| 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 = 1000 * 60 |
| 10 | const DEFAULT_KILL_BEHAVIOR: KillBehavior = KillBehaviors.SOFT |
| 11 | |
| 12 | /** |
| 13 | * Base class containing 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 | /** |
| 34 | * Constructs a new poolifier worker. |
| 35 | * |
| 36 | * @param type The type of async event. |
| 37 | * @param isMain Whether this is the main worker or not. |
| 38 | * @param fn Function processed by the worker when the pool's `execution` function is invoked. |
| 39 | * @param mainWorker Reference to main worker. |
| 40 | * @param opts Options for the worker. |
| 41 | */ |
| 42 | public constructor ( |
| 43 | type: string, |
| 44 | isMain: boolean, |
| 45 | fn: (data: Data) => Response, |
| 46 | protected mainWorker: MainWorker | undefined | null, |
| 47 | public readonly opts: WorkerOptions = { |
| 48 | /** |
| 49 | * The kill behavior option on this Worker or its default value. |
| 50 | */ |
| 51 | killBehavior: DEFAULT_KILL_BEHAVIOR, |
| 52 | /** |
| 53 | * The maximum time to keep this worker alive while idle. |
| 54 | * The pool automatically checks and terminates this worker when the time expires. |
| 55 | */ |
| 56 | maxInactiveTime: DEFAULT_MAX_INACTIVE_TIME |
| 57 | } |
| 58 | ) { |
| 59 | super(type) |
| 60 | this.checkFunctionInput(fn) |
| 61 | this.checkWorkerOptions(this.opts) |
| 62 | this.lastTaskTimestamp = Date.now() |
| 63 | // Keep the worker active |
| 64 | if (!isMain) { |
| 65 | this.aliveInterval = setInterval( |
| 66 | this.checkAlive.bind(this), |
| 67 | (this.opts.maxInactiveTime ?? DEFAULT_MAX_INACTIVE_TIME) / 2 |
| 68 | ) |
| 69 | this.checkAlive.bind(this)() |
| 70 | } |
| 71 | |
| 72 | this.mainWorker?.on('message', (value: MessageValue<Data, MainWorker>) => { |
| 73 | if (value?.data && value.id) { |
| 74 | // Here you will receive messages |
| 75 | if (this.opts.async) { |
| 76 | this.runInAsyncScope(this.runAsync.bind(this), this, fn, value) |
| 77 | } else { |
| 78 | this.runInAsyncScope(this.run.bind(this), this, fn, value) |
| 79 | } |
| 80 | } else if (value.parent) { |
| 81 | // Save a reference of the main worker to communicate with it |
| 82 | // This will be received once |
| 83 | this.mainWorker = value.parent |
| 84 | } else if (value.kill) { |
| 85 | // Here is time to kill this worker, just clearing the interval |
| 86 | if (this.aliveInterval) clearInterval(this.aliveInterval) |
| 87 | this.emitDestroy() |
| 88 | } |
| 89 | }) |
| 90 | } |
| 91 | |
| 92 | private checkWorkerOptions (opts: WorkerOptions) { |
| 93 | this.opts.killBehavior = opts.killBehavior ?? DEFAULT_KILL_BEHAVIOR |
| 94 | this.opts.maxInactiveTime = |
| 95 | opts.maxInactiveTime ?? DEFAULT_MAX_INACTIVE_TIME |
| 96 | /** |
| 97 | * Whether the worker is working asynchronously or not. |
| 98 | */ |
| 99 | this.opts.async = !!opts.async |
| 100 | } |
| 101 | |
| 102 | /** |
| 103 | * Check if the `fn` parameter is passed to the constructor. |
| 104 | * |
| 105 | * @param fn The function that should be defined. |
| 106 | */ |
| 107 | private checkFunctionInput (fn: (data: Data) => Response): void { |
| 108 | if (!fn) throw new Error('fn parameter is mandatory') |
| 109 | } |
| 110 | |
| 111 | /** |
| 112 | * Returns the main worker. |
| 113 | * |
| 114 | * @returns Reference to the main worker. |
| 115 | */ |
| 116 | protected getMainWorker (): MainWorker { |
| 117 | if (!this.mainWorker) { |
| 118 | throw new Error('Main worker was not set') |
| 119 | } |
| 120 | return this.mainWorker |
| 121 | } |
| 122 | |
| 123 | /** |
| 124 | * Send a message to the main worker. |
| 125 | * |
| 126 | * @param message The response message. |
| 127 | */ |
| 128 | protected abstract sendToMainWorker (message: MessageValue<Response>): void |
| 129 | |
| 130 | /** |
| 131 | * Check to see if the worker should be terminated, because its living too long. |
| 132 | */ |
| 133 | protected checkAlive (): void { |
| 134 | if ( |
| 135 | Date.now() - this.lastTaskTimestamp > |
| 136 | (this.opts.maxInactiveTime ?? DEFAULT_MAX_INACTIVE_TIME) |
| 137 | ) { |
| 138 | this.sendToMainWorker({ kill: this.opts.killBehavior }) |
| 139 | } |
| 140 | } |
| 141 | |
| 142 | /** |
| 143 | * Handle an error and convert it to a string so it can be sent back to the main worker. |
| 144 | * |
| 145 | * @param e The error raised by the worker. |
| 146 | * @returns Message of the error. |
| 147 | */ |
| 148 | protected handleError (e: Error | string): string { |
| 149 | return e as string |
| 150 | } |
| 151 | |
| 152 | /** |
| 153 | * Run the given function synchronously. |
| 154 | * |
| 155 | * @param fn Function that will be executed. |
| 156 | * @param value Input data for the given function. |
| 157 | */ |
| 158 | protected run ( |
| 159 | fn: (data?: Data) => Response, |
| 160 | value: MessageValue<Data> |
| 161 | ): void { |
| 162 | try { |
| 163 | const res = fn(value.data) |
| 164 | this.sendToMainWorker({ data: res, id: value.id }) |
| 165 | } catch (e) { |
| 166 | const err = this.handleError(e as Error) |
| 167 | this.sendToMainWorker({ error: err, id: value.id }) |
| 168 | } finally { |
| 169 | this.lastTaskTimestamp = Date.now() |
| 170 | } |
| 171 | } |
| 172 | |
| 173 | /** |
| 174 | * Run the given function asynchronously. |
| 175 | * |
| 176 | * @param fn Function that will be executed. |
| 177 | * @param value Input data for the given function. |
| 178 | */ |
| 179 | protected runAsync ( |
| 180 | fn: (data?: Data) => Promise<Response>, |
| 181 | value: MessageValue<Data> |
| 182 | ): void { |
| 183 | fn(value.data) |
| 184 | .then(res => { |
| 185 | this.sendToMainWorker({ data: res, id: value.id }) |
| 186 | return null |
| 187 | }) |
| 188 | .catch(e => { |
| 189 | const err = this.handleError(e) |
| 190 | this.sendToMainWorker({ error: err, id: value.id }) |
| 191 | }) |
| 192 | .finally(() => { |
| 193 | this.lastTaskTimestamp = Date.now() |
| 194 | }) |
| 195 | .catch(EMPTY_FUNCTION) |
| 196 | } |
| 197 | } |