Add prometheus on backend-javascript

Author: ganatan

backend-javascript/package-lock.json

@@ -81,6 +81,7 @@
     "mysql2": "3.14.2",
     "nodemon": "3.1.10",
     "pg": "8.16.3",
+    "prom-client": "^15.1.3",
     "swagger-jsdoc": "6.2.8",
     "swagger-ui-express": "5.0.1",
     "uuid": "^11.1.0",

backend-javascript/package.json

@@ -16,6 +16,7 @@ import requestLogger from './infrastructure/logger/request-logger.js';
 
 import fakeAuth from './middlewares/auth/fake-auth.js';
 
+import metricsRoutes from './routes/metrics.routes.js';
 import healthRoutes from './routes/health.routes.js';
 import versionRoutes from './routes/version.routes.js';
 import swaggerRoutes from './routes/swagger.routes.js';
@@ -38,6 +39,7 @@ if (['development', 'test'].includes(appConfig.app.nodeEnv)) {
 app.use(correlationIdMiddleware);
 app.use(requestLogger);
 
+app.use(metricsRoutes);
 app.use(healthRoutes);
 
 app.use(versionRoutes);

backend-javascript/src/app.js

@@ -1,6 +1,12 @@
 import logger from './logger.js';
+import { incrementHttpRequests } from '../metrics/metrics.js';
 
 const requestLogger = (req, res, next) => {
+
+  res.on('finish', () => {
+    incrementHttpRequests(req.method, req.originalUrl, res.statusCode);
+  });
+
   logger.info(`[${req.method}] ${req.originalUrl}`, {
     method: req.method,
     route: req.originalUrl,

backend-javascript/src/infrastructure/logger/request-logger.js

@@ -0,0 +1,15 @@
+import client from 'prom-client';
+
+client.collectDefaultMetrics();
+
+const httpRequestCounter = new client.Counter({
+  name: 'http_requests_total',
+  help: 'Nombre total de requêtes HTTP',
+  labelNames: ['method', 'route', 'status'],
+});
+
+function incrementHttpRequests(method, route, status) {
+  httpRequestCounter.inc({ method, route, status });
+}
+
+export { client, incrementHttpRequests };

backend-javascript/src/infrastructure/metrics/metrics.js

@@ -0,0 +1,16 @@
+import express from 'express';
+import { client } from '../infrastructure/metrics/metrics.js';
+
+const router = express.Router();
+
+router.get('/metrics', async (req, res) => {
+  res.set('Content-Type', client.register.contentType);
+  const metric = await client.register.getSingleMetricAsString('http_requests_total');
+  res.end(metric);
+
+  //   res.set('Content-Type', client.register.contentType);
+//   res.end(await client.register.metrics());
+
+});
+
+export default router;