From 9b00853d5a7200727501d9dffa9f05e82c882e6ba638809697471b436f0b1fb7 Mon Sep 17 00:00:00 2001
From: localhorst <localhorst@mosad.xyz>
Date: Sat, 11 Jan 2025 22:59:07 +0100
Subject: [PATCH] use prom-client

---
 server/package-lock.json                   | 38 ++++++++++++++++++++++
 server/package.json                        |  1 +
 server/src/controller/metricsController.ts | 31 +++++++++++++++---
 3 files changed, 65 insertions(+), 5 deletions(-)

diff --git a/server/package-lock.json b/server/package-lock.json
index b8236af..7e49a45 100644
--- a/server/package-lock.json
+++ b/server/package-lock.json
@@ -14,6 +14,7 @@
         "express": "^4.21.2",
         "http-status-codes": "^2.3.0",
         "mariadb": "^3.4.0",
+        "prom-client": "^15.1.3",
         "reflect-metadata": "^0.2.2",
         "sequelize": "^6.37.5",
         "swagger-jsdoc": "^6.2.8",
@@ -120,6 +121,15 @@
       "integrity": "sha512-4JQNk+3mVzK3xh2rqd6RB4J46qUR19azEHBneZyTZM+c456qOrbbM/5xcR8huNCCcbVt7+UmizG6GuUvPvKUYg==",
       "license": "MIT"
     },
+    "node_modules/@opentelemetry/api": {
+      "version": "1.9.0",
+      "resolved": "https://registry.npmjs.org/@opentelemetry/api/-/api-1.9.0.tgz",
+      "integrity": "sha512-3giAOQvZiH5F9bMlMiv8+GSPMeqg0dbaeo58/0SlA9sxSqZhnUtxzX9/2FzyhS9sWQf5S0GJE0AKBrFqjpeYcg==",
+      "license": "Apache-2.0",
+      "engines": {
+        "node": ">=8.0.0"
+      }
+    },
     "node_modules/@scarf/scarf": {
       "version": "1.4.0",
       "resolved": "https://registry.npmjs.org/@scarf/scarf/-/scarf-1.4.0.tgz",
@@ -386,6 +396,12 @@
         "url": "https://github.com/sponsors/sindresorhus"
       }
     },
+    "node_modules/bintrees": {
+      "version": "1.0.2",
+      "resolved": "https://registry.npmjs.org/bintrees/-/bintrees-1.0.2.tgz",
+      "integrity": "sha512-VOMgTMwjAaUG580SXn3LacVgjurrbMme7ZZNYGSSV7mmtY6QQRh0Eg3pwIcntQ77DErK1L0NxkbetjcoXzVwKw==",
+      "license": "MIT"
+    },
     "node_modules/body-parser": {
       "version": "1.20.3",
       "resolved": "https://registry.npmjs.org/body-parser/-/body-parser-1.20.3.tgz",
@@ -1434,6 +1450,19 @@
         "url": "https://github.com/sponsors/jonschlinkert"
       }
     },
+    "node_modules/prom-client": {
+      "version": "15.1.3",
+      "resolved": "https://registry.npmjs.org/prom-client/-/prom-client-15.1.3.tgz",
+      "integrity": "sha512-6ZiOBfCywsD4k1BN9IX0uZhF+tJkV8q8llP64G5Hajs4JOeVLPCwpPVcpXy3BwYiUGgyJzsJJQeOIv7+hDSq8g==",
+      "license": "Apache-2.0",
+      "dependencies": {
+        "@opentelemetry/api": "^1.4.0",
+        "tdigest": "^0.1.1"
+      },
+      "engines": {
+        "node": "^16 || ^18 || >=20"
+      }
+    },
     "node_modules/proxy-addr": {
       "version": "2.0.7",
       "resolved": "https://registry.npmjs.org/proxy-addr/-/proxy-addr-2.0.7.tgz",
@@ -1873,6 +1902,15 @@
         "express": ">=4.0.0 || >=5.0.0-beta"
       }
     },
+    "node_modules/tdigest": {
+      "version": "0.1.2",
+      "resolved": "https://registry.npmjs.org/tdigest/-/tdigest-0.1.2.tgz",
+      "integrity": "sha512-+G0LLgjjo9BZX2MfdvPfH+MKLCrxlXSYec5DaPYP1fe6Iyhf0/fSmJ0bFiZ1F8BT6cGXl2LpltQptzjXKWEkKA==",
+      "license": "MIT",
+      "dependencies": {
+        "bintrees": "1.0.2"
+      }
+    },
     "node_modules/to-regex-range": {
       "version": "5.0.1",
       "resolved": "https://registry.npmjs.org/to-regex-range/-/to-regex-range-5.0.1.tgz",
diff --git a/server/package.json b/server/package.json
index d2fde30..533fd05 100644
--- a/server/package.json
+++ b/server/package.json
@@ -24,6 +24,7 @@
     "express": "^4.21.2",
     "http-status-codes": "^2.3.0",
     "mariadb": "^3.4.0",
+    "prom-client": "^15.1.3",
     "reflect-metadata": "^0.2.2",
     "sequelize": "^6.37.5",
     "swagger-jsdoc": "^6.2.8",
diff --git a/server/src/controller/metricsController.ts b/server/src/controller/metricsController.ts
index bd637fe..eb39302 100644
--- a/server/src/controller/metricsController.ts
+++ b/server/src/controller/metricsController.ts
@@ -1,15 +1,36 @@
 import express, { Request, Response } from "express";
-import { container } from "tsyringe";
-//import { LocationService } from "../services/locationService";
+import { Counter, collectDefaultMetrics, register } from "prom-client";
 
-//const locationService = container.resolve(LocationService);
 const router = express.Router();
 
+
+// Collect default system metrics (e.g., CPU, memory usage)
+const prefix = 'locationhub_';
+collectDefaultMetrics({ prefix });
+
+// Define a custom Counter metric
+const requestCounter = new Counter({
+  name: "http_requests_total",
+  help: "Total number of HTTP requests",
+  labelNames: ["method", "route", "status"], // Labels for filtering in Prometheus
+});
+
+// Define the metrics endpoint
 router.get("/", async (req: Request, res: Response) => {
   try {
-    console.log("Metric Endpoint triggered")
-    res.status(200).send();
+    console.log("Metric Endpoint triggered");
+
+    // Increment the counter with labels
+    requestCounter.inc({ method: req.method, route: req.route.path, status: 200 });
+
+    // Expose metrics in Prometheus format
+    res.set("Content-Type", register.contentType);
+    res.send(await register.metrics());
   } catch (error) {
+    // Increment the counter for errors
+    requestCounter.inc({ method: req.method, route: req.route.path, status: 500 });
+
+    console.error("Error running metrics endpoint:", error);
     res.status(500).json({ error: "Error running metrics endpoint" });
   }
 });