import { AsyncResource } from 'async_hooks'
+import type { Worker } from 'cluster'
+import type { MessagePort } from 'worker_threads'
import type { MessageValue } from '../utility-types'
-import type { WorkerOptions } from './worker-options'
+import { EMPTY_FUNCTION } from '../utils'
+import type { KillBehavior, WorkerOptions } from './worker-options'
+import { KillBehaviors } from './worker-options'
+const DEFAULT_MAX_INACTIVE_TIME = 1000 * 60
+const DEFAULT_KILL_BEHAVIOR: KillBehavior = KillBehaviors.SOFT
+
+/**
+ * Base class containing some shared logic for all poolifier workers.
+ *
+ * @template MainWorker Type of main worker.
+ * @template Data Type of data this worker receives from pool's execution. This can only be serializable data.
+ * @template Response Type of response the worker sends back to the main worker. This can only be serializable data.
+ */
export abstract class AbstractWorker<
- MainWorker,
- // eslint-disable-next-line @typescript-eslint/no-explicit-any
- Data = any,
- // eslint-disable-next-line @typescript-eslint/no-explicit-any
- Response = any
+ MainWorker extends Worker | MessagePort,
+ Data = unknown,
+ Response = unknown
> extends AsyncResource {
- protected readonly maxInactiveTime: number
- protected readonly async: boolean
- protected lastTask: number
- protected readonly interval?: NodeJS.Timeout
+ /**
+ * Timestamp of the last task processed by this worker.
+ */
+ protected lastTaskTimestamp: number
+ /**
+ * Handler Id of the `aliveInterval` worker alive check.
+ */
+ protected readonly aliveInterval?: NodeJS.Timeout
/**
+ * Constructs a new poolifier worker.
*
* @param type The type of async event.
- * @param isMain
- * @param fn
- * @param opts
+ * @param isMain Whether this is the main worker or not.
+ * @param fn Function processed by the worker when the pool's `execution` function is invoked.
+ * @param mainWorker Reference to main worker.
+ * @param opts Options for the worker.
*/
public constructor (
type: string,
isMain: boolean,
fn: (data: Data) => Response,
- public readonly opts: WorkerOptions = {}
+ protected mainWorker: MainWorker | null,
+ public readonly opts: WorkerOptions = {
+ /**
+ * The kill behavior option on this Worker or its default value.
+ */
+ killBehavior: DEFAULT_KILL_BEHAVIOR,
+ /**
+ * The maximum time to keep this worker alive while idle.
+ * The pool automatically checks and terminates this worker when the time expires.
+ */
+ maxInactiveTime: DEFAULT_MAX_INACTIVE_TIME
+ }
) {
super(type)
-
- this.maxInactiveTime = this.opts.maxInactiveTime ?? 1000 * 60
- this.async = !!this.opts.async
- this.lastTask = Date.now()
- if (!fn) throw new Error('Fn parameter is mandatory')
- // keep the worker active
+ this.checkFunctionInput(fn)
+ this.checkWorkerOptions(this.opts)
+ this.lastTaskTimestamp = Date.now()
+ // Keep the worker active
if (!isMain) {
- this.interval = setInterval(
+ this.aliveInterval = setInterval(
this.checkAlive.bind(this),
- this.maxInactiveTime / 2
+ (this.opts.maxInactiveTime ?? DEFAULT_MAX_INACTIVE_TIME) / 2
)
this.checkAlive.bind(this)()
}
+
+ this.mainWorker?.on('message', (value: MessageValue<Data, MainWorker>) => {
+ if (value?.data && value.id) {
+ // Here you will receive messages
+ if (this.opts.async) {
+ this.runInAsyncScope(this.runAsync.bind(this), this, fn, value)
+ } else {
+ this.runInAsyncScope(this.run.bind(this), this, fn, value)
+ }
+ } else if (value.parent) {
+ // Save a reference of the main worker to communicate with it
+ // This will be received once
+ this.mainWorker = value.parent
+ } else if (value.kill) {
+ // Here is time to kill this worker, just clearing the interval
+ if (this.aliveInterval) clearInterval(this.aliveInterval)
+ this.emitDestroy()
+ }
+ })
+ }
+
+ private checkWorkerOptions (opts: WorkerOptions) {
+ this.opts.killBehavior = opts.killBehavior ?? DEFAULT_KILL_BEHAVIOR
+ this.opts.maxInactiveTime =
+ opts.maxInactiveTime ?? DEFAULT_MAX_INACTIVE_TIME
+ /**
+ * Whether the worker is working asynchronously or not.
+ */
+ this.opts.async = !!opts.async
}
- protected abstract getMainWorker (): MainWorker
+ /**
+ * Check if the `fn` parameter is passed to the constructor.
+ *
+ * @param fn The function that should be defined.
+ */
+ private checkFunctionInput (fn: (data: Data) => Response): void {
+ if (!fn) throw new Error('fn parameter is mandatory')
+ }
+ /**
+ * Returns the main worker.
+ *
+ * @returns Reference to the main worker.
+ */
+ protected getMainWorker (): MainWorker {
+ if (!this.mainWorker) {
+ throw new Error('Main worker was not set')
+ }
+ return this.mainWorker
+ }
+
+ /**
+ * Send a message to the main worker.
+ *
+ * @param message The response message.
+ */
protected abstract sendToMainWorker (message: MessageValue<Response>): void
+ /**
+ * Check to see if the worker should be terminated, because its living too long.
+ */
protected checkAlive (): void {
- if (Date.now() - this.lastTask > this.maxInactiveTime) {
- this.sendToMainWorker({ kill: 1 })
+ if (
+ Date.now() - this.lastTaskTimestamp >
+ (this.opts.maxInactiveTime ?? DEFAULT_MAX_INACTIVE_TIME)
+ ) {
+ this.sendToMainWorker({ kill: this.opts.killBehavior })
}
}
+ /**
+ * Handle an error and convert it to a string so it can be sent back to the main worker.
+ *
+ * @param e The error raised by the worker.
+ * @returns Message of the error.
+ */
protected handleError (e: Error | string): string {
- return (e as unknown) as string
+ return e as unknown as string
}
+ /**
+ * Run the given function synchronously.
+ *
+ * @param fn Function that will be executed.
+ * @param value Input data for the given function.
+ */
protected run (
fn: (data?: Data) => Response,
value: MessageValue<Data>
try {
const res = fn(value.data)
this.sendToMainWorker({ data: res, id: value.id })
- this.lastTask = Date.now()
} catch (e) {
const err = this.handleError(e)
this.sendToMainWorker({ error: err, id: value.id })
- this.lastTask = Date.now()
+ } finally {
+ this.lastTaskTimestamp = Date.now()
}
}
+ /**
+ * Run the given function asynchronously.
+ *
+ * @param fn Function that will be executed.
+ * @param value Input data for the given function.
+ */
protected runAsync (
fn: (data?: Data) => Promise<Response>,
value: MessageValue<Data>
fn(value.data)
.then(res => {
this.sendToMainWorker({ data: res, id: value.id })
- this.lastTask = Date.now()
return null
})
.catch(e => {
const err = this.handleError(e)
this.sendToMainWorker({ error: err, id: value.id })
- this.lastTask = Date.now()
})
+ .finally(() => {
+ this.lastTaskTimestamp = Date.now()
+ })
+ .catch(EMPTY_FUNCTION)
}
}