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
'./worker-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, WorkerFunction
<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 taskFunctions - Task function(s) processed by the worker when the pool's `execution` function is invoked. The first function is the default function.
70 * @param mainWorker - Reference to main worker.
71 * @param opts - Options for the worker.
75 protected readonly isMain
: boolean,
77 | WorkerFunction
<Data
, Response
>
78 | TaskFunctions
<Data
, Response
>,
79 protected readonly mainWorker
: MainWorker
,
80 protected readonly opts
: WorkerOptions
= {
82 * The kill behavior option on this worker or its default value.
84 killBehavior
: DEFAULT_KILL_BEHAVIOR
,
86 * The maximum time to keep this worker active while idle.
87 * The pool automatically checks and terminates this worker when the time expires.
89 maxInactiveTime
: DEFAULT_MAX_INACTIVE_TIME
93 this.checkWorkerOptions(this.opts
)
94 this.checkTaskFunctions(taskFunctions
)
96 this.mainWorker
?.on('message', this.messageListener
.bind(this))
100 private checkWorkerOptions (opts
: WorkerOptions
): void {
101 this.opts
.killBehavior
= opts
.killBehavior
?? DEFAULT_KILL_BEHAVIOR
102 this.opts
.maxInactiveTime
=
103 opts
.maxInactiveTime
?? DEFAULT_MAX_INACTIVE_TIME
104 delete this.opts
.async
108 * Checks if the `taskFunctions` parameter is passed to the constructor.
110 * @param taskFunctions - The task function(s) parameter that should be checked.
112 private checkTaskFunctions (
114 | WorkerFunction
<Data
, Response
>
115 | TaskFunctions
<Data
, Response
>
117 if (taskFunctions
== null) {
118 throw new Error('taskFunctions parameter is mandatory')
120 this.taskFunctions
= new Map
<string, WorkerFunction
<Data
, Response
>>()
121 if (typeof taskFunctions
=== 'function') {
122 const boundFn
= taskFunctions
.bind(this)
123 this.taskFunctions
.set(DEFAULT_TASK_NAME
, boundFn
)
124 this.taskFunctions
.set(
125 typeof taskFunctions
.name
=== 'string' &&
126 taskFunctions
.name
.trim().length
> 0
131 } else if (isPlainObject(taskFunctions
)) {
132 let firstEntry
= true
133 for (const [name
, fn
] of Object.entries(taskFunctions
)) {
134 if (typeof name
!== 'string') {
136 'A taskFunctions parameter object key is not a string'
139 if (typeof fn
!== 'function') {
141 'A taskFunctions parameter object value is not a function'
144 const boundFn
= fn
.bind(this)
146 this.taskFunctions
.set(DEFAULT_TASK_NAME
, boundFn
)
149 this.taskFunctions
.set(name
, boundFn
)
152 throw new Error('taskFunctions parameter object is empty')
156 'taskFunctions parameter is not a function or a plain object'
162 * Checks if the worker has a task function with the given name.
164 * @param name - The name of the task function to check.
165 * @returns Whether the worker has a task function with the given name or not.
166 * @throws {@link https://nodejs.org/api/errors.html#class-typeerror} If the `name` parameter is not a string.
168 public hasTaskFunction (name
: string): boolean {
169 if (typeof name
!== 'string') {
170 throw new TypeError('name parameter is not a string')
172 return this.taskFunctions
.has(name
)
176 * Adds a task function to the worker.
177 * If a task function with the same name already exists, it is replaced.
179 * @param name - The name of the task function to add.
180 * @param fn - The task function to add.
181 * @returns Whether the task function was added or not.
182 * @throws {@link https://nodejs.org/api/errors.html#class-typeerror} If the `name` parameter is not a string.
183 * @throws {@link https://nodejs.org/api/errors.html#class-error} If the `name` parameter is the default task function reserved name.
184 * @throws {@link https://nodejs.org/api/errors.html#class-typeerror} If the `fn` parameter is not a function.
186 public addTaskFunction (
188 fn
: WorkerFunction
<Data
, Response
>
190 if (typeof name
!== 'string') {
191 throw new TypeError('name parameter is not a string')
193 if (name
=== DEFAULT_TASK_NAME
) {
195 'Cannot add a task function with the default reserved name'
198 if (typeof fn
!== 'function') {
199 throw new TypeError('fn parameter is not a function')
202 const boundFn
= fn
.bind(this)
204 this.taskFunctions
.get(name
) ===
205 this.taskFunctions
.get(DEFAULT_TASK_NAME
)
207 this.taskFunctions
.set(DEFAULT_TASK_NAME
, boundFn
)
209 this.taskFunctions
.set(name
, boundFn
)
217 * Removes a task function from the worker.
219 * @param name - The name of the task function to remove.
220 * @returns Whether the task function existed and was removed or not.
221 * @throws {@link https://nodejs.org/api/errors.html#class-typeerror} If the `name` parameter is not a string.
222 * @throws {@link https://nodejs.org/api/errors.html#class-error} If the `name` parameter is the default task function reserved name.
223 * @throws {@link https://nodejs.org/api/errors.html#class-error} If the `name` parameter is the task function used as default task function.
225 public removeTaskFunction (name
: string): boolean {
226 if (typeof name
!== 'string') {
227 throw new TypeError('name parameter is not a string')
229 if (name
=== DEFAULT_TASK_NAME
) {
231 'Cannot remove the task function with the default reserved name'
235 this.taskFunctions
.get(name
) === this.taskFunctions
.get(DEFAULT_TASK_NAME
)
238 'Cannot remove the task function used as the default task function'
241 return this.taskFunctions
.delete(name
)
245 * Lists the names of the worker's task functions.
247 * @returns The names of the worker's task functions.
249 public listTaskFunctions (): string[] {
250 return Array.from(this.taskFunctions
.keys())
254 * Sets the default task function to use in the worker.
256 * @param name - The name of the task function to use as default task function.
257 * @returns Whether the default task function was set or not.
258 * @throws {@link https://nodejs.org/api/errors.html#class-typeerror} If the `name` parameter is not a string.
259 * @throws {@link https://nodejs.org/api/errors.html#class-error} If the `name` parameter is the default task function reserved name.
260 * @throws {@link https://nodejs.org/api/errors.html#class-error} If the `name` parameter is a non-existing task function.
262 public setDefaultTaskFunction (name
: string): boolean {
263 if (typeof name
!== 'string') {
264 throw new TypeError('name parameter is not a string')
266 if (name
=== DEFAULT_TASK_NAME
) {
268 'Cannot set the default task function reserved name as the default task function'
271 if (!this.taskFunctions
.has(name
)) {
273 'Cannot set the default task function to a non-existing task function'
277 this.taskFunctions
.set(
279 this.taskFunctions
.get(name
) as WorkerFunction
<Data
, Response
>
288 * Worker message listener.
290 * @param message - The received message.
292 protected messageListener (message
: MessageValue
<Data
, Data
>): void {
293 if (message
.workerId
=== this.id
) {
294 if (message
.ready
!= null) {
295 // Startup message received
296 this.sendReadyResponse()
297 } else if (message
.statistics
!= null) {
298 // Statistics message received
299 this.statistics
= message
.statistics
300 } else if (message
.checkActive
!= null) {
301 // Check active message received
302 !this.isMain
&& message
.checkActive
303 ? this.startCheckActive()
304 : this.stopCheckActive()
305 } else if (message
.id
!= null && message
.data
!= null) {
306 // Task message received
308 } else if (message
.kill
=== true) {
309 // Kill message received
310 !this.isMain
&& this.stopCheckActive()
317 * Sends the ready response to the main worker.
319 protected sendReadyResponse (): void {
320 !this.isMain
&& this.sendToMainWorker({ ready
: true, workerId
: this.id
})
324 * Starts the worker check active interval.
326 private startCheckActive (): void {
327 this.lastTaskTimestamp
= performance
.now()
328 this.activeInterval
= setInterval(
329 this.checkActive
.bind(this),
330 (this.opts
.maxInactiveTime
?? DEFAULT_MAX_INACTIVE_TIME
) / 2
335 * Stops the worker check active interval.
337 private stopCheckActive (): void {
338 if (this.activeInterval
!= null) {
339 clearInterval(this.activeInterval
)
340 delete this.activeInterval
345 * Checks if the worker should be terminated, because its living too long.
347 private checkActive (): void {
349 performance
.now() - this.lastTaskTimestamp
>
350 (this.opts
.maxInactiveTime
?? DEFAULT_MAX_INACTIVE_TIME
)
352 this.sendToMainWorker({ kill
: this.opts
.killBehavior
, workerId
: this.id
})
357 * Returns the main worker.
359 * @returns Reference to the main worker.
361 protected getMainWorker (): MainWorker
{
362 if (this.mainWorker
== null) {
363 throw new Error('Main worker not set')
365 return this.mainWorker
369 * Sends a message to the main worker.
371 * @param message - The response message.
373 protected abstract sendToMainWorker (
374 message
: MessageValue
<Response
, Data
>
378 * Handles an error and convert it to a string so it can be sent back to the main worker.
380 * @param e - The error raised by the worker.
381 * @returns The error message.
383 protected handleError (e
: Error | string): string {
384 return e
instanceof Error ? e
.message
: e
388 * Runs the given task.
390 * @param task - The task to execute.
391 * @throws {@link https://nodejs.org/api/errors.html#class-error} If the task function is not found.
393 protected run (task
: Task
<Data
>): void {
395 throw new Error('Cannot run a task in the main worker')
397 const fn
= this.getTaskFunction(task
.name
)
398 if (isAsyncFunction(fn
)) {
399 this.runInAsyncScope(this.runAsync
.bind(this), this, fn
, task
)
401 this.runInAsyncScope(this.runSync
.bind(this), this, fn
, task
)
406 * Runs the given task function synchronously.
408 * @param fn - Task function that will be executed.
409 * @param task - Input data for the task function.
412 fn
: WorkerSyncFunction
<Data
, Response
>,
416 let taskPerformance
= this.beginTaskPerformance(task
.name
)
417 const res
= fn(task
.data
)
418 taskPerformance
= this.endTaskPerformance(taskPerformance
)
419 this.sendToMainWorker({
426 const errorMessage
= this.handleError(e
as Error | string)
427 this.sendToMainWorker({
429 name
: task
.name
?? DEFAULT_TASK_NAME
,
430 message
: errorMessage
,
437 this.updateLastTaskTimestamp()
442 * Runs the given task function asynchronously.
444 * @param fn - Task function that will be executed.
445 * @param task - Input data for the task function.
448 fn
: WorkerAsyncFunction
<Data
, Response
>,
451 let taskPerformance
= this.beginTaskPerformance(task
.name
)
454 taskPerformance
= this.endTaskPerformance(taskPerformance
)
455 this.sendToMainWorker({
464 const errorMessage
= this.handleError(e
as Error | string)
465 this.sendToMainWorker({
467 name
: task
.name
?? DEFAULT_TASK_NAME
,
468 message
: errorMessage
,
476 this.updateLastTaskTimestamp()
478 .catch(EMPTY_FUNCTION
)
482 * Gets the task function with the given name.
484 * @param name - Name of the task function that will be returned.
485 * @returns The task function.
486 * @throws {@link https://nodejs.org/api/errors.html#class-error} If the task function is not found.
488 private getTaskFunction (name
?: string): WorkerFunction
<Data
, Response
> {
489 name
= name
?? DEFAULT_TASK_NAME
490 const fn
= this.taskFunctions
.get(name
)
492 throw new Error(`Task function '${name}' not found`)
497 private beginTaskPerformance (name
?: string): TaskPerformance
{
498 this.checkStatistics()
500 name
: name
?? DEFAULT_TASK_NAME
,
501 timestamp
: performance
.now(),
502 ...(this.statistics
.elu
&& { elu
: performance
.eventLoopUtilization() })
506 private endTaskPerformance (
507 taskPerformance
: TaskPerformance
509 this.checkStatistics()
512 ...(this.statistics
.runTime
&& {
513 runTime
: performance
.now() - taskPerformance
.timestamp
515 ...(this.statistics
.elu
&& {
516 elu
: performance
.eventLoopUtilization(taskPerformance
.elu
)
521 private checkStatistics (): void {
522 if (this.statistics
== null) {
523 throw new Error('Performance statistics computation requirements not set')
527 private updateLastTaskTimestamp (): void {
528 if (!this.isMain
&& this.activeInterval
!= null) {
529 this.lastTaskTimestamp
= performance
.now()