src/worker/thread-worker.ts

   1 import {
   2   isMainThread,
   3   type MessagePort,
   4   parentPort,
   5   threadId,
   6 } from 'node:worker_threads'
   7
   8 import type { MessageValue } from '../utility-types.js'
   9 import { AbstractWorker } from './abstract-worker.js'
  10 import type { TaskFunction, TaskFunctions } from './task-functions.js'
  11 import type { WorkerOptions } from './worker-options.js'
  12
  13 /**
  14  * A thread worker used by a poolifier `ThreadPool`.
  15  *
  16  * When this worker is inactive for more than the given `maxInactiveTime`,
  17  * it will send a termination request to its main thread.
  18  *
  19  * If you use a `DynamicThreadPool` the extra workers that were created will be terminated,
  20  * but the minimum number of workers will be guaranteed.
  21  * @typeParam Data - Type of data this worker receives from pool's execution. This can only be structured-cloneable data.
  22  * @typeParam Response - Type of response the worker sends back to the main thread. This can only be structured-cloneable data.
  23  * @author [Alessandro Pio Ardizio](https://github.com/pioardi)
  24  * @since 0.0.1
  25  */
  26 export class ThreadWorker<
  27   Data = unknown,
  28   Response = unknown
  29 > extends AbstractWorker<MessagePort, Data, Response> {
  30   /**
  31    * Message port used to communicate with the main worker.
  32    */
  33   private port?: MessagePort
  34
  35   /**
  36    * Constructs a new poolifier thread worker.
  37    * @param taskFunctions - Task function(s) processed by the worker when the pool's `execution` function is invoked.
  38    * @param opts - Options for the worker.
  39    */
  40   public constructor (
  41     taskFunctions: TaskFunction<Data, Response> | TaskFunctions<Data, Response>,
  42     opts: WorkerOptions = {}
  43   ) {
  44     super(isMainThread, parentPort, taskFunctions, opts)
  45   }
  46
  47   /** @inheritDoc */
  48   protected handleReadyMessage (message: MessageValue<Data>): void {
  49     if (
  50       message.workerId === this.id &&
  51       message.ready === false &&
  52       message.port != null
  53     ) {
  54       try {
  55         this.port = message.port
  56         this.port.on('message', this.messageListener.bind(this))
  57         this.sendToMainWorker({
  58           ready: true,
  59           taskFunctionsProperties: this.listTaskFunctionsProperties(),
  60         })
  61       } catch {
  62         this.sendToMainWorker({
  63           ready: false,
  64           taskFunctionsProperties: this.listTaskFunctionsProperties(),
  65         })
  66       }
  67     }
  68   }
  69
  70   /** @inheritDoc */
  71   protected handleKillMessage (message: MessageValue<Data>): void {
  72     super.handleKillMessage(message)
  73     this.port?.unref()
  74     this.port?.close()
  75   }
  76
  77   /** @inheritDoc */
  78   protected get id (): number {
  79     return threadId
  80   }
  81
  82   /** @inheritDoc */
  83   protected readonly sendToMainWorker = (
  84     message: MessageValue<Response>
  85   ): void => {
  86     this.port?.postMessage({
  87       ...message,
  88       workerId: this.id,
  89     } satisfies MessageValue<Response>)
  90   }
  91
  92   /**
  93    * @inheritDoc
  94    */
  95   protected handleError (error: Error | string): string {
  96     return error as string
  97   }
  98 }