src/pools/selection-strategies/less-used-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   WorkerChoiceStrategyOptions
   8 } from './selection-strategies-types'
   9
  10 /**
  11  * Selects the less used worker.
  12  *
  13  * @typeParam Worker - Type of worker which manages the strategy.
  14  * @typeParam Data - Type of data sent to the worker. This can only be serializable data.
  15  * @typeParam Response - Type of execution response. This can only be serializable data.
  16  */
  17 export class LessUsedWorkerChoiceStrategy<
  18     Worker extends IWorker,
  19     Data = unknown,
  20     Response = unknown
  21   >
  22   extends AbstractWorkerChoiceStrategy<Worker, Data, Response>
  23   implements IWorkerChoiceStrategy {
  24   /** @inheritDoc */
  25   public constructor (
  26     pool: IPool<Worker, Data, Response>,
  27     opts: WorkerChoiceStrategyOptions = DEFAULT_WORKER_CHOICE_STRATEGY_OPTIONS
  28   ) {
  29     super(pool, opts)
  30     this.checkOptions(this.opts)
  31   }
  32
  33   /** @inheritDoc */
  34   public reset (): boolean {
  35     return true
  36   }
  37
  38   /** @inheritDoc */
  39   public choose (): number {
  40     const freeWorkerNodeKey = this.findFreeWorkerNodeKey()
  41     if (freeWorkerNodeKey !== -1) {
  42       return freeWorkerNodeKey
  43     }
  44     let minNumberOfTasks = Infinity
  45     let lessUsedWorkerNodeKey!: number
  46     for (const [index, workerNode] of this.pool.workerNodes.entries()) {
  47       const tasksUsage = workerNode.tasksUsage
  48       const workerTasks = tasksUsage.run + tasksUsage.running
  49       if (workerTasks === 0) {
  50         return index
  51       } else if (workerTasks < minNumberOfTasks) {
  52         minNumberOfTasks = workerTasks
  53         lessUsedWorkerNodeKey = index
  54       }
  55     }
  56     return lessUsedWorkerNodeKey
  57   }
  58
  59   /** @inheritDoc */
  60   public remove (workerNodeKey: number): boolean {
  61     return true
  62   }
  63 }