/
event_manager.ts
108 lines (90 loc) · 3.08 KB
/
event_manager.ts
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import log from '@apify/log';
import type { BetterIntervalID } from '@apify/utilities';
import { betterClearInterval, betterSetInterval } from '@apify/utilities';
import { AsyncEventEmitter } from '@vladfrangu/async_event_emitter';
import { Configuration } from '../configuration';
export const enum EventType {
PERSIST_STATE = 'persistState',
SYSTEM_INFO = 'systemInfo',
MIGRATING = 'migrating',
ABORTING = 'aborting',
EXIT = 'exit',
}
export type EventTypeName = EventType | 'systemInfo' | 'persistState' | 'migrating' | 'aborting' | 'exit';
interface Intervals {
persistState?: BetterIntervalID;
systemInfo?: BetterIntervalID;
}
export abstract class EventManager {
protected events = new AsyncEventEmitter();
protected initialized = false;
protected intervals: Intervals = {};
protected log = log.child({ prefix: 'Events' });
constructor(readonly config = Configuration.getGlobalConfig()) {
this.events.setMaxListeners(50);
}
/**
* Initializes the event manager by creating the `persistState` event interval.
* This is automatically called at the beginning of `crawler.run()`.
*/
async init() {
if (this.initialized) {
return;
}
const persistStateIntervalMillis = this.config.get('persistStateIntervalMillis')!;
this.intervals.persistState = betterSetInterval((intervalCallback: () => unknown) => {
this.emit(EventType.PERSIST_STATE, { isMigrating: false });
intervalCallback();
}, persistStateIntervalMillis);
this.initialized = true;
}
/**
* Clears the internal `persistState` event interval.
* This is automatically called at the end of `crawler.run()`.
*/
async close() {
if (!this.initialized) {
return;
}
betterClearInterval(this.intervals.persistState!);
this.initialized = false;
// Emit final PERSIST_STATE event
this.emit(EventType.PERSIST_STATE, { isMigrating: false });
// Wait for PERSIST_STATE to process
await this.waitForAllListenersToComplete();
}
on(event: EventTypeName, listener: (...args: any[]) => any): void {
this.events.on(event, listener);
}
off(event: EventTypeName, listener?: (...args: any[]) => any): void {
if (listener) {
this.events.removeListener(event, listener);
} else {
this.events.removeAllListeners(event);
}
}
emit(event: EventTypeName, ...args: unknown[]): void {
this.events.emit(event, ...args);
}
isInitialized(): boolean {
return this.initialized;
}
/**
* @internal
*/
listenerCount(event: EventTypeName): number {
return this.events.listenerCount(event);
}
/**
* @internal
*/
listeners(event: EventTypeName): (() => Promise<unknown>)[] {
return this.events.listeners(event) as (() => Promise<unknown>)[];
}
/**
* @internal
*/
waitForAllListenersToComplete() {
return this.events.waitForAllListenersToComplete();
}
}