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     waitTime: false,
  31     avgWaitTime: false,
  32     medWaitTime: false
  33   }
  34
  35   /** @inheritDoc */
  36   public constructor (
  37     pool: IPool<Worker, Data, Response>,
  38     opts: WorkerChoiceStrategyOptions = DEFAULT_WORKER_CHOICE_STRATEGY_OPTIONS
  39   ) {
  40     super(pool, opts)
  41     this.setRequiredStatistics(this.opts)
  42   }
  43
  44   /** @inheritDoc */
  45   public reset (): boolean {
  46     return true
  47   }
  48
  49   /** @inheritDoc */
  50   public update (): boolean {
  51     return true
  52   }
  53
  54   /** @inheritDoc */
  55   public choose (): number {
  56     const freeWorkerNodeKey = this.findFreeWorkerNodeKey()
  57     if (freeWorkerNodeKey !== -1) {
  58       return freeWorkerNodeKey
  59     }
  60     let minRunTime = Infinity
  61     let leastBusyWorkerNodeKey!: number
  62     for (const [workerNodeKey, workerNode] of this.pool.workerNodes.entries()) {
  63       const workerRunTime = workerNode.tasksUsage.runTime
  64       if (workerRunTime === 0) {
  65         return workerNodeKey
  66       } else if (workerRunTime < minRunTime) {
  67         minRunTime = workerRunTime
  68         leastBusyWorkerNodeKey = workerNodeKey
  69       }
  70     }
  71     return leastBusyWorkerNodeKey
  72   }
  73
  74   /** @inheritDoc */
  75   public remove (): boolean {
  76     return true
  77   }
  78 }