src/pools/selection-strategies/less-used-worker-choice-strategy.ts

   1 import type { IWorker } from '../worker'
   2 import { AbstractWorkerChoiceStrategy } from './abstract-worker-choice-strategy'
   3 import type { IWorkerChoiceStrategy } from './selection-strategies-types'
   4
   5 /**
   6  * Selects the less used worker.
   7  *
   8  * @typeParam Worker - Type of worker which manages the strategy.
   9  * @typeParam Data - Type of data sent to the worker. This can only be serializable data.
  10  * @typeParam Response - Type of response of execution. This can only be serializable data.
  11  */
  12 export class LessUsedWorkerChoiceStrategy<
  13     Worker extends IWorker,
  14     Data = unknown,
  15     Response = unknown
  16   >
  17   extends AbstractWorkerChoiceStrategy<Worker, Data, Response>
  18   implements IWorkerChoiceStrategy {
  19   /** @inheritDoc */
  20   public reset (): boolean {
  21     return true
  22   }
  23
  24   /** @inheritDoc */
  25   public choose (): number {
  26     const freeWorkerNodeKey = this.pool.findFreeWorkerNodeKey()
  27     if (freeWorkerNodeKey !== -1) {
  28       return freeWorkerNodeKey
  29     }
  30     let minNumberOfTasks = Infinity
  31     let lessUsedWorkerNodeKey!: number
  32     for (const [index, workerNode] of this.pool.workerNodes.entries()) {
  33       const tasksUsage = workerNode.tasksUsage
  34       const workerTasks = tasksUsage.run + tasksUsage.running
  35       if (workerTasks === 0) {
  36         return index
  37       } else if (workerTasks < minNumberOfTasks) {
  38         minNumberOfTasks = workerTasks
  39         lessUsedWorkerNodeKey = index
  40       }
  41     }
  42     return lessUsedWorkerNodeKey
  43   }
  44
  45   /** @inheritDoc */
  46   public remove (workerNodeKey: number): boolean {
  47     return true
  48   }
  49 }