src/pools/thread/dynamic.ts

   1 import { PoolEvents, type PoolType, PoolTypes } from '../pool.js'
   2 import { checkDynamicPoolSize } from '../utils.js'
   3 import { FixedThreadPool, type ThreadPoolOptions } from './fixed.js'
   4
   5 /**
   6  * A thread pool with a dynamic number of threads, but a guaranteed minimum number of threads.
   7  *
   8  * This thread pool creates new threads when the others are busy, up to the maximum number of threads.
   9  * When the maximum number of threads is reached and workers are busy, an event is emitted. If you want to listen to this event, use the pool's `emitter`.
  10  *
  11  * @typeParam Data - Type of data sent to the worker. This can only be structured-cloneable data.
  12  * @typeParam Response - Type of execution response. This can only be structured-cloneable data.
  13  * @author [Alessandro Pio Ardizio](https://github.com/pioardi)
  14  * @since 0.0.1
  15  */
  16 export class DynamicThreadPool<
  17   Data = unknown,
  18   Response = unknown
  19 > extends FixedThreadPool<Data, Response> {
  20   /**
  21    * Constructs a new poolifier dynamic thread pool.
  22    *
  23    * @param min - Minimum number of threads which are always active.
  24    * @param max - Maximum number of threads that can be created by this pool.
  25    * @param filePath - Path to an implementation of a `ThreadWorker` file, which can be relative or absolute.
  26    * @param opts - Options for this dynamic thread pool.
  27    */
  28   public constructor (
  29     min: number,
  30     max: number,
  31     filePath: string,
  32     opts: ThreadPoolOptions = {}
  33   ) {
  34     super(min, filePath, opts, max)
  35     checkDynamicPoolSize(
  36       this.minimumNumberOfWorkers,
  37       this.maximumNumberOfWorkers
  38     )
  39   }
  40
  41   /** @inheritDoc */
  42   protected shallCreateDynamicWorker (): boolean {
  43     return (
  44       (!this.full && this.internalBusy()) ||
  45       (this.minimumNumberOfWorkers === 0 && this.workerNodes.length === 0)
  46     )
  47   }
  48
  49   /** @inheritDoc */
  50   protected checkAndEmitDynamicWorkerCreationEvents (): void {
  51     if (this.full) {
  52       this.emitter?.emit(PoolEvents.full, this.info)
  53     }
  54   }
  55
  56   /** @inheritDoc */
  57   protected get type (): PoolType {
  58     return PoolTypes.dynamic
  59   }
  60
  61   /** @inheritDoc */
  62   protected get busy (): boolean {
  63     return this.full && this.internalBusy()
  64   }
  65 }