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

   1 import type { IPool } from '../pool.js'
   2 import type { IWorker } from '../worker.js'
   3 import { getWorkerChoiceStrategyRetries } from '../../utils.js'
   4 import { FairShareWorkerChoiceStrategy } from './fair-share-worker-choice-strategy.js'
   5 import { InterleavedWeightedRoundRobinWorkerChoiceStrategy } from './interleaved-weighted-round-robin-worker-choice-strategy.js'
   6 import { LeastBusyWorkerChoiceStrategy } from './least-busy-worker-choice-strategy.js'
   7 import { LeastUsedWorkerChoiceStrategy } from './least-used-worker-choice-strategy.js'
   8 import { LeastEluWorkerChoiceStrategy } from './least-elu-worker-choice-strategy.js'
   9 import { RoundRobinWorkerChoiceStrategy } from './round-robin-worker-choice-strategy.js'
  10 import type {
  11   IWorkerChoiceStrategy,
  12   StrategyPolicy,
  13   TaskStatisticsRequirements,
  14   WorkerChoiceStrategy,
  15   WorkerChoiceStrategyOptions
  16 } from './selection-strategies-types.js'
  17 import { WorkerChoiceStrategies } from './selection-strategies-types.js'
  18 import { WeightedRoundRobinWorkerChoiceStrategy } from './weighted-round-robin-worker-choice-strategy.js'
  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   /**
  33    * The worker choice strategy instances registered in the context.
  34    */
  35   private readonly workerChoiceStrategies: Map<
  36   WorkerChoiceStrategy,
  37   IWorkerChoiceStrategy
  38   >
  39
  40   /**
  41    * The number of worker choice strategy execution retries.
  42    */
  43   private readonly retries: number
  44
  45   /**
  46    * Worker choice strategy context constructor.
  47    *
  48    * @param pool - The pool instance.
  49    * @param workerChoiceStrategy - The worker choice strategy.
  50    * @param opts - The worker choice strategy options.
  51    */
  52   public constructor (
  53     pool: IPool<Worker, Data, Response>,
  54     private workerChoiceStrategy: WorkerChoiceStrategy = WorkerChoiceStrategies.ROUND_ROBIN,
  55     opts?: WorkerChoiceStrategyOptions
  56   ) {
  57     this.execute = this.execute.bind(this)
  58     this.workerChoiceStrategies = new Map<
  59     WorkerChoiceStrategy,
  60     IWorkerChoiceStrategy
  61     >([
  62       [
  63         WorkerChoiceStrategies.ROUND_ROBIN,
  64         new (RoundRobinWorkerChoiceStrategy.bind(this))<Worker, Data, Response>(
  65           pool,
  66           opts
  67         )
  68       ],
  69       [
  70         WorkerChoiceStrategies.LEAST_USED,
  71         new (LeastUsedWorkerChoiceStrategy.bind(this))<Worker, Data, Response>(
  72           pool,
  73           opts
  74         )
  75       ],
  76       [
  77         WorkerChoiceStrategies.LEAST_BUSY,
  78         new (LeastBusyWorkerChoiceStrategy.bind(this))<Worker, Data, Response>(
  79           pool,
  80           opts
  81         )
  82       ],
  83       [
  84         WorkerChoiceStrategies.LEAST_ELU,
  85         new (LeastEluWorkerChoiceStrategy.bind(this))<Worker, Data, Response>(
  86           pool,
  87           opts
  88         )
  89       ],
  90       [
  91         WorkerChoiceStrategies.FAIR_SHARE,
  92         new (FairShareWorkerChoiceStrategy.bind(this))<Worker, Data, Response>(
  93           pool,
  94           opts
  95         )
  96       ],
  97       [
  98         WorkerChoiceStrategies.WEIGHTED_ROUND_ROBIN,
  99         new (WeightedRoundRobinWorkerChoiceStrategy.bind(this))<
 100         Worker,
 101         Data,
 102         Response
 103         >(pool, opts)
 104       ],
 105       [
 106         WorkerChoiceStrategies.INTERLEAVED_WEIGHTED_ROUND_ROBIN,
 107         new (InterleavedWeightedRoundRobinWorkerChoiceStrategy.bind(this))<
 108         Worker,
 109         Data,
 110         Response
 111         >(pool, opts)
 112       ]
 113     ])
 114     this.retries = getWorkerChoiceStrategyRetries(pool, opts)
 115   }
 116
 117   /**
 118    * Gets the strategy policy in the context.
 119    *
 120    * @returns The strategy policy.
 121    */
 122   public getStrategyPolicy (): StrategyPolicy {
 123     // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
 124     return this.workerChoiceStrategies.get(this.workerChoiceStrategy)!
 125       .strategyPolicy
 126   }
 127
 128   /**
 129    * Gets the worker choice strategy in the context task statistics requirements.
 130    *
 131    * @returns The task statistics requirements.
 132    */
 133   public getTaskStatisticsRequirements (): TaskStatisticsRequirements {
 134     // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
 135     return this.workerChoiceStrategies.get(this.workerChoiceStrategy)!
 136       .taskStatisticsRequirements
 137   }
 138
 139   /**
 140    * Sets the worker choice strategy to use in the context.
 141    *
 142    * @param workerChoiceStrategy - The worker choice strategy to set.
 143    */
 144   public setWorkerChoiceStrategy (
 145     workerChoiceStrategy: WorkerChoiceStrategy
 146   ): void {
 147     if (this.workerChoiceStrategy !== workerChoiceStrategy) {
 148       this.workerChoiceStrategy = workerChoiceStrategy
 149     }
 150     this.workerChoiceStrategies.get(this.workerChoiceStrategy)?.reset()
 151   }
 152
 153   /**
 154    * Updates the worker node key in the worker choice strategy in the context internals.
 155    *
 156    * @returns `true` if the update is successful, `false` otherwise.
 157    */
 158   public update (workerNodeKey: number): boolean {
 159     // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
 160     return this.workerChoiceStrategies
 161       .get(this.workerChoiceStrategy)!
 162       .update(workerNodeKey)
 163   }
 164
 165   /**
 166    * Executes the worker choice strategy in the context algorithm.
 167    *
 168    * @returns The key of the worker node.
 169    * @throws {@link https://nodejs.org/api/errors.html#class-error} If after computed retries the worker node key is null or undefined.
 170    */
 171   public execute (): number {
 172     return this.executeStrategy(
 173       // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
 174       this.workerChoiceStrategies.get(this.workerChoiceStrategy)!
 175     )
 176   }
 177
 178   /**
 179    * Executes the given worker choice strategy.
 180    *
 181    * @param workerChoiceStrategy - The worker choice strategy.
 182    * @returns The key of the worker node.
 183    * @throws {@link https://nodejs.org/api/errors.html#class-error} If after computed retries the worker node key is null or undefined.
 184    */
 185   private executeStrategy (workerChoiceStrategy: IWorkerChoiceStrategy): number {
 186     let workerNodeKey: number | undefined
 187     let chooseCount = 0
 188     let retriesCount = 0
 189     do {
 190       workerNodeKey = workerChoiceStrategy.choose()
 191       if (workerNodeKey != null && workerNodeKey < 0) {
 192         workerNodeKey = undefined
 193       }
 194       if (workerNodeKey == null && chooseCount > 0) {
 195         retriesCount++
 196       }
 197       chooseCount++
 198     } while (workerNodeKey == null && retriesCount < this.retries)
 199     if (workerNodeKey == null) {
 200       throw new Error(
 201         `Worker node key chosen is null or undefined after ${retriesCount} retries`
 202       )
 203     }
 204     return workerNodeKey
 205   }
 206
 207   /**
 208    * Removes the worker node key from the worker choice strategy in the context.
 209    *
 210    * @param workerNodeKey - The worker node key.
 211    * @returns `true` if the removal is successful, `false` otherwise.
 212    */
 213   public remove (workerNodeKey: number): boolean {
 214     // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
 215     return this.workerChoiceStrategies
 216       .get(this.workerChoiceStrategy)!
 217       .remove(workerNodeKey)
 218   }
 219
 220   /**
 221    * Sets the worker choice strategies in the context options.
 222    *
 223    * @param opts - The worker choice strategy options.
 224    */
 225   public setOptions (opts: WorkerChoiceStrategyOptions | undefined): void {
 226     for (const workerChoiceStrategy of this.workerChoiceStrategies.values()) {
 227       workerChoiceStrategy.setOptions(opts)
 228     }
 229   }
 230 }