prometheus-api-metrics

import express from 'express'; import apiMetrics from 'prometheus-api-metrics'; import { collectDefaultMetrics, register } from 'prom-client'; const app = express(); const port = 3000; // Start collecting default metrics like CPU, memory, etc. // Interval must be a number, use Number() just in case for env vars collectDefaultMetrics({ prefix: 'my_app_', timeout: Number(process.env.DEFAULT_METRICS_INTERVAL || 10000) }); // Use the API metrics middleware app.use(apiMetrics({ metricsPath: '/metrics', durationBuckets: [0.001, 0.005, 0.015, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 1, 2, 5], metricsPrefix: 'my_service_', excludeRoutes: ['/health'] })); // Define a health check endpoint app.get('/health', (req, res) => { res.status(200).send('OK'); }); // Define a sample API endpoint app.get('/data', (req, res) => { setTimeout(() => { res.json({ message: 'Hello, Prometheus!' }); }, Math.random() * 500); }); // Expose the metrics endpoint for Prometheus to scrape app.get('/metrics', async (req, res) => { try { res.set('Content-Type', register.contentType); res.end(await register.metrics()); } catch (ex) { res.status(500).end(ex); } }); app.listen(port, () => { console.log(`Server listening on http://localhost:${port}`); console.log(`Metrics available at http://localhost:${port}/metrics`); });