given workers has done.
+ *
+ * @param worker Worker whose tasks are decreased.
+ */
+ protected decreaseWorkersTasks (worker: Worker): void {
+ this.stepWorkerNumberOfTasks(worker, -1)
+ }
+
+ /**
+ * Step the number of tasks that the given workers has done.
+ *
+ * @param worker Worker whose tasks are set.
+ * @param step Worker number of tasks step.
+ */
+ private stepWorkerNumberOfTasks (worker: Worker, step: number) {
+ const numberOfTasksInProgress = this.tasks.get(worker)
+ if (numberOfTasksInProgress !== undefined) {
+ this.tasks.set(worker, numberOfTasksInProgress + step)
} else {
throw Error('Worker could not be found in tasks map')
}
*/
protected chooseWorker (): Worker {
const chosenWorker = this.workers[this.nextWorkerIndex]
- this.nextWorkerIndex++
- this.nextWorkerIndex %= this.workers.length
+ this.nextWorkerIndex =
+ this.workers.length - 1 === this.nextWorkerIndex
+ ? 0
+ : this.nextWorkerIndex + 1
return chosenWorker
}
message: MessageValue<Data>
): void
- protected abstract registerWorkerMessageListener (
- port: Worker,
- listener: (message: MessageValue<Response>) => void
- ): void
+ protected abstract registerWorkerMessageListener<
+ Message extends Data | Response
+ > (worker: Worker, listener: (message: MessageValue<Message>) => void): void
- protected abstract unregisterWorkerMessageListener (
- port: Worker,
- listener: (message: MessageValue<Response>) => void
- ): void
+ protected abstract unregisterWorkerMessageListener<
+ Message extends Data | Response
+ > (worker: Worker, listener: (message: MessageValue<Message>) => void): void
protected internalExecute (
worker: Worker,
const listener: (message: MessageValue<Response>) => void = message => {
if (message.id === messageId) {
this.unregisterWorkerMessageListener(worker, listener)
- this.increaseWorkersTask(worker)
+ this.decreaseWorkersTasks(worker)
if (message.error) reject(message.error)
else resolve(message.data as Response)
}
protected createAndSetupWorker (): Worker {
const worker: Worker = this.createWorker()
- worker.on('error', this.opts.errorHandler ?? (() => {}))
- worker.on('online', this.opts.onlineHandler ?? (() => {}))
- // TODO handle properly when a worker exit
- worker.on('exit', this.opts.exitHandler ?? (() => {}))
+ worker.on('error', this.opts.errorHandler ?? emptyFunction)
+ worker.on('online', this.opts.onlineHandler ?? emptyFunction)
+ worker.on('exit', this.opts.exitHandler ?? emptyFunction)
+ worker.once('exit', () => this.removeWorker(worker))
this.workers.push(worker)
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