src/worker/abstract-worker.ts

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