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be0676b3 APA |
1 | import type { |
2 | MessageValue, | |
3 | PromiseWorkerResponseWrapper | |
4 | } from '../utility-types' | |
a35560ba S |
5 | import type { IPoolInternal } from './pool-internal' |
6 | import { PoolEmitter } from './pool-internal' | |
7 | import type { WorkerChoiceStrategy } from './selection-strategies' | |
8 | import { | |
9 | WorkerChoiceStrategies, | |
10 | WorkerChoiceStrategyContext | |
11 | } from './selection-strategies' | |
c97c7edb | 12 | |
c510fea7 APA |
13 | /** |
14 | * An intentional empty function. | |
15 | */ | |
a35560ba S |
16 | const EMPTY_FUNCTION: () => void = () => { |
17 | /* Intentionally empty */ | |
c510fea7 APA |
18 | } |
19 | ||
729c563d S |
20 | /** |
21 | * Callback invoked if the worker raised an error. | |
22 | */ | |
c97c7edb | 23 | export type ErrorHandler<Worker> = (this: Worker, e: Error) => void |
729c563d S |
24 | |
25 | /** | |
26 | * Callback invoked when the worker has started successfully. | |
27 | */ | |
c97c7edb | 28 | export type OnlineHandler<Worker> = (this: Worker) => void |
729c563d S |
29 | |
30 | /** | |
31 | * Callback invoked when the worker exits successfully. | |
32 | */ | |
c97c7edb S |
33 | export type ExitHandler<Worker> = (this: Worker, code: number) => void |
34 | ||
729c563d S |
35 | /** |
36 | * Basic interface that describes the minimum required implementation of listener events for a pool-worker. | |
37 | */ | |
c97c7edb | 38 | export interface IWorker { |
3832ad95 S |
39 | /** |
40 | * Register a listener to the error event. | |
41 | * | |
42 | * @param event `'error'`. | |
43 | * @param handler The error handler. | |
44 | */ | |
c97c7edb | 45 | on(event: 'error', handler: ErrorHandler<this>): void |
3832ad95 S |
46 | /** |
47 | * Register a listener to the online event. | |
48 | * | |
49 | * @param event `'online'`. | |
50 | * @param handler The online handler. | |
51 | */ | |
c97c7edb | 52 | on(event: 'online', handler: OnlineHandler<this>): void |
3832ad95 S |
53 | /** |
54 | * Register a listener to the exit event. | |
55 | * | |
56 | * @param event `'exit'`. | |
57 | * @param handler The exit handler. | |
58 | */ | |
c97c7edb | 59 | on(event: 'exit', handler: ExitHandler<this>): void |
3832ad95 S |
60 | /** |
61 | * Register a listener to the exit event that will only performed once. | |
62 | * | |
63 | * @param event `'exit'`. | |
64 | * @param handler The exit handler. | |
65 | */ | |
45dbbb14 | 66 | once(event: 'exit', handler: ExitHandler<this>): void |
c97c7edb S |
67 | } |
68 | ||
729c563d S |
69 | /** |
70 | * Options for a poolifier pool. | |
71 | */ | |
c97c7edb S |
72 | export interface PoolOptions<Worker> { |
73 | /** | |
74 | * A function that will listen for error event on each worker. | |
75 | */ | |
76 | errorHandler?: ErrorHandler<Worker> | |
77 | /** | |
78 | * A function that will listen for online event on each worker. | |
79 | */ | |
80 | onlineHandler?: OnlineHandler<Worker> | |
81 | /** | |
82 | * A function that will listen for exit event on each worker. | |
83 | */ | |
84 | exitHandler?: ExitHandler<Worker> | |
a35560ba S |
85 | /** |
86 | * The work choice strategy to use in this pool. | |
87 | */ | |
88 | workerChoiceStrategy?: WorkerChoiceStrategy | |
c97c7edb S |
89 | } |
90 | ||
729c563d S |
91 | /** |
92 | * Base class containing some shared logic for all poolifier pools. | |
93 | * | |
94 | * @template Worker Type of worker which manages this pool. | |
deb85c12 JB |
95 | * @template Data Type of data sent to the worker. This can only be serializable data. |
96 | * @template Response Type of response of execution. This can only be serializable data. | |
729c563d | 97 | */ |
c97c7edb S |
98 | export abstract class AbstractPool< |
99 | Worker extends IWorker, | |
d3c8a1a8 S |
100 | Data = unknown, |
101 | Response = unknown | |
a35560ba | 102 | > implements IPoolInternal<Worker, Data, Response> { |
be0676b3 APA |
103 | /** |
104 | * The promise map. | |
105 | * | |
106 | * - `key`: This is the message ID of each submitted task. | |
107 | * - `value`: An object that contains the worker, the resolve function and the reject function. | |
108 | * | |
109 | * When we receive a message from the worker we get a map entry and resolve/reject the promise based on the message. | |
110 | */ | |
111 | protected promiseMap: Map< | |
112 | number, | |
113 | PromiseWorkerResponseWrapper<Worker, Response> | |
114 | > = new Map<number, PromiseWorkerResponseWrapper<Worker, Response>>() | |
115 | ||
a35560ba | 116 | /** @inheritdoc */ |
c97c7edb | 117 | public readonly workers: Worker[] = [] |
729c563d | 118 | |
a35560ba | 119 | /** @inheritdoc */ |
c97c7edb S |
120 | public readonly tasks: Map<Worker, number> = new Map<Worker, number>() |
121 | ||
a35560ba | 122 | /** @inheritdoc */ |
c97c7edb S |
123 | public readonly emitter: PoolEmitter |
124 | ||
729c563d S |
125 | /** |
126 | * ID of the next message. | |
127 | */ | |
280c2a77 | 128 | protected nextMessageId: number = 0 |
c97c7edb | 129 | |
a35560ba S |
130 | /** |
131 | * Worker choice strategy instance implementing the worker choice algorithm. | |
132 | * | |
133 | * Default to a strategy implementing a round robin algorithm. | |
134 | */ | |
135 | protected workerChoiceStrategyContext: WorkerChoiceStrategyContext< | |
136 | Worker, | |
137 | Data, | |
138 | Response | |
139 | > | |
140 | ||
729c563d S |
141 | /** |
142 | * Constructs a new poolifier pool. | |
143 | * | |
5c5a1fb7 | 144 | * @param numberOfWorkers Number of workers that this pool should manage. |
729c563d | 145 | * @param filePath Path to the worker-file. |
1927ee67 | 146 | * @param opts Options for the pool. |
729c563d | 147 | */ |
c97c7edb | 148 | public constructor ( |
5c5a1fb7 | 149 | public readonly numberOfWorkers: number, |
c97c7edb | 150 | public readonly filePath: string, |
1927ee67 | 151 | public readonly opts: PoolOptions<Worker> |
c97c7edb S |
152 | ) { |
153 | if (!this.isMain()) { | |
154 | throw new Error('Cannot start a pool from a worker!') | |
155 | } | |
8d3782fa | 156 | this.checkNumberOfWorkers(this.numberOfWorkers) |
c510fea7 | 157 | this.checkFilePath(this.filePath) |
c97c7edb S |
158 | this.setupHook() |
159 | ||
5c5a1fb7 | 160 | for (let i = 1; i <= this.numberOfWorkers; i++) { |
280c2a77 | 161 | this.createAndSetupWorker() |
c97c7edb S |
162 | } |
163 | ||
164 | this.emitter = new PoolEmitter() | |
a35560ba S |
165 | this.workerChoiceStrategyContext = new WorkerChoiceStrategyContext( |
166 | this, | |
167 | opts.workerChoiceStrategy ?? WorkerChoiceStrategies.ROUND_ROBIN | |
168 | ) | |
c97c7edb S |
169 | } |
170 | ||
a35560ba | 171 | private checkFilePath (filePath: string): void { |
c510fea7 APA |
172 | if (!filePath) { |
173 | throw new Error('Please specify a file with a worker implementation') | |
174 | } | |
175 | } | |
176 | ||
8d3782fa JB |
177 | private checkNumberOfWorkers (numberOfWorkers: number): void { |
178 | if (numberOfWorkers == null) { | |
179 | throw new Error( | |
180 | 'Cannot instantiate a pool without specifying the number of workers' | |
181 | ) | |
182 | } else if (!Number.isSafeInteger(numberOfWorkers)) { | |
183 | throw new Error( | |
184 | 'Cannot instantiate a pool with a non integer number of workers' | |
185 | ) | |
186 | } else if (numberOfWorkers < 0) { | |
187 | throw new Error( | |
188 | 'Cannot instantiate a pool with a negative number of workers' | |
189 | ) | |
ff5e76e1 | 190 | } else if (!this.dynamic && numberOfWorkers === 0) { |
8d3782fa JB |
191 | throw new Error('Cannot instantiate a fixed pool with no worker') |
192 | } | |
193 | } | |
194 | ||
a35560ba | 195 | /** @inheritdoc */ |
ff5e76e1 | 196 | public get dynamic (): boolean { |
a35560ba S |
197 | return false |
198 | } | |
199 | ||
200 | /** @inheritdoc */ | |
201 | public setWorkerChoiceStrategy ( | |
202 | workerChoiceStrategy: WorkerChoiceStrategy | |
203 | ): void { | |
b98ec2e6 | 204 | this.opts.workerChoiceStrategy = workerChoiceStrategy |
a35560ba S |
205 | this.workerChoiceStrategyContext.setWorkerChoiceStrategy( |
206 | workerChoiceStrategy | |
207 | ) | |
208 | } | |
209 | ||
210 | /** @inheritdoc */ | |
280c2a77 S |
211 | public execute (data: Data): Promise<Response> { |
212 | // Configure worker to handle message with the specified task | |
213 | const worker = this.chooseWorker() | |
214 | this.increaseWorkersTask(worker) | |
215 | const messageId = ++this.nextMessageId | |
216 | const res = this.internalExecute(worker, messageId) | |
217 | this.sendToWorker(worker, { data: data || ({} as Data), id: messageId }) | |
218 | return res | |
219 | } | |
c97c7edb | 220 | |
a35560ba | 221 | /** @inheritdoc */ |
c97c7edb | 222 | public async destroy (): Promise<void> { |
45dbbb14 | 223 | await Promise.all(this.workers.map(worker => this.destroyWorker(worker))) |
c97c7edb S |
224 | } |
225 | ||
a35560ba S |
226 | /** @inheritdoc */ |
227 | public abstract destroyWorker (worker: Worker): void | Promise<void> | |
c97c7edb | 228 | |
729c563d | 229 | /** |
280c2a77 S |
230 | * Setup hook that can be overridden by a Poolifier pool implementation |
231 | * to run code before workers are created in the abstract constructor. | |
729c563d | 232 | */ |
280c2a77 S |
233 | protected setupHook (): void { |
234 | // Can be overridden | |
235 | } | |
c97c7edb | 236 | |
729c563d | 237 | /** |
280c2a77 S |
238 | * Should return whether the worker is the main worker or not. |
239 | */ | |
240 | protected abstract isMain (): boolean | |
241 | ||
242 | /** | |
243 | * Increase the number of tasks that the given workers has done. | |
729c563d | 244 | * |
f416c098 | 245 | * @param worker Worker whose tasks are increased. |
729c563d | 246 | */ |
280c2a77 | 247 | protected increaseWorkersTask (worker: Worker): void { |
f416c098 | 248 | this.stepWorkerNumberOfTasks(worker, 1) |
c97c7edb S |
249 | } |
250 | ||
c01733f1 | 251 | /** |
d63d3be3 | 252 | * Decrease the number of tasks that the given workers has done. |
c01733f1 | 253 | * |
f416c098 | 254 | * @param worker Worker whose tasks are decreased. |
c01733f1 | 255 | */ |
256 | protected decreaseWorkersTasks (worker: Worker): void { | |
f416c098 JB |
257 | this.stepWorkerNumberOfTasks(worker, -1) |
258 | } | |
259 | ||
260 | /** | |
261 | * Step the number of tasks that the given workers has done. | |
262 | * | |
263 | * @param worker Worker whose tasks are set. | |
264 | * @param step Worker number of tasks step. | |
265 | */ | |
a35560ba | 266 | private stepWorkerNumberOfTasks (worker: Worker, step: number): void { |
d63d3be3 | 267 | const numberOfTasksInProgress = this.tasks.get(worker) |
268 | if (numberOfTasksInProgress !== undefined) { | |
f416c098 | 269 | this.tasks.set(worker, numberOfTasksInProgress + step) |
c01733f1 | 270 | } else { |
271 | throw Error('Worker could not be found in tasks map') | |
272 | } | |
273 | } | |
274 | ||
729c563d S |
275 | /** |
276 | * Removes the given worker from the pool. | |
277 | * | |
278 | * @param worker Worker that will be removed. | |
279 | */ | |
f2fdaa86 JB |
280 | protected removeWorker (worker: Worker): void { |
281 | // Clean worker from data structure | |
282 | const workerIndex = this.workers.indexOf(worker) | |
283 | this.workers.splice(workerIndex, 1) | |
284 | this.tasks.delete(worker) | |
285 | } | |
286 | ||
280c2a77 S |
287 | /** |
288 | * Choose a worker for the next task. | |
289 | * | |
290 | * The default implementation uses a round robin algorithm to distribute the load. | |
291 | * | |
292 | * @returns Worker. | |
293 | */ | |
294 | protected chooseWorker (): Worker { | |
a35560ba | 295 | return this.workerChoiceStrategyContext.execute() |
c97c7edb S |
296 | } |
297 | ||
280c2a77 S |
298 | /** |
299 | * Send a message to the given worker. | |
300 | * | |
301 | * @param worker The worker which should receive the message. | |
302 | * @param message The message. | |
303 | */ | |
304 | protected abstract sendToWorker ( | |
305 | worker: Worker, | |
306 | message: MessageValue<Data> | |
307 | ): void | |
308 | ||
a35560ba S |
309 | /** @inheritdoc */ |
310 | public abstract registerWorkerMessageListener< | |
4f7fa42a S |
311 | Message extends Data | Response |
312 | > (worker: Worker, listener: (message: MessageValue<Message>) => void): void | |
c97c7edb | 313 | |
280c2a77 S |
314 | protected internalExecute ( |
315 | worker: Worker, | |
316 | messageId: number | |
317 | ): Promise<Response> { | |
be0676b3 APA |
318 | return new Promise<Response>((resolve, reject) => { |
319 | this.promiseMap.set(messageId, { resolve, reject, worker }) | |
c97c7edb S |
320 | }) |
321 | } | |
322 | ||
729c563d S |
323 | /** |
324 | * Returns a newly created worker. | |
325 | */ | |
280c2a77 | 326 | protected abstract createWorker (): Worker |
c97c7edb | 327 | |
729c563d S |
328 | /** |
329 | * Function that can be hooked up when a worker has been newly created and moved to the workers registry. | |
330 | * | |
331 | * Can be used to update the `maxListeners` or binding the `main-worker`<->`worker` connection if not bind by default. | |
332 | * | |
333 | * @param worker The newly created worker. | |
334 | */ | |
280c2a77 | 335 | protected abstract afterWorkerSetup (worker: Worker): void |
c97c7edb | 336 | |
a35560ba S |
337 | /** @inheritdoc */ |
338 | public createAndSetupWorker (): Worker { | |
280c2a77 S |
339 | const worker: Worker = this.createWorker() |
340 | ||
a35560ba S |
341 | worker.on('error', this.opts.errorHandler ?? EMPTY_FUNCTION) |
342 | worker.on('online', this.opts.onlineHandler ?? EMPTY_FUNCTION) | |
343 | worker.on('exit', this.opts.exitHandler ?? EMPTY_FUNCTION) | |
45dbbb14 | 344 | worker.once('exit', () => this.removeWorker(worker)) |
280c2a77 | 345 | |
c97c7edb | 346 | this.workers.push(worker) |
280c2a77 S |
347 | |
348 | // Init tasks map | |
c97c7edb | 349 | this.tasks.set(worker, 0) |
280c2a77 S |
350 | |
351 | this.afterWorkerSetup(worker) | |
352 | ||
c97c7edb S |
353 | return worker |
354 | } | |
be0676b3 APA |
355 | |
356 | /** | |
357 | * This function is the listener registered for each worker. | |
358 | * | |
359 | * @returns The listener function to execute when a message is sent from a worker. | |
360 | */ | |
361 | protected workerListener (): (message: MessageValue<Response>) => void { | |
362 | const listener: (message: MessageValue<Response>) => void = message => { | |
363 | if (message.id) { | |
364 | const value = this.promiseMap.get(message.id) | |
365 | if (value) { | |
366 | this.decreaseWorkersTasks(value.worker) | |
367 | if (message.error) value.reject(message.error) | |
368 | else value.resolve(message.data as Response) | |
369 | this.promiseMap.delete(message.id) | |
370 | } | |
371 | } | |
372 | } | |
373 | return listener | |
374 | } | |
c97c7edb | 375 | } |