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'
17 import { KillBehaviors
, type WorkerOptions
} from
'./worker-options'
21 TaskFunctionOperationReturnType
,
24 } from
'./task-functions'
26 const DEFAULT_MAX_INACTIVE_TIME
= 60000
27 const DEFAULT_WORKER_OPTIONS
: WorkerOptions
= {
29 * The kill behavior option on this worker or its default value.
31 killBehavior
: KillBehaviors
.SOFT
,
33 * The maximum time to keep this worker active while idle.
34 * The pool automatically checks and terminates this worker when the time expires.
36 maxInactiveTime
: DEFAULT_MAX_INACTIVE_TIME
,
38 * The function to call when the worker is killed.
40 killHandler
: EMPTY_FUNCTION
44 * Base class that implements some shared logic for all poolifier workers.
46 * @typeParam MainWorker - Type of main worker.
47 * @typeParam Data - Type of data this worker receives from pool's execution. This can only be structured-cloneable data.
48 * @typeParam Response - Type of response the worker sends back to the main worker. This can only be structured-cloneable data.
50 export abstract class AbstractWorker
<
51 MainWorker
extends Worker
| MessagePort
,
54 > extends AsyncResource
{
58 protected abstract id
: number
60 * Task function(s) processed by the worker when the pool's `execution` function is invoked.
62 protected taskFunctions
!: Map
<string, TaskFunction
<Data
, Response
>>
64 * Timestamp of the last task processed by this worker.
66 protected lastTaskTimestamp
!: number
68 * Performance statistics computation requirements.
70 protected statistics
!: WorkerStatistics
72 * Handler id of the `activeInterval` worker activity check.
74 protected activeInterval
?: NodeJS
.Timeout
76 * Constructs a new poolifier worker.
78 * @param type - The type of async event.
79 * @param isMain - Whether this is the main worker or not.
80 * @param mainWorker - Reference to main worker.
81 * @param taskFunctions - Task function(s) processed by the worker when the pool's `execution` function is invoked. The first function is the default function.
82 * @param opts - Options for the worker.
86 protected readonly isMain
: boolean,
87 private readonly mainWorker
: MainWorker
,
88 taskFunctions
: TaskFunction
<Data
, Response
> | TaskFunctions
<Data
, Response
>,
89 protected opts
: WorkerOptions
= DEFAULT_WORKER_OPTIONS
92 if (this.isMain
== null) {
93 throw new Error('isMain parameter is mandatory')
95 this.checkTaskFunctions(taskFunctions
)
96 this.checkWorkerOptions(this.opts
)
98 this.getMainWorker().on('message', this.handleReadyMessage
.bind(this))
102 private checkWorkerOptions (opts
: WorkerOptions
): void {
103 this.opts
= { ...DEFAULT_WORKER_OPTIONS
, ...opts
}
104 delete this.opts
.async
107 private checkValidTaskFunction (
109 fn
: TaskFunction
<Data
, Response
>
111 if (typeof name
!== 'string') {
113 'A taskFunctions parameter object key is not a string'
116 if (typeof name
=== 'string' && name
.trim().length
=== 0) {
118 'A taskFunctions parameter object key is an empty string'
121 if (typeof fn
!== 'function') {
123 'A taskFunctions parameter object value is not a function'
129 * Checks if the `taskFunctions` parameter is passed to the constructor.
131 * @param taskFunctions - The task function(s) parameter that should be checked.
133 private checkTaskFunctions (
134 taskFunctions
: TaskFunction
<Data
, Response
> | TaskFunctions
<Data
, Response
>
136 if (taskFunctions
== null) {
137 throw new Error('taskFunctions parameter is mandatory')
139 this.taskFunctions
= new Map
<string, TaskFunction
<Data
, Response
>>()
140 if (typeof taskFunctions
=== 'function') {
141 const boundFn
= taskFunctions
.bind(this)
142 this.taskFunctions
.set(DEFAULT_TASK_NAME
, boundFn
)
143 this.taskFunctions
.set(
144 typeof taskFunctions
.name
=== 'string' &&
145 taskFunctions
.name
.trim().length
> 0
150 } else if (isPlainObject(taskFunctions
)) {
151 let firstEntry
= true
152 for (const [name
, fn
] of Object.entries(taskFunctions
)) {
153 this.checkValidTaskFunction(name
, fn
)
154 const boundFn
= fn
.bind(this)
156 this.taskFunctions
.set(DEFAULT_TASK_NAME
, boundFn
)
159 this.taskFunctions
.set(name
, boundFn
)
162 throw new Error('taskFunctions parameter object is empty')
166 'taskFunctions parameter is not a function or a plain object'
172 * Checks if the worker has a task function with the given name.
174 * @param name - The name of the task function to check.
175 * @returns Whether the worker has a task function with the given name or not.
177 public hasTaskFunction (name
: string): TaskFunctionOperationReturnType
{
179 this.checkTaskFunctionName(name
)
181 return { status: false, error
: error
as Error }
183 return { status: this.taskFunctions
.has(name
) }
187 * Adds a task function to the worker.
188 * If a task function with the same name already exists, it is replaced.
190 * @param name - The name of the task function to add.
191 * @param fn - The task function to add.
192 * @returns Whether the task function was added or not.
194 public addTaskFunction (
196 fn
: TaskFunction
<Data
, Response
>
197 ): TaskFunctionOperationReturnType
{
199 this.checkTaskFunctionName(name
)
200 if (name
=== DEFAULT_TASK_NAME
) {
202 'Cannot add a task function with the default reserved name'
205 if (typeof fn
!== 'function') {
206 throw new TypeError('fn parameter is not a function')
208 const boundFn
= fn
.bind(this)
210 this.taskFunctions
.get(name
) ===
211 this.taskFunctions
.get(DEFAULT_TASK_NAME
)
213 this.taskFunctions
.set(DEFAULT_TASK_NAME
, boundFn
)
215 this.taskFunctions
.set(name
, boundFn
)
216 this.sendTaskFunctionNamesToMainWorker()
217 return { status: true }
219 return { status: false, error
: error
as Error }
224 * Removes a task function from the worker.
226 * @param name - The name of the task function to remove.
227 * @returns Whether the task function existed and was removed or not.
229 public removeTaskFunction (name
: string): TaskFunctionOperationReturnType
{
231 this.checkTaskFunctionName(name
)
232 if (name
=== DEFAULT_TASK_NAME
) {
234 'Cannot remove the task function with the default reserved name'
238 this.taskFunctions
.get(name
) ===
239 this.taskFunctions
.get(DEFAULT_TASK_NAME
)
242 'Cannot remove the task function used as the default task function'
245 const deleteStatus
= this.taskFunctions
.delete(name
)
246 this.sendTaskFunctionNamesToMainWorker()
247 return { status: deleteStatus
}
249 return { status: false, error
: error
as Error }
254 * Lists the names of the worker's task functions.
256 * @returns The names of the worker's task functions.
258 public listTaskFunctionNames (): string[] {
259 const names
: string[] = [...this.taskFunctions
.keys()]
260 let defaultTaskFunctionName
: string = DEFAULT_TASK_NAME
261 for (const [name
, fn
] of this.taskFunctions
) {
263 name
!== DEFAULT_TASK_NAME
&&
264 fn
=== this.taskFunctions
.get(DEFAULT_TASK_NAME
)
266 defaultTaskFunctionName
= name
271 names
[names
.indexOf(DEFAULT_TASK_NAME
)],
272 defaultTaskFunctionName
,
274 name
=> name
!== DEFAULT_TASK_NAME
&& name
!== defaultTaskFunctionName
280 * Sets the default task function to use in the worker.
282 * @param name - The name of the task function to use as default task function.
283 * @returns Whether the default task function was set or not.
285 public setDefaultTaskFunction (name
: string): TaskFunctionOperationReturnType
{
287 this.checkTaskFunctionName(name
)
288 if (name
=== DEFAULT_TASK_NAME
) {
290 'Cannot set the default task function reserved name as the default task function'
293 if (!this.taskFunctions
.has(name
)) {
295 '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
>
302 return { status: true }
304 return { status: false, error
: error
as Error }
308 private checkTaskFunctionName (name
: string): void {
309 if (typeof name
!== 'string') {
310 throw new TypeError('name parameter is not a string')
312 if (typeof name
=== 'string' && name
.trim().length
=== 0) {
313 throw new TypeError('name parameter is an empty string')
318 * Handles the ready message sent by the main worker.
320 * @param message - The ready message.
322 protected abstract handleReadyMessage (message
: MessageValue
<Data
>): void
325 * Worker message listener.
327 * @param message - The received message.
329 protected messageListener (message
: MessageValue
<Data
>): void {
330 this.checkMessageWorkerId(message
)
331 if (message
.statistics
!= null) {
332 // Statistics message received
333 this.statistics
= message
.statistics
334 } else if (message
.checkActive
!= null) {
335 // Check active message received
336 message
.checkActive
? this.startCheckActive() : this.stopCheckActive()
337 } else if (message
.taskFunctionOperation
!= null) {
338 // Task function operation message received
339 this.handleTaskFunctionOperationMessage(message
)
340 } else if (message
.taskId
!= null && message
.data
!= null) {
341 // Task message received
343 } else if (message
.kill
=== true) {
344 // Kill message received
345 this.handleKillMessage(message
)
349 protected handleTaskFunctionOperationMessage (
350 message
: MessageValue
<Data
>
352 const { taskFunctionOperation
, taskFunction
, taskFunctionName
} = message
353 let response
!: TaskFunctionOperationReturnType
354 if (taskFunctionOperation
=== 'add') {
355 response
= this.addTaskFunction(
356 taskFunctionName
as string,
357 // eslint-disable-next-line @typescript-eslint/no-implied-eval, no-new-func
358 new Function(`return ${taskFunction as string}`)() as TaskFunction
<
363 } else if (taskFunctionOperation
=== 'remove') {
364 response
= this.removeTaskFunction(taskFunctionName
as string)
365 } else if (taskFunctionOperation
=== 'default') {
366 response
= this.setDefaultTaskFunction(taskFunctionName
as string)
368 this.sendToMainWorker({
369 taskFunctionOperation
,
370 taskFunctionOperationStatus
: response
.status,
372 name
: taskFunctionName
as string,
373 message
: this.handleError(response
.error
as Error | string)
380 * Handles a kill message sent by the main worker.
382 * @param message - The kill message.
384 protected handleKillMessage (message
: MessageValue
<Data
>): void {
385 this.stopCheckActive()
386 if (isAsyncFunction(this.opts
.killHandler
)) {
387 (this.opts
.killHandler
?.() as Promise
<void>)
389 this.sendToMainWorker({ kill
: 'success', workerId
: this.id
})
393 this.sendToMainWorker({ kill
: 'failure', workerId
: this.id
})
398 .catch(EMPTY_FUNCTION
)
401 // eslint-disable-next-line @typescript-eslint/no-invalid-void-type
402 this.opts
.killHandler
?.() as void
403 this.sendToMainWorker({ kill
: 'success', workerId
: this.id
})
405 this.sendToMainWorker({ kill
: 'failure', workerId
: this.id
})
413 * Check if the message worker id is set and matches the worker id.
415 * @param message - The message to check.
416 * @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.
418 private checkMessageWorkerId (message
: MessageValue
<Data
>): void {
419 if (message
.workerId
== null) {
420 throw new Error('Message worker id is not set')
421 } else if (message
.workerId
!= null && message
.workerId
!== this.id
) {
423 `Message worker id ${message.workerId} does not match the worker id ${this.id}`
429 * Starts the worker check active interval.
431 private startCheckActive (): void {
432 this.lastTaskTimestamp
= performance
.now()
433 this.activeInterval
= setInterval(
434 this.checkActive
.bind(this),
435 (this.opts
.maxInactiveTime
?? DEFAULT_MAX_INACTIVE_TIME
) / 2
440 * Stops the worker check active interval.
442 private stopCheckActive (): void {
443 if (this.activeInterval
!= null) {
444 clearInterval(this.activeInterval
)
445 delete this.activeInterval
450 * Checks if the worker should be terminated, because its living too long.
452 private checkActive (): void {
454 performance
.now() - this.lastTaskTimestamp
>
455 (this.opts
.maxInactiveTime
?? DEFAULT_MAX_INACTIVE_TIME
)
457 this.sendToMainWorker({ kill
: this.opts
.killBehavior
, workerId
: this.id
})
462 * Returns the main worker.
464 * @returns Reference to the main worker.
465 * @throws {@link https://nodejs.org/api/errors.html#class-error} If the main worker is not set.
467 protected getMainWorker (): MainWorker
{
468 if (this.mainWorker
== null) {
469 throw new Error('Main worker not set')
471 return this.mainWorker
475 * Sends a message to main worker.
477 * @param message - The response message.
479 protected abstract sendToMainWorker (
480 message
: MessageValue
<Response
, Data
>
484 * Sends task function names to the main worker.
486 protected sendTaskFunctionNamesToMainWorker (): void {
487 this.sendToMainWorker({
488 taskFunctionNames
: this.listTaskFunctionNames(),
494 * Handles an error and convert it to a string so it can be sent back to the main worker.
496 * @param error - The error raised by the worker.
497 * @returns The error message.
499 protected handleError (error
: Error | string): string {
500 return error
instanceof Error ? error
.message
: error
504 * Runs the given task.
506 * @param task - The task to execute.
507 * @throws {@link https://nodejs.org/api/errors.html#class-error} If the task function is not found.
509 protected run (task
: Task
<Data
>): void {
510 const { name
, taskId
, data
} = task
511 const fn
= this.taskFunctions
.get(name
?? DEFAULT_TASK_NAME
)
513 this.sendToMainWorker({
515 name
: name
as string,
516 message
: `Task function '${name as string}' not found`,
524 if (isAsyncFunction(fn
)) {
525 this.runInAsyncScope(this.runAsync
.bind(this), this, fn
, task
)
527 this.runInAsyncScope(this.runSync
.bind(this), this, fn
, task
)
532 * Runs the given task function synchronously.
534 * @param fn - Task function that will be executed.
535 * @param task - Input data for the task function.
538 fn
: TaskSyncFunction
<Data
, Response
>,
541 const { name
, taskId
, data
} = task
543 let taskPerformance
= this.beginTaskPerformance(name
)
545 taskPerformance
= this.endTaskPerformance(taskPerformance
)
546 this.sendToMainWorker({
553 this.sendToMainWorker({
555 name
: name
as string,
556 message
: this.handleError(error
as Error | string),
563 this.updateLastTaskTimestamp()
568 * Runs the given task function asynchronously.
570 * @param fn - Task function that will be executed.
571 * @param task - Input data for the task function.
574 fn
: TaskAsyncFunction
<Data
, Response
>,
577 const { name
, taskId
, data
} = task
578 let taskPerformance
= this.beginTaskPerformance(name
)
581 taskPerformance
= this.endTaskPerformance(taskPerformance
)
582 this.sendToMainWorker({
591 this.sendToMainWorker({
593 name
: name
as string,
594 message
: this.handleError(error
as Error | string),
602 this.updateLastTaskTimestamp()
604 .catch(EMPTY_FUNCTION
)
607 private beginTaskPerformance (name
?: string): TaskPerformance
{
608 this.checkStatistics()
610 name
: name
?? DEFAULT_TASK_NAME
,
611 timestamp
: performance
.now(),
612 ...(this.statistics
.elu
&& { elu
: performance
.eventLoopUtilization() })
616 private endTaskPerformance (
617 taskPerformance
: TaskPerformance
619 this.checkStatistics()
622 ...(this.statistics
.runTime
&& {
623 runTime
: performance
.now() - taskPerformance
.timestamp
625 ...(this.statistics
.elu
&& {
626 elu
: performance
.eventLoopUtilization(taskPerformance
.elu
)
631 private checkStatistics (): void {
632 if (this.statistics
== null) {
633 throw new Error('Performance statistics computation requirements not set')
637 private updateLastTaskTimestamp (): void {
638 if (this.activeInterval
!= null) {
639 this.lastTaskTimestamp
= performance
.now()