-import { AsyncResource } from 'async_hooks'
-import type { Worker } from 'cluster'
-import type { MessagePort } from 'worker_threads'
-import type { MessageValue } from '../utility-types'
-import type { KillBehavior, WorkerOptions } from './worker-options'
-import { KillBehaviors } 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,
+ Task,
+ TaskPerformance,
+ WorkerStatistics
+} from '../utility-types'
+import {
+ DEFAULT_TASK_NAME,
+ EMPTY_FUNCTION,
+ isAsyncFunction,
+ isPlainObject
+} from '../utils'
+import { KillBehaviors, type WorkerOptions } from './worker-options'
+import type {
+ TaskAsyncFunction,
+ TaskFunction,
+ TaskFunctions,
+ TaskSyncFunction
+} from './task-functions'
-const DEFAULT_MAX_INACTIVE_TIME = 1000 * 60
-const DEFAULT_KILL_BEHAVIOR: KillBehavior = KillBehaviors.SOFT
+const DEFAULT_MAX_INACTIVE_TIME = 60000
+const DEFAULT_WORKER_OPTIONS: WorkerOptions = {
+ /**
+ * The kill behavior option on this worker or its default value.
+ */
+ killBehavior: KillBehaviors.SOFT,
+ /**
+ * The maximum time to keep this worker active while idle.
+ * The pool automatically checks and terminates this worker when the time expires.
+ */
+ maxInactiveTime: DEFAULT_MAX_INACTIVE_TIME,
+ /**
+ * The function to call when the worker is killed.
+ */
+ killHandler: EMPTY_FUNCTION
+}
/**
- * 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 extends Worker | MessagePort,
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
/**
- * The kill behavior set as option on the Worker constructor or a default value.
+ * Task function(s) processed by the worker when the pool's `execution` function is invoked.
*/
- protected readonly killBehavior: KillBehavior
+ protected taskFunctions!: Map<string, TaskFunction<Data, Response>>
/**
- * Whether the worker is working asynchronously or not.
+ * Timestamp of the last task processed by this worker.
*/
- protected readonly async: boolean
+ protected lastTaskTimestamp!: number
/**
- * Timestamp of the last task processed by this worker.
+ * Performance statistics computation requirements.
*/
- protected lastTask: number
+ protected statistics!: WorkerStatistics
/**
- * Handler ID of the `interval` alive check.
+ * Handler id of the `activeInterval` worker activity check.
*/
- protected readonly interval?: NodeJS.Timeout
-
+ protected activeInterval?: 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 mainWorker Reference to main worker.
- * @param opts Options for the worker.
+ * @param type - The type of async event.
+ * @param isMain - Whether this is the main worker or not.
+ * @param mainWorker - Reference to main worker.
+ * @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 opts - Options for the worker.
*/
public constructor (
type: string,
- isMain: boolean,
- fn: (data: Data) => Response,
- protected mainWorker?: MainWorker | null,
- public readonly opts: WorkerOptions = {
- killBehavior: DEFAULT_KILL_BEHAVIOR,
- maxInactiveTime: DEFAULT_MAX_INACTIVE_TIME
- }
+ protected readonly isMain: boolean,
+ private readonly mainWorker: MainWorker,
+ taskFunctions: TaskFunction<Data, Response> | TaskFunctions<Data, Response>,
+ protected opts: WorkerOptions = DEFAULT_WORKER_OPTIONS
) {
super(type)
- this.killBehavior = this.opts.killBehavior ?? DEFAULT_KILL_BEHAVIOR
- this.maxInactiveTime =
- this.opts.maxInactiveTime ?? DEFAULT_MAX_INACTIVE_TIME
- 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
- )
- this.checkAlive.bind(this)()
+ this.checkWorkerOptions(this.opts)
+ this.checkTaskFunctions(taskFunctions)
+ if (!this.isMain) {
+ this.getMainWorker()?.on('message', this.handleReadyMessage.bind(this))
}
+ }
+
+ private checkWorkerOptions (opts: WorkerOptions): void {
+ this.opts = { ...DEFAULT_WORKER_OPTIONS, ...opts }
+ delete this.opts.async
+ }
- this.mainWorker?.on('message', (value: MessageValue<Data, MainWorker>) => {
- if (value?.data && value.id) {
- // Here you will receive messages
- if (this.async) {
- this.runInAsyncScope(this.runAsync.bind(this), this, fn, value)
- } else {
- this.runInAsyncScope(this.run.bind(this), this, fn, value)
+ /**
+ * Checks if the `taskFunctions` parameter is passed to the constructor.
+ *
+ * @param taskFunctions - The task function(s) parameter that should be checked.
+ */
+ private checkTaskFunctions (
+ taskFunctions: TaskFunction<Data, Response> | TaskFunctions<Data, Response>
+ ): void {
+ if (taskFunctions == null) {
+ throw new Error('taskFunctions parameter is mandatory')
+ }
+ this.taskFunctions = new Map<string, TaskFunction<Data, Response>>()
+ if (typeof taskFunctions === 'function') {
+ const boundFn = taskFunctions.bind(this)
+ this.taskFunctions.set(DEFAULT_TASK_NAME, boundFn)
+ this.taskFunctions.set(
+ typeof taskFunctions.name === 'string' &&
+ taskFunctions.name.trim().length > 0
+ ? taskFunctions.name
+ : 'fn1',
+ boundFn
+ )
+ } else if (isPlainObject(taskFunctions)) {
+ let firstEntry = true
+ for (const [name, fn] of Object.entries(taskFunctions)) {
+ if (typeof name !== 'string') {
+ throw new TypeError(
+ 'A taskFunctions parameter object key is not a string'
+ )
+ }
+ if (typeof name === 'string' && name.trim().length === 0) {
+ throw new TypeError(
+ 'A taskFunctions parameter object key an empty string'
+ )
+ }
+ if (typeof fn !== 'function') {
+ throw new TypeError(
+ 'A taskFunctions parameter object value is not a function'
+ )
+ }
+ const boundFn = fn.bind(this)
+ if (firstEntry) {
+ this.taskFunctions.set(DEFAULT_TASK_NAME, boundFn)
+ firstEntry = false
}
- } else if (value.parent) {
- // Save a reference of the main worker to communicate with it
- // This will be received once
- this.mainWorker = value.parent
- } else if (value.kill) {
- // Here is time to kill this worker, just clearing the interval
- if (this.interval) clearInterval(this.interval)
+ this.taskFunctions.set(name, boundFn)
+ }
+ if (firstEntry) {
+ throw new Error('taskFunctions parameter object is empty')
+ }
+ } else {
+ throw new TypeError(
+ 'taskFunctions parameter is not a function or a plain object'
+ )
+ }
+ }
+
+ /**
+ * Checks if the worker has a task function with the given name.
+ *
+ * @param name - The name of the task function to check.
+ * @returns Whether the worker has a task function with the given name or not.
+ * @throws {@link https://nodejs.org/api/errors.html#class-typeerror} If the `name` parameter is not a string or an empty string.
+ */
+ public hasTaskFunction (name: string): boolean {
+ if (typeof name !== 'string') {
+ throw new TypeError('name parameter is not a string')
+ }
+ if (typeof name === 'string' && name.trim().length === 0) {
+ throw new TypeError('name parameter is an empty string')
+ }
+ return this.taskFunctions.has(name)
+ }
+
+ /**
+ * Adds a task function to the worker.
+ * If a task function with the same name already exists, it is replaced.
+ *
+ * @param name - The name of the task function to add.
+ * @param fn - The task function to add.
+ * @returns Whether the task function was added or not.
+ * @throws {@link https://nodejs.org/api/errors.html#class-typeerror} If the `name` parameter is not a string or an empty string.
+ * @throws {@link https://nodejs.org/api/errors.html#class-error} If the `name` parameter is the default task function reserved name.
+ * @throws {@link https://nodejs.org/api/errors.html#class-typeerror} If the `fn` parameter is not a function.
+ */
+ public addTaskFunction (
+ name: string,
+ fn: TaskFunction<Data, Response>
+ ): boolean {
+ if (typeof name !== 'string') {
+ throw new TypeError('name parameter is not a string')
+ }
+ if (typeof name === 'string' && name.trim().length === 0) {
+ throw new TypeError('name parameter is an empty string')
+ }
+ if (name === DEFAULT_TASK_NAME) {
+ throw new Error(
+ 'Cannot add a task function with the default reserved name'
+ )
+ }
+ if (typeof fn !== 'function') {
+ throw new TypeError('fn parameter is not a function')
+ }
+ try {
+ const boundFn = fn.bind(this)
+ if (
+ this.taskFunctions.get(name) ===
+ this.taskFunctions.get(DEFAULT_TASK_NAME)
+ ) {
+ this.taskFunctions.set(DEFAULT_TASK_NAME, boundFn)
+ }
+ this.taskFunctions.set(name, boundFn)
+ this.sendTaskFunctionsListToMainWorker()
+ return true
+ } catch {
+ return false
+ }
+ }
+
+ /**
+ * Removes a task function from the worker.
+ *
+ * @param name - The name of the task function to remove.
+ * @returns Whether the task function existed and was removed or not.
+ * @throws {@link https://nodejs.org/api/errors.html#class-typeerror} If the `name` parameter is not a string or an empty string.
+ * @throws {@link https://nodejs.org/api/errors.html#class-error} If the `name` parameter is the default task function reserved name.
+ * @throws {@link https://nodejs.org/api/errors.html#class-error} If the `name` parameter is the task function used as default task function.
+ */
+ public removeTaskFunction (name: string): boolean {
+ if (typeof name !== 'string') {
+ throw new TypeError('name parameter is not a string')
+ }
+ if (typeof name === 'string' && name.trim().length === 0) {
+ throw new TypeError('name parameter is an empty string')
+ }
+ if (name === DEFAULT_TASK_NAME) {
+ throw new Error(
+ 'Cannot remove the task function with the default reserved name'
+ )
+ }
+ if (
+ this.taskFunctions.get(name) === this.taskFunctions.get(DEFAULT_TASK_NAME)
+ ) {
+ throw new Error(
+ 'Cannot remove the task function used as the default task function'
+ )
+ }
+ const deleteStatus = this.taskFunctions.delete(name)
+ this.sendTaskFunctionsListToMainWorker()
+ return deleteStatus
+ }
+
+ /**
+ * Lists the names of the worker's task functions.
+ *
+ * @returns The names of the worker's task functions.
+ */
+ public listTaskFunctions (): string[] {
+ const names: string[] = [...this.taskFunctions.keys()]
+ let defaultTaskFunctionName: string = DEFAULT_TASK_NAME
+ for (const [name, fn] of this.taskFunctions) {
+ if (
+ name !== DEFAULT_TASK_NAME &&
+ fn === this.taskFunctions.get(DEFAULT_TASK_NAME)
+ ) {
+ defaultTaskFunctionName = name
+ break
+ }
+ }
+ return [
+ names[names.indexOf(DEFAULT_TASK_NAME)],
+ defaultTaskFunctionName,
+ ...names.filter(
+ (name) => name !== DEFAULT_TASK_NAME && name !== defaultTaskFunctionName
+ )
+ ]
+ }
+
+ /**
+ * Sets the default task function to use in the worker.
+ *
+ * @param name - The name of the task function to use as default task function.
+ * @returns Whether the default task function was set or not.
+ * @throws {@link https://nodejs.org/api/errors.html#class-typeerror} If the `name` parameter is not a string or an empty string.
+ * @throws {@link https://nodejs.org/api/errors.html#class-error} If the `name` parameter is the default task function reserved name.
+ * @throws {@link https://nodejs.org/api/errors.html#class-error} If the `name` parameter is a non-existing task function.
+ */
+ public setDefaultTaskFunction (name: string): boolean {
+ if (typeof name !== 'string') {
+ throw new TypeError('name parameter is not a string')
+ }
+ if (typeof name === 'string' && name.trim().length === 0) {
+ throw new TypeError('name parameter is an empty string')
+ }
+ if (name === DEFAULT_TASK_NAME) {
+ throw new Error(
+ 'Cannot set the default task function reserved name as the default task function'
+ )
+ }
+ if (!this.taskFunctions.has(name)) {
+ throw new Error(
+ 'Cannot set the default task function to a non-existing task function'
+ )
+ }
+ try {
+ this.taskFunctions.set(
+ DEFAULT_TASK_NAME,
+ this.taskFunctions.get(name) as TaskFunction<Data, Response>
+ )
+ return true
+ } catch {
+ return false
+ }
+ }
+
+ /**
+ * Handles the ready message sent by the main worker.
+ *
+ * @param message - The ready message.
+ */
+ protected abstract handleReadyMessage (message: MessageValue<Data>): void
+
+ /**
+ * Worker message listener.
+ *
+ * @param message - The received message.
+ */
+ protected messageListener (message: MessageValue<Data>): void {
+ this.checkMessageWorkerId(message)
+ if (message.statistics != null) {
+ // Statistics message received
+ this.statistics = message.statistics
+ } else if (message.checkActive != null) {
+ // Check active message received
+ message.checkActive ? this.startCheckActive() : this.stopCheckActive()
+ } else if (message.taskId != null && message.data != null) {
+ // Task message received
+ this.run(message)
+ } else if (message.kill === true) {
+ // Kill message received
+ this.handleKillMessage(message)
+ }
+ }
+
+ /**
+ * Handles a kill message sent by the main worker.
+ *
+ * @param message - The kill message.
+ */
+ protected handleKillMessage (message: MessageValue<Data>): void {
+ this.stopCheckActive()
+ if (isAsyncFunction(this.opts.killHandler)) {
+ (this.opts.killHandler?.() as Promise<void>)
+ .then(() => {
+ this.sendToMainWorker({ kill: 'success', workerId: this.id })
+ return null
+ })
+ .catch(() => {
+ this.sendToMainWorker({ kill: 'failure', workerId: this.id })
+ })
+ .finally(() => {
+ this.emitDestroy()
+ })
+ .catch(EMPTY_FUNCTION)
+ } else {
+ try {
+ // eslint-disable-next-line @typescript-eslint/no-invalid-void-type
+ this.opts.killHandler?.() as void
+ this.sendToMainWorker({ kill: 'success', workerId: this.id })
+ } catch {
+ this.sendToMainWorker({ kill: 'failure', workerId: this.id })
+ } finally {
this.emitDestroy()
}
- })
+ }
+ }
+
+ /**
+ * Check if the message worker id is set and matches the worker id.
+ *
+ * @param message - The message to check.
+ * @throws {@link https://nodejs.org/api/errors.html#class-error} If the message worker id is not set or does not match the worker id.
+ */
+ private checkMessageWorkerId (message: MessageValue<Data>): void {
+ if (message.workerId == null) {
+ throw new Error('Message worker id is not set')
+ } else if (message.workerId != null && message.workerId !== this.id) {
+ throw new Error(
+ `Message worker id ${message.workerId} does not match the worker id ${this.id}`
+ )
+ }
+ }
+
+ /**
+ * Starts the worker check active interval.
+ */
+ private startCheckActive (): void {
+ this.lastTaskTimestamp = performance.now()
+ this.activeInterval = setInterval(
+ this.checkActive.bind(this),
+ (this.opts.maxInactiveTime ?? DEFAULT_MAX_INACTIVE_TIME) / 2
+ )
+ }
+
+ /**
+ * Stops the worker check active interval.
+ */
+ private stopCheckActive (): void {
+ if (this.activeInterval != null) {
+ clearInterval(this.activeInterval)
+ delete this.activeInterval
+ }
+ }
+
+ /**
+ * Checks if the worker should be terminated, because its living too long.
+ */
+ private checkActive (): void {
+ if (
+ performance.now() - this.lastTaskTimestamp >
+ (this.opts.maxInactiveTime ?? DEFAULT_MAX_INACTIVE_TIME)
+ ) {
+ this.sendToMainWorker({ kill: this.opts.killBehavior, workerId: this.id })
+ }
}
/**
* @returns Reference to the main worker.
*/
protected getMainWorker (): MainWorker {
- if (!this.mainWorker) {
- throw new Error('Main worker was not set')
+ if (this.mainWorker == null) {
+ throw new Error('Main worker not set')
}
return this.mainWorker
}
/**
- * Send a message to the main worker.
+ * Sends a message to main worker.
*
- * @param message The response message.
+ * @param message - The response message.
*/
- protected abstract sendToMainWorker (message: MessageValue<Response>): void
+ protected abstract sendToMainWorker (
+ message: MessageValue<Response, Data>
+ ): void
/**
- * Check to see if the worker should be terminated, because its living too long.
+ * Sends the list of task function names to the main worker.
*/
- protected checkAlive (): void {
- if (Date.now() - this.lastTask > this.maxInactiveTime) {
- this.sendToMainWorker({ kill: this.killBehavior })
- }
+ protected sendTaskFunctionsListToMainWorker (): void {
+ this.sendToMainWorker({
+ taskFunctions: this.listTaskFunctions(),
+ workerId: this.id
+ })
}
/**
- * Handle an error and convert it to a string so it can be sent back to the main worker.
+ * 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 Message of the error.
+ * @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 task.
*
- * @param fn Function that will be executed.
- * @param value Input data for the given function.
+ * @param task - The task to execute.
+ * @throws {@link https://nodejs.org/api/errors.html#class-error} If the task function is not found.
*/
- protected run (
- fn: (data?: Data) => Response,
- value: MessageValue<Data>
+ protected run (task: Task<Data>): void {
+ const fn = this.getTaskFunction(task.name)
+ if (isAsyncFunction(fn)) {
+ this.runInAsyncScope(this.runAsync.bind(this), this, fn, task)
+ } else {
+ this.runInAsyncScope(this.runSync.bind(this), this, fn, task)
+ }
+ }
+
+ /**
+ * Runs the given task function synchronously.
+ *
+ * @param fn - Task function that will be executed.
+ * @param task - Input data for the task function.
+ */
+ protected runSync (
+ fn: TaskSyncFunction<Data, Response>,
+ task: Task<Data>
): void {
+ const { name, taskId, data } = task
try {
- const res = fn(value.data)
- this.sendToMainWorker({ data: res, id: value.id })
- this.lastTask = Date.now()
+ let taskPerformance = this.beginTaskPerformance(name)
+ const res = fn(data)
+ taskPerformance = this.endTaskPerformance(taskPerformance)
+ this.sendToMainWorker({
+ data: res,
+ taskPerformance,
+ workerId: this.id,
+ taskId
+ })
} 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: {
+ name: name ?? DEFAULT_TASK_NAME,
+ message: errorMessage,
+ data
+ },
+ workerId: this.id,
+ taskId
+ })
+ } finally {
+ this.updateLastTaskTimestamp()
}
}
/**
- * Run the given function asynchronously.
+ * Runs the given task function asynchronously.
*
- * @param fn Function that will be executed.
- * @param value Input data for the given function.
+ * @param fn - Task function that will be executed.
+ * @param task - Input data for the task function.
*/
protected runAsync (
- fn: (data?: Data) => Promise<Response>,
- value: MessageValue<Data>
+ fn: TaskAsyncFunction<Data, Response>,
+ task: Task<Data>
): void {
- fn(value.data)
- .then(res => {
- this.sendToMainWorker({ data: res, id: value.id })
- this.lastTask = Date.now()
+ const { name, taskId, data } = task
+ let taskPerformance = this.beginTaskPerformance(name)
+ fn(data)
+ .then((res) => {
+ taskPerformance = this.endTaskPerformance(taskPerformance)
+ this.sendToMainWorker({
+ data: res,
+ taskPerformance,
+ workerId: this.id,
+ taskId
+ })
return null
})
- .catch(e => {
- const err = this.handleError(e)
- this.sendToMainWorker({ error: err, id: value.id })
- this.lastTask = Date.now()
+ .catch((e) => {
+ const errorMessage = this.handleError(e as Error | string)
+ this.sendToMainWorker({
+ taskError: {
+ name: name ?? DEFAULT_TASK_NAME,
+ message: errorMessage,
+ data
+ },
+ workerId: this.id,
+ taskId
+ })
})
+ .finally(() => {
+ this.updateLastTaskTimestamp()
+ })
+ .catch(EMPTY_FUNCTION)
+ }
+
+ /**
+ * Gets the task function with the given name.
+ *
+ * @param name - Name of the task function that will be returned.
+ * @returns The task function.
+ * @throws {@link https://nodejs.org/api/errors.html#class-error} If the task function is not found.
+ */
+ private getTaskFunction (name?: string): TaskFunction<Data, Response> {
+ name = name ?? DEFAULT_TASK_NAME
+ const fn = this.taskFunctions.get(name)
+ if (fn == null) {
+ throw new Error(`Task function '${name}' not found`)
+ }
+ return fn
+ }
+
+ private beginTaskPerformance (name?: string): TaskPerformance {
+ this.checkStatistics()
+ return {
+ name: name ?? DEFAULT_TASK_NAME,
+ 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')
+ }
+ }
+
+ private updateLastTaskTimestamp (): void {
+ if (this.activeInterval != null) {
+ this.lastTaskTimestamp = performance.now()
+ }
}
}