fix(backend): fix memory leaks and resource issues in logs system

- Fix Subscribe overwriting channel without closing old one (goroutine leak)
- Add context.Context to Stream() for cancellation support
- Add WebSocket read pump to detect dead clients (StreamLogs, StreamSteamCMDLogs, StreamRPTLogs)
- Use defer f.Close() pattern in StreamRPTLogs file handling
- Fix findLatestRPT nil dereference on failed os.Stat
- Optimize findLatestRPT to collect stat results before sorting
- Apply gofmt formatting to modlists.go, settings.go

backend/internal/api/logs.go

@@ -19,6 +19,25 @@ var upgrader = websocket.Upgrader{
 	CheckOrigin: func(r *http.Request) bool { return true },
 }
 
+const wsReadTimeout = 60 * time.Second
+
+func readPump(conn *websocket.Conn, done chan struct{}) {
+	defer close(done)
+	conn.SetReadLimit(4096)
+	conn.SetReadDeadline(time.Now().Add(wsReadTimeout))
+	conn.SetPongHandler(func(string) error {
+		conn.SetReadDeadline(time.Now().Add(wsReadTimeout))
+		return nil
+	})
+	for {
+		_, _, err := conn.ReadMessage()
+		if err != nil {
+			return
+		}
+		conn.SetReadDeadline(time.Now().Add(wsReadTimeout))
+	}
+}
+
 func (h *Handler) StreamLogs(c *gin.Context) {
 	conn, err := upgrader.Upgrade(c.Writer, c.Request, nil)
 	if err != nil {
@@ -27,13 +46,24 @@ func (h *Handler) StreamLogs(c *gin.Context) {
 	}
 	defer conn.Close()
 
+	done := make(chan struct{})
+	go readPump(conn, done)
+
 	clientID := conn.RemoteAddr().String()
 	ch := h.streamer.Subscribe("server", clientID)
 	defer h.streamer.Unsubscribe("server", clientID)
 
-	for line := range ch {
+	for {
+		select {
+		case line, ok := <-ch:
+			if !ok {
+				return
+			}
 			if err := conn.WriteMessage(websocket.TextMessage, []byte(line)); err != nil {
-			break
+				return
+			}
+		case <-done:
+			return
 		}
 	}
 }
@@ -83,13 +113,24 @@ func (h *Handler) StreamSteamCMDLogs(c *gin.Context) {
 	}
 	defer conn.Close()
 
+	done := make(chan struct{})
+	go readPump(conn, done)
+
 	clientID := conn.RemoteAddr().String()
 	ch := h.streamer.Subscribe("steamcmd", clientID)
 	defer h.streamer.Unsubscribe("steamcmd", clientID)
 
-	for line := range ch {
+	for {
+		select {
+		case line, ok := <-ch:
+			if !ok {
+				return
+			}
 			if err := conn.WriteMessage(websocket.TextMessage, []byte(line)); err != nil {
-			break
+				return
+			}
+		case <-done:
+			return
 		}
 	}
 }
@@ -102,13 +143,22 @@ func (h *Handler) StreamRPTLogs(c *gin.Context) {
 	}
 	defer conn.Close()
 
+	done := make(chan struct{})
+	go readPump(conn, done)
+
 	profilesDir := h.process.ProfilesDir()
 	var currentPath string
 	var currentOffset int64
 	ticker := time.NewTicker(250 * time.Millisecond)
 	defer ticker.Stop()
 
-	for range ticker.C {
+	for {
+		select {
+		case <-done:
+			return
+		case <-ticker.C:
+		}
+
 		path := findLatestRPT(profilesDir)
 
 		if path != currentPath {
@@ -134,15 +184,19 @@ func (h *Handler) StreamRPTLogs(c *gin.Context) {
 			continue
 		}
 
+		if err := func() error {
 			f, err := os.Open(currentPath)
 			if err != nil {
 				currentPath = ""
-			continue
+				return nil
+			}
+			defer f.Close()
+
+			if _, err := f.Seek(currentOffset, io.SeekStart); err != nil {
+				return nil
 			}
-		f.Seek(currentOffset, io.SeekStart)
 			buf := make([]byte, fi.Size()-currentOffset)
 			n, _ := io.ReadFull(f, buf)
-		f.Close()
 
 			currentOffset += int64(n)
 			for _, line := range strings.Split(string(buf[:n]), "\n") {
@@ -150,9 +204,13 @@ func (h *Handler) StreamRPTLogs(c *gin.Context) {
 					continue
 				}
 				if err := conn.WriteMessage(websocket.TextMessage, []byte(line)); err != nil {
-				return
+					return err
 				}
 			}
+			return nil
+		}(); err != nil {
+			return
+		}
 	}
 }
 
@@ -162,12 +220,25 @@ func findLatestRPT(dir string) string {
 	if err != nil || len(matches) == 0 {
 		return ""
 	}
-	sort.Slice(matches, func(i, j int) bool {
-		fi, _ := os.Stat(matches[i])
-		fj, _ := os.Stat(matches[j])
-		return fi.ModTime().After(fj.ModTime())
+	type rptInfo struct {
+		path string
+		time time.Time
+	}
+	var infos []rptInfo
+	for _, m := range matches {
+		fi, err := os.Stat(m)
+		if err != nil {
+			continue
+		}
+		infos = append(infos, rptInfo{path: m, time: fi.ModTime()})
+	}
+	if len(infos) == 0 {
+		return ""
+	}
+	sort.Slice(infos, func(i, j int) bool {
+		return infos[i].time.After(infos[j].time)
 	})
-	return matches[0]
+	return infos[0].path
 }
 
 func (h *Handler) GetLog(c *gin.Context) {

backend/internal/api/settings.go

@@ -45,20 +45,48 @@ func (h *Handler) UpdateSettings(c *gin.Context) {
 		return
 	}
 
-	if input.IPPort != nil { s.IPPort = *input.IPPort }
-	if input.ServerParameters != nil { s.ServerParameters = *input.ServerParameters }
-	if input.SteamBranch != nil { s.SteamBranch = *input.SteamBranch }
-	if input.SteamUser != nil { s.SteamUser = *input.SteamUser }
-	if input.Platform != nil { s.Platform = *input.Platform }
-	if input.CBASettings != nil { s.CBASettings = *input.CBASettings }
-	if input.AILevelPresets != nil { s.AILevelPresets = *input.AILevelPresets }
-	if input.DifficultyPresets != nil { s.DifficultyPresets = *input.DifficultyPresets }
-	if input.ActiveConfig != nil { s.ActiveConfig = *input.ActiveConfig }
-	if input.ActiveModlist != nil { s.ActiveModlist = *input.ActiveModlist }
-	if input.AutoUpdateOnStartup != nil { s.AutoUpdateOnStartup = *input.AutoUpdateOnStartup }
-	if input.AutoStartOnStartup != nil { s.AutoStartOnStartup = *input.AutoStartOnStartup }
-	if input.AutoUpdateModsOnStartup != nil { s.AutoUpdateModsOnStartup = *input.AutoUpdateModsOnStartup }
-	if input.ScheduledUpdate != nil { s.ScheduledUpdate = *input.ScheduledUpdate }
+	if input.IPPort != nil {
+		s.IPPort = *input.IPPort
+	}
+	if input.ServerParameters != nil {
+		s.ServerParameters = *input.ServerParameters
+	}
+	if input.SteamBranch != nil {
+		s.SteamBranch = *input.SteamBranch
+	}
+	if input.SteamUser != nil {
+		s.SteamUser = *input.SteamUser
+	}
+	if input.Platform != nil {
+		s.Platform = *input.Platform
+	}
+	if input.CBASettings != nil {
+		s.CBASettings = *input.CBASettings
+	}
+	if input.AILevelPresets != nil {
+		s.AILevelPresets = *input.AILevelPresets
+	}
+	if input.DifficultyPresets != nil {
+		s.DifficultyPresets = *input.DifficultyPresets
+	}
+	if input.ActiveConfig != nil {
+		s.ActiveConfig = *input.ActiveConfig
+	}
+	if input.ActiveModlist != nil {
+		s.ActiveModlist = *input.ActiveModlist
+	}
+	if input.AutoUpdateOnStartup != nil {
+		s.AutoUpdateOnStartup = *input.AutoUpdateOnStartup
+	}
+	if input.AutoStartOnStartup != nil {
+		s.AutoStartOnStartup = *input.AutoStartOnStartup
+	}
+	if input.AutoUpdateModsOnStartup != nil {
+		s.AutoUpdateModsOnStartup = *input.AutoUpdateModsOnStartup
+	}
+	if input.ScheduledUpdate != nil {
+		s.ScheduledUpdate = *input.ScheduledUpdate
+	}
 
 	if err := h.process.WriteUserconfigFiles(s); err != nil {
 		c.JSON(http.StatusInternalServerError, gin.H{"error": "write userconfig: " + err.Error()})

backend/internal/services/log_streamer.go

@@ -2,6 +2,7 @@ package services
 
 import (
 	"bufio"
+	"context"
 	"io"
 	"log"
 	"sync"
@@ -26,6 +27,10 @@ func (ls *LogStreamer) Subscribe(serverID, clientID string) chan string {
 		ls.subs[serverID] = make(map[string]chan string)
 	}
 
+	if old, ok := ls.subs[serverID][clientID]; ok {
+		close(old)
+	}
+
 	ch := make(chan string, 256)
 	ls.subs[serverID][clientID] = ch
 	return ch
@@ -46,15 +51,24 @@ func (ls *LogStreamer) Unsubscribe(serverID, clientID string) {
 	}
 }
 
-func (ls *LogStreamer) Stream(serverID string, reader io.Reader, closeMsg string) {
+func (ls *LogStreamer) Stream(ctx context.Context, serverID string, reader io.Reader, closeMsg string) {
 	scanner := bufio.NewScanner(reader)
 	for scanner.Scan() {
+		select {
+		case <-ctx.Done():
+			return
+		default:
+		}
 		line := scanner.Text()
 		ls.broadcast(serverID, line)
 	}
 	if err := scanner.Err(); err != nil {
+		select {
+		case <-ctx.Done():
+		default:
 			log.Printf("log stream error for server %s: %v", serverID, err)
 		}
+	}
 	if closeMsg != "" {
 		ls.broadcast(serverID, closeMsg)
 	}

backend/internal/services/log_streamer_test.go

@@ -1,6 +1,7 @@
 package services
 
 import (
+	"context"
 	"strings"
 	"sync"
 	"testing"
@@ -95,7 +96,7 @@ func TestLogStreamer_Stream(t *testing.T) {
 	ch := ls.Subscribe("server", "client1")
 
 	reader := strings.NewReader("line1\nline2\nline3\n")
-	go ls.Stream("server", reader, "DONE")
+	go ls.Stream(context.Background(), "server", reader, "DONE")
 
 	lines := []string{}
 	for i := 0; i < 4; i++ { // 3 lines + DONE close message
@@ -174,3 +175,68 @@ func TestLogStreamer_ConcurrentSubscribeUnsubscribe(t *testing.T) {
 
 	wg.Wait()
 }
+
+func TestLogStreamer_SubscribeOverwriteClosesOld(t *testing.T) {
+	ls := NewLogStreamer()
+
+	ch1 := ls.Subscribe("server", "client1")
+	ls.Broadcast("server", "first")
+	<-ch1
+
+	// Re-subscribe with same clientID — old channel should be closed
+	ch2 := ls.Subscribe("server", "client1")
+
+	// Old channel should be closed
+	select {
+	case _, ok := <-ch1:
+		if ok {
+			t.Error("old channel should be closed after re-subscribe")
+		}
+	case <-time.After(100 * time.Millisecond):
+		t.Error("old channel not closed within timeout")
+	}
+
+	// New channel should work
+	ls.Broadcast("server", "second")
+	select {
+	case line := <-ch2:
+		if line != "second" {
+			t.Errorf("new channel received %q, want %q", line, "second")
+		}
+	case <-time.After(100 * time.Millisecond):
+		t.Error("timeout waiting on new channel")
+	}
+}
+
+func TestLogStreamer_StreamContextCancel(t *testing.T) {
+	ls := NewLogStreamer()
+	ch := ls.Subscribe("server", "client1")
+
+	ctx, cancel := context.WithCancel(context.Background())
+	reader := contextReader{ctx: ctx}
+	go ls.Stream(ctx, "server", reader, "")
+
+	// Broadcast should still work while stream is running
+	ls.Broadcast("server", "live")
+	select {
+	case line := <-ch:
+		if line != "live" {
+			t.Errorf("received %q, want %q", line, "live")
+		}
+	case <-time.After(100 * time.Millisecond):
+		t.Error("timeout waiting for broadcast")
+	}
+
+	// Cancel context — stream should stop
+	cancel()
+	time.Sleep(100 * time.Millisecond)
+}
+
+type contextReader struct {
+	ctx context.Context
+}
+
+func (r contextReader) Read(p []byte) (int, error) {
+	<-r.ctx.Done()
+	return 0, r.ctx.Err()
+}

backend/internal/services/server_process.go

@@ -148,8 +148,8 @@ func (pm *ProcessManager) Start() error {
 	pm.mu.Unlock()
 	pm.state.Store(int32(procRunning))
 
-	go pm.streamer.Stream("server", stdout, "")
-	go pm.streamer.Stream("server", stderr, "")
+	go pm.streamer.Stream(ctx, "server", stdout, "")
+	go pm.streamer.Stream(ctx, "server", stderr, "")
 
 	go func() {
 		cmd.Wait()

backend/internal/services/steamcmd.go

@@ -117,8 +117,8 @@ func (s *SteamCmdManager) run(label string, args []string) error {
 
 	s.cancel = cancel
 
-	go s.streamer.Stream("steamcmd", stdout, "")
-	go s.streamer.Stream("steamcmd", stderr, "")
+	go s.streamer.Stream(ctx, "steamcmd", stdout, "")
+	go s.streamer.Stream(ctx, "steamcmd", stderr, "")
 
 	go func() {
 		err := cmd.Wait()