processResources.js

// Copyright The Prometheus Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0

// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

'use strict';
const Gauge = require('../gauge');
const { updateMetrics } = require('./helpers/processMetricsHelpers');

const NODEJS_ACTIVE_RESOURCES = 'nodejs_active_resources';
const NODEJS_ACTIVE_RESOURCES_TOTAL = 'nodejs_active_resources_total';

module.exports = (registry, config = {}) => {
	// Don't do anything if the function does not exist in previous nodes (exists in node@17.3.0)
	// eslint-disable-next-line n/no-unsupported-features/node-builtins
	if (typeof process.getActiveResourcesInfo !== 'function') {
		return;
	}

	const namePrefix = config.prefix ?? '';
	const labels = config.labels ?? {};
	const labelNames = Object.keys(labels);

	new Gauge({
		name: namePrefix + NODEJS_ACTIVE_RESOURCES,
		help: 'Number of active resources that are currently keeping the event loop alive, grouped by async resource type.',
		labelNames: ['type', ...labelNames],
		registers: registry === undefined ? undefined : [registry],
		collect() {
			// eslint-disable-next-line n/no-unsupported-features/node-builtins
			const resources = process.getActiveResourcesInfo();

			const data = {};

			for (let i = 0; i < resources.length; i++) {
				const resource = resources[i];

				if (Object.hasOwn(data, resource)) {
					data[resource] += 1;
				} else {
					data[resource] = 1;
				}
			}

			updateMetrics(this, data, labels);
		},
	});

	new Gauge({
		name: namePrefix + NODEJS_ACTIVE_RESOURCES_TOTAL,
		help: 'Total number of active resources.',
		registers: registry === undefined ? undefined : [registry],
		labelNames,
		collect() {
			// eslint-disable-next-line n/no-unsupported-features/node-builtins
			const resources = process.getActiveResourcesInfo();
			this.set(labels, resources.length);
		},
	});
};

module.exports.metricNames = [
	NODEJS_ACTIVE_RESOURCES,
	NODEJS_ACTIVE_RESOURCES_TOTAL,
];