@metrics/process/lib/collector-eventloop-lag.js

Module for collecting different process and system metrics and providing them as a metric stream

"use strict";

const Metric = require("@metrics/metric");

const CollectorEventloopLag = class CollectorEventloopLag {
	constructor(prefix = "") {
		Object.defineProperty(this, "prefix", {
			value: prefix,
		});
	}

	get [Symbol.toStringTag]() {
		return "CollectorEventloopLag";
	}

	collect(timestamp) {
		const start = process.hrtime();

		return new Promise((resolve) => {
			setImmediate(() => {
				const delta = process.hrtime(start);
				const nanosec = delta[0] * 1e9 + delta[1];
				const seconds = nanosec / 1e9;

				resolve([
					new Metric({
						name: `${this.prefix}nodejs_eventloop_lag_seconds`,
						description: "Lag of eventloop in seconds",
						type: 1,
						value: seconds,
						timestamp,
					}),
				]);
			});
		});
	}
};

module.exports = CollectorEventloopLag;