X-Git-Url: https://git.piment-noir.org/?a=blobdiff_plain;f=src%2Fworker%2Fabstract-worker.ts;h=bb6ac5666e0252195b4f1cafbda38471ec7fcf07;hb=910416386b4f7d0da4e6f0d8551cefa2539c5ced;hp=cb33188e5778a3c9a31cc30f6ae93cb46b33567c;hpb=3d15e8a7b08e6bbe8265793d0fd859d3113c4f4b;p=poolifier.git

diff --git a/src/worker/abstract-worker.ts b/src/worker/abstract-worker.ts
index cb33188e..bb6ac566 100644
--- a/src/worker/abstract-worker.ts
+++ b/src/worker/abstract-worker.ts
@@ -1,180 +1,657 @@
-import { AsyncResource } from 'async_hooks'
-import type { Worker } from 'cluster'
-import type { MessagePort } from 'worker_threads'
-import type { MessageValue, KillBehavior } from '../utility-types'
-import type { WorkerOptions } from './worker-options'
-// import { killBehaviorEnumeration } from './worker-options'
+import type { Worker } from 'node:cluster'
+import { performance } from 'node:perf_hooks'
+import type { MessagePort } from 'node:worker_threads'
 
-const defaultMaxInactiveTime = 1000 * 60
-// TODO fix this and avoid that SOFT/HARD words are replicated so much times into the project
-const defaultKillBehavior: KillBehavior = 'SOFT'
+import type {
+  MessageValue,
+  Task,
+  TaskFunctionProperties,
+  TaskPerformance,
+  WorkerStatistics
+} from '../utility-types.js'
+import {
+  buildTaskFunctionProperties,
+  DEFAULT_TASK_NAME,
+  EMPTY_FUNCTION,
+  isAsyncFunction,
+  isPlainObject
+} from '../utils.js'
+import type {
+  TaskAsyncFunction,
+  TaskFunction,
+  TaskFunctionObject,
+  TaskFunctionOperationResult,
+  TaskFunctions,
+  TaskSyncFunction
+} from './task-functions.js'
+import {
+  checkTaskFunctionName,
+  checkValidTaskFunctionObjectEntry,
+  checkValidWorkerOptions
+} from './utils.js'
+import { KillBehaviors, type WorkerOptions } from './worker-options.js'
+
+const DEFAULT_MAX_INACTIVE_TIME = 60000
+const DEFAULT_WORKER_OPTIONS: WorkerOptions = {
+  /**
+   * The kill behavior option on this worker or its default value.
+   */
+  killBehavior: KillBehaviors.SOFT,
+  /**
+   * The maximum time to keep this worker active while idle.
+   * The pool automatically checks and terminates this worker when the time expires.
+   */
+  maxInactiveTime: DEFAULT_MAX_INACTIVE_TIME,
+  /**
+   * The function to call when the worker is killed.
+   */
+  killHandler: EMPTY_FUNCTION
+}
 
 /**
- * Base class containing some shared logic for all poolifier workers.
+ * Base class that implements some shared logic for all poolifier workers.
  *
- * @template MainWorker Type of main worker.
- * @template Data Type of data this worker receives from pool's execution.
- * @template Response Type of response the worker sends back to the main worker.
+ * @typeParam MainWorker - Type of main worker.
+ * @typeParam Data - Type of data this worker receives from pool's execution. This can only be structured-cloneable data.
+ * @typeParam Response - Type of response the worker sends back to the main worker. This can only be structured-cloneable data.
  */
 export abstract class AbstractWorker<
   MainWorker extends Worker | MessagePort,
   Data = unknown,
   Response = unknown
-> extends AsyncResource {
+> {
   /**
-   * The maximum time to keep this worker alive while idle. The pool automatically checks and terminates this worker when the time expires.
+   * Worker id.
    */
-  protected readonly maxInactiveTime: number
+  protected abstract id: number
   /**
-   * The kill behavior set as option on the Worker constructor or a default value.
+   * Task function object(s) processed by the worker when the pool's `execution` function is invoked.
    */
-  protected readonly killBehavior: KillBehavior
+  protected taskFunctions!: Map<string, TaskFunctionObject<Data, Response>>
   /**
-   * Whether the worker is working asynchronously or not.
+   * Timestamp of the last task processed by this worker.
    */
-  protected readonly async: boolean
+  protected lastTaskTimestamp!: number
   /**
-   * Timestamp of the last task processed by this worker.
+   * Performance statistics computation requirements.
    */
-  protected lastTask: number
+  protected statistics?: WorkerStatistics
   /**
-   * Handler ID of the `interval` alive check.
+   * Handler id of the `activeInterval` worker activity check.
    */
-  protected readonly interval?: NodeJS.Timeout
+  protected activeInterval?: NodeJS.Timeout
 
   /**
    * Constructs a new poolifier worker.
    *
-   * @param type The type of async event.
-   * @param isMain Whether this is the main worker or not.
-   * @param fn Function processed by the worker when the pool's `execution` function is invoked.
-   * @param mainWorker Reference to main worker.
-   * @param opts Options for the worker.
+   * @param isMain - Whether this is the main worker or not.
+   * @param mainWorker - Reference to main worker.
+   * @param taskFunctions - Task function(s) processed by the worker when the pool's `execution` function is invoked. The first function is the default function.
+   * @param opts - Options for the worker.
    */
   public constructor (
-    type: string,
-    isMain: boolean,
-    fn: (data: Data) => Response,
-    protected mainWorker?: MainWorker | null,
-    public readonly opts: WorkerOptions = {
-      killBehavior: defaultKillBehavior,
-      maxInactiveTime: defaultMaxInactiveTime
-    }
+    protected readonly isMain: boolean | undefined,
+    private readonly mainWorker: MainWorker | undefined | null,
+    taskFunctions: TaskFunction<Data, Response> | TaskFunctions<Data, Response>,
+    protected opts: WorkerOptions = DEFAULT_WORKER_OPTIONS
   ) {
-    super(type)
-    this.killBehavior = this.opts.killBehavior ?? defaultKillBehavior
-    this.maxInactiveTime = this.opts.maxInactiveTime ?? defaultMaxInactiveTime
-    this.async = !!this.opts.async
-    this.lastTask = Date.now()
-    if (!fn) throw new Error('fn parameter is mandatory')
-    // Keep the worker active
-    if (!isMain) {
-      this.interval = setInterval(
-        this.checkAlive.bind(this),
-        this.maxInactiveTime / 2
-      )
-      this.checkAlive.bind(this)()
+    if (this.isMain == null) {
+      throw new Error('isMain parameter is mandatory')
     }
+    this.checkTaskFunctions(taskFunctions)
+    this.checkWorkerOptions(this.opts)
+    if (!this.isMain) {
+      // Should be once() but Node.js on windows has a bug that prevents it from working
+      this.getMainWorker().on('message', this.handleReadyMessage.bind(this))
+    }
+  }
 
-    this.mainWorker?.on('message', (value: MessageValue<Data, MainWorker>) => {
-      if (value?.data && value.id) {
-        // Here you will receive messages
-        if (this.async) {
-          this.runInAsyncScope(this.runAsync.bind(this), this, fn, value)
-        } else {
-          this.runInAsyncScope(this.run.bind(this), this, fn, value)
+  private checkWorkerOptions (opts: WorkerOptions): void {
+    checkValidWorkerOptions(opts)
+    this.opts = { ...DEFAULT_WORKER_OPTIONS, ...opts }
+  }
+
+  /**
+   * Checks if the `taskFunctions` parameter is passed to the constructor and valid.
+   *
+   * @param taskFunctions - The task function(s) parameter that should be checked.
+   */
+  private checkTaskFunctions (
+    taskFunctions:
+    | TaskFunction<Data, Response>
+    | TaskFunctions<Data, Response>
+    | undefined
+  ): void {
+    if (taskFunctions == null) {
+      throw new Error('taskFunctions parameter is mandatory')
+    }
+    this.taskFunctions = new Map<string, TaskFunctionObject<Data, Response>>()
+    if (typeof taskFunctions === 'function') {
+      const fnObj = { taskFunction: taskFunctions.bind(this) }
+      this.taskFunctions.set(DEFAULT_TASK_NAME, fnObj)
+      this.taskFunctions.set(
+        typeof taskFunctions.name === 'string' &&
+          taskFunctions.name.trim().length > 0
+          ? taskFunctions.name
+          : 'fn1',
+        fnObj
+      )
+    } else if (isPlainObject(taskFunctions)) {
+      let firstEntry = true
+      for (let [name, fnObj] of Object.entries(taskFunctions)) {
+        if (typeof fnObj === 'function') {
+          fnObj = { taskFunction: fnObj } satisfies TaskFunctionObject<
+          Data,
+          Response
+          >
+        }
+        checkValidTaskFunctionObjectEntry<Data, Response>(name, fnObj)
+        fnObj.taskFunction = fnObj.taskFunction.bind(this)
+        if (firstEntry) {
+          this.taskFunctions.set(DEFAULT_TASK_NAME, fnObj)
+          firstEntry = false
         }
-      } else if (value.parent) {
-        // Save a reference of the main worker to communicate with it
-        // This will be received once
-        this.mainWorker = value.parent
-      } else if (value.kill) {
-        // Here is time to kill this worker, just clearing the interval
-        if (this.interval) clearInterval(this.interval)
-        this.emitDestroy()
+        this.taskFunctions.set(name, fnObj)
+      }
+      if (firstEntry) {
+        throw new Error('taskFunctions parameter object is empty')
+      }
+    } else {
+      throw new TypeError(
+        'taskFunctions parameter is not a function or a plain object'
+      )
+    }
+  }
+
+  /**
+   * Checks if the worker has a task function with the given name.
+   *
+   * @param name - The name of the task function to check.
+   * @returns Whether the worker has a task function with the given name or not.
+   */
+  public hasTaskFunction (name: string): TaskFunctionOperationResult {
+    try {
+      checkTaskFunctionName(name)
+    } catch (error) {
+      return { status: false, error: error as Error }
+    }
+    return { status: this.taskFunctions.has(name) }
+  }
+
+  /**
+   * Adds a task function to the worker.
+   * If a task function with the same name already exists, it is replaced.
+   *
+   * @param name - The name of the task function to add.
+   * @param fn - The task function to add.
+   * @returns Whether the task function was added or not.
+   */
+  public addTaskFunction (
+    name: string,
+    fn: TaskFunction<Data, Response> | TaskFunctionObject<Data, Response>
+  ): TaskFunctionOperationResult {
+    try {
+      checkTaskFunctionName(name)
+      if (name === DEFAULT_TASK_NAME) {
+        throw new Error(
+          'Cannot add a task function with the default reserved name'
+        )
+      }
+      if (typeof fn === 'function') {
+        fn = { taskFunction: fn } satisfies TaskFunctionObject<Data, Response>
+      }
+      checkValidTaskFunctionObjectEntry<Data, Response>(name, fn)
+      fn.taskFunction = fn.taskFunction.bind(this)
+      if (
+        this.taskFunctions.get(name) ===
+        this.taskFunctions.get(DEFAULT_TASK_NAME)
+      ) {
+        this.taskFunctions.set(DEFAULT_TASK_NAME, fn)
+      }
+      this.taskFunctions.set(name, fn)
+      this.sendTaskFunctionsPropertiesToMainWorker()
+      return { status: true }
+    } catch (error) {
+      return { status: false, error: error as Error }
+    }
+  }
+
+  /**
+   * Removes a task function from the worker.
+   *
+   * @param name - The name of the task function to remove.
+   * @returns Whether the task function existed and was removed or not.
+   */
+  public removeTaskFunction (name: string): TaskFunctionOperationResult {
+    try {
+      checkTaskFunctionName(name)
+      if (name === DEFAULT_TASK_NAME) {
+        throw new Error(
+          'Cannot remove the task function with the default reserved name'
+        )
+      }
+      if (
+        this.taskFunctions.get(name) ===
+        this.taskFunctions.get(DEFAULT_TASK_NAME)
+      ) {
+        throw new Error(
+          'Cannot remove the task function used as the default task function'
+        )
+      }
+      const deleteStatus = this.taskFunctions.delete(name)
+      this.sendTaskFunctionsPropertiesToMainWorker()
+      return { status: deleteStatus }
+    } catch (error) {
+      return { status: false, error: error as Error }
+    }
+  }
+
+  /**
+   * Lists the properties of the worker's task functions.
+   *
+   * @returns The properties of the worker's task functions.
+   */
+  public listTaskFunctionsProperties (): TaskFunctionProperties[] {
+    let defaultTaskFunctionName = DEFAULT_TASK_NAME
+    for (const [name, fnObj] of this.taskFunctions) {
+      if (
+        name !== DEFAULT_TASK_NAME &&
+        fnObj === this.taskFunctions.get(DEFAULT_TASK_NAME)
+      ) {
+        defaultTaskFunctionName = name
+        break
+      }
+    }
+    const taskFunctionsProperties: TaskFunctionProperties[] = []
+    for (const [name, fnObj] of this.taskFunctions) {
+      if (name === DEFAULT_TASK_NAME || name === defaultTaskFunctionName) {
+        continue
+      }
+      taskFunctionsProperties.push(buildTaskFunctionProperties(name, fnObj))
+    }
+    return [
+      buildTaskFunctionProperties(
+        DEFAULT_TASK_NAME,
+        this.taskFunctions.get(DEFAULT_TASK_NAME)
+      ),
+      buildTaskFunctionProperties(
+        defaultTaskFunctionName,
+        this.taskFunctions.get(defaultTaskFunctionName)
+      ),
+      ...taskFunctionsProperties
+    ]
+  }
+
+  /**
+   * Sets the default task function to use in the worker.
+   *
+   * @param name - The name of the task function to use as default task function.
+   * @returns Whether the default task function was set or not.
+   */
+  public setDefaultTaskFunction (name: string): TaskFunctionOperationResult {
+    try {
+      checkTaskFunctionName(name)
+      if (name === DEFAULT_TASK_NAME) {
+        throw new Error(
+          'Cannot set the default task function reserved name as the default task function'
+        )
       }
+      if (!this.taskFunctions.has(name)) {
+        throw new Error(
+          'Cannot set the default task function to a non-existing task function'
+        )
+      }
+      // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
+      this.taskFunctions.set(DEFAULT_TASK_NAME, this.taskFunctions.get(name)!)
+      this.sendTaskFunctionsPropertiesToMainWorker()
+      return { status: true }
+    } catch (error) {
+      return { status: false, error: error as Error }
+    }
+  }
+
+  /**
+   * Handles the ready message sent by the main worker.
+   *
+   * @param message - The ready message.
+   */
+  protected abstract handleReadyMessage (message: MessageValue<Data>): void
+
+  /**
+   * Worker message listener.
+   *
+   * @param message - The received message.
+   */
+  protected messageListener (message: MessageValue<Data>): void {
+    this.checkMessageWorkerId(message)
+    const {
+      statistics,
+      checkActive,
+      taskFunctionOperation,
+      taskId,
+      data,
+      kill
+    } = message
+    if (statistics != null) {
+      // Statistics message received
+      this.statistics = statistics
+    } else if (checkActive != null) {
+      // Check active message received
+      checkActive ? this.startCheckActive() : this.stopCheckActive()
+    } else if (taskFunctionOperation != null) {
+      // Task function operation message received
+      this.handleTaskFunctionOperationMessage(message)
+    } else if (taskId != null && data != null) {
+      // Task message received
+      this.run(message)
+    } else if (kill === true) {
+      // Kill message received
+      this.handleKillMessage(message)
+    }
+  }
+
+  protected handleTaskFunctionOperationMessage (
+    message: MessageValue<Data>
+  ): void {
+    const { taskFunctionOperation, taskFunctionProperties, taskFunction } =
+      message
+    if (taskFunctionProperties == null) {
+      throw new Error(
+        'Cannot handle task function operation message without task function properties'
+      )
+    }
+    let response: TaskFunctionOperationResult
+    switch (taskFunctionOperation) {
+      case 'add':
+        response = this.addTaskFunction(taskFunctionProperties.name, {
+          // eslint-disable-next-line @typescript-eslint/no-implied-eval, no-new-func
+          taskFunction: new Function(
+            `return ${taskFunction}`
+          )() as TaskFunction<Data, Response>,
+          ...(taskFunctionProperties.priority != null && {
+            priority: taskFunctionProperties.priority
+          }),
+          ...(taskFunctionProperties.strategy != null && {
+            strategy: taskFunctionProperties.strategy
+          })
+        })
+        break
+      case 'remove':
+        response = this.removeTaskFunction(taskFunctionProperties.name)
+        break
+      case 'default':
+        response = this.setDefaultTaskFunction(taskFunctionProperties.name)
+        break
+      default:
+        response = { status: false, error: new Error('Unknown task operation') }
+        break
+    }
+    this.sendToMainWorker({
+      taskFunctionOperation,
+      taskFunctionOperationStatus: response.status,
+      taskFunctionProperties,
+      ...(!response.status &&
+        response.error != null && {
+        workerError: {
+          name: taskFunctionProperties.name,
+          message: this.handleError(response.error as Error | string)
+        }
+      })
     })
   }
 
+  /**
+   * Handles a kill message sent by the main worker.
+   *
+   * @param message - The kill message.
+   */
+  protected handleKillMessage (_message: MessageValue<Data>): void {
+    this.stopCheckActive()
+    if (isAsyncFunction(this.opts.killHandler)) {
+      (this.opts.killHandler() as Promise<void>)
+        .then(() => {
+          this.sendToMainWorker({ kill: 'success' })
+          return undefined
+        })
+        .catch(() => {
+          this.sendToMainWorker({ kill: 'failure' })
+        })
+    } else {
+      try {
+        // eslint-disable-next-line @typescript-eslint/no-invalid-void-type
+        this.opts.killHandler?.() as void
+        this.sendToMainWorker({ kill: 'success' })
+      } catch {
+        this.sendToMainWorker({ kill: 'failure' })
+      }
+    }
+  }
+
+  /**
+   * Check if the message worker id is set and matches the worker id.
+   *
+   * @param message - The message to check.
+   * @throws {@link https://nodejs.org/api/errors.html#class-error} If the message worker id is not set or does not match the worker id.
+   */
+  private checkMessageWorkerId (message: MessageValue<Data>): void {
+    if (message.workerId == null) {
+      throw new Error('Message worker id is not set')
+    } else if (message.workerId !== this.id) {
+      throw new Error(
+        `Message worker id ${message.workerId} does not match the worker id ${this.id}`
+      )
+    }
+  }
+
+  /**
+   * Starts the worker check active interval.
+   */
+  private startCheckActive (): void {
+    this.lastTaskTimestamp = performance.now()
+    this.activeInterval = setInterval(
+      this.checkActive.bind(this),
+      (this.opts.maxInactiveTime ?? DEFAULT_MAX_INACTIVE_TIME) / 2
+    )
+  }
+
+  /**
+   * Stops the worker check active interval.
+   */
+  private stopCheckActive (): void {
+    if (this.activeInterval != null) {
+      clearInterval(this.activeInterval)
+      delete this.activeInterval
+    }
+  }
+
+  /**
+   * Checks if the worker should be terminated, because its living too long.
+   */
+  private checkActive (): void {
+    if (
+      performance.now() - this.lastTaskTimestamp >
+      (this.opts.maxInactiveTime ?? DEFAULT_MAX_INACTIVE_TIME)
+    ) {
+      this.sendToMainWorker({ kill: this.opts.killBehavior })
+    }
+  }
+
   /**
    * Returns the main worker.
    *
    * @returns Reference to the main worker.
+   * @throws {@link https://nodejs.org/api/errors.html#class-error} If the main worker is not set.
    */
   protected getMainWorker (): MainWorker {
-    if (!this.mainWorker) {
-      throw new Error('Main worker was not set')
+    if (this.mainWorker == null) {
+      throw new Error('Main worker not set')
     }
     return this.mainWorker
   }
 
   /**
-   * Send a message to the main worker.
+   * Sends a message to main worker.
    *
-   * @param message The response message.
+   * @param message - The response message.
    */
-  protected abstract sendToMainWorker (message: MessageValue<Response>): void
+  protected abstract sendToMainWorker (
+    message: MessageValue<Response, Data>
+  ): void
 
   /**
-   * Check to see if the worker should be terminated, because its living too long.
+   * Sends task functions properties to the main worker.
    */
-  protected checkAlive (): void {
-    if (Date.now() - this.lastTask > this.maxInactiveTime) {
-      this.sendToMainWorker({ kill: this.killBehavior })
-    }
+  protected sendTaskFunctionsPropertiesToMainWorker (): void {
+    this.sendToMainWorker({
+      taskFunctionsProperties: this.listTaskFunctionsProperties()
+    })
   }
 
   /**
-   * Handle an error and convert it to a string so it can be sent back to the main worker.
+   * Handles an error and convert it to a string so it can be sent back to the main worker.
    *
-   * @param e The error raised by the worker.
-   * @returns Message of the error.
+   * @param error - The error raised by the worker.
+   * @returns The error message.
    */
-  protected handleError (e: Error | string): string {
-    return (e as unknown) as string
+  protected handleError (error: Error | string): string {
+    return error instanceof Error ? error.message : error
   }
 
   /**
-   * Run the given function synchronously.
+   * Runs the given task.
    *
-   * @param fn Function that will be executed.
-   * @param value Input data for the given function.
+   * @param task - The task to execute.
    */
-  protected run (
-    fn: (data?: Data) => Response,
-    value: MessageValue<Data>
-  ): void {
+  protected readonly run = (task: Task<Data>): void => {
+    const { name, taskId, data } = task
+    const taskFunctionName = name ?? DEFAULT_TASK_NAME
+    if (!this.taskFunctions.has(taskFunctionName)) {
+      this.sendToMainWorker({
+        workerError: {
+          // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
+          name: name!,
+          message: `Task function '${name}' not found`,
+          data
+        },
+        taskId
+      })
+      return
+    }
+    const fn = this.taskFunctions.get(taskFunctionName)?.taskFunction
+    if (isAsyncFunction(fn)) {
+      this.runAsync(fn as TaskAsyncFunction<Data, Response>, task)
+    } else {
+      this.runSync(fn as TaskSyncFunction<Data, Response>, task)
+    }
+  }
+
+  /**
+   * Runs the given task function synchronously.
+   *
+   * @param fn - Task function that will be executed.
+   * @param task - Input data for the task function.
+   */
+  protected readonly runSync = (
+    fn: TaskSyncFunction<Data, Response>,
+    task: Task<Data>
+  ): void => {
+    const { name, taskId, data } = task
     try {
-      const res = fn(value.data)
-      this.sendToMainWorker({ data: res, id: value.id })
-      this.lastTask = Date.now()
-    } catch (e) {
-      const err = this.handleError(e)
-      this.sendToMainWorker({ error: err, id: value.id })
-      this.lastTask = Date.now()
+      let taskPerformance = this.beginTaskPerformance(name)
+      const res = fn(data)
+      taskPerformance = this.endTaskPerformance(taskPerformance)
+      this.sendToMainWorker({
+        data: res,
+        taskPerformance,
+        taskId
+      })
+    } catch (error) {
+      this.sendToMainWorker({
+        workerError: {
+          // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
+          name: name!,
+          message: this.handleError(error as Error | string),
+          data
+        },
+        taskId
+      })
+    } finally {
+      this.updateLastTaskTimestamp()
     }
   }
 
   /**
-   * Run the given function asynchronously.
+   * Runs the given task function asynchronously.
    *
-   * @param fn Function that will be executed.
-   * @param value Input data for the given function.
+   * @param fn - Task function that will be executed.
+   * @param task - Input data for the task function.
    */
-  protected runAsync (
-    fn: (data?: Data) => Promise<Response>,
-    value: MessageValue<Data>
-  ): void {
-    fn(value.data)
+  protected readonly runAsync = (
+    fn: TaskAsyncFunction<Data, Response>,
+    task: Task<Data>
+  ): void => {
+    const { name, taskId, data } = task
+    let taskPerformance = this.beginTaskPerformance(name)
+    fn(data)
       .then(res => {
-        this.sendToMainWorker({ data: res, id: value.id })
-        this.lastTask = Date.now()
-        return null
+        taskPerformance = this.endTaskPerformance(taskPerformance)
+        this.sendToMainWorker({
+          data: res,
+          taskPerformance,
+          taskId
+        })
+        return undefined
+      })
+      .catch((error: unknown) => {
+        this.sendToMainWorker({
+          workerError: {
+            // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
+            name: name!,
+            message: this.handleError(error as Error | string),
+            data
+          },
+          taskId
+        })
+      })
+      .finally(() => {
+        this.updateLastTaskTimestamp()
+      })
+      .catch(EMPTY_FUNCTION)
+  }
+
+  private beginTaskPerformance (name?: string): TaskPerformance {
+    if (this.statistics == null) {
+      throw new Error('Performance statistics computation requirements not set')
+    }
+    return {
+      name: name ?? DEFAULT_TASK_NAME,
+      timestamp: performance.now(),
+      ...(this.statistics.elu && {
+        elu: performance.eventLoopUtilization()
       })
-      .catch(e => {
-        const err = this.handleError(e)
-        this.sendToMainWorker({ error: err, id: value.id })
-        this.lastTask = Date.now()
+    }
+  }
+
+  private endTaskPerformance (
+    taskPerformance: TaskPerformance
+  ): TaskPerformance {
+    if (this.statistics == null) {
+      throw new Error('Performance statistics computation requirements not set')
+    }
+    return {
+      ...taskPerformance,
+      ...(this.statistics.runTime && {
+        runTime: performance.now() - taskPerformance.timestamp
+      }),
+      ...(this.statistics.elu && {
+        elu: performance.eventLoopUtilization(taskPerformance.elu)
       })
+    }
+  }
+
+  private updateLastTaskTimestamp (): void {
+    if (this.activeInterval != null) {
+      this.lastTaskTimestamp = performance.now()
+    }
   }
 }