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