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

   1 import type { IPoolInternal } from '../pool-internal'
   2 import type { IWorker } from '../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 IWorker,
  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 workerChoiceStrategyType - The worker choice strategy.
  37    */
  38   public constructor (
  39     pool: IPoolInternal<Worker, Data, Response>,
  40     private workerChoiceStrategyType: WorkerChoiceStrategy = WorkerChoiceStrategies.ROUND_ROBIN
  41   ) {
  42     this.execute.bind(this)
  43     this.workerChoiceStrategies = new Map<
  44     WorkerChoiceStrategy,
  45     IWorkerChoiceStrategy
  46     >([
  47       [
  48         WorkerChoiceStrategies.ROUND_ROBIN,
  49         new RoundRobinWorkerChoiceStrategy<Worker, Data, Response>(pool)
  50       ],
  51       [
  52         WorkerChoiceStrategies.LESS_USED,
  53         new LessUsedWorkerChoiceStrategy<Worker, Data, Response>(pool)
  54       ],
  55       [
  56         WorkerChoiceStrategies.LESS_BUSY,
  57         new LessBusyWorkerChoiceStrategy<Worker, Data, Response>(pool)
  58       ],
  59       [
  60         WorkerChoiceStrategies.FAIR_SHARE,
  61         new FairShareWorkerChoiceStrategy<Worker, Data, Response>(pool)
  62       ],
  63       [
  64         WorkerChoiceStrategies.WEIGHTED_ROUND_ROBIN,
  65         new WeightedRoundRobinWorkerChoiceStrategy<Worker, Data, Response>(pool)
  66       ]
  67     ])
  68   }
  69
  70   /**
  71    * Gets the worker choice strategy in the context required statistics.
  72    *
  73    * @returns The required statistics.
  74    */
  75   public getRequiredStatistics (): RequiredStatistics {
  76     return (
  77       this.workerChoiceStrategies.get(
  78         this.workerChoiceStrategyType
  79       ) as IWorkerChoiceStrategy
  80     ).requiredStatistics
  81   }
  82
  83   /**
  84    * Sets the worker choice strategy to use in the context.
  85    *
  86    * @param workerChoiceStrategy - The worker choice strategy to set.
  87    */
  88   public setWorkerChoiceStrategy (
  89     workerChoiceStrategy: WorkerChoiceStrategy
  90   ): void {
  91     if (this.workerChoiceStrategyType !== workerChoiceStrategy) {
  92       this.workerChoiceStrategyType = workerChoiceStrategy
  93     }
  94     this.workerChoiceStrategies.get(this.workerChoiceStrategyType)?.reset()
  95   }
  96
  97   /**
  98    * Executes the worker choice strategy algorithm in the context.
  99    *
 100    * @returns The key of the worker node.
 101    */
 102   public execute (): number {
 103     return (
 104       this.workerChoiceStrategies.get(
 105         this.workerChoiceStrategyType
 106       ) as IWorkerChoiceStrategy
 107     ).choose()
 108   }
 109
 110   /**
 111    * Removes a worker node key from the worker choice strategy in the context.
 112    *
 113    * @param workerNodeKey - The key of the worker node.
 114    * @returns `true` if the removal is successful, `false` otherwise.
 115    */
 116   public remove (workerNodeKey: number): boolean {
 117     return (
 118       this.workerChoiceStrategies.get(
 119         this.workerChoiceStrategyType
 120       ) as IWorkerChoiceStrategy
 121     ).remove(workerNodeKey)
 122   }
 123 }