src/worker/abstract-worker.ts

   1 import { AsyncResource } from 'node:async_hooks'
   2 import type { Worker } from 'node:cluster'
   3 import type { MessagePort } from 'node:worker_threads'
   4 import { performance } from 'node:perf_hooks'
   5 import type {
   6   MessageValue,
   7   Task,
   8   TaskPerformance,
   9   WorkerStatistics
  10 } from '../utility-types'
  11 import {
  12   DEFAULT_TASK_NAME,
  13   EMPTY_FUNCTION,
  14   isAsyncFunction,
  15   isPlainObject
  16 } from '../utils'
  17 import { KillBehaviors, type WorkerOptions } from './worker-options'
  18 import type {
  19   TaskAsyncFunction,
  20   TaskFunction,
  21   TaskFunctionOperationReturnType,
  22   TaskFunctions,
  23   TaskSyncFunction
  24 } from './task-functions'
  25
  26 const DEFAULT_MAX_INACTIVE_TIME = 60000
  27 const DEFAULT_WORKER_OPTIONS: WorkerOptions = {
  28   /**
  29    * The kill behavior option on this worker or its default value.
  30    */
  31   killBehavior: KillBehaviors.SOFT,
  32   /**
  33    * The maximum time to keep this worker active while idle.
  34    * The pool automatically checks and terminates this worker when the time expires.
  35    */
  36   maxInactiveTime: DEFAULT_MAX_INACTIVE_TIME,
  37   /**
  38    * The function to call when the worker is killed.
  39    */
  40   killHandler: EMPTY_FUNCTION
  41 }
  42
  43 /**
  44  * Base class that implements some shared logic for all poolifier workers.
  45  *
  46  * @typeParam MainWorker - Type of main worker.
  47  * @typeParam Data - Type of data this worker receives from pool's execution. This can only be structured-cloneable data.
  48  * @typeParam Response - Type of response the worker sends back to the main worker. This can only be structured-cloneable data.
  49  */
  50 export abstract class AbstractWorker<
  51   MainWorker extends Worker | MessagePort,
  52   Data = unknown,
  53   Response = unknown
  54 > extends AsyncResource {
  55   /**
  56    * Worker id.
  57    */
  58   protected abstract id: number
  59   /**
  60    * Task function(s) processed by the worker when the pool's `execution` function is invoked.
  61    */
  62   protected taskFunctions!: Map<string, TaskFunction<Data, Response>>
  63   /**
  64    * Timestamp of the last task processed by this worker.
  65    */
  66   protected lastTaskTimestamp!: number
  67   /**
  68    * Performance statistics computation requirements.
  69    */
  70   protected statistics!: WorkerStatistics
  71   /**
  72    * Handler id of the `activeInterval` worker activity check.
  73    */
  74   protected activeInterval?: NodeJS.Timeout
  75   /**
  76    * Constructs a new poolifier worker.
  77    *
  78    * @param type - The type of async event.
  79    * @param isMain - Whether this is the main worker or not.
  80    * @param mainWorker - Reference to main worker.
  81    * @param taskFunctions - Task function(s) processed by the worker when the pool's `execution` function is invoked. The first function is the default function.
  82    * @param opts - Options for the worker.
  83    */
  84   public constructor (
  85     type: string,
  86     protected readonly isMain: boolean,
  87     private readonly mainWorker: MainWorker,
  88     taskFunctions: TaskFunction<Data, Response> | TaskFunctions<Data, Response>,
  89     protected opts: WorkerOptions = DEFAULT_WORKER_OPTIONS
  90   ) {
  91     super(type)
  92     if (this.isMain == null) {
  93       throw new Error('isMain parameter is mandatory')
  94     }
  95     this.checkTaskFunctions(taskFunctions)
  96     this.checkWorkerOptions(this.opts)
  97     if (!this.isMain) {
  98       this.getMainWorker().on('message', this.handleReadyMessage.bind(this))
  99     }
 100   }
 101
 102   private checkWorkerOptions (opts: WorkerOptions): void {
 103     if (opts != null && !isPlainObject(opts)) {
 104       throw new TypeError('opts worker options parameter is not a plain object')
 105     }
 106     if (
 107       opts?.killBehavior != null &&
 108       !Object.values(KillBehaviors).includes(opts.killBehavior)
 109     ) {
 110       throw new TypeError(
 111         `killBehavior option '${opts.killBehavior}' is not valid`
 112       )
 113     }
 114     if (
 115       opts?.maxInactiveTime != null &&
 116       !Number.isSafeInteger(opts.maxInactiveTime)
 117     ) {
 118       throw new TypeError('maxInactiveTime option is not an integer')
 119     }
 120     if (opts?.maxInactiveTime != null && opts.maxInactiveTime < 5) {
 121       throw new TypeError(
 122         'maxInactiveTime option is not a positive integer greater or equal than 5'
 123       )
 124     }
 125     if (opts?.killHandler != null && typeof opts.killHandler !== 'function') {
 126       throw new TypeError('killHandler option is not a function')
 127     }
 128     if (opts?.async != null) {
 129       throw new Error('async option is deprecated')
 130     }
 131     this.opts = { ...DEFAULT_WORKER_OPTIONS, ...opts }
 132   }
 133
 134   private checkValidTaskFunctionEntry (
 135     name: string,
 136     fn: TaskFunction<Data, Response>
 137   ): void {
 138     if (typeof name !== 'string') {
 139       throw new TypeError(
 140         'A taskFunctions parameter object key is not a string'
 141       )
 142     }
 143     if (typeof name === 'string' && name.trim().length === 0) {
 144       throw new TypeError(
 145         'A taskFunctions parameter object key is an empty string'
 146       )
 147     }
 148     if (typeof fn !== 'function') {
 149       throw new TypeError(
 150         'A taskFunctions parameter object value is not a function'
 151       )
 152     }
 153   }
 154
 155   /**
 156    * Checks if the `taskFunctions` parameter is passed to the constructor and valid.
 157    *
 158    * @param taskFunctions - The task function(s) parameter that should be checked.
 159    */
 160   private checkTaskFunctions (
 161     taskFunctions: TaskFunction<Data, Response> | TaskFunctions<Data, Response>
 162   ): void {
 163     if (taskFunctions == null) {
 164       throw new Error('taskFunctions parameter is mandatory')
 165     }
 166     this.taskFunctions = new Map<string, TaskFunction<Data, Response>>()
 167     if (typeof taskFunctions === 'function') {
 168       const boundFn = taskFunctions.bind(this)
 169       this.taskFunctions.set(DEFAULT_TASK_NAME, boundFn)
 170       this.taskFunctions.set(
 171         typeof taskFunctions.name === 'string' &&
 172         taskFunctions.name.trim().length > 0
 173           ? taskFunctions.name
 174           : 'fn1',
 175         boundFn
 176       )
 177     } else if (isPlainObject(taskFunctions)) {
 178       let firstEntry = true
 179       for (const [name, fn] of Object.entries(taskFunctions)) {
 180         this.checkValidTaskFunctionEntry(name, fn)
 181         const boundFn = fn.bind(this)
 182         if (firstEntry) {
 183           this.taskFunctions.set(DEFAULT_TASK_NAME, boundFn)
 184           firstEntry = false
 185         }
 186         this.taskFunctions.set(name, boundFn)
 187       }
 188       if (firstEntry) {
 189         throw new Error('taskFunctions parameter object is empty')
 190       }
 191     } else {
 192       throw new TypeError(
 193         'taskFunctions parameter is not a function or a plain object'
 194       )
 195     }
 196   }
 197
 198   /**
 199    * Checks if the worker has a task function with the given name.
 200    *
 201    * @param name - The name of the task function to check.
 202    * @returns Whether the worker has a task function with the given name or not.
 203    */
 204   public hasTaskFunction (name: string): TaskFunctionOperationReturnType {
 205     try {
 206       this.checkTaskFunctionName(name)
 207     } catch (error) {
 208       return { status: false, error: error as Error }
 209     }
 210     return { status: this.taskFunctions.has(name) }
 211   }
 212
 213   /**
 214    * Adds a task function to the worker.
 215    * If a task function with the same name already exists, it is replaced.
 216    *
 217    * @param name - The name of the task function to add.
 218    * @param fn - The task function to add.
 219    * @returns Whether the task function was added or not.
 220    */
 221   public addTaskFunction (
 222     name: string,
 223     fn: TaskFunction<Data, Response>
 224   ): TaskFunctionOperationReturnType {
 225     try {
 226       this.checkTaskFunctionName(name)
 227       if (name === DEFAULT_TASK_NAME) {
 228         throw new Error(
 229           'Cannot add a task function with the default reserved name'
 230         )
 231       }
 232       if (typeof fn !== 'function') {
 233         throw new TypeError('fn parameter is not a function')
 234       }
 235       const boundFn = fn.bind(this)
 236       if (
 237         this.taskFunctions.get(name) ===
 238         this.taskFunctions.get(DEFAULT_TASK_NAME)
 239       ) {
 240         this.taskFunctions.set(DEFAULT_TASK_NAME, boundFn)
 241       }
 242       this.taskFunctions.set(name, boundFn)
 243       this.sendTaskFunctionNamesToMainWorker()
 244       return { status: true }
 245     } catch (error) {
 246       return { status: false, error: error as Error }
 247     }
 248   }
 249
 250   /**
 251    * Removes a task function from the worker.
 252    *
 253    * @param name - The name of the task function to remove.
 254    * @returns Whether the task function existed and was removed or not.
 255    */
 256   public removeTaskFunction (name: string): TaskFunctionOperationReturnType {
 257     try {
 258       this.checkTaskFunctionName(name)
 259       if (name === DEFAULT_TASK_NAME) {
 260         throw new Error(
 261           'Cannot remove the task function with the default reserved name'
 262         )
 263       }
 264       if (
 265         this.taskFunctions.get(name) ===
 266         this.taskFunctions.get(DEFAULT_TASK_NAME)
 267       ) {
 268         throw new Error(
 269           'Cannot remove the task function used as the default task function'
 270         )
 271       }
 272       const deleteStatus = this.taskFunctions.delete(name)
 273       this.sendTaskFunctionNamesToMainWorker()
 274       return { status: deleteStatus }
 275     } catch (error) {
 276       return { status: false, error: error as Error }
 277     }
 278   }
 279
 280   /**
 281    * Lists the names of the worker's task functions.
 282    *
 283    * @returns The names of the worker's task functions.
 284    */
 285   public listTaskFunctionNames (): string[] {
 286     const names: string[] = [...this.taskFunctions.keys()]
 287     let defaultTaskFunctionName: string = DEFAULT_TASK_NAME
 288     for (const [name, fn] of this.taskFunctions) {
 289       if (
 290         name !== DEFAULT_TASK_NAME &&
 291         fn === this.taskFunctions.get(DEFAULT_TASK_NAME)
 292       ) {
 293         defaultTaskFunctionName = name
 294         break
 295       }
 296     }
 297     return [
 298       names[names.indexOf(DEFAULT_TASK_NAME)],
 299       defaultTaskFunctionName,
 300       ...names.filter(
 301         name => name !== DEFAULT_TASK_NAME && name !== defaultTaskFunctionName
 302       )
 303     ]
 304   }
 305
 306   /**
 307    * Sets the default task function to use in the worker.
 308    *
 309    * @param name - The name of the task function to use as default task function.
 310    * @returns Whether the default task function was set or not.
 311    */
 312   public setDefaultTaskFunction (name: string): TaskFunctionOperationReturnType {
 313     try {
 314       this.checkTaskFunctionName(name)
 315       if (name === DEFAULT_TASK_NAME) {
 316         throw new Error(
 317           'Cannot set the default task function reserved name as the default task function'
 318         )
 319       }
 320       if (!this.taskFunctions.has(name)) {
 321         throw new Error(
 322           'Cannot set the default task function to a non-existing task function'
 323         )
 324       }
 325       this.taskFunctions.set(
 326         DEFAULT_TASK_NAME,
 327         this.taskFunctions.get(name) as TaskFunction<Data, Response>
 328       )
 329       return { status: true }
 330     } catch (error) {
 331       return { status: false, error: error as Error }
 332     }
 333   }
 334
 335   private checkTaskFunctionName (name: string): void {
 336     if (typeof name !== 'string') {
 337       throw new TypeError('name parameter is not a string')
 338     }
 339     if (typeof name === 'string' && name.trim().length === 0) {
 340       throw new TypeError('name parameter is an empty string')
 341     }
 342   }
 343
 344   /**
 345    * Handles the ready message sent by the main worker.
 346    *
 347    * @param message - The ready message.
 348    */
 349   protected abstract handleReadyMessage (message: MessageValue<Data>): void
 350
 351   /**
 352    * Worker message listener.
 353    *
 354    * @param message - The received message.
 355    */
 356   protected messageListener (message: MessageValue<Data>): void {
 357     this.checkMessageWorkerId(message)
 358     if (message.statistics != null) {
 359       // Statistics message received
 360       this.statistics = message.statistics
 361     } else if (message.checkActive != null) {
 362       // Check active message received
 363       message.checkActive ? this.startCheckActive() : this.stopCheckActive()
 364     } else if (message.taskFunctionOperation != null) {
 365       // Task function operation message received
 366       this.handleTaskFunctionOperationMessage(message)
 367     } else if (message.taskId != null && message.data != null) {
 368       // Task message received
 369       this.run(message)
 370     } else if (message.kill === true) {
 371       // Kill message received
 372       this.handleKillMessage(message)
 373     }
 374   }
 375
 376   protected handleTaskFunctionOperationMessage (
 377     message: MessageValue<Data>
 378   ): void {
 379     const { taskFunctionOperation, taskFunction, taskFunctionName } = message
 380     let response!: TaskFunctionOperationReturnType
 381     if (taskFunctionOperation === 'add') {
 382       response = this.addTaskFunction(
 383         taskFunctionName as string,
 384         // eslint-disable-next-line @typescript-eslint/no-implied-eval, no-new-func
 385         new Function(`return ${taskFunction as string}`)() as TaskFunction<
 386         Data,
 387         Response
 388         >
 389       )
 390     } else if (taskFunctionOperation === 'remove') {
 391       response = this.removeTaskFunction(taskFunctionName as string)
 392     } else if (taskFunctionOperation === 'default') {
 393       response = this.setDefaultTaskFunction(taskFunctionName as string)
 394     }
 395     this.sendToMainWorker({
 396       taskFunctionOperation,
 397       taskFunctionOperationStatus: response.status,
 398       workerError: {
 399         name: taskFunctionName as string,
 400         message: this.handleError(response.error as Error | string)
 401       }
 402     })
 403   }
 404
 405   /**
 406    * Handles a kill message sent by the main worker.
 407    *
 408    * @param message - The kill message.
 409    */
 410   protected handleKillMessage (message: MessageValue<Data>): void {
 411     this.stopCheckActive()
 412     if (isAsyncFunction(this.opts.killHandler)) {
 413       (this.opts.killHandler?.() as Promise<void>)
 414         .then(() => {
 415           this.sendToMainWorker({ kill: 'success' })
 416           return null
 417         })
 418         .catch(() => {
 419           this.sendToMainWorker({ kill: 'failure' })
 420         })
 421         .finally(() => {
 422           this.emitDestroy()
 423         })
 424         .catch(EMPTY_FUNCTION)
 425     } else {
 426       try {
 427         // eslint-disable-next-line @typescript-eslint/no-invalid-void-type
 428         this.opts.killHandler?.() as void
 429         this.sendToMainWorker({ kill: 'success' })
 430       } catch {
 431         this.sendToMainWorker({ kill: 'failure' })
 432       } finally {
 433         this.emitDestroy()
 434       }
 435     }
 436   }
 437
 438   /**
 439    * Check if the message worker id is set and matches the worker id.
 440    *
 441    * @param message - The message to check.
 442    * @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.
 443    */
 444   private checkMessageWorkerId (message: MessageValue<Data>): void {
 445     if (message.workerId == null) {
 446       throw new Error('Message worker id is not set')
 447     } else if (message.workerId != null && message.workerId !== this.id) {
 448       throw new Error(
 449         `Message worker id ${message.workerId} does not match the worker id ${this.id}`
 450       )
 451     }
 452   }
 453
 454   /**
 455    * Starts the worker check active interval.
 456    */
 457   private startCheckActive (): void {
 458     this.lastTaskTimestamp = performance.now()
 459     this.activeInterval = setInterval(
 460       this.checkActive.bind(this),
 461       (this.opts.maxInactiveTime ?? DEFAULT_MAX_INACTIVE_TIME) / 2
 462     )
 463   }
 464
 465   /**
 466    * Stops the worker check active interval.
 467    */
 468   private stopCheckActive (): void {
 469     if (this.activeInterval != null) {
 470       clearInterval(this.activeInterval)
 471       delete this.activeInterval
 472     }
 473   }
 474
 475   /**
 476    * Checks if the worker should be terminated, because its living too long.
 477    */
 478   private checkActive (): void {
 479     if (
 480       performance.now() - this.lastTaskTimestamp >
 481       (this.opts.maxInactiveTime ?? DEFAULT_MAX_INACTIVE_TIME)
 482     ) {
 483       this.sendToMainWorker({ kill: this.opts.killBehavior })
 484     }
 485   }
 486
 487   /**
 488    * Returns the main worker.
 489    *
 490    * @returns Reference to the main worker.
 491    * @throws {@link https://nodejs.org/api/errors.html#class-error} If the main worker is not set.
 492    */
 493   protected getMainWorker (): MainWorker {
 494     if (this.mainWorker == null) {
 495       throw new Error('Main worker not set')
 496     }
 497     return this.mainWorker
 498   }
 499
 500   /**
 501    * Sends a message to main worker.
 502    *
 503    * @param message - The response message.
 504    */
 505   protected abstract sendToMainWorker (
 506     message: MessageValue<Response, Data>
 507   ): void
 508
 509   /**
 510    * Sends task function names to the main worker.
 511    */
 512   protected sendTaskFunctionNamesToMainWorker (): void {
 513     this.sendToMainWorker({
 514       taskFunctionNames: this.listTaskFunctionNames()
 515     })
 516   }
 517
 518   /**
 519    * Handles an error and convert it to a string so it can be sent back to the main worker.
 520    *
 521    * @param error - The error raised by the worker.
 522    * @returns The error message.
 523    */
 524   protected handleError (error: Error | string): string {
 525     return error instanceof Error ? error.message : error
 526   }
 527
 528   /**
 529    * Runs the given task.
 530    *
 531    * @param task - The task to execute.
 532    * @throws {@link https://nodejs.org/api/errors.html#class-error} If the task function is not found.
 533    */
 534   protected run (task: Task<Data>): void {
 535     const { name, taskId, data } = task
 536     const fn = this.taskFunctions.get(name ?? DEFAULT_TASK_NAME)
 537     if (fn == null) {
 538       this.sendToMainWorker({
 539         workerError: {
 540           name: name as string,
 541           message: `Task function '${name as string}' not found`,
 542           data
 543         },
 544         taskId
 545       })
 546       return
 547     }
 548     if (isAsyncFunction(fn)) {
 549       this.runInAsyncScope(this.runAsync.bind(this), this, fn, task)
 550     } else {
 551       this.runInAsyncScope(this.runSync.bind(this), this, fn, task)
 552     }
 553   }
 554
 555   /**
 556    * Runs the given task function synchronously.
 557    *
 558    * @param fn - Task function that will be executed.
 559    * @param task - Input data for the task function.
 560    */
 561   protected runSync (
 562     fn: TaskSyncFunction<Data, Response>,
 563     task: Task<Data>
 564   ): void {
 565     const { name, taskId, data } = task
 566     try {
 567       let taskPerformance = this.beginTaskPerformance(name)
 568       const res = fn(data)
 569       taskPerformance = this.endTaskPerformance(taskPerformance)
 570       this.sendToMainWorker({
 571         data: res,
 572         taskPerformance,
 573         taskId
 574       })
 575     } catch (error) {
 576       this.sendToMainWorker({
 577         workerError: {
 578           name: name as string,
 579           message: this.handleError(error as Error | string),
 580           data
 581         },
 582         taskId
 583       })
 584     } finally {
 585       this.updateLastTaskTimestamp()
 586     }
 587   }
 588
 589   /**
 590    * Runs the given task function asynchronously.
 591    *
 592    * @param fn - Task function that will be executed.
 593    * @param task - Input data for the task function.
 594    */
 595   protected runAsync (
 596     fn: TaskAsyncFunction<Data, Response>,
 597     task: Task<Data>
 598   ): void {
 599     const { name, taskId, data } = task
 600     let taskPerformance = this.beginTaskPerformance(name)
 601     fn(data)
 602       .then(res => {
 603         taskPerformance = this.endTaskPerformance(taskPerformance)
 604         this.sendToMainWorker({
 605           data: res,
 606           taskPerformance,
 607           taskId
 608         })
 609         return null
 610       })
 611       .catch(error => {
 612         this.sendToMainWorker({
 613           workerError: {
 614             name: name as string,
 615             message: this.handleError(error as Error | string),
 616             data
 617           },
 618           taskId
 619         })
 620       })
 621       .finally(() => {
 622         this.updateLastTaskTimestamp()
 623       })
 624       .catch(EMPTY_FUNCTION)
 625   }
 626
 627   private beginTaskPerformance (name?: string): TaskPerformance {
 628     this.checkStatistics()
 629     return {
 630       name: name ?? DEFAULT_TASK_NAME,
 631       timestamp: performance.now(),
 632       ...(this.statistics.elu && { elu: performance.eventLoopUtilization() })
 633     }
 634   }
 635
 636   private endTaskPerformance (
 637     taskPerformance: TaskPerformance
 638   ): TaskPerformance {
 639     this.checkStatistics()
 640     return {
 641       ...taskPerformance,
 642       ...(this.statistics.runTime && {
 643         runTime: performance.now() - taskPerformance.timestamp
 644       }),
 645       ...(this.statistics.elu && {
 646         elu: performance.eventLoopUtilization(taskPerformance.elu)
 647       })
 648     }
 649   }
 650
 651   private checkStatistics (): void {
 652     if (this.statistics == null) {
 653       throw new Error('Performance statistics computation requirements not set')
 654     }
 655   }
 656
 657   private updateLastTaskTimestamp (): void {
 658     if (this.activeInterval != null) {
 659       this.lastTaskTimestamp = performance.now()
 660     }
 661   }
 662 }