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'
23 } from
'./task-functions'
25 const DEFAULT_MAX_INACTIVE_TIME
= 60000
26 const DEFAULT_WORKER_OPTIONS
: WorkerOptions
= {
28 * The kill behavior option on this worker or its default value.
30 killBehavior
: KillBehaviors
.SOFT
,
32 * The maximum time to keep this worker active while idle.
33 * The pool automatically checks and terminates this worker when the time expires.
35 maxInactiveTime
: DEFAULT_MAX_INACTIVE_TIME
,
37 * The function to call when the worker is killed.
39 killHandler
: EMPTY_FUNCTION
43 * Base class that implements some shared logic for all poolifier workers.
45 * @typeParam MainWorker - Type of main worker.
46 * @typeParam Data - Type of data this worker receives from pool's execution. This can only be structured-cloneable data.
47 * @typeParam Response - Type of response the worker sends back to the main worker. This can only be structured-cloneable data.
49 export abstract class AbstractWorker
<
50 MainWorker
extends Worker
| MessagePort
,
53 > extends AsyncResource
{
57 protected abstract id
: number
59 * Task function(s) processed by the worker when the pool's `execution` function is invoked.
61 protected taskFunctions
!: Map
<string, TaskFunction
<Data
, Response
>>
63 * Timestamp of the last task processed by this worker.
65 protected lastTaskTimestamp
!: number
67 * Performance statistics computation requirements.
69 protected statistics
!: WorkerStatistics
71 * Handler id of the `activeInterval` worker activity check.
73 protected activeInterval
?: NodeJS
.Timeout
75 * Constructs a new poolifier worker.
77 * @param type - The type of async event.
78 * @param isMain - Whether this is the main worker or not.
79 * @param mainWorker - Reference to main worker.
80 * @param taskFunctions - Task function(s) processed by the worker when the pool's `execution` function is invoked. The first function is the default function.
81 * @param opts - Options for the worker.
85 protected readonly isMain
: boolean,
86 private readonly mainWorker
: MainWorker
,
87 taskFunctions
: TaskFunction
<Data
, Response
> | TaskFunctions
<Data
, Response
>,
88 protected opts
: WorkerOptions
= DEFAULT_WORKER_OPTIONS
91 if (this.isMain
== null) {
92 throw new Error('isMain parameter is mandatory')
94 this.checkTaskFunctions(taskFunctions
)
95 this.checkWorkerOptions(this.opts
)
97 this.getMainWorker().on('message', this.handleReadyMessage
.bind(this))
101 private checkWorkerOptions (opts
: WorkerOptions
): void {
102 this.opts
= { ...DEFAULT_WORKER_OPTIONS
, ...opts
}
103 delete this.opts
.async
106 private checkValidTaskFunction (
108 fn
: TaskFunction
<Data
, Response
>
110 if (typeof name
!== 'string') {
112 'A taskFunctions parameter object key is not a string'
115 if (typeof name
=== 'string' && name
.trim().length
=== 0) {
117 'A taskFunctions parameter object key is an empty string'
120 if (typeof fn
!== 'function') {
122 'A taskFunctions parameter object value is not a function'
128 * Checks if the `taskFunctions` parameter is passed to the constructor.
130 * @param taskFunctions - The task function(s) parameter that should be checked.
132 private checkTaskFunctions (
133 taskFunctions
: TaskFunction
<Data
, Response
> | TaskFunctions
<Data
, Response
>
135 if (taskFunctions
== null) {
136 throw new Error('taskFunctions parameter is mandatory')
138 this.taskFunctions
= new Map
<string, TaskFunction
<Data
, Response
>>()
139 if (typeof taskFunctions
=== 'function') {
140 const boundFn
= taskFunctions
.bind(this)
141 this.taskFunctions
.set(DEFAULT_TASK_NAME
, boundFn
)
142 this.taskFunctions
.set(
143 typeof taskFunctions
.name
=== 'string' &&
144 taskFunctions
.name
.trim().length
> 0
149 } else if (isPlainObject(taskFunctions
)) {
150 let firstEntry
= true
151 for (const [name
, fn
] of Object.entries(taskFunctions
)) {
152 this.checkValidTaskFunction(name
, fn
)
153 const boundFn
= fn
.bind(this)
155 this.taskFunctions
.set(DEFAULT_TASK_NAME
, boundFn
)
158 this.taskFunctions
.set(name
, boundFn
)
161 throw new Error('taskFunctions parameter object is empty')
165 'taskFunctions parameter is not a function or a plain object'
171 * Checks if the worker has a task function with the given name.
173 * @param name - The name of the task function to check.
174 * @returns Whether the worker has a task function with the given name or not.
175 * @throws {@link https://nodejs.org/api/errors.html#class-typeerror} If the `name` parameter is not a string or an empty string.
177 public hasTaskFunction (name
: string): boolean {
178 this.checkTaskFunctionName(name
)
179 return this.taskFunctions
.has(name
)
183 * Adds a task function to the worker.
184 * If a task function with the same name already exists, it is replaced.
186 * @param name - The name of the task function to add.
187 * @param fn - The task function to add.
188 * @returns Whether the task function was added or not.
189 * @throws {@link https://nodejs.org/api/errors.html#class-typeerror} If the `name` parameter is not a string or an empty string.
190 * @throws {@link https://nodejs.org/api/errors.html#class-error} If the `name` parameter is the default task function reserved name.
191 * @throws {@link https://nodejs.org/api/errors.html#class-typeerror} If the `fn` parameter is not a function.
193 public addTaskFunction (
195 fn
: TaskFunction
<Data
, Response
>
197 this.checkTaskFunctionName(name
)
198 if (name
=== DEFAULT_TASK_NAME
) {
200 'Cannot add a task function with the default reserved name'
203 if (typeof fn
!== 'function') {
204 throw new TypeError('fn parameter is not a function')
207 const boundFn
= fn
.bind(this)
209 this.taskFunctions
.get(name
) ===
210 this.taskFunctions
.get(DEFAULT_TASK_NAME
)
212 this.taskFunctions
.set(DEFAULT_TASK_NAME
, boundFn
)
214 this.taskFunctions
.set(name
, boundFn
)
215 this.sendTaskFunctionsListToMainWorker()
223 * Removes a task function from the worker.
225 * @param name - The name of the task function to remove.
226 * @returns Whether the task function existed and was removed or not.
227 * @throws {@link https://nodejs.org/api/errors.html#class-typeerror} If the `name` parameter is not a string or an empty string.
228 * @throws {@link https://nodejs.org/api/errors.html#class-error} If the `name` parameter is the default task function reserved name.
229 * @throws {@link https://nodejs.org/api/errors.html#class-error} If the `name` parameter is the task function used as default task function.
231 public removeTaskFunction (name
: string): boolean {
232 this.checkTaskFunctionName(name
)
233 if (name
=== DEFAULT_TASK_NAME
) {
235 'Cannot remove the task function with the default reserved name'
239 this.taskFunctions
.get(name
) === 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.sendTaskFunctionsListToMainWorker()
251 * Lists the names of the worker's task functions.
253 * @returns The names of the worker's task functions.
255 public listTaskFunctions (): string[] {
256 const names
: string[] = [...this.taskFunctions
.keys()]
257 let defaultTaskFunctionName
: string = DEFAULT_TASK_NAME
258 for (const [name
, fn
] of this.taskFunctions
) {
260 name
!== DEFAULT_TASK_NAME
&&
261 fn
=== this.taskFunctions
.get(DEFAULT_TASK_NAME
)
263 defaultTaskFunctionName
= name
268 names
[names
.indexOf(DEFAULT_TASK_NAME
)],
269 defaultTaskFunctionName
,
271 name
=> name
!== DEFAULT_TASK_NAME
&& name
!== defaultTaskFunctionName
277 * Sets the default task function to use in the worker.
279 * @param name - The name of the task function to use as default task function.
280 * @returns Whether the default task function was set or not.
281 * @throws {@link https://nodejs.org/api/errors.html#class-typeerror} If the `name` parameter is not a string or an empty string.
282 * @throws {@link https://nodejs.org/api/errors.html#class-error} If the `name` parameter is the default task function reserved name.
283 * @throws {@link https://nodejs.org/api/errors.html#class-error} If the `name` parameter is a non-existing task function.
285 public setDefaultTaskFunction (name
: string): boolean {
286 this.checkTaskFunctionName(name
)
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
>
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
.taskId
!= null && message
.data
!= null) {
338 // Task message received
340 } else if (message
.kill
=== true) {
341 // Kill message received
342 this.handleKillMessage(message
)
347 * Handles a kill message sent by the main worker.
349 * @param message - The kill message.
351 protected handleKillMessage (message
: MessageValue
<Data
>): void {
352 this.stopCheckActive()
353 if (isAsyncFunction(this.opts
.killHandler
)) {
354 (this.opts
.killHandler
?.() as Promise
<void>)
356 this.sendToMainWorker({ kill
: 'success', workerId
: this.id
})
360 this.sendToMainWorker({ kill
: 'failure', workerId
: this.id
})
365 .catch(EMPTY_FUNCTION
)
368 // eslint-disable-next-line @typescript-eslint/no-invalid-void-type
369 this.opts
.killHandler
?.() as void
370 this.sendToMainWorker({ kill
: 'success', workerId
: this.id
})
372 this.sendToMainWorker({ kill
: 'failure', workerId
: this.id
})
380 * Check if the message worker id is set and matches the worker id.
382 * @param message - The message to check.
383 * @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.
385 private checkMessageWorkerId (message
: MessageValue
<Data
>): void {
386 if (message
.workerId
== null) {
387 throw new Error('Message worker id is not set')
388 } else if (message
.workerId
!= null && message
.workerId
!== this.id
) {
390 `Message worker id ${message.workerId} does not match the worker id ${this.id}`
396 * Starts the worker check active interval.
398 private startCheckActive (): void {
399 this.lastTaskTimestamp
= performance
.now()
400 this.activeInterval
= setInterval(
401 this.checkActive
.bind(this),
402 (this.opts
.maxInactiveTime
?? DEFAULT_MAX_INACTIVE_TIME
) / 2
407 * Stops the worker check active interval.
409 private stopCheckActive (): void {
410 if (this.activeInterval
!= null) {
411 clearInterval(this.activeInterval
)
412 delete this.activeInterval
417 * Checks if the worker should be terminated, because its living too long.
419 private checkActive (): void {
421 performance
.now() - this.lastTaskTimestamp
>
422 (this.opts
.maxInactiveTime
?? DEFAULT_MAX_INACTIVE_TIME
)
424 this.sendToMainWorker({ kill
: this.opts
.killBehavior
, workerId
: this.id
})
429 * Returns the main worker.
431 * @returns Reference to the main worker.
432 * @throws {@link https://nodejs.org/api/errors.html#class-error} If the main worker is not set.
434 protected getMainWorker (): MainWorker
{
435 if (this.mainWorker
== null) {
436 throw new Error('Main worker not set')
438 return this.mainWorker
442 * Sends a message to main worker.
444 * @param message - The response message.
446 protected abstract sendToMainWorker (
447 message
: MessageValue
<Response
, Data
>
451 * Sends the list of task function names to the main worker.
453 protected sendTaskFunctionsListToMainWorker (): void {
454 this.sendToMainWorker({
455 taskFunctions
: this.listTaskFunctions(),
461 * Handles an error and convert it to a string so it can be sent back to the main worker.
463 * @param e - The error raised by the worker.
464 * @returns The error message.
466 protected handleError (e
: Error | string): string {
467 return e
instanceof Error ? e
.message
: e
471 * Runs the given task.
473 * @param task - The task to execute.
474 * @throws {@link https://nodejs.org/api/errors.html#class-error} If the task function is not found.
476 protected run (task
: Task
<Data
>): void {
477 const { name
, taskId
, data
} = task
478 const fn
= this.taskFunctions
.get(name
?? DEFAULT_TASK_NAME
)
480 this.sendToMainWorker({
482 name
: name
as string,
483 message
: `Task function '${name as string}' not found`,
491 if (isAsyncFunction(fn
)) {
492 this.runInAsyncScope(this.runAsync
.bind(this), this, fn
, task
)
494 this.runInAsyncScope(this.runSync
.bind(this), this, fn
, task
)
499 * Runs the given task function synchronously.
501 * @param fn - Task function that will be executed.
502 * @param task - Input data for the task function.
505 fn
: TaskSyncFunction
<Data
, Response
>,
508 const { name
, taskId
, data
} = task
510 let taskPerformance
= this.beginTaskPerformance(name
)
512 taskPerformance
= this.endTaskPerformance(taskPerformance
)
513 this.sendToMainWorker({
520 const errorMessage
= this.handleError(e
as Error | string)
521 this.sendToMainWorker({
523 name
: name
as string,
524 message
: errorMessage
,
531 this.updateLastTaskTimestamp()
536 * Runs the given task function asynchronously.
538 * @param fn - Task function that will be executed.
539 * @param task - Input data for the task function.
542 fn
: TaskAsyncFunction
<Data
, Response
>,
545 const { name
, taskId
, data
} = task
546 let taskPerformance
= this.beginTaskPerformance(name
)
549 taskPerformance
= this.endTaskPerformance(taskPerformance
)
550 this.sendToMainWorker({
559 const errorMessage
= this.handleError(e
as Error | string)
560 this.sendToMainWorker({
562 name
: name
as string,
563 message
: errorMessage
,
571 this.updateLastTaskTimestamp()
573 .catch(EMPTY_FUNCTION
)
576 private beginTaskPerformance (name
?: string): TaskPerformance
{
577 this.checkStatistics()
579 name
: name
?? DEFAULT_TASK_NAME
,
580 timestamp
: performance
.now(),
581 ...(this.statistics
.elu
&& { elu
: performance
.eventLoopUtilization() })
585 private endTaskPerformance (
586 taskPerformance
: TaskPerformance
588 this.checkStatistics()
591 ...(this.statistics
.runTime
&& {
592 runTime
: performance
.now() - taskPerformance
.timestamp
594 ...(this.statistics
.elu
&& {
595 elu
: performance
.eventLoopUtilization(taskPerformance
.elu
)
600 private checkStatistics (): void {
601 if (this.statistics
== null) {
602 throw new Error('Performance statistics computation requirements not set')
606 private updateLastTaskTimestamp (): void {
607 if (this.activeInterval
!= null) {
608 this.lastTaskTimestamp
= performance
.now()