src/worker/abstract-worker.ts

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