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     elu: false
  34   }
  35
  36   /** @inheritDoc */
  37   public constructor (
  38     pool: IPool<Worker, Data, Response>,
  39     opts: WorkerChoiceStrategyOptions = DEFAULT_WORKER_CHOICE_STRATEGY_OPTIONS
  40   ) {
  41     super(pool, opts)
  42     this.setRequiredStatistics(this.opts)
  43   }
  44
  45   /** @inheritDoc */
  46   public reset (): boolean {
  47     return true
  48   }
  49
  50   /** @inheritDoc */
  51   public update (): boolean {
  52     return true
  53   }
  54
  55   /** @inheritDoc */
  56   public choose (): number {
  57     const freeWorkerNodeKey = this.findFreeWorkerNodeKey()
  58     if (freeWorkerNodeKey !== -1) {
  59       return freeWorkerNodeKey
  60     }
  61     let minRunTime = Infinity
  62     let leastBusyWorkerNodeKey!: number
  63     for (const [workerNodeKey, workerNode] of this.pool.workerNodes.entries()) {
  64       const workerRunTime = workerNode.tasksUsage.runTime
  65       if (workerRunTime === 0) {
  66         return workerNodeKey
  67       } else if (workerRunTime < minRunTime) {
  68         minRunTime = workerRunTime
  69         leastBusyWorkerNodeKey = workerNodeKey
  70       }
  71     }
  72     return leastBusyWorkerNodeKey
  73   }
  74
  75   /** @inheritDoc */
  76   public remove (): boolean {
  77     return true
  78   }
  79 }