Support timeout to auto clean up zombie/stale lobbies

Author: teejusb

src/events/events.gateway.ts

@@ -53,6 +53,13 @@ export class EventsGateway implements OnGatewayConnection, OnGatewayDisconnect {
     >
   >;
 
+  /** Cleanup interval in milliseconds */
+  private readonly CLEANUP_INTERVAL = 30000; // 30 seconds
+  /** Lobby inactivity timeout in milliseconds */
+  private readonly LOBBY_INACTIVITY_TIMEOUT = 30 * 60 * 1000; // 30 minutes
+  
+  private cleanupIntervalId: NodeJS.Timeout | null = null;
+
   constructor(private readonly clients: ClientService) {}
 
   afterInit() {
@@ -66,6 +73,80 @@ export class EventsGateway implements OnGatewayConnection, OnGatewayDisconnect {
       lobbyState: this.lobbyState,
       selectSong: this.selectSong,
     };
+    
+    // Start the cleanup interval to remove stale lobbies
+    this.startCleanupInterval();
+  }
+
+  /**
+   * Updates a lobby's lastUpdate timestamp to track activity.
+   * This is used for inactivity-based cleanup of zombie lobbies.
+   * @param code The lobby code to update
+   */
+  private updateLobbyActivity(code: LobbyCode): void {
+    const lobby = LOBBYMAN.lobbies[code];
+    if (lobby) {
+      lobby.lastUpdate = Date.now();
+    }
+  }
+
+  /**
+   * Starts the periodic cleanup interval to remove stale lobbies.
+   * Lobbies that haven't been updated for LOBBY_INACTIVITY_TIMEOUT are deleted.
+   */
+  private startCleanupInterval(): void {
+    if (this.cleanupIntervalId) {
+      clearInterval(this.cleanupIntervalId);
+    }
+    this.cleanupIntervalId = setInterval(() => {
+      this.cleanupStaleLobbies();
+    }, this.CLEANUP_INTERVAL);
+  }
+
+  /**
+   * Cleans up lobbies that haven't been updated within LOBBY_INACTIVITY_TIMEOUT.
+   * This prevents zombie lobbies from accumulating in memory.
+   */
+  private cleanupStaleLobbies(): void {
+    const now = Date.now();
+    const lobbyCodes = Object.keys(LOBBYMAN.lobbies);
+    
+    for (const code of lobbyCodes) {
+      const lobby = LOBBYMAN.lobbies[code];
+      if (!lobby) {
+        continue;
+      }
+      
+      const timeSinceLastUpdate = now - lobby.lastUpdate;
+      if (timeSinceLastUpdate > this.LOBBY_INACTIVITY_TIMEOUT) {
+        console.log(
+          `Cleaning up stale lobby ${code} (inactive for ${Math.round(
+            timeSinceLastUpdate / 1000 / 60,
+          )} minutes)`,
+        );
+        
+        // Disconnect all spectators
+        for (const spectator of Object.values(lobby.spectators)) {
+          if (spectator.socketId) {
+            ROOMMAN.leave(spectator.socketId, code);
+            this.clients.disconnect(spectator.socketId);
+            delete LOBBYMAN.spectatorConnections[spectator.socketId];
+          }
+        }
+        
+        // Disconnect all machines
+        for (const machine of Object.values(lobby.machines)) {
+          if (machine.socketId) {
+            ROOMMAN.leave(machine.socketId, code);
+            delete LOBBYMAN.machineConnections[machine.socketId];
+          }
+        }
+        
+        // Delete the lobby and its room
+        delete ROOMMAN.rooms[code];
+        delete LOBBYMAN.lobbies[code];
+      }
+    }
   }
 
   /**
@@ -168,11 +249,13 @@ export class EventsGateway implements OnGatewayConnection, OnGatewayDisconnect {
         },
       },
       spectators: {},
+      lastUpdate: Date.now(),
     };
     console.log('Created lobby', { code });
 
     ROOMMAN.join(socketId, code);
     LOBBYMAN.machineConnections[socketId] = code;
+    this.updateLobbyActivity(code);
 
     this.broadcastLobbyState(code);
     return undefined;
@@ -238,6 +321,7 @@ export class EventsGateway implements OnGatewayConnection, OnGatewayDisconnect {
     ROOMMAN.join(socketId, normalizedCode);
     LOBBYMAN.machineConnections[socketId] = normalizedCode;
 
+    this.updateLobbyActivity(normalizedCode);
     this.broadcastLobbyState(normalizedCode);
 
     return undefined;
@@ -279,6 +363,7 @@ export class EventsGateway implements OnGatewayConnection, OnGatewayDisconnect {
       });
     }
 
+    this.updateLobbyActivity(lobby.code);
     this.broadcastLobbyState(lobby.code);
     return undefined;
   }
@@ -315,6 +400,7 @@ export class EventsGateway implements OnGatewayConnection, OnGatewayDisconnect {
     }
     lobby.songInfo = songInfo;
 
+    this.updateLobbyActivity(code);
     this.broadcastLobbyState(code);
 
     return undefined;
@@ -329,8 +415,12 @@ export class EventsGateway implements OnGatewayConnection, OnGatewayDisconnect {
     socketId: SocketId,
     {},
   ): Promise<EventMessage<LobbyLeftPayload>> {
+    const code = LOBBYMAN.machineConnections[socketId];
     let left = false;
     left = this.disconnectMachine(socketId);
+    if (code) {
+      this.updateLobbyActivity(code);
+    }
     return { event: 'lobbyLeft', data: { left } };
   }
 
@@ -374,6 +464,7 @@ export class EventsGateway implements OnGatewayConnection, OnGatewayDisconnect {
 
     // Broadcasts an updated spectator count to all machines
     // and the initial lobby state for the newly-added spectator
+    this.updateLobbyActivity(code.toUpperCase());
     this.broadcastLobbyState(code);
 
     return undefined;

src/types/models.types.ts

@@ -82,6 +82,9 @@ export interface Lobby {
   spectators: Record<SocketId, Spectator>;
 
   songInfo?: SongInfo;
+  
+  // Timestamp of the last activity in this lobby (for inactivity cleanup)
+  lastUpdate: number;
 }
 
 export interface LobbyInfo {