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'
9 const DEFAULT_MAX_INACTIVE_TIME
= 1000 * 60
10 const DEFAULT_KILL_BEHAVIOR
: KillBehavior
= KillBehaviors
.SOFT
13 * Base class containing some shared logic for all poolifier workers.
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.
19 export abstract class AbstractWorker
<
20 MainWorker
extends Worker
| MessagePort
,
23 > extends AsyncResource
{
25 * The maximum time to keep this worker alive while idle. The pool automatically checks and terminates this worker when the time expires.
27 protected readonly maxInactiveTime
: number
29 * The kill behavior set as option on the Worker constructor or a default value.
31 protected readonly killBehavior
: KillBehavior
33 * Whether the worker is working asynchronously or not.
35 protected readonly async: boolean
37 * Timestamp of the last task processed by this worker.
39 protected lastTask
: number
41 * Handler ID of the `interval` alive check.
43 protected readonly interval
?: NodeJS
.Timeout
46 * Constructs a new poolifier worker.
48 * @param type The type of async event.
49 * @param isMain Whether this is the main worker or not.
50 * @param fn Function processed by the worker when the pool's `execution` function is invoked.
51 * @param mainWorker Reference to main worker.
52 * @param opts Options for the worker.
57 fn
: (data
: Data
) => Response
,
58 protected mainWorker
?: MainWorker
| null,
59 public readonly opts
: WorkerOptions
= {
60 killBehavior
: DEFAULT_KILL_BEHAVIOR
,
61 maxInactiveTime
: DEFAULT_MAX_INACTIVE_TIME
65 this.killBehavior
= this.opts
.killBehavior
?? DEFAULT_KILL_BEHAVIOR
66 this.maxInactiveTime
=
67 this.opts
.maxInactiveTime
?? DEFAULT_MAX_INACTIVE_TIME
68 this.async = !!this.opts
.async
69 this.lastTask
= Date.now()
70 this.checkFunctionInput(fn
)
71 // Keep the worker active
73 this.interval
= setInterval(
74 this.checkAlive
.bind(this),
75 this.maxInactiveTime
/ 2
77 this.checkAlive
.bind(this)()
80 this.mainWorker
?.on('message', (value
: MessageValue
<Data
, MainWorker
>) => {
81 if (value
?.data
&& value
.id
) {
82 // Here you will receive messages
84 this.runInAsyncScope(this.runAsync
.bind(this), this, fn
, value
)
86 this.runInAsyncScope(this.run
.bind(this), this, fn
, value
)
88 } else if (value
.parent) {
89 // Save a reference of the main worker to communicate with it
90 // This will be received once
91 this.mainWorker
= value
.parent
92 } else if (value
.kill
) {
93 // Here is time to kill this worker, just clearing the interval
94 if (this.interval
) clearInterval(this.interval
)
101 * Check if the `fn` parameter is passed to the constructor.
103 * @param fn The function that should be defined.
105 private checkFunctionInput (fn
: (data
: Data
) => Response
): void {
106 if (!fn
) throw new Error('fn parameter is mandatory')
110 * Returns the main worker.
112 * @returns Reference to the main worker.
114 protected getMainWorker (): MainWorker
{
115 if (!this.mainWorker
) {
116 throw new Error('Main worker was not set')
118 return this.mainWorker
122 * Send a message to the main worker.
124 * @param message The response message.
126 protected abstract sendToMainWorker (message
: MessageValue
<Response
>): void
129 * Check to see if the worker should be terminated, because its living too long.
131 protected checkAlive (): void {
132 if (Date.now() - this.lastTask
> this.maxInactiveTime
) {
133 this.sendToMainWorker({ kill
: this.killBehavior
})
138 * Handle an error and convert it to a string so it can be sent back to the main worker.
140 * @param e The error raised by the worker.
141 * @returns Message of the error.
143 protected handleError (e
: Error | string): string {
144 return (e
as unknown
) as string
148 * Run the given function synchronously.
150 * @param fn Function that will be executed.
151 * @param value Input data for the given function.
154 fn
: (data
?: Data
) => Response
,
155 value
: MessageValue
<Data
>
158 const res
= fn(value
.data
)
159 this.sendToMainWorker({ data
: res
, id
: value
.id
})
161 const err
= this.handleError(e
)
162 this.sendToMainWorker({ error
: err
, id
: value
.id
})
164 this.lastTask
= Date.now()
169 * Run the given function asynchronously.
171 * @param fn Function that will be executed.
172 * @param value Input data for the given function.
175 fn
: (data
?: Data
) => Promise
<Response
>,
176 value
: MessageValue
<Data
>
180 this.sendToMainWorker({ data
: res
, id
: value
.id
})
184 const err
= this.handleError(e
)
185 this.sendToMainWorker({ error
: err
, id
: value
.id
})
188 this.lastTask
= Date.now()
190 .catch(EMPTY_FUNCTION
)