src/pools/selection-strategies/worker-choice-strategy-context.ts

   1 import type { IPoolInternal } from '../pool-internal'
   2 import type { IPoolWorker } from '../pool-worker'
   3 import type {
   4   IWorkerChoiceStrategy,
   5   RequiredStatistics,
   6   WorkerChoiceStrategy
   7 } from './selection-strategies-types'
   8 import { WorkerChoiceStrategies } from './selection-strategies-types'
   9 import { getWorkerChoiceStrategy } from './selection-strategies-utils'
  10
  11 /**
  12  * The worker choice strategy context.
  13  *
  14  * @typeParam Worker - Type of worker.
  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 WorkerChoiceStrategyContext<
  19   Worker extends IPoolWorker,
  20   Data,
  21   Response
  22 > {
  23   private workerChoiceStrategy: IWorkerChoiceStrategy<Worker, Data, Response>
  24
  25   /**
  26    * Worker choice strategy context constructor.
  27    *
  28    * @param pool - The pool instance.
  29    * @param createWorkerCallback - The worker creation callback for dynamic pool.
  30    * @param workerChoiceStrategy - The worker choice strategy.
  31    */
  32   public constructor (
  33     pool: IPoolInternal<Worker, Data, Response>,
  34     private readonly createWorkerCallback: () => number,
  35     workerChoiceStrategy: WorkerChoiceStrategy = WorkerChoiceStrategies.ROUND_ROBIN
  36   ) {
  37     this.execute.bind(this)
  38     this.workerChoiceStrategy = getWorkerChoiceStrategy<Worker, Data, Response>(
  39       pool,
  40       workerChoiceStrategy
  41     )
  42   }
  43
  44   /**
  45    * Gets the worker choice strategy required statistics.
  46    *
  47    * @returns The required statistics.
  48    */
  49   public getRequiredStatistics (): RequiredStatistics {
  50     return this.workerChoiceStrategy.requiredStatistics
  51   }
  52
  53   /**
  54    * Sets the worker choice strategy to use in the context.
  55    *
  56    * @param workerChoiceStrategy - The worker choice strategy to set.
  57    */
  58   public setWorkerChoiceStrategy (
  59     pool: IPoolInternal<Worker, Data, Response>,
  60     workerChoiceStrategy: WorkerChoiceStrategy
  61   ): void {
  62     this.workerChoiceStrategy?.reset()
  63     this.workerChoiceStrategy = getWorkerChoiceStrategy<Worker, Data, Response>(
  64       pool,
  65       workerChoiceStrategy
  66     )
  67   }
  68
  69   /**
  70    * Chooses a worker with the worker choice strategy.
  71    *
  72    * @returns The key of the chosen one.
  73    */
  74   public execute (): number {
  75     if (
  76       this.workerChoiceStrategy.isDynamicPool &&
  77       !this.workerChoiceStrategy.pool.full &&
  78       this.workerChoiceStrategy.pool.findFreeWorkerKey() === -1
  79     ) {
  80       return this.createWorkerCallback()
  81     }
  82     return this.workerChoiceStrategy.choose()
  83   }
  84
  85   /**
  86    * Removes a worker in the worker choice strategy internals.
  87    *
  88    * @param workerKey - The key of the worker to remove.
  89    * @returns `true` if the removal is successful, `false` otherwise.
  90    */
  91   public remove (workerKey: number): boolean {
  92     return this.workerChoiceStrategy.remove(workerKey)
  93   }
  94 }