refactor: factor out common code in worker choice strategies

[poolifier.git] / src / pools / selection-strategies / abstract-worker-choice-strategy.ts

diff --git a/src/pools/selection-strategies/abstract-worker-choice-strategy.ts b/src/pools/selection-strategies/abstract-worker-choice-strategy.ts
index 2f1905782f7c4a6c3d6d4c98053b3965eaa8021d..6e798fbc4349d98bf5b5761d884013382efa601f 100644 (file)
--- a/src/pools/selection-strategies/abstract-worker-choice-strategy.ts
+++ b/src/pools/selection-strategies/abstract-worker-choice-strategy.ts
@@ -1,5 +1,6 @@
+import { cpus } from 'node:os'
 import { DEFAULT_WORKER_CHOICE_STRATEGY_OPTIONS } from '../../utils'
-import { PoolType, type IPool } from '../pool'
+import type { IPool } from '../pool'
 import type { IWorker } from '../worker'
 import type {
   IWorkerChoiceStrategy,
@@ -19,13 +20,18 @@ export abstract class AbstractWorkerChoiceStrategy<
   Data = unknown,
   Response = unknown
 > implements IWorkerChoiceStrategy {
-  /** @inheritDoc */
-  protected readonly isDynamicPool: boolean
+  /**
+   * Toggles finding the last free worker node key.
+   */
+  private toggleFindLastFreeWorkerNodeKey: boolean = false
   /** @inheritDoc */
   public readonly requiredStatistics: RequiredStatistics = {
     runTime: false,
     avgRunTime: false,
-    medRunTime: false
+    medRunTime: false,
+    waitTime: false,
+    avgWaitTime: false,
+    medWaitTime: false
   }
 
   /**
@@ -38,11 +44,10 @@ export abstract class AbstractWorkerChoiceStrategy<
     protected readonly pool: IPool<Worker, Data, Response>,
     protected opts: WorkerChoiceStrategyOptions = DEFAULT_WORKER_CHOICE_STRATEGY_OPTIONS
   ) {
-    this.isDynamicPool = this.pool.type === PoolType.DYNAMIC
     this.choose = this.choose.bind(this)
   }
 
-  protected checkOptions (opts: WorkerChoiceStrategyOptions): void {
+  protected setRequiredStatistics (opts: WorkerChoiceStrategyOptions): void {
     if (this.requiredStatistics.avgRunTime && opts.medRunTime === true) {
       this.requiredStatistics.avgRunTime = false
       this.requiredStatistics.medRunTime = opts.medRunTime as boolean
@@ -51,11 +56,22 @@ export abstract class AbstractWorkerChoiceStrategy<
       this.requiredStatistics.avgRunTime = true
       this.requiredStatistics.medRunTime = opts.medRunTime as boolean
     }
+    if (this.requiredStatistics.avgWaitTime && opts.medWaitTime === true) {
+      this.requiredStatistics.avgWaitTime = false
+      this.requiredStatistics.medWaitTime = opts.medWaitTime as boolean
+    }
+    if (this.requiredStatistics.medWaitTime && opts.medWaitTime === false) {
+      this.requiredStatistics.avgWaitTime = true
+      this.requiredStatistics.medWaitTime = opts.medWaitTime as boolean
+    }
   }
 
   /** @inheritDoc */
   public abstract reset (): boolean
 
+  /** @inheritDoc */
+  public abstract update (workerNodeKey: number): boolean
+
   /** @inheritDoc */
   public abstract choose (): number
 
@@ -65,7 +81,101 @@ export abstract class AbstractWorkerChoiceStrategy<
   /** @inheritDoc */
   public setOptions (opts: WorkerChoiceStrategyOptions): void {
     opts = opts ?? DEFAULT_WORKER_CHOICE_STRATEGY_OPTIONS
-    this.checkOptions(opts)
+    this.setRequiredStatistics(opts)
     this.opts = opts
   }
+
+  /**
+   * Finds a free worker node key.
+   *
+   * @returns The free worker node key or `-1` if there is no free worker node.
+   */
+  protected findFreeWorkerNodeKey (): number {
+    if (this.toggleFindLastFreeWorkerNodeKey) {
+      this.toggleFindLastFreeWorkerNodeKey = false
+      return this.findLastFreeWorkerNodeKey()
+    }
+    this.toggleFindLastFreeWorkerNodeKey = true
+    return this.findFirstFreeWorkerNodeKey()
+  }
+
+  /**
+   * Gets the worker task runtime.
+   * If the required statistics are `avgRunTime`, the average runtime is returned.
+   * If the required statistics are `medRunTime`, the median runtime is returned.
+   *
+   * @param workerNodeKey - The worker node key.
+   * @returns The worker task runtime.
+   */
+  protected getWorkerTaskRunTime (workerNodeKey: number): number {
+    return this.requiredStatistics.medRunTime
+      ? this.pool.workerNodes[workerNodeKey].tasksUsage.medRunTime
+      : this.pool.workerNodes[workerNodeKey].tasksUsage.avgRunTime
+  }
+
+  /**
+   * Gets the worker task wait time.
+   * If the required statistics are `avgWaitTime`, the average wait time is returned.
+   * If the required statistics are `medWaitTime`, the median wait time is returned.
+   *
+   * @param workerNodeKey - The worker node key.
+   * @returns The worker task wait time.
+   */
+  protected getWorkerWaitTime (workerNodeKey: number): number {
+    return this.requiredStatistics.medWaitTime
+      ? this.pool.workerNodes[workerNodeKey].tasksUsage.medWaitTime
+      : this.pool.workerNodes[workerNodeKey].tasksUsage.avgWaitTime
+  }
+
+  protected computeDefaultWorkerWeight (): number {
+    let cpusCycleTimeWeight = 0
+    for (const cpu of cpus()) {
+      // CPU estimated cycle time
+      const numberOfDigits = cpu.speed.toString().length - 1
+      const cpuCycleTime = 1 / (cpu.speed / Math.pow(10, numberOfDigits))
+      cpusCycleTimeWeight += cpuCycleTime * Math.pow(10, numberOfDigits)
+    }
+    return Math.round(cpusCycleTimeWeight / cpus().length)
+  }
+
+  /**
+   * Finds the first free worker node key based on the number of tasks the worker has applied.
+   *
+   * If a worker is found with `0` running tasks, it is detected as free and its worker node key is returned.
+   *
+   * If no free worker is found, `-1` is returned.
+   *
+   * @returns A worker node key if there is one, `-1` otherwise.
+   */
+  private findFirstFreeWorkerNodeKey (): number {
+    return this.pool.workerNodes.findIndex(workerNode => {
+      return workerNode.tasksUsage.running === 0
+    })
+  }
+
+  /**
+   * Finds the last free worker node key based on the number of tasks the worker has applied.
+   *
+   * If a worker is found with `0` running tasks, it is detected as free and its worker node key is returned.
+   *
+   * If no free worker is found, `-1` is returned.
+   *
+   * @returns A worker node key if there is one, `-1` otherwise.
+   */
+  private findLastFreeWorkerNodeKey (): number {
+    // It requires node >= 18.0.0:
+    // return this.workerNodes.findLastIndex(workerNode => {
+    //   return workerNode.tasksUsage.running === 0
+    // })
+    for (
+      let workerNodeKey = this.pool.workerNodes.length - 1;
+      workerNodeKey >= 0;
+      workerNodeKey--
+    ) {
+      if (this.pool.workerNodes[workerNodeKey].tasksUsage.running === 0) {
+        return workerNodeKey
+      }
+    }
+    return -1
+  }
 }