| 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' |
| 5 | import type { |
| 6 | MessageValue, |
| 7 | TaskPerformance, |
| 8 | WorkerStatistics |
| 9 | } from '../utility-types' |
| 10 | import { EMPTY_FUNCTION, isPlainObject } from '../utils' |
| 11 | import { |
| 12 | type KillBehavior, |
| 13 | KillBehaviors, |
| 14 | type WorkerOptions |
| 15 | } from './worker-options' |
| 16 | import type { |
| 17 | TaskFunctions, |
| 18 | WorkerAsyncFunction, |
| 19 | WorkerFunction, |
| 20 | WorkerSyncFunction |
| 21 | } from './worker-functions' |
| 22 | |
| 23 | const DEFAULT_FUNCTION_NAME = 'default' |
| 24 | const DEFAULT_MAX_INACTIVE_TIME = 60000 |
| 25 | const DEFAULT_KILL_BEHAVIOR: KillBehavior = KillBehaviors.SOFT |
| 26 | |
| 27 | /** |
| 28 | * Base class that implements some shared logic for all poolifier workers. |
| 29 | * |
| 30 | * @typeParam MainWorker - Type of main worker. |
| 31 | * @typeParam Data - Type of data this worker receives from pool's execution. This can only be serializable data. |
| 32 | * @typeParam Response - Type of response the worker sends back to the main worker. This can only be serializable data. |
| 33 | */ |
| 34 | export abstract class AbstractWorker< |
| 35 | MainWorker extends Worker | MessagePort, |
| 36 | Data = unknown, |
| 37 | Response = unknown |
| 38 | > extends AsyncResource { |
| 39 | /** |
| 40 | * Task function(s) processed by the worker when the pool's `execution` function is invoked. |
| 41 | */ |
| 42 | protected taskFunctions!: Map<string, WorkerFunction<Data, Response>> |
| 43 | /** |
| 44 | * Timestamp of the last task processed by this worker. |
| 45 | */ |
| 46 | protected lastTaskTimestamp!: number |
| 47 | /** |
| 48 | * Performance statistics computation requirements. |
| 49 | */ |
| 50 | protected statistics!: WorkerStatistics |
| 51 | /** |
| 52 | * Handler id of the `aliveInterval` worker alive check. |
| 53 | */ |
| 54 | protected readonly aliveInterval?: NodeJS.Timeout |
| 55 | /** |
| 56 | * Constructs a new poolifier worker. |
| 57 | * |
| 58 | * @param type - The type of async event. |
| 59 | * @param isMain - Whether this is the main worker or not. |
| 60 | * @param taskFunctions - Task function(s) processed by the worker when the pool's `execution` function is invoked. The first function is the default function. |
| 61 | * @param mainWorker - Reference to main worker. |
| 62 | * @param opts - Options for the worker. |
| 63 | */ |
| 64 | public constructor ( |
| 65 | type: string, |
| 66 | protected readonly isMain: boolean, |
| 67 | taskFunctions: |
| 68 | | WorkerFunction<Data, Response> |
| 69 | | TaskFunctions<Data, Response>, |
| 70 | protected mainWorker: MainWorker | undefined | null, |
| 71 | protected readonly opts: WorkerOptions = { |
| 72 | /** |
| 73 | * The kill behavior option on this worker or its default value. |
| 74 | */ |
| 75 | killBehavior: DEFAULT_KILL_BEHAVIOR, |
| 76 | /** |
| 77 | * The maximum time to keep this worker alive while idle. |
| 78 | * The pool automatically checks and terminates this worker when the time expires. |
| 79 | */ |
| 80 | maxInactiveTime: DEFAULT_MAX_INACTIVE_TIME |
| 81 | } |
| 82 | ) { |
| 83 | super(type) |
| 84 | this.checkWorkerOptions(this.opts) |
| 85 | this.checkTaskFunctions(taskFunctions) |
| 86 | if (!this.isMain) { |
| 87 | this.lastTaskTimestamp = performance.now() |
| 88 | this.aliveInterval = setInterval( |
| 89 | this.checkAlive.bind(this), |
| 90 | (this.opts.maxInactiveTime ?? DEFAULT_MAX_INACTIVE_TIME) / 2 |
| 91 | ) |
| 92 | this.checkAlive.bind(this)() |
| 93 | } |
| 94 | this.mainWorker?.on('message', this.messageListener.bind(this)) |
| 95 | } |
| 96 | |
| 97 | private checkWorkerOptions (opts: WorkerOptions): void { |
| 98 | this.opts.killBehavior = opts.killBehavior ?? DEFAULT_KILL_BEHAVIOR |
| 99 | this.opts.maxInactiveTime = |
| 100 | opts.maxInactiveTime ?? DEFAULT_MAX_INACTIVE_TIME |
| 101 | delete this.opts.async |
| 102 | } |
| 103 | |
| 104 | /** |
| 105 | * Checks if the `taskFunctions` parameter is passed to the constructor. |
| 106 | * |
| 107 | * @param taskFunctions - The task function(s) parameter that should be checked. |
| 108 | */ |
| 109 | private checkTaskFunctions ( |
| 110 | taskFunctions: |
| 111 | | WorkerFunction<Data, Response> |
| 112 | | TaskFunctions<Data, Response> |
| 113 | ): void { |
| 114 | if (taskFunctions == null) { |
| 115 | throw new Error('taskFunctions parameter is mandatory') |
| 116 | } |
| 117 | this.taskFunctions = new Map<string, WorkerFunction<Data, Response>>() |
| 118 | if (typeof taskFunctions === 'function') { |
| 119 | this.taskFunctions.set(DEFAULT_FUNCTION_NAME, taskFunctions.bind(this)) |
| 120 | } else if (isPlainObject(taskFunctions)) { |
| 121 | let firstEntry = true |
| 122 | for (const [name, fn] of Object.entries(taskFunctions)) { |
| 123 | if (typeof fn !== 'function') { |
| 124 | throw new TypeError( |
| 125 | 'A taskFunctions parameter object value is not a function' |
| 126 | ) |
| 127 | } |
| 128 | this.taskFunctions.set(name, fn.bind(this)) |
| 129 | if (firstEntry) { |
| 130 | this.taskFunctions.set(DEFAULT_FUNCTION_NAME, fn.bind(this)) |
| 131 | firstEntry = false |
| 132 | } |
| 133 | } |
| 134 | if (firstEntry) { |
| 135 | throw new Error('taskFunctions parameter object is empty') |
| 136 | } |
| 137 | } else { |
| 138 | throw new TypeError( |
| 139 | 'taskFunctions parameter is not a function or a plain object' |
| 140 | ) |
| 141 | } |
| 142 | } |
| 143 | |
| 144 | /** |
| 145 | * Worker message listener. |
| 146 | * |
| 147 | * @param message - Message received. |
| 148 | */ |
| 149 | protected messageListener ( |
| 150 | message: MessageValue<Data, Data, MainWorker> |
| 151 | ): void { |
| 152 | if (message.id != null && message.data != null) { |
| 153 | // Task message received |
| 154 | const fn = this.getTaskFunction(message.name) |
| 155 | if (fn?.constructor.name === 'AsyncFunction') { |
| 156 | this.runInAsyncScope(this.runAsync.bind(this), this, fn, message) |
| 157 | } else { |
| 158 | this.runInAsyncScope(this.runSync.bind(this), this, fn, message) |
| 159 | } |
| 160 | } else if (message.parent != null) { |
| 161 | // Main worker reference message received |
| 162 | this.mainWorker = message.parent |
| 163 | } else if (message.statistics != null) { |
| 164 | // Statistics message received |
| 165 | this.statistics = message.statistics |
| 166 | } else if (message.kill != null) { |
| 167 | // Kill message received |
| 168 | this.aliveInterval != null && clearInterval(this.aliveInterval) |
| 169 | this.emitDestroy() |
| 170 | } |
| 171 | } |
| 172 | |
| 173 | /** |
| 174 | * Returns the main worker. |
| 175 | * |
| 176 | * @returns Reference to the main worker. |
| 177 | */ |
| 178 | protected getMainWorker (): MainWorker { |
| 179 | if (this.mainWorker == null) { |
| 180 | throw new Error('Main worker was not set') |
| 181 | } |
| 182 | return this.mainWorker |
| 183 | } |
| 184 | |
| 185 | /** |
| 186 | * Sends a message to the main worker. |
| 187 | * |
| 188 | * @param message - The response message. |
| 189 | */ |
| 190 | protected abstract sendToMainWorker ( |
| 191 | message: MessageValue<Response, Data> |
| 192 | ): void |
| 193 | |
| 194 | /** |
| 195 | * Checks if the worker should be terminated, because its living too long. |
| 196 | */ |
| 197 | protected checkAlive (): void { |
| 198 | if ( |
| 199 | performance.now() - this.lastTaskTimestamp > |
| 200 | (this.opts.maxInactiveTime ?? DEFAULT_MAX_INACTIVE_TIME) |
| 201 | ) { |
| 202 | this.sendToMainWorker({ kill: this.opts.killBehavior }) |
| 203 | } |
| 204 | } |
| 205 | |
| 206 | /** |
| 207 | * Handles an error and convert it to a string so it can be sent back to the main worker. |
| 208 | * |
| 209 | * @param e - The error raised by the worker. |
| 210 | * @returns Message of the error. |
| 211 | */ |
| 212 | protected handleError (e: Error | string): string { |
| 213 | return e as string |
| 214 | } |
| 215 | |
| 216 | /** |
| 217 | * Runs the given function synchronously. |
| 218 | * |
| 219 | * @param fn - Function that will be executed. |
| 220 | * @param message - Input data for the given function. |
| 221 | */ |
| 222 | protected runSync ( |
| 223 | fn: WorkerSyncFunction<Data, Response>, |
| 224 | message: MessageValue<Data> |
| 225 | ): void { |
| 226 | try { |
| 227 | let taskPerformance = this.beginTaskPerformance() |
| 228 | const res = fn(message.data) |
| 229 | taskPerformance = this.endTaskPerformance(taskPerformance) |
| 230 | this.sendToMainWorker({ |
| 231 | data: res, |
| 232 | taskPerformance, |
| 233 | id: message.id |
| 234 | }) |
| 235 | } catch (e) { |
| 236 | const err = this.handleError(e as Error) |
| 237 | this.sendToMainWorker({ |
| 238 | taskError: { |
| 239 | message: err, |
| 240 | data: message.data |
| 241 | }, |
| 242 | id: message.id |
| 243 | }) |
| 244 | } finally { |
| 245 | !this.isMain && (this.lastTaskTimestamp = performance.now()) |
| 246 | } |
| 247 | } |
| 248 | |
| 249 | /** |
| 250 | * Runs the given function asynchronously. |
| 251 | * |
| 252 | * @param fn - Function that will be executed. |
| 253 | * @param message - Input data for the given function. |
| 254 | */ |
| 255 | protected runAsync ( |
| 256 | fn: WorkerAsyncFunction<Data, Response>, |
| 257 | message: MessageValue<Data> |
| 258 | ): void { |
| 259 | let taskPerformance = this.beginTaskPerformance() |
| 260 | fn(message.data) |
| 261 | .then(res => { |
| 262 | taskPerformance = this.endTaskPerformance(taskPerformance) |
| 263 | this.sendToMainWorker({ |
| 264 | data: res, |
| 265 | taskPerformance, |
| 266 | id: message.id |
| 267 | }) |
| 268 | return null |
| 269 | }) |
| 270 | .catch(e => { |
| 271 | const err = this.handleError(e as Error) |
| 272 | this.sendToMainWorker({ |
| 273 | taskError: { |
| 274 | message: err, |
| 275 | data: message.data |
| 276 | }, |
| 277 | id: message.id |
| 278 | }) |
| 279 | }) |
| 280 | .finally(() => { |
| 281 | !this.isMain && (this.lastTaskTimestamp = performance.now()) |
| 282 | }) |
| 283 | .catch(EMPTY_FUNCTION) |
| 284 | } |
| 285 | |
| 286 | /** |
| 287 | * Gets the task function in the given scope. |
| 288 | * |
| 289 | * @param name - Name of the function that will be returned. |
| 290 | */ |
| 291 | private getTaskFunction (name?: string): WorkerFunction<Data, Response> { |
| 292 | name = name ?? DEFAULT_FUNCTION_NAME |
| 293 | const fn = this.taskFunctions.get(name) |
| 294 | if (fn == null) { |
| 295 | throw new Error(`Task function '${name}' not found`) |
| 296 | } |
| 297 | return fn |
| 298 | } |
| 299 | |
| 300 | private beginTaskPerformance (): TaskPerformance { |
| 301 | this.checkStatistics() |
| 302 | return { |
| 303 | timestamp: performance.now(), |
| 304 | ...(this.statistics.elu && { elu: performance.eventLoopUtilization() }) |
| 305 | } |
| 306 | } |
| 307 | |
| 308 | private endTaskPerformance ( |
| 309 | taskPerformance: TaskPerformance |
| 310 | ): TaskPerformance { |
| 311 | this.checkStatistics() |
| 312 | return { |
| 313 | ...taskPerformance, |
| 314 | ...(this.statistics.runTime && { |
| 315 | runTime: performance.now() - taskPerformance.timestamp |
| 316 | }), |
| 317 | ...(this.statistics.elu && { |
| 318 | elu: performance.eventLoopUtilization(taskPerformance.elu) |
| 319 | }) |
| 320 | } |
| 321 | } |
| 322 | |
| 323 | private checkStatistics (): void { |
| 324 | if (this.statistics == null) { |
| 325 | throw new Error('Performance statistics computation requirements not set') |
| 326 | } |
| 327 | } |
| 328 | } |