Guard room creation with a mutex

Possible fix for the concurrent room creation while other is not destroyed properly.

pkg/worker/coordinatorhandlers.go

@@ -50,9 +50,7 @@ func (c *coordinator) HandleWebrtcInit(rq api.WebrtcInitRequest[com.Uid], w *Wor
 
 	user := room.NewGameSession(rq.Id, peer) // use user uid from the coordinator
 	c.log.Info().Msgf("Peer connection: %s", user.Id())
-	c.log.Debug().Msgf("Users before add: %v", w.router.Users())
 	w.router.AddUser(user)
-	c.log.Debug().Msgf("Users after add: %v", w.router.Users())
 
 	return api.Out{Payload: sdp}
 }
@@ -83,11 +81,23 @@ func (c *coordinator) HandleGameStart(rq api.StartGameRequest[com.Uid], w *Worke
 
 	r := w.router.FindRoom(rq.Rid)
 
-	if r == nil {
+	if r == nil { // new room
 		uid := rq.Room.Rid
 		if uid == "" {
 			uid = games.GenerateRoomID(rq.Game.Name)
 		}
+		game := games.GameMetadata(rq.Game)
+
+		r = room.NewRoom[*room.GameSession](uid, nil, w.router.Users(), nil)
+		r.HandleClose = func() { c.CloseRoom(uid) }
+
+		if other := w.router.Room(); other != nil {
+			c.log.Error().Msgf("concurrent room creation: %v", uid)
+			return api.EmptyPacket
+		}
+
+		w.router.SetRoom(r)
+		c.log.Info().Str("room", r.Id()).Str("game", game.Name).Msg("New room")
 
 		// start the emulator
 		app := room.WithEmulator(w.mana.Get(caged.Libretro))
@@ -97,13 +107,14 @@ func (c *coordinator) HandleGameStart(rq api.StartGameRequest[com.Uid], w *Worke
 		app.EnableCloudStorage(uid, w.storage)
 		app.EnableRecording(rq.Record, rq.RecordUser, rq.Game.Name)
 
-		w.log.Info().Msgf("Starting game: %v", rq.Game.Name)
-		game := games.GameMetadata(rq.Game)
+		w.log.Info().Msgf("Starting the game: %v", rq.Game.Name)
 		if err := app.Load(game, w.conf.Worker.Library.BasePath); err != nil {
 			c.log.Error().Err(err).Msgf("couldn't load the game %v", game)
 			app.Close()
+			w.router.SetRoom(nil)
 			return api.EmptyPacket
 		}
+		r.SetApp(app)
 
 		m := media.NewWebRtcMediaPipe(w.conf.Encoder.Audio, w.conf.Encoder.Video, w.log)
 		m.AudioSrcHz = app.AudioSampleRate()
@@ -112,19 +123,15 @@ func (c *coordinator) HandleGameStart(rq api.StartGameRequest[com.Uid], w *Worke
 		if err := m.Init(); err != nil {
 			c.log.Error().Err(err).Msgf("couldn't init the media")
 			app.Close()
+			w.router.SetRoom(nil)
 			return api.EmptyPacket
 		}
 		if app.Flipped() {
 			m.SetVideoFlip(true)
 		}
+		r.SetMedia(m)
 
-		// make the room
-		r = room.NewRoom[*room.GameSession](uid, app, w.router.Users(), m)
-		r.HandleClose = func() { c.CloseRoom(uid) }
-
-		w.router.SetRoom(r)
-		c.log.Info().Str("room", r.Id()).Str("game", game.Name).Msg("New room")
-
+		r.BindAppMedia()
 		r.StartApp()
 	}
 
@@ -146,10 +153,8 @@ func (c *coordinator) HandleTerminateSession(rq api.TerminateSessionRequest[com.
 
 // HandleQuitGame handles cases when a user manually exits the game.
 func (c *coordinator) HandleQuitGame(rq api.GameQuitRequest[com.Uid], w *Worker) {
-	w.log.Debug().Msgf("Users before remove: %v", w.router.Users())
 	if user := w.router.FindUser(rq.Id); user != nil {
 		w.router.Remove(user)
-		w.log.Debug().Msgf("Users after remove: %v", w.router.Users())
 	}
 }
 

pkg/worker/room/room.go

@@ -53,8 +53,10 @@ type Room[T Session] struct {
 
 func NewRoom[T Session](id string, app app.App, um SessionManager[T], media MediaPipe) *Room[T] {
 	room := &Room[T]{id: id, app: app, users: um, media: media}
-	room.InitVideo()
-	room.InitAudio()
+	if app != nil && media != nil {
+		room.InitVideo()
+		room.InitAudio()
+	}
 	return room
 }
 
@@ -70,9 +72,12 @@ func (r *Room[T]) InitVideo() {
 	})
 }
 
-func (r *Room[T]) App() app.App { return r.app }
-func (r *Room[T]) Id() string   { return r.id }
-func (r *Room[T]) StartApp()    { r.app.Start() }
+func (r *Room[T]) App() app.App         { return r.app }
+func (r *Room[T]) BindAppMedia()        { r.InitAudio(); r.InitVideo() }
+func (r *Room[T]) Id() string           { return r.id }
+func (r *Room[T]) SetApp(app app.App)   { r.app = app }
+func (r *Room[T]) SetMedia(m MediaPipe) { r.media = m }
+func (r *Room[T]) StartApp()            { r.app.Start() }
 
 func (r *Room[T]) Close() {
 	if r.closed {
@@ -124,6 +129,7 @@ func (r *Router[T]) Remove(user T) {
 		r.Close()
 	}
 }
+func (r *Router[T]) Room() *Room[T]           { r.mu.Lock(); defer r.mu.Unlock(); return r.room }
 func (r *Router[T]) FindUser(uid Uid) T       { return r.users.Find(uid.Id()) }
 func (r *Router[T]) SetRoom(room *Room[T])    { r.mu.Lock(); r.room = room; r.mu.Unlock() }
 func (r *Router[T]) Users() SessionManager[T] { return r.users }