src/pools/selection-strategies/least-busy-worker-choice-strategy.ts

   1 import { DEFAULT_WORKER_CHOICE_STRATEGY_OPTIONS } from '../../utils'
   2 import type { IPool } from '../pool'
   3 import type { IWorker } from '../worker'
   4 import { AbstractWorkerChoiceStrategy } from './abstract-worker-choice-strategy'
   5 import type {
   6   IWorkerChoiceStrategy,
   7   TaskStatisticsRequirements,
   8   WorkerChoiceStrategyOptions
   9 } from './selection-strategies-types'
  10
  11 /**
  12  * Selects the least busy worker.
  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 serializable data.
  16  * @typeParam Response - Type of execution response. This can only be serializable data.
  17  */
  18 export class LeastBusyWorkerChoiceStrategy<
  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: false,
  30       median: false
  31     },
  32     waitTime: {
  33       aggregate: true,
  34       average: false,
  35       median: false
  36     },
  37     elu: false
  38   }
  39
  40   /** @inheritDoc */
  41   public constructor (
  42     pool: IPool<Worker, Data, Response>,
  43     opts: WorkerChoiceStrategyOptions = DEFAULT_WORKER_CHOICE_STRATEGY_OPTIONS
  44   ) {
  45     super(pool, opts)
  46     this.setTaskStatisticsRequirements(this.opts)
  47   }
  48
  49   /** @inheritDoc */
  50   public reset (): boolean {
  51     return true
  52   }
  53
  54   /** @inheritDoc */
  55   public update (): boolean {
  56     return true
  57   }
  58
  59   /** @inheritDoc */
  60   public choose (): number {
  61     let minTime = Infinity
  62     let leastBusyWorkerNodeKey!: number
  63     for (const [workerNodeKey, workerNode] of this.pool.workerNodes.entries()) {
  64       const workerTime =
  65         workerNode.workerUsage.runTime.aggregate +
  66         workerNode.workerUsage.waitTime.aggregate
  67       if (workerTime === 0) {
  68         return workerNodeKey
  69       } else if (workerTime < minTime) {
  70         minTime = workerTime
  71         leastBusyWorkerNodeKey = workerNodeKey
  72       }
  73     }
  74     return leastBusyWorkerNodeKey
  75   }
  76
  77   /** @inheritDoc */
  78   public remove (): boolean {
  79     return true
  80   }
  81 }