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 > extends AbstractWorkerChoiceStrategy<Worker, Data, Response> {
  23   private readonly workerChoiceStrategy: IWorkerChoiceStrategy
  24
  25   /**
  26    * Constructs a worker choice strategy for dynamic pool.
  27    *
  28    * @param pool - The pool instance.
  29    * @param createWorkerCallback - The worker creation callback for dynamic pool.
  30    * @param workerChoiceStrategy - The worker choice strategy when the pool is busy.
  31    */
  32   public constructor (
  33     pool: IPoolInternal<Worker, Data, Response>,
  34     private readonly createWorkerCallback: () => number,
  35     workerChoiceStrategy: WorkerChoiceStrategy = WorkerChoiceStrategies.ROUND_ROBIN
  36   ) {
  37     super(pool)
  38     this.workerChoiceStrategy = getWorkerChoiceStrategy(
  39       this.pool,
  40       workerChoiceStrategy
  41     )
  42     this.requiredStatistics = this.workerChoiceStrategy.requiredStatistics
  43   }
  44
  45   /** {@inheritDoc} */
  46   public reset (): boolean {
  47     return this.workerChoiceStrategy.reset()
  48   }
  49
  50   /** {@inheritDoc} */
  51   public choose (): number {
  52     const freeWorkerKey = this.pool.findFreeWorkerKey()
  53     if (freeWorkerKey !== false) {
  54       return freeWorkerKey
  55     }
  56
  57     if (this.pool.busy) {
  58       return this.workerChoiceStrategy.choose()
  59     }
  60
  61     // All workers are busy, create a new worker
  62     return this.createWorkerCallback()
  63   }
  64
  65   /** {@inheritDoc} */
  66   public remove (workerKey: number): boolean {
  67     return this.workerChoiceStrategy.remove(workerKey)
  68   }
  69 }