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

   1 import { getDefaultInternalWorkerChoiceStrategyOptions } 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   InternalWorkerChoiceStrategyOptions,
  13   StrategyPolicy,
  14   TaskStatisticsRequirements,
  15   WorkerChoiceStrategy
  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     private opts?: InternalWorkerChoiceStrategyOptions
  48   ) {
  49     this.opts = {
  50       ...getDefaultInternalWorkerChoiceStrategyOptions(
  51         pool.info.maxSize +
  52           Object.keys((this.opts?.weights as Record<number, number>) ?? {})
  53             .length
  54       ),
  55       ...this.opts
  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           this.opts
  67         )
  68       ],
  69       [
  70         WorkerChoiceStrategies.LEAST_USED,
  71         new (LeastUsedWorkerChoiceStrategy.bind(this))<Worker, Data, Response>(
  72           pool,
  73           this.opts
  74         )
  75       ],
  76       [
  77         WorkerChoiceStrategies.LEAST_BUSY,
  78         new (LeastBusyWorkerChoiceStrategy.bind(this))<Worker, Data, Response>(
  79           pool,
  80           this.opts
  81         )
  82       ],
  83       [
  84         WorkerChoiceStrategies.LEAST_ELU,
  85         new (LeastEluWorkerChoiceStrategy.bind(this))<Worker, Data, Response>(
  86           pool,
  87           this.opts
  88         )
  89       ],
  90       [
  91         WorkerChoiceStrategies.FAIR_SHARE,
  92         new (FairShareWorkerChoiceStrategy.bind(this))<Worker, Data, Response>(
  93           pool,
  94           this.opts
  95         )
  96       ],
  97       [
  98         WorkerChoiceStrategies.WEIGHTED_ROUND_ROBIN,
  99         new (WeightedRoundRobinWorkerChoiceStrategy.bind(this))<
 100         Worker,
 101         Data,
 102         Response
 103         >(pool, this.opts)
 104       ],
 105       [
 106         WorkerChoiceStrategies.INTERLEAVED_WEIGHTED_ROUND_ROBIN,
 107         new (InterleavedWeightedRoundRobinWorkerChoiceStrategy.bind(this))<
 108         Worker,
 109         Data,
 110         Response
 111         >(pool, this.opts)
 112       ]
 113     ])
 114   }
 115
 116   /**
 117    * Gets the strategy policy in the context.
 118    *
 119    * @returns The strategy policy.
 120    */
 121   public getStrategyPolicy (): StrategyPolicy {
 122     return (
 123       this.workerChoiceStrategies.get(
 124         this.workerChoiceStrategy
 125       ) as IWorkerChoiceStrategy
 126     ).strategyPolicy
 127   }
 128
 129   /**
 130    * Gets the worker choice strategy in the context task statistics requirements.
 131    *
 132    * @returns The task statistics requirements.
 133    */
 134   public getTaskStatisticsRequirements (): TaskStatisticsRequirements {
 135     return (
 136       this.workerChoiceStrategies.get(
 137         this.workerChoiceStrategy
 138       ) as IWorkerChoiceStrategy
 139     ).taskStatisticsRequirements
 140   }
 141
 142   /**
 143    * Sets the worker choice strategy to use in the context.
 144    *
 145    * @param workerChoiceStrategy - The worker choice strategy to set.
 146    */
 147   public setWorkerChoiceStrategy (
 148     workerChoiceStrategy: WorkerChoiceStrategy
 149   ): void {
 150     if (this.workerChoiceStrategy !== workerChoiceStrategy) {
 151       this.workerChoiceStrategy = workerChoiceStrategy
 152     }
 153     this.workerChoiceStrategies.get(this.workerChoiceStrategy)?.reset()
 154   }
 155
 156   /**
 157    * Updates the worker node key in the worker choice strategy in the context internals.
 158    *
 159    * @returns `true` if the update is successful, `false` otherwise.
 160    */
 161   public update (workerNodeKey: number): boolean {
 162     return (
 163       this.workerChoiceStrategies.get(
 164         this.workerChoiceStrategy
 165       ) as IWorkerChoiceStrategy
 166     ).update(workerNodeKey)
 167   }
 168
 169   /**
 170    * Executes the worker choice strategy in the context algorithm.
 171    *
 172    * @returns The key of the worker node.
 173    * @throws {@link https://nodejs.org/api/errors.html#class-error} If after configured retries the worker node key is null or undefined.
 174    */
 175   public execute (): number {
 176     const workerChoiceStrategy = this.workerChoiceStrategies.get(
 177       this.workerChoiceStrategy
 178     ) as IWorkerChoiceStrategy
 179     if (!workerChoiceStrategy.hasPoolWorkerNodesReady()) {
 180       return this.execute()
 181     }
 182     return this.executeStrategy(workerChoiceStrategy)
 183   }
 184
 185   /**
 186    * Executes the given worker choice strategy.
 187    *
 188    * @param workerChoiceStrategy - The worker choice strategy.
 189    * @returns The key of the worker node.
 190    * @throws {@link https://nodejs.org/api/errors.html#class-error} If after configured retries the worker node key is null or undefined.
 191    */
 192   private executeStrategy (workerChoiceStrategy: IWorkerChoiceStrategy): number {
 193     let workerNodeKey: number | undefined
 194     let chooseCount = 0
 195     let retriesCount = 0
 196     do {
 197       workerNodeKey = workerChoiceStrategy.choose()
 198       if (workerNodeKey == null && chooseCount > 0) {
 199         retriesCount++
 200       }
 201       chooseCount++
 202     } while (
 203       workerNodeKey == null &&
 204       retriesCount < (this.opts?.retries as number)
 205     )
 206     if (workerNodeKey == null) {
 207       throw new Error(
 208         `Worker node key chosen is null or undefined after ${retriesCount} retries`
 209       )
 210     }
 211     return workerNodeKey
 212   }
 213
 214   /**
 215    * Removes the worker node key from the worker choice strategy in the context.
 216    *
 217    * @param workerNodeKey - The worker node key.
 218    * @returns `true` if the removal is successful, `false` otherwise.
 219    */
 220   public remove (workerNodeKey: number): boolean {
 221     return (
 222       this.workerChoiceStrategies.get(
 223         this.workerChoiceStrategy
 224       ) as IWorkerChoiceStrategy
 225     ).remove(workerNodeKey)
 226   }
 227
 228   /**
 229    * Sets the worker choice strategies in the context options.
 230    *
 231    * @param pool - The pool instance.
 232    * @param opts - The worker choice strategy options.
 233    */
 234   public setOptions (
 235     pool: IPool<Worker, Data, Response>,
 236     opts?: InternalWorkerChoiceStrategyOptions
 237   ): void {
 238     this.opts = {
 239       ...getDefaultInternalWorkerChoiceStrategyOptions(
 240         pool.info.maxSize +
 241           Object.keys((opts?.weights as Record<number, number>) ?? {}).length
 242       ),
 243       ...opts
 244     }
 245     for (const workerChoiceStrategy of this.workerChoiceStrategies.values()) {
 246       workerChoiceStrategy.setOptions(this.opts)
 247     }
 248   }
 249 }