src/pools/selection-strategies/interleaved-weighted-round-robin-worker-choice-strategy.ts

   1 import type { IWorker } from '../worker.js'
   2 import type { IPool } from '../pool.js'
   3 import { DEFAULT_MEASUREMENT_STATISTICS_REQUIREMENTS } from '../../utils.js'
   4 import { AbstractWorkerChoiceStrategy } from './abstract-worker-choice-strategy.js'
   5 import type {
   6   IWorkerChoiceStrategy,
   7   InternalWorkerChoiceStrategyOptions,
   8   TaskStatisticsRequirements
   9 } from './selection-strategies-types.js'
  10
  11 /**
  12  * Selects the next worker with an interleaved weighted round robin scheduling algorithm.
  13  *
  14  * @typeParam Worker - Type of worker which manages the strategy.
  15  * @typeParam Data - Type of data sent to the worker. This can only be structured-cloneable data.
  16  * @typeParam Response - Type of execution response. This can only be structured-cloneable data.
  17  */
  18 export class InterleavedWeightedRoundRobinWorkerChoiceStrategy<
  19     Worker extends IWorker,
  20     Data = unknown,
  21     Response = unknown
  22   >
  23   extends AbstractWorkerChoiceStrategy<Worker, Data, Response>
  24   implements IWorkerChoiceStrategy {
  25   /** @inheritDoc */
  26   public readonly taskStatisticsRequirements: TaskStatisticsRequirements = {
  27     runTime: {
  28       aggregate: true,
  29       average: true,
  30       median: false
  31     },
  32     waitTime: DEFAULT_MEASUREMENT_STATISTICS_REQUIREMENTS,
  33     elu: DEFAULT_MEASUREMENT_STATISTICS_REQUIREMENTS
  34   }
  35
  36   /**
  37    * Round id.
  38    */
  39   private roundId: number = 0
  40   /**
  41    * Round weights.
  42    */
  43   private roundWeights: number[]
  44   /**
  45    * Worker node id.
  46    */
  47   private workerNodeId: number = 0
  48   /**
  49    * Worker node virtual task runtime.
  50    */
  51   private workerNodeVirtualTaskRunTime: number = 0
  52
  53   /** @inheritDoc */
  54   public constructor (
  55     pool: IPool<Worker, Data, Response>,
  56     opts: InternalWorkerChoiceStrategyOptions
  57   ) {
  58     super(pool, opts)
  59     this.setTaskStatisticsRequirements(this.opts)
  60     this.roundWeights = this.getRoundWeights()
  61   }
  62
  63   /** @inheritDoc */
  64   public reset (): boolean {
  65     this.resetWorkerNodeKeyProperties()
  66     this.roundId = 0
  67     this.workerNodeId = 0
  68     this.workerNodeVirtualTaskRunTime = 0
  69     return true
  70   }
  71
  72   /** @inheritDoc */
  73   public update (): boolean {
  74     return true
  75   }
  76
  77   /** @inheritDoc */
  78   public choose (): number | undefined {
  79     for (
  80       let roundIndex = this.roundId;
  81       roundIndex < this.roundWeights.length;
  82       roundIndex++
  83     ) {
  84       this.roundId = roundIndex
  85       for (
  86         let workerNodeKey = this.workerNodeId;
  87         workerNodeKey < this.pool.workerNodes.length;
  88         workerNodeKey++
  89       ) {
  90         this.workerNodeId = workerNodeKey
  91         if (
  92           this.workerNodeId !== this.nextWorkerNodeKey &&
  93           this.workerNodeVirtualTaskRunTime !== 0
  94         ) {
  95           this.workerNodeVirtualTaskRunTime = 0
  96         }
  97         const workerWeight = this.opts.weights?.[workerNodeKey] as number
  98         if (
  99           this.isWorkerNodeReady(workerNodeKey) &&
 100           workerWeight >= this.roundWeights[roundIndex] &&
 101           this.workerNodeVirtualTaskRunTime < workerWeight
 102         ) {
 103           this.workerNodeVirtualTaskRunTime =
 104             this.workerNodeVirtualTaskRunTime +
 105             this.getWorkerNodeTaskRunTime(workerNodeKey)
 106           this.setPreviousWorkerNodeKey(this.nextWorkerNodeKey)
 107           this.nextWorkerNodeKey = workerNodeKey
 108           return this.nextWorkerNodeKey
 109         }
 110       }
 111     }
 112     this.interleavedWeightedRoundRobinNextWorkerNodeId()
 113   }
 114
 115   private interleavedWeightedRoundRobinNextWorkerNodeId (): void {
 116     if (
 117       this.roundId === this.roundWeights.length - 1 &&
 118       this.workerNodeId === this.pool.workerNodes.length - 1
 119     ) {
 120       this.roundId = 0
 121       this.workerNodeId = 0
 122     } else if (this.workerNodeId === this.pool.workerNodes.length - 1) {
 123       this.roundId = this.roundId + 1
 124       this.workerNodeId = 0
 125     } else {
 126       this.workerNodeId = this.workerNodeId + 1
 127     }
 128   }
 129
 130   /** @inheritDoc */
 131   public remove (workerNodeKey: number): boolean {
 132     if (this.pool.workerNodes.length === 0) {
 133       this.reset()
 134     }
 135     if (
 136       this.workerNodeId === workerNodeKey &&
 137       this.workerNodeId > this.pool.workerNodes.length - 1
 138     ) {
 139       this.workerNodeId = this.pool.workerNodes.length - 1
 140     }
 141     if (
 142       this.previousWorkerNodeKey === workerNodeKey &&
 143       this.previousWorkerNodeKey > this.pool.workerNodes.length - 1
 144     ) {
 145       this.previousWorkerNodeKey = this.pool.workerNodes.length - 1
 146     }
 147     return true
 148   }
 149
 150   /** @inheritDoc */
 151   public setOptions (opts: InternalWorkerChoiceStrategyOptions): void {
 152     super.setOptions(opts)
 153     this.roundWeights = this.getRoundWeights()
 154   }
 155
 156   private getRoundWeights (): number[] {
 157     return [
 158       ...new Set(
 159         Object.values(this.opts.weights as Record<number, number>)
 160           .slice()
 161           .sort((a, b) => a - b)
 162       )
 163     ]
 164   }
 165 }