-import { AsyncResource } from 'async_hooks'
-import type { MessageValue } from '../utility-types'
-import type { WorkerOptions } from './worker-options'
+import { AsyncResource } from 'node:async_hooks'
+import type { Worker } from 'node:cluster'
+import type { MessagePort } from 'node:worker_threads'
+import { performance } from 'node:perf_hooks'
+import type {
+ MessageValue,
+ TaskPerformance,
+ WorkerStatistics
+} from '../utility-types'
+import { EMPTY_FUNCTION, isAsyncFunction, isPlainObject } from '../utils'
+import {
+ type KillBehavior,
+ KillBehaviors,
+ type WorkerOptions
+} from './worker-options'
+import type {
+ TaskFunctions,
+ WorkerAsyncFunction,
+ WorkerFunction,
+ WorkerSyncFunction
+} from './worker-functions'
+
+const DEFAULT_FUNCTION_NAME = 'default'
+const DEFAULT_MAX_INACTIVE_TIME = 60000
+const DEFAULT_KILL_BEHAVIOR: KillBehavior = KillBehaviors.SOFT
/**
- * Base class containing some shared logic for all poolifier workers.
+ * Base class that implements some shared logic for all poolifier workers.
*
- * @template MainWorker Type of main worker.
- * @template Data Type of data this worker receives from pool's execution.
- * @template Response Type of response the worker sends back to the main worker.
+ * @typeParam MainWorker - Type of main worker.
+ * @typeParam Data - Type of data this worker receives from pool's execution. This can only be structured-cloneable data.
+ * @typeParam Response - Type of response the worker sends back to the main worker. This can only be structured-cloneable data.
*/
export abstract class AbstractWorker<
- MainWorker,
+ MainWorker extends Worker | MessagePort,
Data = unknown,
Response = unknown
> extends AsyncResource {
/**
- * The maximum time to keep this worker alive while idle. The pool automatically checks and terminates this worker when the time expires.
+ * Worker id.
*/
- protected readonly maxInactiveTime: number
+ protected abstract id: number
/**
- * Whether the worker is working asynchronously or not.
+ * Task function(s) processed by the worker when the pool's `execution` function is invoked.
*/
- protected readonly async: boolean
+ protected taskFunctions!: Map<string, WorkerFunction<Data, Response>>
/**
* Timestamp of the last task processed by this worker.
*/
- protected lastTask: number
+ protected lastTaskTimestamp!: number
/**
- * Handler ID of the `interval` alive check.
+ * Performance statistics computation requirements.
*/
- protected readonly interval?: NodeJS.Timeout
-
+ protected statistics!: WorkerStatistics
+ /**
+ * Handler id of the `aliveInterval` worker alive check.
+ */
+ protected aliveInterval?: NodeJS.Timeout
/**
* Constructs a new poolifier worker.
*
- * @param type The type of async event.
- * @param isMain Whether this is the main worker or not.
- * @param fn Function processed by the worker when the pool's `execution` function is invoked.
- * @param opts Options for the worker.
+ * @param type - The type of async event.
+ * @param isMain - Whether this is the main worker or not.
+ * @param taskFunctions - Task function(s) processed by the worker when the pool's `execution` function is invoked. The first function is the default function.
+ * @param mainWorker - Reference to main worker.
+ * @param opts - Options for the worker.
*/
public constructor (
type: string,
- isMain: boolean,
- fn: (data: Data) => Response,
- public readonly opts: WorkerOptions = {}
+ protected readonly isMain: boolean,
+ taskFunctions:
+ | WorkerFunction<Data, Response>
+ | TaskFunctions<Data, Response>,
+ protected readonly mainWorker: MainWorker,
+ protected readonly opts: WorkerOptions = {
+ /**
+ * The kill behavior option on this worker or its default value.
+ */
+ killBehavior: DEFAULT_KILL_BEHAVIOR,
+ /**
+ * The maximum time to keep this worker alive while idle.
+ * The pool automatically checks and terminates this worker when the time expires.
+ */
+ maxInactiveTime: DEFAULT_MAX_INACTIVE_TIME
+ }
) {
super(type)
+ this.checkWorkerOptions(this.opts)
+ this.checkTaskFunctions(taskFunctions)
+ if (!this.isMain) {
+ this.mainWorker?.on('message', this.messageListener.bind(this))
+ }
+ }
- this.maxInactiveTime = this.opts.maxInactiveTime ?? 1000 * 60
- this.async = !!this.opts.async
- this.lastTask = Date.now()
- if (!fn) throw new Error('fn parameter is mandatory')
- // keep the worker active
- if (!isMain) {
- this.interval = setInterval(
- this.checkAlive.bind(this),
- this.maxInactiveTime / 2
+ private checkWorkerOptions (opts: WorkerOptions): void {
+ this.opts.killBehavior = opts.killBehavior ?? DEFAULT_KILL_BEHAVIOR
+ this.opts.maxInactiveTime =
+ opts.maxInactiveTime ?? DEFAULT_MAX_INACTIVE_TIME
+ delete this.opts.async
+ }
+
+ /**
+ * Checks if the `taskFunctions` parameter is passed to the constructor.
+ *
+ * @param taskFunctions - The task function(s) parameter that should be checked.
+ */
+ private checkTaskFunctions (
+ taskFunctions:
+ | WorkerFunction<Data, Response>
+ | TaskFunctions<Data, Response>
+ ): void {
+ if (taskFunctions == null) {
+ throw new Error('taskFunctions parameter is mandatory')
+ }
+ this.taskFunctions = new Map<string, WorkerFunction<Data, Response>>()
+ if (typeof taskFunctions === 'function') {
+ this.taskFunctions.set(DEFAULT_FUNCTION_NAME, taskFunctions.bind(this))
+ } else if (isPlainObject(taskFunctions)) {
+ let firstEntry = true
+ for (const [name, fn] of Object.entries(taskFunctions)) {
+ if (typeof fn !== 'function') {
+ throw new TypeError(
+ 'A taskFunctions parameter object value is not a function'
+ )
+ }
+ this.taskFunctions.set(name, fn.bind(this))
+ if (firstEntry) {
+ this.taskFunctions.set(DEFAULT_FUNCTION_NAME, fn.bind(this))
+ firstEntry = false
+ }
+ }
+ if (firstEntry) {
+ throw new Error('taskFunctions parameter object is empty')
+ }
+ } else {
+ throw new TypeError(
+ 'taskFunctions parameter is not a function or a plain object'
)
- this.checkAlive.bind(this)()
}
}
/**
- * Returns the main worker.
+ * Worker message listener.
+ *
+ * @param message - Message received.
*/
- protected abstract getMainWorker (): MainWorker
+ protected messageListener (message: MessageValue<Data, Data>): void {
+ if (message.ready != null && message.workerId === this.id) {
+ // Startup message received
+ this.workerReady()
+ } else if (message.statistics != null && message.workerId === this.id) {
+ // Statistics message received
+ this.statistics = message.statistics
+ } else if (message.checkAlive != null && message.workerId === this.id) {
+ // Check alive message received
+ message.checkAlive ? this.startCheckAlive() : this.stopCheckAlive()
+ } else if (
+ message.id != null &&
+ message.data != null &&
+ message.workerId === this.id
+ ) {
+ // Task message received
+ const fn = this.getTaskFunction(message.name)
+ if (isAsyncFunction(fn)) {
+ this.runInAsyncScope(this.runAsync.bind(this), this, fn, message)
+ } else {
+ this.runInAsyncScope(this.runSync.bind(this), this, fn, message)
+ }
+ } else if (message.kill === true && message.workerId === this.id) {
+ // Kill message received
+ this.stopCheckAlive()
+ this.emitDestroy()
+ }
+ }
/**
- * Send a message to the main worker.
- *
- * @param message The response message.
+ * Notifies the main worker that this worker is ready to process tasks.
+ */
+ protected workerReady (): void {
+ !this.isMain && this.sendToMainWorker({ ready: true, workerId: this.id })
+ }
+
+ /**
+ * Starts the worker alive check interval.
+ */
+ private startCheckAlive (): void {
+ this.lastTaskTimestamp = performance.now()
+ this.aliveInterval = setInterval(
+ this.checkAlive.bind(this),
+ (this.opts.maxInactiveTime ?? DEFAULT_MAX_INACTIVE_TIME) / 2
+ )
+ this.checkAlive.bind(this)()
+ }
+
+ /**
+ * Stops the worker alive check interval.
+ */
+ private stopCheckAlive (): void {
+ this.aliveInterval != null && clearInterval(this.aliveInterval)
+ }
+
+ /**
+ * Checks if the worker should be terminated, because its living too long.
*/
- protected abstract sendToMainWorker (message: MessageValue<Response>): void
+ private checkAlive (): void {
+ if (
+ performance.now() - this.lastTaskTimestamp >
+ (this.opts.maxInactiveTime ?? DEFAULT_MAX_INACTIVE_TIME)
+ ) {
+ this.sendToMainWorker({ kill: this.opts.killBehavior, workerId: this.id })
+ }
+ }
/**
- * Check to see if the worker should be terminated, because its living too long.
+ * Returns the main worker.
+ *
+ * @returns Reference to the main worker.
*/
- protected checkAlive (): void {
- if (Date.now() - this.lastTask > this.maxInactiveTime) {
- this.sendToMainWorker({ kill: 1 })
+ protected getMainWorker (): MainWorker {
+ if (this.mainWorker == null) {
+ throw new Error('Main worker not set')
}
+ return this.mainWorker
}
/**
- * Handle an error and convert it to a string so it can be sent back to the main worker.
+ * Sends a message to the main worker.
*
- * @param e The error raised by the worker.
+ * @param message - The response message.
+ */
+ protected abstract sendToMainWorker (
+ message: MessageValue<Response, Data>
+ ): void
+
+ /**
+ * Handles an error and convert it to a string so it can be sent back to the main worker.
+ *
+ * @param e - The error raised by the worker.
+ * @returns The error message.
*/
protected handleError (e: Error | string): string {
- return (e as unknown) as string
+ return e instanceof Error ? e.message : e
}
/**
- * Run the given function synchronously.
+ * Runs the given function synchronously.
*
- * @param fn Function that will be executed.
- * @param value Input data for the given function.
+ * @param fn - Function that will be executed.
+ * @param message - Input data for the given function.
*/
- protected run (
- fn: (data?: Data) => Response,
- value: MessageValue<Data>
+ protected runSync (
+ fn: WorkerSyncFunction<Data, Response>,
+ message: MessageValue<Data>
): void {
try {
- const res = fn(value.data)
- this.sendToMainWorker({ data: res, id: value.id })
- this.lastTask = Date.now()
+ let taskPerformance = this.beginTaskPerformance()
+ const res = fn(message.data)
+ taskPerformance = this.endTaskPerformance(taskPerformance)
+ this.sendToMainWorker({
+ data: res,
+ taskPerformance,
+ workerId: this.id,
+ id: message.id
+ })
} catch (e) {
- const err = this.handleError(e)
- this.sendToMainWorker({ error: err, id: value.id })
- this.lastTask = Date.now()
+ const errorMessage = this.handleError(e as Error | string)
+ this.sendToMainWorker({
+ taskError: {
+ message: errorMessage,
+ data: message.data
+ },
+ workerId: this.id,
+ id: message.id
+ })
+ } finally {
+ if (!this.isMain && this.aliveInterval != null) {
+ this.lastTaskTimestamp = performance.now()
+ }
}
}
/**
- * Run the given function asynchronously.
+ * Runs the given function asynchronously.
*
- * @param fn Function that will be executed.
- * @param value Input data for the given function.
+ * @param fn - Function that will be executed.
+ * @param message - Input data for the given function.
*/
protected runAsync (
- fn: (data?: Data) => Promise<Response>,
- value: MessageValue<Data>
+ fn: WorkerAsyncFunction<Data, Response>,
+ message: MessageValue<Data>
): void {
- fn(value.data)
+ let taskPerformance = this.beginTaskPerformance()
+ fn(message.data)
.then(res => {
- this.sendToMainWorker({ data: res, id: value.id })
- this.lastTask = Date.now()
+ taskPerformance = this.endTaskPerformance(taskPerformance)
+ this.sendToMainWorker({
+ data: res,
+ taskPerformance,
+ workerId: this.id,
+ id: message.id
+ })
return null
})
.catch(e => {
- const err = this.handleError(e)
- this.sendToMainWorker({ error: err, id: value.id })
- this.lastTask = Date.now()
+ const errorMessage = this.handleError(e as Error | string)
+ this.sendToMainWorker({
+ taskError: {
+ message: errorMessage,
+ data: message.data
+ },
+ workerId: this.id,
+ id: message.id
+ })
})
+ .finally(() => {
+ if (!this.isMain && this.aliveInterval != null) {
+ this.lastTaskTimestamp = performance.now()
+ }
+ })
+ .catch(EMPTY_FUNCTION)
+ }
+
+ /**
+ * Gets the task function in the given scope.
+ *
+ * @param name - Name of the function that will be returned.
+ */
+ private getTaskFunction (name?: string): WorkerFunction<Data, Response> {
+ name = name ?? DEFAULT_FUNCTION_NAME
+ const fn = this.taskFunctions.get(name)
+ if (fn == null) {
+ throw new Error(`Task function '${name}' not found`)
+ }
+ return fn
+ }
+
+ private beginTaskPerformance (): TaskPerformance {
+ this.checkStatistics()
+ return {
+ timestamp: performance.now(),
+ ...(this.statistics.elu && { elu: performance.eventLoopUtilization() })
+ }
+ }
+
+ private endTaskPerformance (
+ taskPerformance: TaskPerformance
+ ): TaskPerformance {
+ this.checkStatistics()
+ return {
+ ...taskPerformance,
+ ...(this.statistics.runTime && {
+ runTime: performance.now() - taskPerformance.timestamp
+ }),
+ ...(this.statistics.elu && {
+ elu: performance.eventLoopUtilization(taskPerformance.elu)
+ })
+ }
+ }
+
+ private checkStatistics (): void {
+ if (this.statistics == null) {
+ throw new Error('Performance statistics computation requirements not set')
+ }
}
}