Prometheus + Grafana

infra/grafana/Dockerfile

@@ -0,0 +1,5 @@
+FROM grafana/grafana:11.1.4
+FROM grafana/grafana:11.1.4
+
+# Copy provisioning configs
+COPY provisioning /etc/grafana/provisioning

infra/grafana/provisioning/dashboards/dashboards.yml

@@ -0,0 +1,11 @@
+apiVersion: 1
+
+providers:
+  - name: "default"
+    orgId: 1
+    folder: ""
+    type: file
+    disableDeletion: false
+    updateIntervalSeconds: 30
+    options:
+      path: /etc/grafana/provisioning/dashboards

infra/grafana/provisioning/dashboards/nodejs-dashboard.json

@@ -0,0 +1,71 @@
+{
+  "id": null,
+  "title": "Node.js App Observability",
+  "tags": ["nodejs", "prometheus"],
+  "timezone": "browser",
+  "schemaVersion": 36,
+  "version": 1,
+  "refresh": "10s",
+  "panels": [
+    {
+      "type": "graph",
+      "title": "CPU Usage (%)",
+      "targets": [
+        {
+          "expr": "process_cpu_user_seconds_total",
+          "legendFormat": "CPU User Time",
+          "refId": "A"
+        }
+      ],
+      "id": 1
+    },
+    {
+      "type": "graph",
+      "title": "Memory Usage (MB)",
+      "targets": [
+        {
+          "expr": "process_resident_memory_bytes / 1024 / 1024",
+          "legendFormat": "Resident Memory",
+          "refId": "A"
+        }
+      ],
+      "id": 2
+    },
+    {
+      "type": "graph",
+      "title": "HTTP Requests per Second",
+      "targets": [
+        {
+          "expr": "rate(http_requests_total[1m])",
+          "legendFormat": "{{method}} {{route}}",
+          "refId": "A"
+        }
+      ],
+      "id": 3
+    },
+    {
+      "type": "graph",
+      "title": "Error Rate (5xx per Second)",
+      "targets": [
+        {
+          "expr": "rate(http_requests_total{status=~\"5..\"}[5m])",
+          "legendFormat": "Errors (5xx)",
+          "refId": "A"
+        }
+      ],
+      "id": 4
+    },
+    {
+      "type": "graph",
+      "title": "95th Percentile Latency",
+      "targets": [
+        {
+          "expr": "histogram_quantile(0.95, sum(rate(http_request_duration_seconds_bucket[5m])) by (le))",
+          "legendFormat": "p95 latency",
+          "refId": "A"
+        }
+      ],
+      "id": 5
+    }
+  ]
+}

infra/grafana/provisioning/datasources/prometheus.yml

@@ -0,0 +1,8 @@
+apiVersion: 1
+
+datasources:
+  - name: Prometheus
+    type: prometheus
+    access: proxy
+    url: http://prometheus:9090
+    isDefault: true

infra/prometheus/Dockerfile

@@ -0,0 +1,6 @@
+FROM prom/prometheus:v2.53.0
+
+# Copy custom config
+COPY prometheus.yml /etc/prometheus/prometheus.yml
+# force rebuild
+ARG CACHEBUST=1

infra/prometheus/prometheus.yml

@@ -0,0 +1,12 @@
+global:
+  scrape_interval: 15s
+  evaluation_interval: 15s
+
+scrape_configs:
+  - job_name: "mydev"
+    metrics_path: /metrics
+    scheme: https   # Render apps use HTTPS
+    static_configs:
+      - targets:
+          - "mydev-staging.onrender.com"
+          - "mydev-prod.onrender.com"

package.json

@@ -17,7 +17,8 @@
   "dependencies": {
     "@sentry/node": "^7.120.4",
     "@sentry/tracing": "^7.120.4",
-    "express": "^4.21.2"
+    "express": "^4.21.2",
+    "prom-client": "^15.1.3"
   },
   "devDependencies": {
     "eslint": "^8.57.1",

render.yaml

@@ -30,3 +30,25 @@ services:
         value: 10000
       - key: SENTRY_DSN
         sync: false   
+
+  - type: web
+    name: prometheus
+    env: docker
+    plan: free
+    rootDir: ./infra/prometheus
+    dockerfilePath: Dockerfile   
+    autoDeploy: false
+    envVars:
+      - key: PORT
+        value: 9090
+
+  - type: web
+    name: grafana
+    env: docker
+    plan: free
+    rootDir: ./infra/grafana
+    dockerfilePath: Dockerfile
+    autoDeploy: false
+    envVars:
+      - key: PORT
+        value: 3000

src/app.js

@@ -1,19 +1,42 @@
 const express = require("express");
 const Sentry = require("@sentry/node");
 const Tracing = require("@sentry/tracing");
+const client = require("prom-client");
 
 const app = express();
 
-// Initialize Sentry (v7 API)
+// --- Prometheus Setup ---
+const collectDefaultMetrics = client.collectDefaultMetrics;
+collectDefaultMetrics(); // Collect Node.js process metrics
+
+// Custom counter
+const httpRequestCounter = new client.Counter({
+  name: "http_requests_total",
+  help: "Total number of HTTP requests",
+  labelNames: ["method", "route", "status"],
+});
+
+// Middleware to count requests
+app.use((req, res, next) => {
+  res.on("finish", () => {
+    httpRequestCounter.labels(req.method, req.path, res.statusCode).inc();
+  });
+  next();
+});
+
+// Expose /metrics endpoint for Prometheus
+app.get("/metrics", async (req, res) => {
+  res.set("Content-Type", client.register.contentType);
+  res.end(await client.register.metrics());
+});
+
+// --- Sentry Setup (v7) ---
 Sentry.init({
   dsn: process.env.SENTRY_DSN || "",
-  integrations: [
-    new Tracing.Integrations.Express({ app }), // works fine with v7
-  ],
-  tracesSampleRate: 1.0, // lower this in prod (e.g. 0.1)
+  integrations: [new Tracing.Integrations.Express({ app })],
+  tracesSampleRate: 1.0,
 });
 
-// Request handler (before routes)
 app.use(Sentry.Handlers.requestHandler());
 app.use(Sentry.Handlers.tracingHandler());
 
@@ -22,13 +45,12 @@ app.get("/", (req, res) => {
   res.send("You are safe in Wizfi's Pipeline!");
 });
 
-// Debug route to test Sentry (ESLint safe)
+// Debug route
 app.get("/debug-sentry", (req, res) => {
   res.status(500).send("Triggering Sentry debug error...");
   throw new Error("Debug Sentry error!");
 });
 
-// Error handler (after routes)
 app.use(Sentry.Handlers.errorHandler());
 
 module.exports = app;