Add Prometheus metric exporter to web package

packages/web/package.json

@@ -1,10 +1,10 @@
 {
   "name": "@sabia/web",
   "scripts": {
-    "dev": "cross-env NODE_ICU_DATA=node_modules/full-icu APP_ENV=development next dev -p 8000",
+    "dev": "cross-env NODE_ICU_DATA=node_modules/full-icu APP_ENV=development node server.js",
     "build": "cross-env NODE_ICU_DATA=node_modules/full-icu next build",
     "start:ci": "cross-env APP_ENV=testing NODE_ENV=production npm run build && APP_ENV=testing npm run start",
-    "start": "cross-env NODE_ICU_DATA=node_modules/full-icu NODE_ENV=production next start -p 8000",
+    "start": "cross-env NODE_ICU_DATA=node_modules/full-icu NODE_ENV=production node server.js",
     "storybook": "start-storybook -p 9009 -s public",
     "build-storybook": "build-storybook",
     "jest": "cross-env APP_ENV=testing NODE_ICU_DATA=node_modules/full-icu jest --coverage --maxWorkers=50%",
@@ -23,6 +23,7 @@
     "algoliasearch": "^4.1.0",
     "dotenv": "^8.2.0",
     "express": "^4.17.1",
+    "express-prom-bundle": "^6.3.6",
     "google-maps-react": "^2.0.6",
     "html-react-parser": "^0.13.0",
     "isomorphic-dompurify": "^0.3.0",
@@ -34,6 +35,7 @@
     "next-translate": "^1.0.6",
     "npm": "^6.14.8",
     "nprogress": "^0.2.0",
+    "prom-client": "^13.1.0",
     "prop-types": "^15.7.2",
     "query-string": "^6.12.1",
     "react": "^17.0.1",

packages/web/server.js

@@ -0,0 +1,33 @@
+const express = require('express');
+const next = require('next');
+const promBundle = require('express-prom-bundle');
+const { collectDefaultMetrics } = require('prom-client');
+
+const port = parseInt(process.env.PORT, 10) || 8000;
+const dev = process.env.NODE_ENV !== 'production';
+const server = next({ dev });
+const handle = server.getRequestHandler();
+const metricsMiddleware = promBundle({
+	promClient: {
+		collectDefaultMetrics,
+	},
+});
+
+server.prepare().then(() => {
+	const app = express();
+
+	app.use(metricsMiddleware);
+
+	app.all('*', (req, res) => {
+		return handle(req, res);
+	});
+
+	app.listen(port, (err) => {
+		if (err) {
+			throw err;
+		}
+
+		// eslint-disable-next-line no-console
+		console.log(`> Ready on http://localhost:${port}`);
+	});
+});