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   RequiredStatistics,
   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 requiredStatistics: RequiredStatistics = {
  27     runTime: true,
  28     avgRunTime: false,
  29     medRunTime: false
  30   }
  31
  32   /** @inheritDoc */
  33   public constructor (
  34     pool: IPool<Worker, Data, Response>,
  35     opts: WorkerChoiceStrategyOptions = DEFAULT_WORKER_CHOICE_STRATEGY_OPTIONS
  36   ) {
  37     super(pool, opts)
  38     this.setRequiredStatistics(this.opts)
  39   }
  40
  41   /** @inheritDoc */
  42   public reset (): boolean {
  43     return true
  44   }
  45
  46   /** @inheritDoc */
  47   public update (): boolean {
  48     return true
  49   }
  50
  51   /** @inheritDoc */
  52   public choose (): number {
  53     const freeWorkerNodeKey = this.findFreeWorkerNodeKey()
  54     if (freeWorkerNodeKey !== -1) {
  55       return freeWorkerNodeKey
  56     }
  57     let minRunTime = Infinity
  58     let leastBusyWorkerNodeKey!: number
  59     for (const [workerNodeKey, workerNode] of this.pool.workerNodes.entries()) {
  60       const workerRunTime = workerNode.tasksUsage.runTime
  61       if (workerRunTime === 0) {
  62         return workerNodeKey
  63       } else if (workerRunTime < minRunTime) {
  64         minRunTime = workerRunTime
  65         leastBusyWorkerNodeKey = workerNodeKey
  66       }
  67     }
  68     return leastBusyWorkerNodeKey
  69   }
  70
  71   /** @inheritDoc */
  72   public remove (): boolean {
  73     return true
  74   }
  75 }