added metrics

backend/index.ts

@@ -1,5 +1,6 @@
 import { on } from "./events";
 import { handleRequest } from "./router";
+import promClient, { Histogram } from "prom-client";
 
 const allowCors = {
   "Access-Control-Allow-Origin": "*",
@@ -7,6 +8,17 @@ const allowCors = {
   "Access-Control-Allow-Headers": "Content-Type",
 };
 
+promClient.collectDefaultMetrics();
+
+const requestDuration = new Histogram({
+  name: "request_duration",
+  help: "Request duration",
+  labelNames: ["action"],
+});
+
+const metricsUser = process.env.METRICS_USER;
+const metricsPassword = process.env.METRICS_PASSWORD;
+
 const server = Bun.serve({
   async fetch(request: Request) {
     if (request.method === "OPTIONS") {
@@ -16,6 +28,22 @@ const server = Bun.serve({
     if (request.url.endsWith("ws")) {
       if (server.upgrade(request)) return new Response("ok");
     }
+    if (request.url.endsWith("metrics")) {
+      const [type, auth] =
+        request.headers.get("Authorization")?.split(" ") ?? [];
+      const [user, password] = Buffer.from(auth, "base64")
+        .toString("utf-8")
+        .split(":");
+      if (
+        type !== "Basic" ||
+        user !== metricsUser ||
+        password !== metricsPassword
+      ) {
+        return new Response("Unauthorized", { status: 401 });
+      }
+      return new Response(await promClient.register.metrics());
+    }
+    return new Response("Not Found", { status: 404 });
   },
   websocket: {
     message: (ws, message) => {
@@ -25,7 +53,10 @@ const server = Bun.serve({
       try {
         const msg = JSON.parse(message);
         console.log("Received message", msg);
+        const start = Date.now();
         handleRequest(msg, ws);
+        const duration = Date.now() - start;
+        requestDuration.observe({ action: msg.type }, duration);
       } catch (e) {
         console.error("Faulty request", message, e);
         return;

package.json

@@ -39,6 +39,7 @@
     "pixi-viewport": "^5.0.3",
     "pixi.js": "^7.0.0",
     "pixi.js-legacy": "^7.4.2",
+    "prom-client": "^15.1.3",
     "react": "^18.3.1",
     "react-confetti-boom": "^1.0.0",
     "react-dom": "^18.3.1",