fix(logging): Prevent race conditions in FileStreamingLogWriter

internal/logging/request_logger.go

@@ -13,6 +13,7 @@ import (
 	"path/filepath"
 	"regexp"
 	"strings"
+	"sync"
 	"time"
 
 	"github.com/router-for-me/CLIProxyAPI/v6/internal/interfaces"
@@ -493,6 +494,12 @@ type FileStreamingLogWriter struct {
 
 	// statusWritten indicates whether the response status has been written.
 	statusWritten bool
+
+	// mu protects concurrent access to the writer state.
+	mu sync.RWMutex
+
+	// closed indicates whether the streaming writer has been closed.
+	closed bool
 }
 
 // WriteChunkAsync writes a response chunk asynchronously (non-blocking).
@@ -500,7 +507,10 @@ type FileStreamingLogWriter struct {
 // Parameters:
 //   - chunk: The response chunk to write
 func (w *FileStreamingLogWriter) WriteChunkAsync(chunk []byte) {
-	if w.chunkChan == nil {
+	w.mu.RLock()
+	defer w.mu.RUnlock()
+
+	if w.chunkChan == nil || w.closed {
 		return
 	}
 
@@ -525,6 +535,9 @@ func (w *FileStreamingLogWriter) WriteChunkAsync(chunk []byte) {
 // Returns:
 //   - error: An error if writing fails, nil otherwise
 func (w *FileStreamingLogWriter) WriteStatus(status int, headers map[string][]string) error {
+	w.mu.Lock()
+	defer w.mu.Unlock()
+
 	if w.file == nil || w.statusWritten {
 		return nil
 	}
@@ -553,21 +566,38 @@ func (w *FileStreamingLogWriter) WriteStatus(status int, headers map[string][]st
 // Returns:
 //   - error: An error if closing fails, nil otherwise
 func (w *FileStreamingLogWriter) Close() error {
-	if w.chunkChan != nil {
-		close(w.chunkChan)
+	w.mu.Lock()
+	if w.closed {
+		w.mu.Unlock()
+		return nil
+	}
+	w.closed = true
+	chunkChan := w.chunkChan
+	closeChan := w.closeChan
+	file := w.file
+	w.mu.Unlock()
+
+	if chunkChan != nil {
+		close(chunkChan)
 	}
 
 	// Wait for async writer to finish
-	if w.closeChan != nil {
-		<-w.closeChan
-		w.chunkChan = nil
+	if closeChan != nil {
+		<-closeChan
 	}
 
-	if w.file != nil {
-		return w.file.Close()
+	var err error
+	if file != nil {
+		err = file.Close()
 	}
 
-	return nil
+	w.mu.Lock()
+	w.chunkChan = nil
+	w.closeChan = nil
+	w.file = nil
+	w.mu.Unlock()
+
+	return err
 }
 
 // asyncWriter runs in a goroutine to handle async chunk writing.