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

   1 import { DEFAULT_WORKER_CHOICE_STRATEGY_OPTIONS } from '../../utils'
   2 import type { IPool } from '../pool'
   3 import type { IWorker } from '../worker'
   4 import { FairShareWorkerChoiceStrategy } from './fair-share-worker-choice-strategy'
   5 import { LessBusyWorkerChoiceStrategy } from './less-busy-worker-choice-strategy'
   6 import { LessUsedWorkerChoiceStrategy } from './less-used-worker-choice-strategy'
   7 import { RoundRobinWorkerChoiceStrategy } from './round-robin-worker-choice-strategy'
   8 import type {
   9   IWorkerChoiceStrategy,
  10   RequiredStatistics,
  11   WorkerChoiceStrategy,
  12   WorkerChoiceStrategyOptions
  13 } from './selection-strategies-types'
  14 import { WorkerChoiceStrategies } from './selection-strategies-types'
  15 import { WeightedRoundRobinWorkerChoiceStrategy } from './weighted-round-robin-worker-choice-strategy'
  16
  17 /**
  18  * The worker choice strategy context.
  19  *
  20  * @typeParam Worker - Type of worker.
  21  * @typeParam Data - Type of data sent to the worker. This can only be serializable data.
  22  * @typeParam Response - Type of execution response. This can only be serializable data.
  23  */
  24 export class WorkerChoiceStrategyContext<
  25   Worker extends IWorker,
  26   Data = unknown,
  27   Response = unknown
  28 > {
  29   private readonly workerChoiceStrategies: Map<
  30   WorkerChoiceStrategy,
  31   IWorkerChoiceStrategy
  32   >
  33
  34   /**
  35    * Worker choice strategy context constructor.
  36    *
  37    * @param pool - The pool instance.
  38    * @param workerChoiceStrategy - The worker choice strategy.
  39    * @param opts - The worker choice strategy options.
  40    */
  41   public constructor (
  42     pool: IPool<Worker, Data, Response>,
  43     private workerChoiceStrategy: WorkerChoiceStrategy = WorkerChoiceStrategies.ROUND_ROBIN,
  44     opts: WorkerChoiceStrategyOptions = DEFAULT_WORKER_CHOICE_STRATEGY_OPTIONS
  45   ) {
  46     this.execute = this.execute.bind(this)
  47     this.workerChoiceStrategies = new Map<
  48     WorkerChoiceStrategy,
  49     IWorkerChoiceStrategy
  50     >([
  51       [
  52         WorkerChoiceStrategies.ROUND_ROBIN,
  53         new (RoundRobinWorkerChoiceStrategy.bind(this))<Worker, Data, Response>(
  54           pool,
  55           opts
  56         )
  57       ],
  58       [
  59         WorkerChoiceStrategies.LESS_USED,
  60         new (LessUsedWorkerChoiceStrategy.bind(this))<Worker, Data, Response>(
  61           pool,
  62           opts
  63         )
  64       ],
  65       [
  66         WorkerChoiceStrategies.LESS_BUSY,
  67         new (LessBusyWorkerChoiceStrategy.bind(this))<Worker, Data, Response>(
  68           pool,
  69           opts
  70         )
  71       ],
  72       [
  73         WorkerChoiceStrategies.FAIR_SHARE,
  74         new (FairShareWorkerChoiceStrategy.bind(this))<Worker, Data, Response>(
  75           pool,
  76           opts
  77         )
  78       ],
  79       [
  80         WorkerChoiceStrategies.WEIGHTED_ROUND_ROBIN,
  81         new (WeightedRoundRobinWorkerChoiceStrategy.bind(this))<
  82         Worker,
  83         Data,
  84         Response
  85         >(pool, opts)
  86       ]
  87     ])
  88   }
  89
  90   /**
  91    * Gets the worker choice strategy in the context required statistics.
  92    *
  93    * @returns The required statistics.
  94    */
  95   public getRequiredStatistics (): RequiredStatistics {
  96     return (
  97       this.workerChoiceStrategies.get(
  98         this.workerChoiceStrategy
  99       ) as IWorkerChoiceStrategy
 100     ).requiredStatistics
 101   }
 102
 103   /**
 104    * Sets the worker choice strategy to use in the context.
 105    *
 106    * @param workerChoiceStrategy - The worker choice strategy to set.
 107    */
 108   public setWorkerChoiceStrategy (
 109     workerChoiceStrategy: WorkerChoiceStrategy
 110   ): void {
 111     if (this.workerChoiceStrategy !== workerChoiceStrategy) {
 112       this.workerChoiceStrategy = workerChoiceStrategy
 113     }
 114     this.workerChoiceStrategies.get(this.workerChoiceStrategy)?.reset()
 115   }
 116
 117   /**
 118    * Updates the worker node key in the worker choice strategy internals in the context.
 119    *
 120    * @returns `true` if the update is successful, `false` otherwise.
 121    */
 122   public update (workerNodeKey: number): boolean {
 123     return (
 124       this.workerChoiceStrategies.get(
 125         this.workerChoiceStrategy
 126       ) as IWorkerChoiceStrategy
 127     ).update(workerNodeKey)
 128   }
 129
 130   /**
 131    * Executes the worker choice strategy algorithm in the context.
 132    *
 133    * @returns The key of the worker node.
 134    */
 135   public execute (): number {
 136     return (
 137       this.workerChoiceStrategies.get(
 138         this.workerChoiceStrategy
 139       ) as IWorkerChoiceStrategy
 140     ).choose()
 141   }
 142
 143   /**
 144    * Removes the worker node key from the worker choice strategy in the context.
 145    *
 146    * @param workerNodeKey - The key of the worker node.
 147    * @returns `true` if the removal is successful, `false` otherwise.
 148    */
 149   public remove (workerNodeKey: number): boolean {
 150     return (
 151       this.workerChoiceStrategies.get(
 152         this.workerChoiceStrategy
 153       ) as IWorkerChoiceStrategy
 154     ).remove(workerNodeKey)
 155   }
 156
 157   /**
 158    * Sets the worker choice strategies in the context options.
 159    *
 160    * @param opts - The worker choice strategy options.
 161    */
 162   public setOptions (opts: WorkerChoiceStrategyOptions): void {
 163     this.workerChoiceStrategies.forEach(workerChoiceStrategy => {
 164       workerChoiceStrategy.setOptions(opts)
 165     })
 166   }
 167 }