| 1 | import { AsyncResource } from 'async_hooks' |
| 2 | import type { Worker } from 'cluster' |
| 3 | import type { MessagePort } from 'worker_threads' |
| 4 | import type { MessageValue } from '../utility-types' |
| 5 | import { EMPTY_FUNCTION } from '../utils' |
| 6 | import type { KillBehavior, WorkerOptions } from './worker-options' |
| 7 | import { KillBehaviors } from './worker-options' |
| 8 | |
| 9 | const DEFAULT_MAX_INACTIVE_TIME = 60000 |
| 10 | const DEFAULT_KILL_BEHAVIOR: KillBehavior = KillBehaviors.SOFT |
| 11 | |
| 12 | /** |
| 13 | * Base class that implements some shared logic for all poolifier workers. |
| 14 | * |
| 15 | * @template MainWorker Type of main worker. |
| 16 | * @template Data Type of data this worker receives from pool's execution. This can only be serializable data. |
| 17 | * @template Response Type of response the worker sends back to the main worker. This can only be serializable data. |
| 18 | */ |
| 19 | export abstract class AbstractWorker< |
| 20 | MainWorker extends Worker | MessagePort, |
| 21 | Data = unknown, |
| 22 | Response = unknown |
| 23 | > extends AsyncResource { |
| 24 | /** |
| 25 | * Timestamp of the last task processed by this worker. |
| 26 | */ |
| 27 | protected lastTaskTimestamp: number |
| 28 | /** |
| 29 | * Handler Id of the `aliveInterval` worker alive check. |
| 30 | */ |
| 31 | protected readonly aliveInterval?: NodeJS.Timeout |
| 32 | /** |
| 33 | * Options for the worker. |
| 34 | */ |
| 35 | public readonly opts: WorkerOptions |
| 36 | /** |
| 37 | * Constructs a new poolifier worker. |
| 38 | * |
| 39 | * @param type The type of async event. |
| 40 | * @param isMain Whether this is the main worker or not. |
| 41 | * @param fn Function processed by the worker when the pool's `execution` function is invoked. |
| 42 | * @param mainWorker Reference to main worker. |
| 43 | * @param opts Options for the worker. |
| 44 | */ |
| 45 | public constructor ( |
| 46 | type: string, |
| 47 | isMain: boolean, |
| 48 | fn: (data: Data) => Response, |
| 49 | protected mainWorker: MainWorker | undefined | null, |
| 50 | opts: WorkerOptions = { |
| 51 | /** |
| 52 | * The kill behavior option on this Worker or its default value. |
| 53 | */ |
| 54 | killBehavior: DEFAULT_KILL_BEHAVIOR, |
| 55 | /** |
| 56 | * The maximum time to keep this worker alive while idle. |
| 57 | * The pool automatically checks and terminates this worker when the time expires. |
| 58 | */ |
| 59 | maxInactiveTime: DEFAULT_MAX_INACTIVE_TIME |
| 60 | } |
| 61 | ) { |
| 62 | super(type) |
| 63 | this.opts = opts |
| 64 | this.checkFunctionInput(fn) |
| 65 | this.checkWorkerOptions(this.opts) |
| 66 | this.lastTaskTimestamp = Date.now() |
| 67 | // Keep the worker active |
| 68 | if (isMain === false) { |
| 69 | this.aliveInterval = setInterval( |
| 70 | this.checkAlive.bind(this), |
| 71 | (this.opts.maxInactiveTime ?? DEFAULT_MAX_INACTIVE_TIME) / 2 |
| 72 | ) |
| 73 | this.checkAlive.bind(this)() |
| 74 | } |
| 75 | |
| 76 | this.mainWorker?.on('message', (value: MessageValue<Data, MainWorker>) => { |
| 77 | this.messageListener(value, fn) |
| 78 | }) |
| 79 | } |
| 80 | |
| 81 | protected messageListener ( |
| 82 | value: MessageValue<Data, MainWorker>, |
| 83 | fn: (data: Data) => Response |
| 84 | ): void { |
| 85 | if (value.data !== undefined && value.id !== undefined) { |
| 86 | // Here you will receive messages |
| 87 | if (this.opts.async) { |
| 88 | this.runInAsyncScope(this.runAsync.bind(this), this, fn, value) |
| 89 | } else { |
| 90 | this.runInAsyncScope(this.run.bind(this), this, fn, value) |
| 91 | } |
| 92 | } else if (value.parent !== undefined) { |
| 93 | // Save a reference of the main worker to communicate with it |
| 94 | // This will be received once |
| 95 | this.mainWorker = value.parent |
| 96 | } else if (value.kill !== undefined) { |
| 97 | // Here is time to kill this worker, just clearing the interval |
| 98 | if (this.aliveInterval) clearInterval(this.aliveInterval) |
| 99 | this.emitDestroy() |
| 100 | } |
| 101 | } |
| 102 | |
| 103 | private checkWorkerOptions (opts: WorkerOptions) { |
| 104 | this.opts.killBehavior = opts.killBehavior ?? DEFAULT_KILL_BEHAVIOR |
| 105 | this.opts.maxInactiveTime = |
| 106 | opts.maxInactiveTime ?? DEFAULT_MAX_INACTIVE_TIME |
| 107 | /** |
| 108 | * Whether the worker is working asynchronously or not. |
| 109 | */ |
| 110 | this.opts.async = !!opts.async |
| 111 | } |
| 112 | |
| 113 | /** |
| 114 | * Check if the `fn` parameter is passed to the constructor. |
| 115 | * |
| 116 | * @param fn The function that should be defined. |
| 117 | */ |
| 118 | private checkFunctionInput (fn: (data: Data) => Response): void { |
| 119 | if (!fn) throw new Error('fn parameter is mandatory') |
| 120 | } |
| 121 | |
| 122 | /** |
| 123 | * Returns the main worker. |
| 124 | * |
| 125 | * @returns Reference to the main worker. |
| 126 | */ |
| 127 | protected getMainWorker (): MainWorker { |
| 128 | if (!this.mainWorker) { |
| 129 | throw new Error('Main worker was not set') |
| 130 | } |
| 131 | return this.mainWorker |
| 132 | } |
| 133 | |
| 134 | /** |
| 135 | * Send a message to the main worker. |
| 136 | * |
| 137 | * @param message The response message. |
| 138 | */ |
| 139 | protected abstract sendToMainWorker (message: MessageValue<Response>): void |
| 140 | |
| 141 | /** |
| 142 | * Check to see if the worker should be terminated, because its living too long. |
| 143 | */ |
| 144 | protected checkAlive (): void { |
| 145 | if ( |
| 146 | Date.now() - this.lastTaskTimestamp > |
| 147 | (this.opts.maxInactiveTime ?? DEFAULT_MAX_INACTIVE_TIME) |
| 148 | ) { |
| 149 | this.sendToMainWorker({ kill: this.opts.killBehavior }) |
| 150 | } |
| 151 | } |
| 152 | |
| 153 | /** |
| 154 | * Handle an error and convert it to a string so it can be sent back to the main worker. |
| 155 | * |
| 156 | * @param e The error raised by the worker. |
| 157 | * @returns Message of the error. |
| 158 | */ |
| 159 | protected handleError (e: Error | string): string { |
| 160 | return e as string |
| 161 | } |
| 162 | |
| 163 | /** |
| 164 | * Run the given function synchronously. |
| 165 | * |
| 166 | * @param fn Function that will be executed. |
| 167 | * @param value Input data for the given function. |
| 168 | */ |
| 169 | protected run ( |
| 170 | fn: (data?: Data) => Response, |
| 171 | value: MessageValue<Data> |
| 172 | ): void { |
| 173 | try { |
| 174 | const startTaskTimestamp = Date.now() |
| 175 | const res = fn(value.data) |
| 176 | const taskRunTime = Date.now() - startTaskTimestamp |
| 177 | this.sendToMainWorker({ data: res, id: value.id, taskRunTime }) |
| 178 | } catch (e) { |
| 179 | const err = this.handleError(e as Error) |
| 180 | this.sendToMainWorker({ error: err, id: value.id }) |
| 181 | } finally { |
| 182 | this.lastTaskTimestamp = Date.now() |
| 183 | } |
| 184 | } |
| 185 | |
| 186 | /** |
| 187 | * Run the given function asynchronously. |
| 188 | * |
| 189 | * @param fn Function that will be executed. |
| 190 | * @param value Input data for the given function. |
| 191 | */ |
| 192 | protected runAsync ( |
| 193 | fn: (data?: Data) => Promise<Response>, |
| 194 | value: MessageValue<Data> |
| 195 | ): void { |
| 196 | const startTaskTimestamp = Date.now() |
| 197 | fn(value.data) |
| 198 | .then(res => { |
| 199 | const taskRunTime = Date.now() - startTaskTimestamp |
| 200 | this.sendToMainWorker({ data: res, id: value.id, taskRunTime }) |
| 201 | return null |
| 202 | }) |
| 203 | .catch(e => { |
| 204 | const err = this.handleError(e as Error) |
| 205 | this.sendToMainWorker({ error: err, id: value.id }) |
| 206 | }) |
| 207 | .finally(() => { |
| 208 | this.lastTaskTimestamp = Date.now() |
| 209 | }) |
| 210 | .catch(EMPTY_FUNCTION) |
| 211 | } |
| 212 | } |