1 import { AsyncResource
} from
'node:async_hooks'
2 import type { Worker
} from
'node:cluster'
3 import type { MessagePort
} from
'node:worker_threads'
4 import { performance
} from
'node:perf_hooks'
10 } from
'../utility-types'
21 } from
'./worker-options'
27 } from
'./task-functions'
29 const DEFAULT_MAX_INACTIVE_TIME
= 60000
30 const DEFAULT_KILL_BEHAVIOR
: KillBehavior
= KillBehaviors
.SOFT
33 * Base class that implements some shared logic for all poolifier workers.
35 * @typeParam MainWorker - Type of main worker.
36 * @typeParam Data - Type of data this worker receives from pool's execution. This can only be structured-cloneable data.
37 * @typeParam Response - Type of response the worker sends back to the main worker. This can only be structured-cloneable data.
39 export abstract class AbstractWorker
<
40 MainWorker
extends Worker
| MessagePort
,
43 > extends AsyncResource
{
47 protected abstract id
: number
49 * Task function(s) processed by the worker when the pool's `execution` function is invoked.
51 protected taskFunctions
!: Map
<string, TaskFunction
<Data
, Response
>>
53 * Timestamp of the last task processed by this worker.
55 protected lastTaskTimestamp
!: number
57 * Performance statistics computation requirements.
59 protected statistics
!: WorkerStatistics
61 * Handler id of the `activeInterval` worker activity check.
63 protected activeInterval
?: NodeJS
.Timeout
65 * Constructs a new poolifier worker.
67 * @param type - The type of async event.
68 * @param isMain - Whether this is the main worker or not.
69 * @param mainWorker - Reference to main worker.
70 * @param taskFunctions - Task function(s) processed by the worker when the pool's `execution` function is invoked. The first function is the default function.
71 * @param opts - Options for the worker.
75 protected readonly isMain
: boolean,
76 private readonly mainWorker
: MainWorker
,
77 taskFunctions
: TaskFunction
<Data
, Response
> | TaskFunctions
<Data
, Response
>,
78 protected readonly opts
: WorkerOptions
= {
80 * The kill behavior option on this worker or its default value.
82 killBehavior
: DEFAULT_KILL_BEHAVIOR
,
84 * The maximum time to keep this worker active while idle.
85 * The pool automatically checks and terminates this worker when the time expires.
87 maxInactiveTime
: DEFAULT_MAX_INACTIVE_TIME
,
89 * The function to call when the worker is killed.
91 killHandler
: EMPTY_FUNCTION
95 this.checkWorkerOptions(this.opts
)
96 this.checkTaskFunctions(taskFunctions
)
98 this.getMainWorker()?.on('message', this.handleReadyMessage
.bind(this))
102 private checkWorkerOptions (opts
: WorkerOptions
): void {
103 this.opts
.killBehavior
= opts
.killBehavior
?? DEFAULT_KILL_BEHAVIOR
104 this.opts
.maxInactiveTime
=
105 opts
.maxInactiveTime
?? DEFAULT_MAX_INACTIVE_TIME
106 delete this.opts
.async
107 this.opts
.killHandler
= opts
.killHandler
?? EMPTY_FUNCTION
111 * Checks if the `taskFunctions` parameter is passed to the constructor.
113 * @param taskFunctions - The task function(s) parameter that should be checked.
115 private checkTaskFunctions (
116 taskFunctions
: TaskFunction
<Data
, Response
> | TaskFunctions
<Data
, Response
>
118 if (taskFunctions
== null) {
119 throw new Error('taskFunctions parameter is mandatory')
121 this.taskFunctions
= new Map
<string, TaskFunction
<Data
, Response
>>()
122 if (typeof taskFunctions
=== 'function') {
123 const boundFn
= taskFunctions
.bind(this)
124 this.taskFunctions
.set(DEFAULT_TASK_NAME
, boundFn
)
125 this.taskFunctions
.set(
126 typeof taskFunctions
.name
=== 'string' &&
127 taskFunctions
.name
.trim().length
> 0
132 } else if (isPlainObject(taskFunctions
)) {
133 let firstEntry
= true
134 for (const [name
, fn
] of Object.entries(taskFunctions
)) {
135 if (typeof name
!== 'string') {
137 'A taskFunctions parameter object key is not a string'
140 if (typeof name
=== 'string' && name
.trim().length
=== 0) {
142 'A taskFunctions parameter object key an empty string'
145 if (typeof fn
!== 'function') {
147 'A taskFunctions parameter object value is not a function'
150 const boundFn
= fn
.bind(this)
152 this.taskFunctions
.set(DEFAULT_TASK_NAME
, boundFn
)
155 this.taskFunctions
.set(name
, boundFn
)
158 throw new Error('taskFunctions parameter object is empty')
162 'taskFunctions parameter is not a function or a plain object'
168 * Checks if the worker has a task function with the given name.
170 * @param name - The name of the task function to check.
171 * @returns Whether the worker has a task function with the given name or not.
172 * @throws {@link https://nodejs.org/api/errors.html#class-typeerror} If the `name` parameter is not a string.
174 public hasTaskFunction (name
: string): boolean {
175 if (typeof name
!== 'string') {
176 throw new TypeError('name parameter is not a string')
178 if (typeof name
=== 'string' && name
.trim().length
=== 0) {
179 throw new TypeError('name parameter is an empty string')
181 return this.taskFunctions
.has(name
)
185 * Adds a task function to the worker.
186 * If a task function with the same name already exists, it is replaced.
188 * @param name - The name of the task function to add.
189 * @param fn - The task function to add.
190 * @returns Whether the task function was added or not.
191 * @throws {@link https://nodejs.org/api/errors.html#class-typeerror} If the `name` parameter is not a string.
192 * @throws {@link https://nodejs.org/api/errors.html#class-error} If the `name` parameter is the default task function reserved name.
193 * @throws {@link https://nodejs.org/api/errors.html#class-typeerror} If the `fn` parameter is not a function.
195 public addTaskFunction (
197 fn
: TaskFunction
<Data
, Response
>
199 if (typeof name
!== 'string') {
200 throw new TypeError('name parameter is not a string')
202 if (typeof name
=== 'string' && name
.trim().length
=== 0) {
203 throw new TypeError('name parameter is an empty string')
205 if (name
=== DEFAULT_TASK_NAME
) {
207 'Cannot add a task function with the default reserved name'
210 if (typeof fn
!== 'function') {
211 throw new TypeError('fn parameter is not a function')
214 const boundFn
= fn
.bind(this)
216 this.taskFunctions
.get(name
) ===
217 this.taskFunctions
.get(DEFAULT_TASK_NAME
)
219 this.taskFunctions
.set(DEFAULT_TASK_NAME
, boundFn
)
221 this.taskFunctions
.set(name
, boundFn
)
222 this.sendTaskFunctionsListToMainWorker()
230 * Removes a task function from the worker.
232 * @param name - The name of the task function to remove.
233 * @returns Whether the task function existed and was removed or not.
234 * @throws {@link https://nodejs.org/api/errors.html#class-typeerror} If the `name` parameter is not a string.
235 * @throws {@link https://nodejs.org/api/errors.html#class-error} If the `name` parameter is the default task function reserved name.
236 * @throws {@link https://nodejs.org/api/errors.html#class-error} If the `name` parameter is the task function used as default task function.
238 public removeTaskFunction (name
: string): boolean {
239 if (typeof name
!== 'string') {
240 throw new TypeError('name parameter is not a string')
242 if (typeof name
=== 'string' && name
.trim().length
=== 0) {
243 throw new TypeError('name parameter is an empty string')
245 if (name
=== DEFAULT_TASK_NAME
) {
247 'Cannot remove the task function with the default reserved name'
251 this.taskFunctions
.get(name
) === this.taskFunctions
.get(DEFAULT_TASK_NAME
)
254 'Cannot remove the task function used as the default task function'
257 const deleteStatus
= this.taskFunctions
.delete(name
)
258 this.sendTaskFunctionsListToMainWorker()
263 * Lists the names of the worker's task functions.
265 * @returns The names of the worker's task functions.
267 public listTaskFunctions (): string[] {
268 return [...this.taskFunctions
.keys()]
272 * Sets the default task function to use in the worker.
274 * @param name - The name of the task function to use as default task function.
275 * @returns Whether the default task function was set or not.
276 * @throws {@link https://nodejs.org/api/errors.html#class-typeerror} If the `name` parameter is not a string.
277 * @throws {@link https://nodejs.org/api/errors.html#class-error} If the `name` parameter is the default task function reserved name.
278 * @throws {@link https://nodejs.org/api/errors.html#class-error} If the `name` parameter is a non-existing task function.
280 public setDefaultTaskFunction (name
: string): boolean {
281 if (typeof name
!== 'string') {
282 throw new TypeError('name parameter is not a string')
284 if (typeof name
=== 'string' && name
.trim().length
=== 0) {
285 throw new TypeError('name parameter is an empty string')
287 if (name
=== DEFAULT_TASK_NAME
) {
289 'Cannot set the default task function reserved name as the default task function'
292 if (!this.taskFunctions
.has(name
)) {
294 'Cannot set the default task function to a non-existing task function'
298 this.taskFunctions
.set(
300 this.taskFunctions
.get(name
) as TaskFunction
<Data
, Response
>
309 * Handles the ready message sent by the main worker.
311 * @param message - The ready message.
313 protected abstract handleReadyMessage (message
: MessageValue
<Data
>): void
316 * Worker message listener.
318 * @param message - The received message.
320 protected messageListener (message
: MessageValue
<Data
>): void {
322 throw new Error('Cannot handle message to worker in main worker')
323 } else if (message
.workerId
!= null && message
.workerId
!== this.id
) {
325 `Message worker id ${message.workerId} does not match the worker id ${this.id}`
327 } else if (message
.workerId
=== this.id
) {
328 if (message
.statistics
!= null) {
329 // Statistics message received
330 this.statistics
= message
.statistics
331 } else if (message
.checkActive
!= null) {
332 // Check active message received
333 message
.checkActive
? this.startCheckActive() : this.stopCheckActive()
334 } else if (message
.taskId
!= null && message
.data
!= null) {
335 // Task message received
337 } else if (message
.kill
=== true) {
338 // Kill message received
339 this.handleKillMessage(message
)
345 * Handles a kill message sent by the main worker.
347 * @param message - The kill message.
349 protected handleKillMessage (message
: MessageValue
<Data
>): void {
350 this.stopCheckActive()
351 if (isAsyncFunction(this.opts
.killHandler
)) {
352 (this.opts
.killHandler
?.() as Promise
<void>)
354 this.sendToMainWorker({ kill
: 'success', workerId
: this.id
})
358 this.sendToMainWorker({ kill
: 'failure', workerId
: this.id
})
363 .catch(EMPTY_FUNCTION
)
366 // eslint-disable-next-line @typescript-eslint/no-invalid-void-type
367 this.opts
.killHandler
?.() as void
368 this.sendToMainWorker({ kill
: 'success', workerId
: this.id
})
370 this.sendToMainWorker({ kill
: 'failure', workerId
: this.id
})
378 * Starts the worker check active interval.
380 private startCheckActive (): void {
381 this.lastTaskTimestamp
= performance
.now()
382 this.activeInterval
= setInterval(
383 this.checkActive
.bind(this),
384 (this.opts
.maxInactiveTime
?? DEFAULT_MAX_INACTIVE_TIME
) / 2
389 * Stops the worker check active interval.
391 private stopCheckActive (): void {
392 if (this.activeInterval
!= null) {
393 clearInterval(this.activeInterval
)
394 delete this.activeInterval
399 * Checks if the worker should be terminated, because its living too long.
401 private checkActive (): void {
403 performance
.now() - this.lastTaskTimestamp
>
404 (this.opts
.maxInactiveTime
?? DEFAULT_MAX_INACTIVE_TIME
)
406 this.sendToMainWorker({ kill
: this.opts
.killBehavior
, workerId
: this.id
})
411 * Returns the main worker.
413 * @returns Reference to the main worker.
415 protected getMainWorker (): MainWorker
{
416 if (this.mainWorker
== null) {
417 throw new Error('Main worker not set')
419 return this.mainWorker
423 * Sends a message to main worker.
425 * @param message - The response message.
427 protected abstract sendToMainWorker (
428 message
: MessageValue
<Response
, Data
>
432 * Sends the list of task function names to the main worker.
434 protected sendTaskFunctionsListToMainWorker (): void {
435 this.sendToMainWorker({
436 taskFunctions
: this.listTaskFunctions(),
442 * Handles an error and convert it to a string so it can be sent back to the main worker.
444 * @param e - The error raised by the worker.
445 * @returns The error message.
447 protected handleError (e
: Error | string): string {
448 return e
instanceof Error ? e
.message
: e
452 * Runs the given task.
454 * @param task - The task to execute.
455 * @throws {@link https://nodejs.org/api/errors.html#class-error} If the task function is not found.
457 protected run (task
: Task
<Data
>): void {
458 const fn
= this.getTaskFunction(task
.name
)
459 if (isAsyncFunction(fn
)) {
460 this.runInAsyncScope(this.runAsync
.bind(this), this, fn
, task
)
462 this.runInAsyncScope(this.runSync
.bind(this), this, fn
, task
)
467 * Runs the given task function synchronously.
469 * @param fn - Task function that will be executed.
470 * @param task - Input data for the task function.
473 fn
: TaskSyncFunction
<Data
, Response
>,
477 let taskPerformance
= this.beginTaskPerformance(task
.name
)
478 const res
= fn(task
.data
)
479 taskPerformance
= this.endTaskPerformance(taskPerformance
)
480 this.sendToMainWorker({
487 const errorMessage
= this.handleError(e
as Error | string)
488 this.sendToMainWorker({
490 name
: task
.name
?? DEFAULT_TASK_NAME
,
491 message
: errorMessage
,
498 this.updateLastTaskTimestamp()
503 * Runs the given task function asynchronously.
505 * @param fn - Task function that will be executed.
506 * @param task - Input data for the task function.
509 fn
: TaskAsyncFunction
<Data
, Response
>,
512 let taskPerformance
= this.beginTaskPerformance(task
.name
)
515 taskPerformance
= this.endTaskPerformance(taskPerformance
)
516 this.sendToMainWorker({
525 const errorMessage
= this.handleError(e
as Error | string)
526 this.sendToMainWorker({
528 name
: task
.name
?? DEFAULT_TASK_NAME
,
529 message
: errorMessage
,
537 this.updateLastTaskTimestamp()
539 .catch(EMPTY_FUNCTION
)
543 * Gets the task function with the given name.
545 * @param name - Name of the task function that will be returned.
546 * @returns The task function.
547 * @throws {@link https://nodejs.org/api/errors.html#class-error} If the task function is not found.
549 private getTaskFunction (name
?: string): TaskFunction
<Data
, Response
> {
550 name
= name
?? DEFAULT_TASK_NAME
551 const fn
= this.taskFunctions
.get(name
)
553 throw new Error(`Task function '${name}' not found`)
558 private beginTaskPerformance (name
?: string): TaskPerformance
{
559 this.checkStatistics()
561 name
: name
?? DEFAULT_TASK_NAME
,
562 timestamp
: performance
.now(),
563 ...(this.statistics
.elu
&& { elu
: performance
.eventLoopUtilization() })
567 private endTaskPerformance (
568 taskPerformance
: TaskPerformance
570 this.checkStatistics()
573 ...(this.statistics
.runTime
&& {
574 runTime
: performance
.now() - taskPerformance
.timestamp
576 ...(this.statistics
.elu
&& {
577 elu
: performance
.eventLoopUtilization(taskPerformance
.elu
)
582 private checkStatistics (): void {
583 if (this.statistics
== null) {
584 throw new Error('Performance statistics computation requirements not set')
588 private updateLastTaskTimestamp (): void {
589 if (this.activeInterval
!= null) {
590 this.lastTaskTimestamp
= performance
.now()