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.execute.bind(this)
  40     this.setWorkerChoiceStrategy(workerChoiceStrategy)
  41   }
  42
  43   /**
  44    * Gets the worker choice strategy instance specific to the pool type.
  45    *
  46    * @param workerChoiceStrategy - The worker choice strategy.
  47    * @returns The worker choice strategy instance for the pool type.
  48    */
  49   private getPoolWorkerChoiceStrategy (
  50     workerChoiceStrategy: WorkerChoiceStrategy = WorkerChoiceStrategies.ROUND_ROBIN
  51   ): IWorkerChoiceStrategy {
  52     if (this.pool.type === PoolType.DYNAMIC) {
  53       return new DynamicPoolWorkerChoiceStrategy(
  54         this.pool,
  55         this.createWorkerCallback,
  56         workerChoiceStrategy
  57       )
  58     }
  59     return getWorkerChoiceStrategy(this.pool, workerChoiceStrategy)
  60   }
  61
  62   /**
  63    * Gets the worker choice strategy required statistics.
  64    *
  65    * @returns The required statistics.
  66    */
  67   public getRequiredStatistics (): RequiredStatistics {
  68     return this.workerChoiceStrategy.requiredStatistics
  69   }
  70
  71   /**
  72    * Sets the worker choice strategy to use in the context.
  73    *
  74    * @param workerChoiceStrategy - The worker choice strategy to set.
  75    */
  76   public setWorkerChoiceStrategy (
  77     workerChoiceStrategy: WorkerChoiceStrategy
  78   ): void {
  79     this.workerChoiceStrategy?.reset()
  80     this.workerChoiceStrategy =
  81       this.getPoolWorkerChoiceStrategy(workerChoiceStrategy)
  82   }
  83
  84   /**
  85    * Chooses a worker with the underlying selection strategy.
  86    *
  87    * @returns The key of the chosen one.
  88    */
  89   public execute (): number {
  90     return this.workerChoiceStrategy.choose()
  91   }
  92
  93   /**
  94    * Removes a worker in the underlying selection strategy internals.
  95    *
  96    * @param workerKey - The key of the worker to remove.
  97    * @returns `true` if the removal is successful, `false` otherwise.
  98    */
  99   public remove (workerKey: number): boolean {
 100     return this.workerChoiceStrategy.remove(workerKey)
 101   }
 102 }