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     const {
 328       statistics,
 329       checkActive,
 330       taskFunctionOperation,
 331       taskId,
 332       data,
 333       kill
 334     } = message
 335     if (statistics != null) {
 336       // Statistics message received
 337       this.statistics = statistics
 338     } else if (checkActive != null) {
 339       // Check active message received
 340       checkActive ? this.startCheckActive() : this.stopCheckActive()
 341     } else if (taskFunctionOperation != null) {
 342       // Task function operation message received
 343       this.handleTaskFunctionOperationMessage(message)
 344     } else if (taskId != null && data != null) {
 345       // Task message received
 346       this.run(message)
 347     } else if (kill === true) {
 348       // Kill message received
 349       this.handleKillMessage(message)
 350     }
 351   }
 352
 353   protected handleTaskFunctionOperationMessage (
 354     message: MessageValue<Data>
 355   ): void {
 356     const { taskFunctionOperation, taskFunctionProperties, taskFunction } =
 357       message
 358     if (taskFunctionProperties == null) {
 359       throw new Error(
 360         'Cannot handle task function operation message without task function properties'
 361       )
 362     }
 363     let response: TaskFunctionOperationResult
 364     switch (taskFunctionOperation) {
 365       case 'add':
 366         response = this.addTaskFunction(taskFunctionProperties.name, {
 367           // eslint-disable-next-line @typescript-eslint/no-implied-eval, no-new-func
 368           taskFunction: new Function(
 369             `return ${taskFunction}`
 370           )() as TaskFunction<Data, Response>,
 371           ...(taskFunctionProperties.priority != null && {
 372             priority: taskFunctionProperties.priority
 373           }),
 374           ...(taskFunctionProperties.strategy != null && {
 375             strategy: taskFunctionProperties.strategy
 376           })
 377         })
 378         break
 379       case 'remove':
 380         response = this.removeTaskFunction(taskFunctionProperties.name)
 381         break
 382       case 'default':
 383         response = this.setDefaultTaskFunction(taskFunctionProperties.name)
 384         break
 385       default:
 386         response = { status: false, error: new Error('Unknown task operation') }
 387         break
 388     }
 389     this.sendToMainWorker({
 390       taskFunctionOperation,
 391       taskFunctionOperationStatus: response.status,
 392       taskFunctionProperties,
 393       ...(!response.status &&
 394         response.error != null && {
 395         workerError: {
 396           name: taskFunctionProperties.name,
 397           message: this.handleError(response.error as Error | string)
 398         }
 399       })
 400     })
 401   }
 402
 403   /**
 404    * Handles a kill message sent by the main worker.
 405    *
 406    * @param message - The kill message.
 407    */
 408   protected handleKillMessage (_message: MessageValue<Data>): void {
 409     this.stopCheckActive()
 410     if (isAsyncFunction(this.opts.killHandler)) {
 411       (this.opts.killHandler() as Promise<void>)
 412         .then(() => {
 413           this.sendToMainWorker({ kill: 'success' })
 414           return undefined
 415         })
 416         .catch(() => {
 417           this.sendToMainWorker({ kill: 'failure' })
 418         })
 419     } else {
 420       try {
 421         // eslint-disable-next-line @typescript-eslint/no-invalid-void-type
 422         this.opts.killHandler?.() as void
 423         this.sendToMainWorker({ kill: 'success' })
 424       } catch {
 425         this.sendToMainWorker({ kill: 'failure' })
 426       }
 427     }
 428   }
 429
 430   /**
 431    * Check if the message worker id is set and matches the worker id.
 432    *
 433    * @param message - The message to check.
 434    * @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.
 435    */
 436   private checkMessageWorkerId (message: MessageValue<Data>): void {
 437     if (message.workerId == null) {
 438       throw new Error('Message worker id is not set')
 439     } else if (message.workerId !== this.id) {
 440       throw new Error(
 441         `Message worker id ${message.workerId} does not match the worker id ${this.id}`
 442       )
 443     }
 444   }
 445
 446   /**
 447    * Starts the worker check active interval.
 448    */
 449   private startCheckActive (): void {
 450     this.lastTaskTimestamp = performance.now()
 451     this.activeInterval = setInterval(
 452       this.checkActive.bind(this),
 453       (this.opts.maxInactiveTime ?? DEFAULT_MAX_INACTIVE_TIME) / 2
 454     )
 455   }
 456
 457   /**
 458    * Stops the worker check active interval.
 459    */
 460   private stopCheckActive (): void {
 461     if (this.activeInterval != null) {
 462       clearInterval(this.activeInterval)
 463       delete this.activeInterval
 464     }
 465   }
 466
 467   /**
 468    * Checks if the worker should be terminated, because its living too long.
 469    */
 470   private checkActive (): void {
 471     if (
 472       performance.now() - this.lastTaskTimestamp >
 473       (this.opts.maxInactiveTime ?? DEFAULT_MAX_INACTIVE_TIME)
 474     ) {
 475       this.sendToMainWorker({ kill: this.opts.killBehavior })
 476     }
 477   }
 478
 479   /**
 480    * Returns the main worker.
 481    *
 482    * @returns Reference to the main worker.
 483    * @throws {@link https://nodejs.org/api/errors.html#class-error} If the main worker is not set.
 484    */
 485   protected getMainWorker (): MainWorker {
 486     if (this.mainWorker == null) {
 487       throw new Error('Main worker not set')
 488     }
 489     return this.mainWorker
 490   }
 491
 492   /**
 493    * Sends a message to main worker.
 494    *
 495    * @param message - The response message.
 496    */
 497   protected abstract sendToMainWorker (
 498     message: MessageValue<Response, Data>
 499   ): void
 500
 501   /**
 502    * Sends task functions properties to the main worker.
 503    */
 504   protected sendTaskFunctionsPropertiesToMainWorker (): void {
 505     this.sendToMainWorker({
 506       taskFunctionsProperties: this.listTaskFunctionsProperties()
 507     })
 508   }
 509
 510   /**
 511    * Handles an error and convert it to a string so it can be sent back to the main worker.
 512    *
 513    * @param error - The error raised by the worker.
 514    * @returns The error message.
 515    */
 516   protected handleError (error: Error | string): string {
 517     return error instanceof Error ? error.message : error
 518   }
 519
 520   /**
 521    * Runs the given task.
 522    *
 523    * @param task - The task to execute.
 524    */
 525   protected readonly run = (task: Task<Data>): void => {
 526     const { name, taskId, data } = task
 527     const taskFunctionName = name ?? DEFAULT_TASK_NAME
 528     if (!this.taskFunctions.has(taskFunctionName)) {
 529       this.sendToMainWorker({
 530         workerError: {
 531           // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
 532           name: name!,
 533           message: `Task function '${name}' not found`,
 534           data
 535         },
 536         taskId
 537       })
 538       return
 539     }
 540     const fn = this.taskFunctions.get(taskFunctionName)?.taskFunction
 541     if (isAsyncFunction(fn)) {
 542       this.runAsync(fn as TaskAsyncFunction<Data, Response>, task)
 543     } else {
 544       this.runSync(fn as TaskSyncFunction<Data, Response>, task)
 545     }
 546   }
 547
 548   /**
 549    * Runs the given task function synchronously.
 550    *
 551    * @param fn - Task function that will be executed.
 552    * @param task - Input data for the task function.
 553    */
 554   protected readonly runSync = (
 555     fn: TaskSyncFunction<Data, Response>,
 556     task: Task<Data>
 557   ): void => {
 558     const { name, taskId, data } = task
 559     try {
 560       let taskPerformance = this.beginTaskPerformance(name)
 561       const res = fn(data)
 562       taskPerformance = this.endTaskPerformance(taskPerformance)
 563       this.sendToMainWorker({
 564         data: res,
 565         taskPerformance,
 566         taskId
 567       })
 568     } catch (error) {
 569       this.sendToMainWorker({
 570         workerError: {
 571           // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
 572           name: name!,
 573           message: this.handleError(error as Error | string),
 574           data
 575         },
 576         taskId
 577       })
 578     } finally {
 579       this.updateLastTaskTimestamp()
 580     }
 581   }
 582
 583   /**
 584    * Runs the given task function asynchronously.
 585    *
 586    * @param fn - Task function that will be executed.
 587    * @param task - Input data for the task function.
 588    */
 589   protected readonly runAsync = (
 590     fn: TaskAsyncFunction<Data, Response>,
 591     task: Task<Data>
 592   ): void => {
 593     const { name, taskId, data } = task
 594     let taskPerformance = this.beginTaskPerformance(name)
 595     fn(data)
 596       .then(res => {
 597         taskPerformance = this.endTaskPerformance(taskPerformance)
 598         this.sendToMainWorker({
 599           data: res,
 600           taskPerformance,
 601           taskId
 602         })
 603         return undefined
 604       })
 605       .catch((error: unknown) => {
 606         this.sendToMainWorker({
 607           workerError: {
 608             // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
 609             name: name!,
 610             message: this.handleError(error as Error | string),
 611             data
 612           },
 613           taskId
 614         })
 615       })
 616       .finally(() => {
 617         this.updateLastTaskTimestamp()
 618       })
 619       .catch(EMPTY_FUNCTION)
 620   }
 621
 622   private beginTaskPerformance (name?: string): TaskPerformance {
 623     if (this.statistics == null) {
 624       throw new Error('Performance statistics computation requirements not set')
 625     }
 626     return {
 627       name: name ?? DEFAULT_TASK_NAME,
 628       timestamp: performance.now(),
 629       ...(this.statistics.elu && {
 630         elu: performance.eventLoopUtilization()
 631       })
 632     }
 633   }
 634
 635   private endTaskPerformance (
 636     taskPerformance: TaskPerformance
 637   ): TaskPerformance {
 638     if (this.statistics == null) {
 639       throw new Error('Performance statistics computation requirements not set')
 640     }
 641     return {
 642       ...taskPerformance,
 643       ...(this.statistics.runTime && {
 644         runTime: performance.now() - taskPerformance.timestamp
 645       }),
 646       ...(this.statistics.elu && {
 647         elu: performance.eventLoopUtilization(taskPerformance.elu)
 648       })
 649     }
 650   }
 651
 652   private updateLastTaskTimestamp (): void {
 653     if (this.activeInterval != null) {
 654       this.lastTaskTimestamp = performance.now()
 655     }
 656   }
 657 }