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

   1 import { buildInternalWorkerChoiceStrategyOptions } from '../../utils.js'
   2 import type { IPool } from '../pool.js'
   3 import type { IWorker } from '../worker.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   InternalWorkerChoiceStrategyOptions,
  13   StrategyPolicy,
  14   TaskStatisticsRequirements,
  15   WorkerChoiceStrategy
  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   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 = buildInternalWorkerChoiceStrategyOptions(
  50       pool.info.maxSize,
  51       this.opts
  52     )
  53     this.execute = this.execute.bind(this)
  54     this.workerChoiceStrategies = new Map<
  55     WorkerChoiceStrategy,
  56     IWorkerChoiceStrategy
  57     >([
  58       [
  59         WorkerChoiceStrategies.ROUND_ROBIN,
  60         new (RoundRobinWorkerChoiceStrategy.bind(this))<Worker, Data, Response>(
  61           pool,
  62           this.opts
  63         )
  64       ],
  65       [
  66         WorkerChoiceStrategies.LEAST_USED,
  67         new (LeastUsedWorkerChoiceStrategy.bind(this))<Worker, Data, Response>(
  68           pool,
  69           this.opts
  70         )
  71       ],
  72       [
  73         WorkerChoiceStrategies.LEAST_BUSY,
  74         new (LeastBusyWorkerChoiceStrategy.bind(this))<Worker, Data, Response>(
  75           pool,
  76           this.opts
  77         )
  78       ],
  79       [
  80         WorkerChoiceStrategies.LEAST_ELU,
  81         new (LeastEluWorkerChoiceStrategy.bind(this))<Worker, Data, Response>(
  82           pool,
  83           this.opts
  84         )
  85       ],
  86       [
  87         WorkerChoiceStrategies.FAIR_SHARE,
  88         new (FairShareWorkerChoiceStrategy.bind(this))<Worker, Data, Response>(
  89           pool,
  90           this.opts
  91         )
  92       ],
  93       [
  94         WorkerChoiceStrategies.WEIGHTED_ROUND_ROBIN,
  95         new (WeightedRoundRobinWorkerChoiceStrategy.bind(this))<
  96         Worker,
  97         Data,
  98         Response
  99         >(pool, this.opts)
 100       ],
 101       [
 102         WorkerChoiceStrategies.INTERLEAVED_WEIGHTED_ROUND_ROBIN,
 103         new (InterleavedWeightedRoundRobinWorkerChoiceStrategy.bind(this))<
 104         Worker,
 105         Data,
 106         Response
 107         >(pool, this.opts)
 108       ]
 109     ])
 110   }
 111
 112   /**
 113    * Gets the strategy policy in the context.
 114    *
 115    * @returns The strategy policy.
 116    */
 117   public getStrategyPolicy (): StrategyPolicy {
 118     // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
 119     return this.workerChoiceStrategies.get(this.workerChoiceStrategy)!
 120       .strategyPolicy
 121   }
 122
 123   /**
 124    * Gets the worker choice strategy in the context task statistics requirements.
 125    *
 126    * @returns The task statistics requirements.
 127    */
 128   public getTaskStatisticsRequirements (): TaskStatisticsRequirements {
 129     // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
 130     return this.workerChoiceStrategies.get(this.workerChoiceStrategy)!
 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 in the context internals.
 150    *
 151    * @returns `true` if the update is successful, `false` otherwise.
 152    */
 153   public update (workerNodeKey: number): boolean {
 154     // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
 155     return this.workerChoiceStrategies
 156       .get(this.workerChoiceStrategy)!
 157       .update(workerNodeKey)
 158   }
 159
 160   /**
 161    * Executes the worker choice strategy in the context algorithm.
 162    *
 163    * @returns The key of the worker node.
 164    * @throws {@link https://nodejs.org/api/errors.html#class-error} If after configured retries the worker node key is null or undefined.
 165    */
 166   public execute (): number {
 167     // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
 168     const workerChoiceStrategy = this.workerChoiceStrategies.get(
 169       this.workerChoiceStrategy
 170     )!
 171     if (!workerChoiceStrategy.hasPoolWorkerNodesReady()) {
 172       return this.execute()
 173     }
 174     return this.executeStrategy(workerChoiceStrategy)
 175   }
 176
 177   /**
 178    * Executes the given worker choice strategy.
 179    *
 180    * @param workerChoiceStrategy - The worker choice strategy.
 181    * @returns The key of the worker node.
 182    * @throws {@link https://nodejs.org/api/errors.html#class-error} If after configured retries the worker node key is null or undefined.
 183    */
 184   private executeStrategy (workerChoiceStrategy: IWorkerChoiceStrategy): number {
 185     let workerNodeKey: number | undefined
 186     let chooseCount = 0
 187     let retriesCount = 0
 188     do {
 189       workerNodeKey = workerChoiceStrategy.choose()
 190       if (workerNodeKey == null && chooseCount > 0) {
 191         retriesCount++
 192       }
 193       chooseCount++
 194       // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
 195     } while (workerNodeKey == null && retriesCount < this.opts!.retries!)
 196     if (workerNodeKey == null) {
 197       throw new Error(
 198         `Worker node key chosen is null or undefined after ${retriesCount} retries`
 199       )
 200     }
 201     return workerNodeKey
 202   }
 203
 204   /**
 205    * Removes the worker node key from the worker choice strategy in the context.
 206    *
 207    * @param workerNodeKey - The worker node key.
 208    * @returns `true` if the removal is successful, `false` otherwise.
 209    */
 210   public remove (workerNodeKey: number): boolean {
 211     // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
 212     return this.workerChoiceStrategies
 213       .get(this.workerChoiceStrategy)!
 214       .remove(workerNodeKey)
 215   }
 216
 217   /**
 218    * Sets the worker choice strategies in the context options.
 219    *
 220    * @param pool - The pool instance.
 221    * @param opts - The worker choice strategy options.
 222    */
 223   public setOptions (
 224     pool: IPool<Worker, Data, Response>,
 225     opts?: InternalWorkerChoiceStrategyOptions
 226   ): void {
 227     this.opts = buildInternalWorkerChoiceStrategyOptions(
 228       pool.info.maxSize,
 229       opts
 230     )
 231     for (const workerChoiceStrategy of this.workerChoiceStrategies.values()) {
 232       workerChoiceStrategy.setOptions(this.opts)
 233     }
 234   }
 235 }