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

   1 import type { IPoolInternal } from '../pool-internal'
   2 import { PoolType } from '../pool-internal'
   3 import type { IPoolWorker } from '../pool-worker'
   4 import { DynamicPoolWorkerChoiceStrategy } from './dynamic-pool-worker-choice-strategy'
   5 import type {
   6   IWorkerChoiceStrategy,
   7   RequiredStatistics,
   8   WorkerChoiceStrategy
   9 } from './selection-strategies-types'
  10 import { WorkerChoiceStrategies } from './selection-strategies-types'
  11 import { getWorkerChoiceStrategy } from './selection-strategies-utils'
  12
  13 /**
  14  * The worker choice strategy context.
  15  *
  16  * @typeParam Worker - Type of worker.
  17  * @typeParam Data - Type of data sent to the worker. This can only be serializable data.
  18  * @typeParam Response - Type of response of execution. This can only be serializable data.
  19  */
  20 export class WorkerChoiceStrategyContext<
  21   Worker extends IPoolWorker,
  22   Data,
  23   Response
  24 > {
  25   private workerChoiceStrategy!: IWorkerChoiceStrategy
  26
  27   /**
  28    * Worker choice strategy context constructor.
  29    *
  30    * @param pool - The pool instance.
  31    * @param createWorkerCallback - The worker creation callback for dynamic pool.
  32    * @param workerChoiceStrategy - The worker choice strategy.
  33    */
  34   public constructor (
  35     private readonly pool: IPoolInternal<Worker, Data, Response>,
  36     private readonly createWorkerCallback: () => number,
  37     workerChoiceStrategy: WorkerChoiceStrategy = WorkerChoiceStrategies.ROUND_ROBIN
  38   ) {
  39     this.setWorkerChoiceStrategy(workerChoiceStrategy)
  40   }
  41
  42   /**
  43    * Gets the worker choice strategy instance specific to the pool type.
  44    *
  45    * @param workerChoiceStrategy - The worker choice strategy.
  46    * @returns The worker choice strategy instance for the pool type.
  47    */
  48   private getPoolWorkerChoiceStrategy (
  49     workerChoiceStrategy: WorkerChoiceStrategy = WorkerChoiceStrategies.ROUND_ROBIN
  50   ): IWorkerChoiceStrategy {
  51     if (this.pool.type === PoolType.DYNAMIC) {
  52       return new DynamicPoolWorkerChoiceStrategy(
  53         this.pool,
  54         this.createWorkerCallback,
  55         workerChoiceStrategy
  56       )
  57     }
  58     return getWorkerChoiceStrategy(this.pool, workerChoiceStrategy)
  59   }
  60
  61   /**
  62    * Gets the worker choice strategy required statistics.
  63    *
  64    * @returns The required statistics.
  65    */
  66   public getRequiredStatistics (): RequiredStatistics {
  67     return this.workerChoiceStrategy.requiredStatistics
  68   }
  69
  70   /**
  71    * Sets the worker choice strategy to use in the context.
  72    *
  73    * @param workerChoiceStrategy - The worker choice strategy to set.
  74    */
  75   public setWorkerChoiceStrategy (
  76     workerChoiceStrategy: WorkerChoiceStrategy
  77   ): void {
  78     this.workerChoiceStrategy?.reset()
  79     this.workerChoiceStrategy =
  80       this.getPoolWorkerChoiceStrategy(workerChoiceStrategy)
  81   }
  82
  83   /**
  84    * Chooses a worker with the underlying selection strategy.
  85    *
  86    * @returns The key of the chosen one.
  87    */
  88   public execute (): number {
  89     return this.workerChoiceStrategy.choose()
  90   }
  91
  92   /**
  93    * Removes a worker in the underlying selection strategy internals.
  94    *
  95    * @param workerKey - The key of the worker to remove.
  96    * @returns `true` if the removal is successful, `false` otherwise.
  97    */
  98   public remove (workerKey: number): boolean {
  99     return this.workerChoiceStrategy.remove(workerKey)
 100   }
 101 }