Add optional "log_file" configuration option.

main.go

@@ -40,7 +40,7 @@ func main() {
 		}
 
 		if isDaemon {
-			startDaemon()
+			startDaemon(cfg.LogFile)
 			return
 		}
 		runEngine(cfg)
@@ -78,13 +78,17 @@ func printUsage() {
 	fmt.Println("Usage: engine [command] [--daemon]")
 	fmt.Println("\nCommands:")
 	fmt.Println("  run       Start the WebSocket ingestor and processing engine")
-	fmt.Println("            Use --daemon to run in background and log to engine.log")
+	fmt.Println("            Use --daemon to run in background and log to the file defined in config")
 	fmt.Println("  recover   Run startup recovery to migrate stale ticks")
 	fmt.Println("  maintain  Run a single maintenance cycle (cleanup/retention)")
 	fmt.Println("  help      Show this help message")
 }
 
-func startDaemon() {
+func startDaemon(logPath string) {
+	if logPath == "" {
+		logPath = "engine.log"
+	}
+
 	// Prepare arguments for the child process (remove --daemon)
 	args := []string{}
 	for _, arg := range os.Args[1:] {
@@ -93,24 +97,24 @@ func startDaemon() {
 		}
 	}
 
-	// Prepare the command
+	// Prepare the command to re-run the current binary
 	cmd := exec.Command(os.Args[0], args...)
 	
-	// Open log file for output redirection
-	logFile, err := os.OpenFile("engine.log", os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0666)
+	// Open the configured log file for output redirection
+	logFile, err := os.OpenFile(logPath, os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0666)
 	if err != nil {
-		log.Fatalf("Failed to open log file: %v", err)
+		log.Fatalf("Failed to open log file %s: %v", logPath, err)
 	}
 
 	cmd.Stdout = logFile
 	cmd.Stderr = logFile
 
-	// Start the process
+	// Start the process in the background
 	if err := cmd.Start(); err != nil {
 		log.Fatalf("Failed to start daemon: %v", err)
 	}
 
-	fmt.Printf("Engine started in background (PID: %d). Logs: engine.log\n", cmd.Process.Pid)
+	fmt.Printf("Engine started in background (PID: %d). Logs: %s\n", cmd.Process.Pid, logPath)
 	os.Exit(0)
 }