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 number of worker choice strategy execution retries.
  34    */
  35   public retriesCount: number
  36
  37   /**
  38    * The worker choice strategy instances registered in the context.
  39    */
  40   private readonly workerChoiceStrategies: Map<
  41   WorkerChoiceStrategy,
  42   IWorkerChoiceStrategy
  43   >
  44
  45   /**
  46    * The maximum number of worker choice strategy execution retries.
  47    */
  48   private readonly retries: number
  49
  50   /**
  51    * Worker choice strategy context constructor.
  52    *
  53    * @param pool - The pool instance.
  54    * @param workerChoiceStrategy - The worker choice strategy.
  55    * @param opts - The worker choice strategy options.
  56    */
  57   public constructor (
  58     pool: IPool<Worker, Data, Response>,
  59     private workerChoiceStrategy: WorkerChoiceStrategy = WorkerChoiceStrategies.ROUND_ROBIN,
  60     opts?: WorkerChoiceStrategyOptions
  61   ) {
  62     this.execute = this.execute.bind(this)
  63     this.workerChoiceStrategies = new Map<
  64     WorkerChoiceStrategy,
  65     IWorkerChoiceStrategy
  66     >([
  67       [
  68         WorkerChoiceStrategies.ROUND_ROBIN,
  69         new (RoundRobinWorkerChoiceStrategy.bind(this))<Worker, Data, Response>(
  70           pool,
  71           opts
  72         )
  73       ],
  74       [
  75         WorkerChoiceStrategies.LEAST_USED,
  76         new (LeastUsedWorkerChoiceStrategy.bind(this))<Worker, Data, Response>(
  77           pool,
  78           opts
  79         )
  80       ],
  81       [
  82         WorkerChoiceStrategies.LEAST_BUSY,
  83         new (LeastBusyWorkerChoiceStrategy.bind(this))<Worker, Data, Response>(
  84           pool,
  85           opts
  86         )
  87       ],
  88       [
  89         WorkerChoiceStrategies.LEAST_ELU,
  90         new (LeastEluWorkerChoiceStrategy.bind(this))<Worker, Data, Response>(
  91           pool,
  92           opts
  93         )
  94       ],
  95       [
  96         WorkerChoiceStrategies.FAIR_SHARE,
  97         new (FairShareWorkerChoiceStrategy.bind(this))<Worker, Data, Response>(
  98           pool,
  99           opts
 100         )
 101       ],
 102       [
 103         WorkerChoiceStrategies.WEIGHTED_ROUND_ROBIN,
 104         new (WeightedRoundRobinWorkerChoiceStrategy.bind(this))<
 105         Worker,
 106         Data,
 107         Response
 108         >(pool, opts)
 109       ],
 110       [
 111         WorkerChoiceStrategies.INTERLEAVED_WEIGHTED_ROUND_ROBIN,
 112         new (InterleavedWeightedRoundRobinWorkerChoiceStrategy.bind(this))<
 113         Worker,
 114         Data,
 115         Response
 116         >(pool, opts)
 117       ]
 118     ])
 119     this.retriesCount = 0
 120     this.retries = getWorkerChoiceStrategyRetries(pool, opts)
 121   }
 122
 123   /**
 124    * Gets the strategy policy in the context.
 125    *
 126    * @returns The strategy policy.
 127    */
 128   public getStrategyPolicy (): StrategyPolicy {
 129     // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
 130     return this.workerChoiceStrategies.get(this.workerChoiceStrategy)!
 131       .strategyPolicy
 132   }
 133
 134   /**
 135    * Gets the worker choice strategy in the context task statistics requirements.
 136    *
 137    * @returns The task statistics requirements.
 138    */
 139   public getTaskStatisticsRequirements (): TaskStatisticsRequirements {
 140     // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
 141     return this.workerChoiceStrategies.get(this.workerChoiceStrategy)!
 142       .taskStatisticsRequirements
 143   }
 144
 145   /**
 146    * Sets the worker choice strategy to use in the context.
 147    *
 148    * @param workerChoiceStrategy - The worker choice strategy to set.
 149    */
 150   public setWorkerChoiceStrategy (
 151     workerChoiceStrategy: WorkerChoiceStrategy
 152   ): void {
 153     if (this.workerChoiceStrategy !== workerChoiceStrategy) {
 154       this.workerChoiceStrategy = workerChoiceStrategy
 155     }
 156     this.workerChoiceStrategies.get(this.workerChoiceStrategy)?.reset()
 157   }
 158
 159   /**
 160    * Updates the worker node key in the worker choice strategy in the context internals.
 161    *
 162    * @returns `true` if the update is successful, `false` otherwise.
 163    */
 164   public update (workerNodeKey: number): boolean {
 165     // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
 166     return this.workerChoiceStrategies
 167       .get(this.workerChoiceStrategy)!
 168       .update(workerNodeKey)
 169   }
 170
 171   /**
 172    * Executes the worker choice strategy in the context algorithm.
 173    *
 174    * @returns The key of the worker node.
 175    * @throws {@link https://nodejs.org/api/errors.html#class-error} If after computed retries the worker node key is null or undefined.
 176    */
 177   public execute (): number {
 178     return this.executeStrategy(
 179       // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
 180       this.workerChoiceStrategies.get(this.workerChoiceStrategy)!
 181     )
 182   }
 183
 184   /**
 185    * Executes the given worker choice strategy.
 186    *
 187    * @param workerChoiceStrategy - The worker choice strategy.
 188    * @returns The key of the worker node.
 189    * @throws {@link https://nodejs.org/api/errors.html#class-error} If after computed retries the worker node key is null or undefined.
 190    */
 191   private executeStrategy (workerChoiceStrategy: IWorkerChoiceStrategy): number {
 192     let workerNodeKey: number | undefined
 193     let chooseCount = 0
 194     let retriesCount = 0
 195     do {
 196       workerNodeKey = workerChoiceStrategy.choose()
 197       if (workerNodeKey == null && chooseCount > 0) {
 198         ++retriesCount
 199         ++this.retriesCount
 200       }
 201       ++chooseCount
 202     } while (workerNodeKey == null && retriesCount < this.retries)
 203     if (workerNodeKey == null) {
 204       throw new Error(
 205         `Worker node key chosen is null or undefined after ${retriesCount} retries`
 206       )
 207     }
 208     return workerNodeKey
 209   }
 210
 211   /**
 212    * Removes the worker node key from the worker choice strategy in the context.
 213    *
 214    * @param workerNodeKey - The worker node key.
 215    * @returns `true` if the removal is successful, `false` otherwise.
 216    */
 217   public remove (workerNodeKey: number): boolean {
 218     // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
 219     return this.workerChoiceStrategies
 220       .get(this.workerChoiceStrategy)!
 221       .remove(workerNodeKey)
 222   }
 223
 224   /**
 225    * Sets the worker choice strategies in the context options.
 226    *
 227    * @param opts - The worker choice strategy options.
 228    */
 229   public setOptions (opts: WorkerChoiceStrategyOptions | undefined): void {
 230     for (const workerChoiceStrategy of this.workerChoiceStrategies.values()) {
 231       workerChoiceStrategy.setOptions(opts)
 232     }
 233   }
 234 }