src/pools/selection-strategies/dynamic-pool-worker-choice-strategy.ts

   1 import type { IPoolInternal } from '../pool-internal'
   2 import type { IPoolWorker } from '../pool-worker'
   3 import { AbstractWorkerChoiceStrategy } from './abstract-worker-choice-strategy'
   4 import type {
   5   IWorkerChoiceStrategy,
   6   WorkerChoiceStrategy
   7 } from './selection-strategies-types'
   8 import { WorkerChoiceStrategies } from './selection-strategies-types'
   9 import { getWorkerChoiceStrategy } from './selection-strategies-utils'
  10
  11 /**
  12  * Selects the next worker for dynamic pool.
  13  *
  14  * @typeParam Worker - Type of worker which manages the strategy.
  15  * @typeParam Data - Type of data sent to the worker. This can only be serializable data.
  16  * @typeParam Response - Type of response of execution. This can only be serializable data.
  17  */
  18 export class DynamicPoolWorkerChoiceStrategy<
  19     Worker extends IPoolWorker,
  20     Data,
  21     Response
  22   >
  23   extends AbstractWorkerChoiceStrategy<Worker, Data, Response>
  24   implements IWorkerChoiceStrategy {
  25   private readonly workerChoiceStrategy: IWorkerChoiceStrategy
  26
  27   /**
  28    * Constructs a worker choice strategy for dynamic pool.
  29    *
  30    * @param pool - The pool instance.
  31    * @param createWorkerCallback - The worker creation callback for dynamic pool.
  32    * @param workerChoiceStrategy - The worker choice strategy when the pool is busy.
  33    */
  34   public constructor (
  35     pool: IPoolInternal<Worker, Data, Response>,
  36     private readonly createWorkerCallback: () => number,
  37     workerChoiceStrategy: WorkerChoiceStrategy = WorkerChoiceStrategies.ROUND_ROBIN
  38   ) {
  39     super(pool)
  40     this.workerChoiceStrategy = getWorkerChoiceStrategy(
  41       this.pool,
  42       workerChoiceStrategy
  43     )
  44     this.requiredStatistics = this.workerChoiceStrategy.requiredStatistics
  45   }
  46
  47   /** {@inheritDoc} */
  48   public reset (): boolean {
  49     return this.workerChoiceStrategy.reset()
  50   }
  51
  52   /** {@inheritDoc} */
  53   public choose (): number {
  54     if (this.pool.busy) {
  55       return this.workerChoiceStrategy.choose()
  56     }
  57     const freeWorkerKey = this.pool.findFreeWorkerKey()
  58     if (freeWorkerKey === -1) {
  59       return this.createWorkerCallback()
  60     }
  61     return this.workerChoiceStrategy.choose()
  62   }
  63
  64   /** {@inheritDoc} */
  65   public remove (workerKey: number): boolean {
  66     return this.workerChoiceStrategy.remove(workerKey)
  67   }
  68 }