src/worker/abstract-worker.ts

   1 import { AsyncResource } from 'async_hooks'
   2 import type { MessageValue } from '../utility-types'
   3 import type { WorkerOptions } from './worker-options'
   4
   5 export abstract class AbstractWorker<
   6   MainWorker,
   7   Data = unknown,
   8   Response = unknown
   9 > extends AsyncResource {
  10   protected readonly maxInactiveTime: number
  11   protected readonly async: boolean
  12   protected lastTask: number
  13   protected readonly interval?: NodeJS.Timeout
  14
  15   /**
  16    *
  17    * @param type The type of async event.
  18    * @param isMain
  19    * @param fn
  20    * @param opts
  21    */
  22   public constructor (
  23     type: string,
  24     isMain: boolean,
  25     fn: (data: Data) => Response,
  26     public readonly opts: WorkerOptions = {}
  27   ) {
  28     super(type)
  29
  30     this.maxInactiveTime = this.opts.maxInactiveTime ?? 1000 * 60
  31     this.async = !!this.opts.async
  32     this.lastTask = Date.now()
  33     if (!fn) throw new Error('Fn parameter is mandatory')
  34     // keep the worker active
  35     if (!isMain) {
  36       this.interval = setInterval(
  37         this.checkAlive.bind(this),
  38         this.maxInactiveTime / 2
  39       )
  40       this.checkAlive.bind(this)()
  41     }
  42   }
  43
  44   protected abstract getMainWorker (): MainWorker
  45
  46   protected abstract sendToMainWorker (message: MessageValue<Response>): void
  47
  48   protected checkAlive (): void {
  49     if (Date.now() - this.lastTask > this.maxInactiveTime) {
  50       this.sendToMainWorker({ kill: 1 })
  51     }
  52   }
  53
  54   protected handleError (e: Error | string): string {
  55     return (e as unknown) as string
  56   }
  57
  58   protected run (
  59     fn: (data?: Data) => Response,
  60     value: MessageValue<Data>
  61   ): void {
  62     try {
  63       const res = fn(value.data)
  64       this.sendToMainWorker({ data: res, id: value.id })
  65       this.lastTask = Date.now()
  66     } catch (e) {
  67       const err = this.handleError(e)
  68       this.sendToMainWorker({ error: err, id: value.id })
  69       this.lastTask = Date.now()
  70     }
  71   }
  72
  73   protected runAsync (
  74     fn: (data?: Data) => Promise<Response>,
  75     value: MessageValue<Data>
  76   ): void {
  77     fn(value.data)
  78       .then(res => {
  79         this.sendToMainWorker({ data: res, id: value.id })
  80         this.lastTask = Date.now()
  81         return null
  82       })
  83       .catch(e => {
  84         const err = this.handleError(e)
  85         this.sendToMainWorker({ error: err, id: value.id })
  86         this.lastTask = Date.now()
  87       })
  88   }
  89 }