1 import crypto from
'node:crypto'
2 import type { MessageValue
, PromiseResponseWrapper
} from
'../utility-types'
3 import { EMPTY_FUNCTION
} from
'../utils'
4 import { KillBehaviors
, isKillBehavior
} from
'../worker/worker-options'
5 import type { PoolOptions
} from
'./pool'
6 import { PoolEmitter
} from
'./pool'
7 import type { IPoolInternal
, TasksUsage
, WorkerType
} from
'./pool-internal'
8 import { PoolType
} from
'./pool-internal'
9 import type { IPoolWorker
} from
'./pool-worker'
11 WorkerChoiceStrategies
,
12 type WorkerChoiceStrategy
13 } from
'./selection-strategies/selection-strategies-types'
14 import { WorkerChoiceStrategyContext
} from
'./selection-strategies/worker-choice-strategy-context'
17 * Base class that implements some shared logic for all poolifier pools.
19 * @typeParam Worker - Type of worker which manages this pool.
20 * @typeParam Data - Type of data sent to the worker. This can only be serializable data.
21 * @typeParam Response - Type of response of execution. This can only be serializable data.
23 export abstract class AbstractPool
<
24 Worker
extends IPoolWorker
,
27 > implements IPoolInternal
<Worker
, Data
, Response
> {
29 public readonly workers
: Array<WorkerType
<Worker
>> = []
32 public readonly emitter
?: PoolEmitter
35 * The promise response map.
37 * - `key`: The message id of each submitted task.
38 * - `value`: An object that contains the worker, the promise resolve and reject callbacks.
40 * When we receive a message from the worker we get a map entry with the promise resolve/reject bound to the message.
42 protected promiseResponseMap
: Map
<
44 PromiseResponseWrapper
<Worker
, Response
>
45 > = new Map
<string, PromiseResponseWrapper
<Worker
, Response
>>()
48 * Worker choice strategy instance implementing the worker choice algorithm.
50 * Default to a strategy implementing a round robin algorithm.
52 protected workerChoiceStrategyContext
: WorkerChoiceStrategyContext
<
59 * Constructs a new poolifier pool.
61 * @param numberOfWorkers - Number of workers that this pool should manage.
62 * @param filePath - Path to the worker-file.
63 * @param opts - Options for the pool.
66 public readonly numberOfWorkers
: number,
67 public readonly filePath
: string,
68 public readonly opts
: PoolOptions
<Worker
>
71 throw new Error('Cannot start a pool from a worker!')
73 this.checkNumberOfWorkers(this.numberOfWorkers
)
74 this.checkFilePath(this.filePath
)
75 this.checkPoolOptions(this.opts
)
77 this.chooseWorker
.bind(this)
78 this.internalExecute
.bind(this)
79 this.checkAndEmitFull
.bind(this)
80 this.checkAndEmitBusy
.bind(this)
81 this.sendToWorker
.bind(this)
85 for (let i
= 1; i
<= this.numberOfWorkers
; i
++) {
86 this.createAndSetupWorker()
89 if (this.opts
.enableEvents
=== true) {
90 this.emitter
= new PoolEmitter()
92 this.workerChoiceStrategyContext
= new WorkerChoiceStrategyContext
<
99 const createdWorker
= this.createAndSetupWorker()
100 this.registerWorkerMessageListener(createdWorker
, message
=> {
102 isKillBehavior(KillBehaviors
.HARD
, message
.kill
) ||
103 this.getWorkerTasksUsage(createdWorker
)?.running
=== 0
105 // Kill received from the worker, means that no new tasks are submitted to that worker for a while ( > maxInactiveTime)
106 void this.destroyWorker(createdWorker
)
109 return this.getWorkerKey(createdWorker
)
111 this.opts
.workerChoiceStrategy
115 private checkFilePath (filePath
: string): void {
118 (typeof filePath
=== 'string' && filePath
.trim().length
=== 0)
120 throw new Error('Please specify a file with a worker implementation')
124 private checkNumberOfWorkers (numberOfWorkers
: number): void {
125 if (numberOfWorkers
== null) {
127 'Cannot instantiate a pool without specifying the number of workers'
129 } else if (!Number.isSafeInteger(numberOfWorkers
)) {
131 'Cannot instantiate a pool with a non integer number of workers'
133 } else if (numberOfWorkers
< 0) {
134 throw new RangeError(
135 'Cannot instantiate a pool with a negative number of workers'
137 } else if (this.type === PoolType
.FIXED
&& numberOfWorkers
=== 0) {
138 throw new Error('Cannot instantiate a fixed pool with no worker')
142 private checkPoolOptions (opts
: PoolOptions
<Worker
>): void {
143 this.opts
.workerChoiceStrategy
=
144 opts
.workerChoiceStrategy
?? WorkerChoiceStrategies
.ROUND_ROBIN
145 this.opts
.enableEvents
= opts
.enableEvents
?? true
149 public abstract get
type (): PoolType
152 * Number of tasks concurrently running.
154 private get
numberOfRunningTasks (): number {
155 return this.promiseResponseMap
.size
159 * Gets the given worker key.
161 * @param worker - The worker.
162 * @returns The worker key if the worker is found in the pool, `-1` otherwise.
164 private getWorkerKey (worker
: Worker
): number {
165 return this.workers
.findIndex(workerItem
=> workerItem
.worker
=== worker
)
169 public setWorkerChoiceStrategy (
170 workerChoiceStrategy
: WorkerChoiceStrategy
172 this.opts
.workerChoiceStrategy
= workerChoiceStrategy
173 for (const [index
, workerItem
] of this.workers
.entries()) {
174 this.setWorker(index
, workerItem
.worker
, {
182 this.workerChoiceStrategyContext
.setWorkerChoiceStrategy(
189 public abstract get
full (): boolean
192 public abstract get
busy (): boolean
194 protected internalBusy (): boolean {
196 this.numberOfRunningTasks
>= this.numberOfWorkers
&&
197 this.findFreeWorkerKey() === -1
202 public findFreeWorkerKey (): number {
203 return this.workers
.findIndex(workerItem
=> {
204 return workerItem
.tasksUsage
.running
=== 0
209 public async execute (data
: Data
): Promise
<Response
> {
210 const [workerKey
, worker
] = this.chooseWorker()
211 const messageId
= crypto
.randomUUID()
212 const res
= this.internalExecute(workerKey
, worker
, messageId
)
213 this.checkAndEmitFull()
214 this.checkAndEmitBusy()
215 this.sendToWorker(worker
, {
216 // eslint-disable-next-line @typescript-eslint/consistent-type-assertions
217 data
: data
?? ({} as Data
),
220 // eslint-disable-next-line @typescript-eslint/return-await
225 public async destroy (): Promise
<void> {
227 this.workers
.map(async workerItem
=> {
228 await this.destroyWorker(workerItem
.worker
)
234 * Shutdowns given worker.
236 * @param worker - A worker within `workers`.
238 protected abstract destroyWorker (worker
: Worker
): void | Promise
<void>
241 * Setup hook that can be overridden by a Poolifier pool implementation
242 * to run code before workers are created in the abstract constructor.
244 protected setupHook (): void {
249 * Should return whether the worker is the main worker or not.
251 protected abstract isMain (): boolean
254 * Hook executed before the worker task promise resolution.
257 * @param workerKey - The worker key.
259 protected beforePromiseResponseHook (workerKey
: number): void {
260 ++this.workers
[workerKey
].tasksUsage
.running
264 * Hook executed after the worker task promise resolution.
267 * @param worker - The worker.
268 * @param message - The received message.
270 protected afterPromiseResponseHook (
272 message
: MessageValue
<Response
>
274 const workerTasksUsage
= this.getWorkerTasksUsage(worker
) as TasksUsage
275 --workerTasksUsage
.running
276 ++workerTasksUsage
.run
277 if (message
.error
!= null) {
278 ++workerTasksUsage
.error
280 if (this.workerChoiceStrategyContext
.getRequiredStatistics().runTime
) {
281 workerTasksUsage
.runTime
+= message
.taskRunTime
?? 0
283 this.workerChoiceStrategyContext
.getRequiredStatistics().avgRunTime
&&
284 workerTasksUsage
.run
!== 0
286 workerTasksUsage
.avgRunTime
=
287 workerTasksUsage
.runTime
/ workerTasksUsage
.run
293 * Removes the given worker from the pool.
295 * @param worker - The worker that will be removed.
297 protected removeWorker (worker
: Worker
): void {
298 const workerKey
= this.getWorkerKey(worker
)
299 this.workers
.splice(workerKey
, 1)
300 this.workerChoiceStrategyContext
.remove(workerKey
)
304 * Chooses a worker for the next task.
306 * The default implementation uses a round robin algorithm to distribute the load.
308 * @returns [worker key, worker].
310 protected chooseWorker (): [number, Worker
] {
311 const workerKey
= this.workerChoiceStrategyContext
.execute()
312 return [workerKey
, this.workers
[workerKey
].worker
]
316 * Sends a message to the given worker.
318 * @param worker - The worker which should receive the message.
319 * @param message - The message.
321 protected abstract sendToWorker (
323 message
: MessageValue
<Data
>
327 * Registers a listener callback on a given worker.
329 * @param worker - The worker which should register a listener.
330 * @param listener - The message listener callback.
332 protected abstract registerWorkerMessageListener
<
333 Message
extends Data
| Response
334 >(worker
: Worker
, listener
: (message
: MessageValue
<Message
>) => void): void
337 * Returns a newly created worker.
339 protected abstract createWorker (): Worker
342 * Function that can be hooked up when a worker has been newly created and moved to the workers registry.
344 * Can be used to update the `maxListeners` or binding the `main-worker`\<-\>`worker` connection if not bind by default.
346 * @param worker - The newly created worker.
348 protected abstract afterWorkerSetup (worker
: Worker
): void
351 * Creates a new worker for this pool and sets it up completely.
353 * @returns New, completely set up worker.
355 protected createAndSetupWorker (): Worker
{
356 const worker
= this.createWorker()
358 worker
.on('message', this.opts
.messageHandler
?? EMPTY_FUNCTION
)
359 worker
.on('error', this.opts
.errorHandler
?? EMPTY_FUNCTION
)
360 worker
.on('online', this.opts
.onlineHandler
?? EMPTY_FUNCTION
)
361 worker
.on('exit', this.opts
.exitHandler
?? EMPTY_FUNCTION
)
362 worker
.once('exit', () => {
363 this.removeWorker(worker
)
366 this.pushWorker(worker
, {
374 this.afterWorkerSetup(worker
)
380 * This function is the listener registered for each worker.
382 * @returns The listener function to execute when a message is received from a worker.
384 protected workerListener (): (message
: MessageValue
<Response
>) => void {
386 if (message
.id
!== undefined) {
387 const promiseResponse
= this.promiseResponseMap
.get(message
.id
)
388 if (promiseResponse
!== undefined) {
389 if (message
.error
!= null) {
390 promiseResponse
.reject(message
.error
)
392 promiseResponse
.resolve(message
.data
as Response
)
394 this.afterPromiseResponseHook(promiseResponse
.worker
, message
)
395 this.promiseResponseMap
.delete(message
.id
)
401 private async internalExecute (
405 ): Promise
<Response
> {
406 this.beforePromiseResponseHook(workerKey
)
407 return await new Promise
<Response
>((resolve
, reject
) => {
408 this.promiseResponseMap
.set(messageId
, { resolve
, reject
, worker
})
412 private checkAndEmitBusy (): void {
413 if (this.opts
.enableEvents
=== true && this.busy
) {
414 this.emitter
?.emit('busy')
418 private checkAndEmitFull (): void {
420 this.type === PoolType
.DYNAMIC
&&
421 this.opts
.enableEvents
=== true &&
424 this.emitter
?.emit('full')
429 * Gets worker tasks usage.
431 * @param worker - The worker.
432 * @returns The worker tasks usage.
434 private getWorkerTasksUsage (worker
: Worker
): TasksUsage
| undefined {
435 const workerKey
= this.getWorkerKey(worker
)
436 if (workerKey
!== -1) {
437 return this.workers
[workerKey
].tasksUsage
439 throw new Error('Worker could not be found in the pool')
443 * Pushes the given worker.
445 * @param worker - The worker.
446 * @param tasksUsage - The worker tasks usage.
448 private pushWorker (worker
: Worker
, tasksUsage
: TasksUsage
): void {
456 * Sets the given worker.
458 * @param workerKey - The worker key.
459 * @param worker - The worker.
460 * @param tasksUsage - The worker tasks usage.
465 tasksUsage
: TasksUsage
467 this.workers
[workerKey
] = {