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 { InterleavedWeightedRoundRobinWorkerChoiceStrategy } from './interleaved-weighted-round-robin-worker-choice-strategy'
   6 import { LeastBusyWorkerChoiceStrategy } from './least-busy-worker-choice-strategy'
   7 import { LeastUsedWorkerChoiceStrategy } from './least-used-worker-choice-strategy'
   8 import { LeastEluWorkerChoiceStrategy } from './least-elu-worker-choice-strategy'
   9 import { RoundRobinWorkerChoiceStrategy } from './round-robin-worker-choice-strategy'
  10 import type {
  11   IWorkerChoiceStrategy,
  12   StrategyPolicy,
  13   TaskStatisticsRequirements,
  14   WorkerChoiceStrategy,
  15   WorkerChoiceStrategyOptions
  16 } from './selection-strategies-types'
  17 import { WorkerChoiceStrategies } from './selection-strategies-types'
  18 import { WeightedRoundRobinWorkerChoiceStrategy } from './weighted-round-robin-worker-choice-strategy'
  19
  20 /**
  21  * The worker choice strategy context.
  22  *
  23  * @typeParam Worker - Type of worker.
  24  * @typeParam Data - Type of data sent to the worker. This can only be structured-cloneable data.
  25  * @typeParam Response - Type of execution response. This can only be structured-cloneable data.
  26  */
  27 export class WorkerChoiceStrategyContext<
  28   Worker extends IWorker,
  29   Data = unknown,
  30   Response = unknown
  31 > {
  32   private readonly workerChoiceStrategies: Map<
  33   WorkerChoiceStrategy,
  34   IWorkerChoiceStrategy
  35   >
  36
  37   /**
  38    * Worker choice strategy context constructor.
  39    *
  40    * @param pool - The pool instance.
  41    * @param workerChoiceStrategy - The worker choice strategy.
  42    * @param opts - The worker choice strategy options.
  43    */
  44   public constructor (
  45     pool: IPool<Worker, Data, Response>,
  46     private workerChoiceStrategy: WorkerChoiceStrategy = WorkerChoiceStrategies.ROUND_ROBIN,
  47     opts: WorkerChoiceStrategyOptions = DEFAULT_WORKER_CHOICE_STRATEGY_OPTIONS
  48   ) {
  49     this.execute = this.execute.bind(this)
  50     this.workerChoiceStrategies = new Map<
  51     WorkerChoiceStrategy,
  52     IWorkerChoiceStrategy
  53     >([
  54       [
  55         WorkerChoiceStrategies.ROUND_ROBIN,
  56         new (RoundRobinWorkerChoiceStrategy.bind(this))<Worker, Data, Response>(
  57           pool,
  58           opts
  59         )
  60       ],
  61       [
  62         WorkerChoiceStrategies.LEAST_USED,
  63         new (LeastUsedWorkerChoiceStrategy.bind(this))<Worker, Data, Response>(
  64           pool,
  65           opts
  66         )
  67       ],
  68       [
  69         WorkerChoiceStrategies.LEAST_BUSY,
  70         new (LeastBusyWorkerChoiceStrategy.bind(this))<Worker, Data, Response>(
  71           pool,
  72           opts
  73         )
  74       ],
  75       [
  76         WorkerChoiceStrategies.LEAST_ELU,
  77         new (LeastEluWorkerChoiceStrategy.bind(this))<Worker, Data, Response>(
  78           pool,
  79           opts
  80         )
  81       ],
  82       [
  83         WorkerChoiceStrategies.FAIR_SHARE,
  84         new (FairShareWorkerChoiceStrategy.bind(this))<Worker, Data, Response>(
  85           pool,
  86           opts
  87         )
  88       ],
  89       [
  90         WorkerChoiceStrategies.WEIGHTED_ROUND_ROBIN,
  91         new (WeightedRoundRobinWorkerChoiceStrategy.bind(this))<
  92         Worker,
  93         Data,
  94         Response
  95         >(pool, opts)
  96       ],
  97       [
  98         WorkerChoiceStrategies.INTERLEAVED_WEIGHTED_ROUND_ROBIN,
  99         new (InterleavedWeightedRoundRobinWorkerChoiceStrategy.bind(this))<
 100         Worker,
 101         Data,
 102         Response
 103         >(pool, opts)
 104       ]
 105     ])
 106   }
 107
 108   /**
 109    * Gets the strategy policy in the context.
 110    *
 111    * @returns The strategy policy.
 112    */
 113   public getStrategyPolicy (): StrategyPolicy {
 114     return (
 115       this.workerChoiceStrategies.get(
 116         this.workerChoiceStrategy
 117       ) as IWorkerChoiceStrategy
 118     ).strategyPolicy
 119   }
 120
 121   /**
 122    * Gets the worker choice strategy task statistics requirements in the context.
 123    *
 124    * @returns The task statistics requirements.
 125    */
 126   public getTaskStatisticsRequirements (): TaskStatisticsRequirements {
 127     return (
 128       this.workerChoiceStrategies.get(
 129         this.workerChoiceStrategy
 130       ) as IWorkerChoiceStrategy
 131     ).taskStatisticsRequirements
 132   }
 133
 134   /**
 135    * Sets the worker choice strategy to use in the context.
 136    *
 137    * @param workerChoiceStrategy - The worker choice strategy to set.
 138    */
 139   public setWorkerChoiceStrategy (
 140     workerChoiceStrategy: WorkerChoiceStrategy
 141   ): void {
 142     if (this.workerChoiceStrategy !== workerChoiceStrategy) {
 143       this.workerChoiceStrategy = workerChoiceStrategy
 144     }
 145     this.workerChoiceStrategies.get(this.workerChoiceStrategy)?.reset()
 146   }
 147
 148   /**
 149    * Updates the worker node key in the worker choice strategy internals in the context.
 150    *
 151    * @returns `true` if the update is successful, `false` otherwise.
 152    */
 153   public update (workerNodeKey: number): boolean {
 154     return (
 155       this.workerChoiceStrategies.get(
 156         this.workerChoiceStrategy
 157       ) as IWorkerChoiceStrategy
 158     ).update(workerNodeKey)
 159   }
 160
 161   /**
 162    * Executes the worker choice strategy algorithm in the context.
 163    *
 164    * @returns The key of the worker node.
 165    * @throws {@link Error} If the worker node key is null or undefined.
 166    */
 167   public execute (): number {
 168     const workerNodeKey = (
 169       this.workerChoiceStrategies.get(
 170         this.workerChoiceStrategy
 171       ) as IWorkerChoiceStrategy
 172     ).choose()
 173     if (workerNodeKey == null) {
 174       throw new Error('Worker node key chosen is null or undefined')
 175     }
 176     return workerNodeKey
 177   }
 178
 179   /**
 180    * Removes the worker node key from the worker choice strategy in the context.
 181    *
 182    * @param workerNodeKey - The key of the worker node.
 183    * @returns `true` if the removal is successful, `false` otherwise.
 184    */
 185   public remove (workerNodeKey: number): boolean {
 186     return (
 187       this.workerChoiceStrategies.get(
 188         this.workerChoiceStrategy
 189       ) as IWorkerChoiceStrategy
 190     ).remove(workerNodeKey)
 191   }
 192
 193   /**
 194    * Sets the worker choice strategies in the context options.
 195    *
 196    * @param opts - The worker choice strategy options.
 197    */
 198   public setOptions (opts: WorkerChoiceStrategyOptions): void {
 199     for (const workerChoiceStrategy of this.workerChoiceStrategies.values()) {
 200       workerChoiceStrategy.setOptions(opts)
 201     }
 202   }
 203 }