http-metrics-middleware

const express = require('express'); const MetricsMiddleware = require('http-metrics-middleware'); const promClient = require('http-metrics-middleware').promClient; const app = express(); const port = 3000; // Initialize the middleware with custom options const metrics = new MetricsMiddleware({ metricsPath: '/app-metrics', // Custom path for metrics endpoint includePath: true, // Include path label (use with caution for high cardinality) timeBuckets: [0.001, 0.005, 0.01, 0.05, 0.1, 0.5, 1, 2], // More granular buckets }); // Use the middleware to expose the metrics endpoint app.use(metrics.initRoutes()); // Example custom metric using the exposed promClient const myCustomCounter = new promClient.Counter({ name: 'my_app_custom_operations_total', help: 'Total number of custom operations', labelNames: ['operation_type'], }); // Sample API route to increment custom metric app.get('/api/data', (req, res) => { myCustomCounter.inc({ operation_type: 'read' }); res.status(200).json({ message: 'Data fetched successfully' }); }); app.post('/api/data', (req, res) => { myCustomCounter.inc({ operation_type: 'write' }); res.status(201).json({ message: 'Data created successfully' }); }); // Root route app.get('/', (req, res) => { res.send('Hello from http-metrics-middleware example!'); }); app.listen(port, () => { console.log(`Server listening at http://localhost:${port}`); console.log(`Prometheus metrics available at http://localhost:${port}/app-metrics`); });