server.js

const express = require('express');
const path = require('path');

const app = express();
const PORT = process.env.PORT || 3000;

// Servir archivos estáticos
app.use(express.static(path.join(__dirname, 'public')));

// Ruta principal
app.get('/', (req, res) => {
    res.sendFile(path.join(__dirname, 'public', 'index.html'));
});

app.listen(PORT, () => {
    console.log(`Servidor corriendo en http://localhost:${PORT}`);
});

// Crea un registro y métricas
const register = new client.Registry();
const httpRequestDuration = new client.Histogram({
  name: 'http_request_duration_seconds',
  help: 'Duration of HTTP requests in seconds',
  labelNames: ['method', 'route', 'status_code'],
});
register.registerMetric(httpRequestDuration);

// Middleware para medir tiempo de respuesta
app.use((req, res, next) => {
  const end = httpRequestDuration.startTimer();
  res.on('finish', () => {
    end({ method: req.method, route: req.path, status_code: res.statusCode });
  });
  next();
});

// Exponer métricas en el endpoint /metrics
app.get('/metrics', async (req, res) => {
  res.set('Content-Type', register.contentType);
  res.end(await register.metrics());
});