-import type { SendHandle } from 'child_process'
import { fork, isMaster, setupMaster, Worker } from 'cluster'
import type { MessageValue } from '../../utility-types'
+import type { PoolOptions } from '../abstract-pool'
+import { AbstractPool } from '../abstract-pool'
-export type WorkerWithMessageChannel = Worker // & Draft<MessageChannel>
-
-export interface FixedClusterPoolOptions {
- /**
- * A function that will listen for error event on each worker.
- */
- errorHandler?: (this: Worker, e: Error) => void
- /**
- * A function that will listen for online event on each worker.
- */
- onlineHandler?: (this: Worker) => void
- /**
- * A function that will listen for exit event on each worker.
- */
- exitHandler?: (this: Worker, code: number) => void
- /**
- * This is just to avoid not useful warnings message, is used to set `maxListeners` on event emitters (workers are event emitters).
- *
- * @default 1000
- */
- maxTasks?: number
+export interface ClusterPoolOptions extends PoolOptions<Worker> {
/**
* Key/value pairs to add to worker process environment.
*
* @since 2.0.0
*/
// eslint-disable-next-line @typescript-eslint/no-explicit-any
-export class FixedClusterPool<Data = any, Response = any> {
- public readonly workers: WorkerWithMessageChannel[] = []
- public nextWorker: number = 0
-
- // workerId as key and an integer value
- public readonly tasks: Map<WorkerWithMessageChannel, number> = new Map<
- WorkerWithMessageChannel,
- number
- >()
-
- protected id: number = 0
-
+export class FixedClusterPool<Data = any, Response = any> extends AbstractPool<
+ Worker,
+ Data,
+ Response
+> {
/**
* @param numWorkers Number of workers for this pool.
* @param filePath A file path with implementation of `ClusterWorker` class, relative path is fine.
* @param opts An object with possible options for example `errorHandler`, `onlineHandler`. Default: `{ maxTasks: 1000 }`
*/
public constructor (
- public readonly numWorkers: number,
- public readonly filePath: string,
- public readonly opts: FixedClusterPoolOptions = { maxTasks: 1000 }
+ numWorkers: number,
+ filePath: string,
+ public readonly opts: ClusterPoolOptions = { maxTasks: 1000 }
) {
- if (!isMaster) {
- throw new Error('Cannot start a cluster pool from a worker!')
- }
- // TODO christopher 2021-02-09: 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')
- }
+ super(numWorkers, filePath, opts)
+ }
+ protected setupHook (): void {
setupMaster({
exec: this.filePath
})
+ }
- for (let i = 1; i <= this.numWorkers; i++) {
- this.newWorker()
- }
+ protected isMain (): boolean {
+ return isMaster
}
- public destroy (): void {
- for (const worker of this.workers) {
- worker.kill()
- }
+ protected destroyWorker (worker: Worker): void {
+ worker.kill()
}
- /**
- * Execute the task specified into the constructor with the data parameter.
- *
- * @param data The input for the task specified.
- * @returns Promise that is resolved when the task is done.
- */
- public execute (data: Data): Promise<Response> {
- // configure worker to handle message with the specified task
- const worker: WorkerWithMessageChannel = this.chooseWorker()
- // console.log('FixedClusterPool#execute choosen worker:', worker)
- const previousWorkerIndex = this.tasks.get(worker)
- if (previousWorkerIndex !== undefined) {
- this.tasks.set(worker, previousWorkerIndex + 1)
- } else {
- throw Error('Worker could not be found in tasks map')
- }
- const id: number = ++this.id
- const res: Promise<Response> = this.internalExecute(worker, id)
- // console.log('FixedClusterPool#execute send data to worker:', worker)
- worker.send({ data: data || {}, id: id })
- return res
+ protected sendToWorker (worker: Worker, message: MessageValue<Data>): void {
+ worker.send(message)
}
- protected internalExecute (
- worker: WorkerWithMessageChannel,
- id: number
- ): Promise<Response> {
- return new Promise((resolve, reject) => {
- const listener: (
- message: MessageValue<Response>,
- handle: SendHandle
- ) => void = message => {
- // console.log('FixedClusterPool#internalExecute listener:', message)
- if (message.id === id) {
- worker.removeListener('message', listener)
- const previousWorkerIndex = this.tasks.get(worker)
- if (previousWorkerIndex !== undefined) {
- this.tasks.set(worker, previousWorkerIndex + 1)
- } else {
- throw Error('Worker could not be found in tasks map')
- }
- if (message.error) reject(message.error)
- else resolve(message.data as Response)
- }
- }
- worker.on('message', listener)
- })
+ protected registerWorkerMessageListener (
+ port: Worker,
+ listener: (message: MessageValue<Response>) => void
+ ): void {
+ port.on('message', listener)
+ }
+
+ protected unregisterWorkerMessageListener (
+ port: Worker,
+ listener: (message: MessageValue<Response>) => void
+ ): void {
+ port.removeListener('message', listener)
}
- protected chooseWorker (): WorkerWithMessageChannel {
- if (this.workers.length - 1 === this.nextWorker) {
- this.nextWorker = 0
- return this.workers[this.nextWorker]
- } else {
- this.nextWorker++
- return this.workers[this.nextWorker]
- }
+ protected newWorker (): Worker {
+ return fork(this.opts.env)
}
- protected newWorker (): WorkerWithMessageChannel {
- const worker: WorkerWithMessageChannel = fork(this.opts.env)
- 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 ?? (() => {}))
- this.workers.push(worker)
+ protected afterNewWorkerPushed (worker: Worker): void {
// we will attach a listener for every task,
// when task is completed the listener will be removed but to avoid warnings we are increasing the max listeners size
worker.setMaxListeners(this.opts.maxTasks ?? 1000)
- // init tasks map
- this.tasks.set(worker, 0)
- return worker
}
}
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