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 { FairShareWorkerChoiceStrategy } from './fair-share-worker-choice-strategy'
   4 import { LessBusyWorkerChoiceStrategy } from './less-busy-worker-choice-strategy'
   5 import { LessUsedWorkerChoiceStrategy } from './less-used-worker-choice-strategy'
   6 import { RoundRobinWorkerChoiceStrategy } from './round-robin-worker-choice-strategy'
   7 import type {
   8   IWorkerChoiceStrategy,
   9   RequiredStatistics,
  10   WorkerChoiceStrategy
  11 } from './selection-strategies-types'
  12 import { WorkerChoiceStrategies } from './selection-strategies-types'
  13 import { WeightedRoundRobinWorkerChoiceStrategy } from './weighted-round-robin-worker-choice-strategy'
  14
  15 /**
  16  * The worker choice strategy context.
  17  *
  18  * @typeParam Worker - Type of worker.
  19  * @typeParam Data - Type of data sent to the worker. This can only be serializable data.
  20  * @typeParam Response - Type of response of execution. This can only be serializable data.
  21  */
  22 export class WorkerChoiceStrategyContext<
  23   Worker extends IPoolWorker,
  24   Data = unknown,
  25   Response = unknown
  26 > {
  27   private readonly workerChoiceStrategies: Map<
  28   WorkerChoiceStrategy,
  29   IWorkerChoiceStrategy
  30   >
  31
  32   /**
  33    * Worker choice strategy context constructor.
  34    *
  35    * @param pool - The pool instance.
  36    * @param createWorkerCallback - The worker creation callback for dynamic pool.
  37    * @param workerChoiceStrategy - The worker choice strategy.
  38    */
  39   public constructor (
  40     pool: IPoolInternal<Worker, Data, Response>,
  41     private workerChoiceStrategyType: WorkerChoiceStrategy = WorkerChoiceStrategies.ROUND_ROBIN
  42   ) {
  43     this.execute.bind(this)
  44     this.workerChoiceStrategies = new Map<
  45     WorkerChoiceStrategy,
  46     IWorkerChoiceStrategy
  47     >([
  48       [
  49         WorkerChoiceStrategies.ROUND_ROBIN,
  50         new RoundRobinWorkerChoiceStrategy<Worker, Data, Response>(pool)
  51       ],
  52       [
  53         WorkerChoiceStrategies.LESS_USED,
  54         new LessUsedWorkerChoiceStrategy<Worker, Data, Response>(pool)
  55       ],
  56       [
  57         WorkerChoiceStrategies.LESS_BUSY,
  58         new LessBusyWorkerChoiceStrategy<Worker, Data, Response>(pool)
  59       ],
  60       [
  61         WorkerChoiceStrategies.FAIR_SHARE,
  62         new FairShareWorkerChoiceStrategy<Worker, Data, Response>(pool)
  63       ],
  64       [
  65         WorkerChoiceStrategies.WEIGHTED_ROUND_ROBIN,
  66         new WeightedRoundRobinWorkerChoiceStrategy<Worker, Data, Response>(pool)
  67       ]
  68     ])
  69   }
  70
  71   /**
  72    * Gets the worker choice strategy in the context required statistics.
  73    *
  74    * @returns The required statistics.
  75    */
  76   public getRequiredStatistics (): RequiredStatistics {
  77     return (
  78       this.workerChoiceStrategies.get(
  79         this.workerChoiceStrategyType
  80       ) as IWorkerChoiceStrategy
  81     ).requiredStatistics
  82   }
  83
  84   /**
  85    * Sets the worker choice strategy to use in the context.
  86    *
  87    * @param workerChoiceStrategy - The worker choice strategy to set.
  88    */
  89   public setWorkerChoiceStrategy (
  90     workerChoiceStrategy: WorkerChoiceStrategy
  91   ): void {
  92     if (this.workerChoiceStrategyType !== workerChoiceStrategy) {
  93       this.workerChoiceStrategyType = workerChoiceStrategy
  94     }
  95     this.workerChoiceStrategies.get(this.workerChoiceStrategyType)?.reset()
  96   }
  97
  98   /**
  99    * Executes the worker choice strategy algorithm in the context.
 100    *
 101    * @returns The key of the chosen one.
 102    */
 103   public execute (): number {
 104     return (
 105       this.workerChoiceStrategies.get(
 106         this.workerChoiceStrategyType
 107       ) as IWorkerChoiceStrategy
 108     ).choose()
 109   }
 110
 111   /**
 112    * Removes a worker from the worker choice strategy in the context.
 113    *
 114    * @param workerKey - The key of the worker to remove.
 115    * @returns `true` if the removal is successful, `false` otherwise.
 116    */
 117   public remove (workerKey: number): boolean {
 118     return (
 119       this.workerChoiceStrategies.get(
 120         this.workerChoiceStrategyType
 121       ) as IWorkerChoiceStrategy
 122     ).remove(workerKey)
 123   }
 124 }