@crawlee/core/autoscaling/event_loop_load_signal.js

The scalable web crawling and scraping library for JavaScript/Node.js. Enables development of data extraction and web automation jobs (not only) with headless Chrome and Puppeteer.

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.createEventLoopLoadSignal = createEventLoopLoadSignal;
const load_signal_1 = require("./load_signal");
/**
 * Periodically measures event loop delay and reports overload when the
 * delay exceeds a configured threshold.
 */
function createEventLoopLoadSignal(options = {}) {
    const intervalMillis = (options.eventLoopSnapshotIntervalSecs ?? 0.5) * 1000;
    const maxBlockedMillis = options.maxBlockedMillis ?? 50;
    const signal = load_signal_1.SnapshotStore.fromInterval({
        name: 'eventLoopInfo',
        overloadedRatio: options.overloadedRatio ?? 0.6,
        intervalMillis,
        snapshotHistoryMillis: options.snapshotHistoryMillis,
        handler(store, intervalCallback) {
            const now = new Date();
            const snapshot = {
                createdAt: now,
                isOverloaded: false,
                exceededMillis: 0,
            };
            const all = store.getAll();
            const previousSnapshot = all[all.length - 1];
            if (previousSnapshot) {
                const { createdAt } = previousSnapshot;
                const delta = now.getTime() - +createdAt - intervalMillis;
                if (delta > maxBlockedMillis)
                    snapshot.isOverloaded = true;
                snapshot.exceededMillis = Math.max(delta - maxBlockedMillis, 0);
            }
            store.push(snapshot, now);
            intervalCallback();
        },
    });
    return signal;
}