chore: add prom client

packages/sdk-socket-server-next/package.json

@@ -51,6 +51,7 @@
     "ioredis": "^5.3.2",
     "logform": "^2.6.0",
     "lru-cache": "^10.0.0",
+    "prom-client": "^15.1.3",
     "rate-limiter-flexible": "^2.3.8",
     "redis": "^4.6.12",
     "rimraf": "^4.4.0",

packages/sdk-socket-server-next/src/index.ts

@@ -11,7 +11,7 @@ import packageJson from '../package.json';
 import { isDevelopment, withAdminUI } from './config';
 import { analytics, app } from './analytics-api';
 import { getLogger } from './logger';
-import { extractMetrics } from './metrics';
+import { readMetrics } from './metrics';
 import { configureSocketServer } from './socket-config';
 import { cleanupAndExit } from './utils';
 
@@ -49,8 +49,7 @@ configureSocketServer(server)
     // Make sure to protect the endpoint to be only available within the cluster for prometheus
     app.get('/metrics', async (_req, res) => {
       res.set('Content-Type', 'text/plain');
-      const metrics = extractMetrics({ ioServer });
-      res.send(metrics);
+      res.send(await readMetrics());
     });
 
     app.get('/version', (_req, res) => {

packages/sdk-socket-server-next/src/metrics.ts

@@ -1,15 +1,31 @@
-import { Server } from 'socket.io';
+import { collectDefaultMetrics, Gauge, Registry } from 'prom-client';
 
-export const extractMetrics = ({ ioServer }: { ioServer: Server }) => {
-  const totalClients = ioServer.engine.clientsCount;
-  let fullMetrics = `# HELP socket_io_server_total_clients Total number of connected clients\n`;
-  fullMetrics += `# TYPE socket_io_server_total_clients gauge\n`;
-  fullMetrics += `socket_io_server_total_clients ${totalClients}\n`;
+const register = new Registry();
 
-  const totalRooms = ioServer.sockets.adapter.rooms.size;
-  fullMetrics += `# HELP socket_io_server_total_rooms Total number of rooms\n`;
-  fullMetrics += `# TYPE socket_io_server_total_rooms gauge\n`;
-  fullMetrics += `socket_io_server_total_rooms ${totalRooms}\n`;
+collectDefaultMetrics({ register });
 
-  return fullMetrics;
-};
+export async function readMetrics() {
+  return await register.metrics();
+}
+
+const socketIoServerTotalClients = new Gauge({
+  name: 'socket_io_server_total_clients',
+  help: 'Total number of connected clients',
+  labelNames: [],
+  registers: [register],
+});
+
+const socketIoServerTotalRooms = new Gauge({
+  name: 'socket_io_server_total_rooms',
+  help: 'Total number of rooms',
+  labelNames: [],
+  registers: [register],
+});
+
+export function setSocketIoServerTotalClients(count: number) {
+  socketIoServerTotalClients.set(count);
+}
+
+export function setSocketIoServerTotalRooms(count: number) {
+  socketIoServerTotalRooms.set(count);
+}

packages/sdk-socket-server-next/src/socket-config.ts

@@ -20,6 +20,10 @@ import {
 } from './protocol/handleJoinChannel';
 import { handleMessage, MessageParams } from './protocol/handleMessage';
 import { handlePing } from './protocol/handlePing';
+import {
+  setSocketIoServerTotalClients,
+  setSocketIoServerTotalRooms,
+} from './metrics';
 
 const logger = getLogger();
 
@@ -68,6 +72,8 @@ export const configureSocketServer = async (
     },
   });
 
+  watchSocketIoServerMetrics(io);
+
   io.of('/').adapter.on('join-room', async (roomId, socketId) => {
     logger.debug(`'join-room' socket ${socketId} has joined room ${roomId}`);
     if (!validate(roomId)) {
@@ -357,3 +363,10 @@ export const configureSocketServer = async (
 
   return io;
 };
+
+function watchSocketIoServerMetrics(io: Server) {
+  setInterval(() => {
+    setSocketIoServerTotalClients(io.engine.clientsCount);
+    setSocketIoServerTotalRooms(io.sockets.adapter.rooms.size);
+  }, 5_000);
+}

yarn.lock

@@ -10305,6 +10305,7 @@ __metadata:
     lru-cache: ^10.0.0
     nodemon: ^3.1.0
     prettier: ^2.8.8
+    prom-client: ^15.1.3
     rate-limiter-flexible: ^2.3.8
     redis: ^4.6.12
     rimraf: ^4.4.0
@@ -11204,6 +11205,13 @@ __metadata:
   languageName: node
   linkType: hard
 
+"@opentelemetry/api@npm:^1.4.0":
+  version: 1.9.0
+  resolution: "@opentelemetry/api@npm:1.9.0"
+  checksum: 9e88e59d53ced668f3daaecfd721071c5b85a67dd386f1c6f051d1be54375d850016c881f656ffbe9a03bedae85f7e89c2f2b635313f9c9b195ad033cdc31020
+  languageName: node
+  linkType: hard
+
 "@parcel/watcher-android-arm64@npm:2.3.0":
   version: 2.3.0
   resolution: "@parcel/watcher-android-arm64@npm:2.3.0"
@@ -22117,6 +22125,13 @@ __metadata:
   languageName: node
   linkType: hard
 
+"bintrees@npm:1.0.2":
+  version: 1.0.2
+  resolution: "bintrees@npm:1.0.2"
+  checksum: 56a52b7d3634e30002b1eda740d2517a22fa8e9e2eb088e919f37c030a0ed86e364ab59e472fc770fc8751308054bb1c892979d150e11d9e11ac33bcc1b5d16e
+  languageName: node
+  linkType: hard
+
 "bl@npm:^4.0.3, bl@npm:^4.1.0":
   version: 4.1.0
   resolution: "bl@npm:4.1.0"
@@ -41190,6 +41205,16 @@ __metadata:
   languageName: node
   linkType: hard
 
+"prom-client@npm:^15.1.3":
+  version: 15.1.3
+  resolution: "prom-client@npm:15.1.3"
+  dependencies:
+    "@opentelemetry/api": ^1.4.0
+    tdigest: ^0.1.1
+  checksum: 9a57f3c16f39aa9a03da021883a4231c0bb56fc9d02f6ef9c28f913379f275640a5a33b98d9946ebf53c71011a29b580e9d2d6e3806cb1c229a3f59c65993968
+  languageName: node
+  linkType: hard
+
 "promise-inflight@npm:^1.0.1":
   version: 1.0.1
   resolution: "promise-inflight@npm:1.0.1"
@@ -46618,6 +46643,15 @@ __metadata:
   languageName: node
   linkType: hard
 
+"tdigest@npm:^0.1.1":
+  version: 0.1.2
+  resolution: "tdigest@npm:0.1.2"
+  dependencies:
+    bintrees: 1.0.2
+  checksum: 44de8246752b6f8c2924685f969fd3d94c36949f22b0907e99bef2b2220726dd8467f4730ea96b06040b9aa2587c0866049640039d1b956952dfa962bc2075a3
+  languageName: node
+  linkType: hard
+
 "telejson@npm:^6.0.8":
   version: 6.0.8
   resolution: "telejson@npm:6.0.8"