improvment: added prometheus metrics for the number of groups in a room

back/src/Controller/PrometheusController.ts

@@ -1,5 +1,4 @@
 import {App} from "../Server/sifrr.server";
-import {IoSocketController} from "_Controller/IoSocketController";
 import {HttpRequest, HttpResponse} from "uWebSockets.js";
 const register = require('prom-client').register;
 const collectDefaultMetrics = require('prom-client').collectDefaultMetrics;

back/src/Model/GameRoom.ts

@@ -152,7 +152,7 @@ export class GameRoom {
                     closestItem.join(user);
                 } else {
                     const closestUser : User = closestItem;
-                    const group: Group = new Group([
+                    const group: Group = new Group(this.roomId,[
                         user,
                         closestUser
                     ], this.connectCallback, this.disconnectCallback, this.positionNotifier);
@@ -200,7 +200,6 @@ export class GameRoom {
         if (group === undefined) {
             throw new Error("The user is part of no group");
         }
-        const oldPosition = group.getPosition();
         group.leave(user);
         if (group.isEmpty()) {
             this.positionNotifier.leave(group);
@@ -209,6 +208,7 @@ export class GameRoom {
                 throw new Error("Could not find group "+group.getId()+" referenced by user "+user.id+" in World.");
             }
             this.groups.delete(group);
+            //todo: is the group garbage collected?
         } else {
             group.updatePosition();
             //this.positionNotifier.updatePosition(group, group.getPosition(), oldPosition);

back/src/Model/Group.ts

@@ -3,6 +3,7 @@ import { User } from "./User";
 import {PositionInterface} from "_Model/PositionInterface";
 import {Movable} from "_Model/Movable";
 import {PositionNotifier} from "_Model/PositionNotifier";
+import {gaugeManager} from "../Services/GaugeManager";
 
 export class Group implements Movable {
     static readonly MAX_PER_GROUP = 4;
@@ -13,12 +14,23 @@ export class Group implements Movable {
     private users: Set<User>;
     private x!: number;
     private y!: number;
+    private hasEditedGauge: boolean = false;
+    private wasDestroyed: boolean = false;
+    private roomId: string;
 
 
-    constructor(users: User[], private connectCallback: ConnectCallback, private disconnectCallback: DisconnectCallback, private positionNotifier: PositionNotifier) {
+    constructor(roomId: string, users: User[], private connectCallback: ConnectCallback, private disconnectCallback: DisconnectCallback, private positionNotifier: PositionNotifier) {
+        this.roomId = roomId;
         this.users = new Set<User>();
         this.id = Group.nextId;
         Group.nextId++;
+        //we only send a event for prometheus metrics if the group lives more than 5 seconds
+        setTimeout(() => {
+            if (!this.wasDestroyed) {
+                this.hasEditedGauge = true;
+                gaugeManager.incNbGroupsPerRoomGauge(roomId);
+            }
+        }, 5000);
 
         users.forEach((user: User) => {
             this.join(user);
@@ -113,9 +125,11 @@ export class Group implements Movable {
      */
     destroy(): void
     {
+        if (this.hasEditedGauge) gaugeManager.decNbGroupsPerRoomGauge(this.roomId);
         for (const user of this.users) {
             this.leave(user);
         }
+        this.wasDestroyed = true;
     }
 
     get getSize(){

back/src/Services/GaugeManager.ts

@@ -0,0 +1,54 @@
+import {Counter, Gauge} from "prom-client";
+
+//this class should manage all the custom metrics used by prometheus
+class GaugeManager {
+    private nbClientsGauge: Gauge<string>;
+    private nbClientsPerRoomGauge: Gauge<string>;
+    private nbGroupsPerRoomGauge: Gauge<string>;
+    private nbGroupsPerRoomCounter: Counter<string>;
+
+    constructor() {
+        this.nbClientsGauge = new Gauge({
+            name: 'workadventure_nb_sockets',
+            help: 'Number of connected sockets',
+            labelNames: [ ]
+        });
+        this.nbClientsPerRoomGauge = new Gauge({
+            name: 'workadventure_nb_clients_per_room',
+            help: 'Number of clients per room',
+            labelNames: [ 'room' ]
+        });
+
+        this.nbGroupsPerRoomCounter = new Counter({
+            name: 'workadventure_counter_groups_per_room',
+            help: 'Counter of groups per room',
+            labelNames: [ 'room' ]
+        });
+        this.nbGroupsPerRoomGauge = new Gauge({
+            name: 'workadventure_nb_groups_per_room',
+            help: 'Number of groups per room',
+            labelNames: [ 'room' ]
+        });
+    }
+
+    incNbClientPerRoomGauge(roomId: string): void {
+        this.nbClientsGauge.inc();
+        this.nbClientsPerRoomGauge.inc({ room: roomId });
+    }
+
+    decNbClientPerRoomGauge(roomId: string): void {
+        this.nbClientsGauge.dec();
+        this.nbClientsPerRoomGauge.dec({ room: roomId });
+    }
+
+    incNbGroupsPerRoomGauge(roomId: string): void {
+        this.nbGroupsPerRoomCounter.inc({ room: roomId })
+        this.nbGroupsPerRoomGauge.inc({ room: roomId })
+    }
+    
+    decNbGroupsPerRoomGauge(roomId: string): void {
+        this.nbGroupsPerRoomGauge.dec({ room: roomId })
+    }
+}
+
+export const gaugeManager = new GaugeManager();

back/src/Services/SocketManager.ts

@@ -23,7 +23,6 @@ import {
     WebRtcStartMessage,
     QueryJitsiJwtMessage,
     SendJitsiJwtMessage,
-    CharacterLayerMessage,
     SendUserMessage
 } from "../Messages/generated/messages_pb";
 import {PointInterface} from "../Model/Websocket/PointInterface";
@@ -37,11 +36,11 @@ import {Movable} from "../Model/Movable";
 import {PositionInterface} from "../Model/PositionInterface";
 import {adminApi, CharacterTexture} from "./AdminApi";
 import Direction = PositionMessage.Direction;
-import {Gauge} from "prom-client";
 import {emitError, emitInBatch} from "./IoSocketHelpers";
 import Jwt from "jsonwebtoken";
 import {JITSI_URL} from "../Enum/EnvironmentVariable";
 import {clientEventsEmitter} from "./ClientEventsEmitter";
+import {gaugeManager} from "./GaugeManager";
 
 interface AdminSocketRoomsList {
     [index: string]: number;
@@ -58,30 +57,13 @@ export interface AdminSocketData {
 export class SocketManager {
     private Worlds: Map<string, GameRoom> = new Map<string, GameRoom>();
     private sockets: Map<number, ExSocketInterface> = new Map<number, ExSocketInterface>();
-    private nbClientsGauge: Gauge<string>;
+    
-    private nbClientsPerRoomGauge: Gauge<string>;
-
     constructor() {
-        this.nbClientsGauge = new Gauge({
+        clientEventsEmitter.registerToClientJoin((clientUUid: string, roomId: string) => {
-            name: 'workadventure_nb_sockets',
+            gaugeManager.incNbClientPerRoomGauge(roomId);
-            help: 'Number of connected sockets',
-            labelNames: [ ]
         });
-        this.nbClientsPerRoomGauge = new Gauge({
+        clientEventsEmitter.registerToClientLeave((clientUUid: string, roomId: string) => {
-            name: 'workadventure_nb_clients_per_room',
+            gaugeManager.decNbClientPerRoomGauge(roomId);
-            help: 'Number of clients per room',
-            labelNames: [ 'room' ]
-        });
-
-        clientEventsEmitter.registerToClientJoin((clientUUid, roomId) => {
-            this.nbClientsGauge.inc();
-            // Let's log server load when a user joins
-            console.log(new Date().toISOString() + ' A user joined (', this.sockets.size, ' connected users)');
-        });
-        clientEventsEmitter.registerToClientLeave((clientUUid, roomId) => {
-            this.nbClientsGauge.dec();
-            // Let's log server load when a user leaves
-            console.log('A user left (', this.sockets.size, ' connected users)');
         });
     }
 
@@ -107,7 +89,6 @@ export class SocketManager {
         const viewport = client.viewport;
         try {
             this.sockets.set(client.userId, client); //todo: should this be at the end of the function?
-            clientEventsEmitter.emitClientJoin(client.userUuid, client.roomId);
             //join new previous room
             const gameRoom = this.joinRoom(client, position);
 
@@ -377,8 +358,8 @@ export class SocketManager {
             } finally {
                 //delete Client.roomId;
                 this.sockets.delete(Client.userId);
-                this.nbClientsPerRoomGauge.dec({ room: Client.roomId });
                 clientEventsEmitter.emitClientLeave(Client.userUuid, Client.roomId);
+                console.log('A user left (', this.sockets.size, ' connected users)');
             }
         }
     }
@@ -410,8 +391,6 @@ export class SocketManager {
     private joinRoom(client : ExSocketInterface, position: PointInterface): GameRoom {
 
         const roomId = client.roomId;
-        //join user in room
-        this.nbClientsPerRoomGauge.inc({ room: roomId });
         client.position = position;
 
         const world = this.Worlds.get(roomId)
@@ -425,6 +404,8 @@ export class SocketManager {
         });
         //join world
         world.join(client, client.position);
+        clientEventsEmitter.emitClientJoin(client.userUuid, client.roomId);
+        console.log(new Date().toISOString() + ' A user joined (', this.sockets.size, ' connected users)');
         return world;
     }