src/worker/thread-worker.ts

   1 import {
   2   type MessagePort,
   3   isMainThread,
   4   parentPort,
   5   threadId
   6 } from 'node:worker_threads'
   7 import type { MessageValue } from '../utility-types'
   8 import { AbstractWorker } from './abstract-worker'
   9 import type { WorkerOptions } from './worker-options'
  10 import type { TaskFunctions, WorkerFunction } from './worker-functions'
  11
  12 /**
  13  * A thread worker used by a poolifier `ThreadPool`.
  14  *
  15  * When this worker is inactive for more than the given `maxInactiveTime`,
  16  * it will send a termination request to its main thread.
  17  *
  18  * If you use a `DynamicThreadPool` the extra workers that were created will be terminated,
  19  * but the minimum number of workers will be guaranteed.
  20  *
  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 thread.
  32    */
  33   private port!: MessagePort
  34   /**
  35    * Constructs a new poolifier thread worker.
  36    *
  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:
  42     | WorkerFunction<Data, Response>
  43     | TaskFunctions<Data, Response>,
  44     opts: WorkerOptions = {}
  45   ) {
  46     super(
  47       'worker-thread-pool:poolifier',
  48       isMainThread,
  49       parentPort as MessagePort,
  50       taskFunctions,
  51       opts
  52     )
  53   }
  54
  55   /** @inheritDoc */
  56   protected handleReadyMessage (message: MessageValue<Data>): void {
  57     if (
  58       message.workerId === this.id &&
  59       message.ready != null &&
  60       message.port != null
  61     ) {
  62       if (!this.isMain) {
  63         this.port = message.port
  64         this.port.on('message', this.messageListener.bind(this))
  65         this.sendToMainWorker({ ready: true, workerId: this.id })
  66       }
  67     }
  68   }
  69
  70   /** @inheritDoc */
  71   protected get id (): number {
  72     return threadId
  73   }
  74
  75   /** @inheritDoc */
  76   protected sendToMainWorker (message: MessageValue<Response>): void {
  77     this.port.postMessage(message)
  78   }
  79
  80   /** @inheritDoc */
  81   protected handleError (e: Error | string): string {
  82     return e as string
  83   }
  84 }