XTLS/Xray-core · error · errors.Error

failed to start logger

Error message

failed to start logger

What it means

RestartLogger's final step: after a successful Close it calls logger.Start(); if re-initializing the log writers fails, this error wraps the cause. Start re-runs initAccessLogger/initErrorLogger, so the same file-path problems that break initial startup break the restart.

Source

Thrown at app/log/command/command.go:27

	"github.com/xtls/xray-core/core"
	grpc "google.golang.org/grpc"
)

type LoggerServer struct {
	V *core.Instance
}

// RestartLogger implements LoggerService.
func (s *LoggerServer) RestartLogger(ctx context.Context, request *RestartLoggerRequest) (*RestartLoggerResponse, error) {
	logger := s.V.GetFeature((*log.Instance)(nil))
	if logger == nil {
		return nil, errors.New("unable to get logger instance")
	}
	if err := logger.Close(); err != nil {
		return nil, errors.New("failed to close logger").Base(err)
	}
	if err := logger.Start(); err != nil {
		return nil, errors.New("failed to start logger").Base(err)
	}
	return &RestartLoggerResponse{}, nil
}

func (s *LoggerServer) mustEmbedUnimplementedLoggerServiceServer() {}

type service struct {
	v *core.Instance
}

func (s *service) Register(server *grpc.Server) {
	ls := &LoggerServer{
		V: s.v,
	}
	RegisterLoggerServiceServer(server, ls)

	// For compatibility purposes
	vCoreDesc := LoggerService_ServiceDesc

View on GitHub (pinned to 7d214f8b09)

Solutions

1. Inspect the Base error for the file create/open failure and fix the path or permissions
2. Validate that the log directory exists and is writable before issuing RestartLogger
3. If the path is genuinely gone, fix the config and restart the instance rather than the logger

// Ensure the log directory is writable before issuing the restart:
if err := os.MkdirAll(filepath.Dir(logPath), 0o755); err != nil {
    return err
}

resp, err := loggerClient.RestartLogger(ctx, req)
if err != nil && strings.Contains(err.Error(), "failed to start logger") {
    // writer reopen failed: fix the path, then retry the restart once
}

When it happens

Trigger: RestartLogger called when the configured access/error log path became invalid between startup and restart — deleted directory, changed ownership, unwritable mount.

Common situations: Container restarts with ephemeral /var/log; misconfigured log paths that only fail on reopen; concurrent restarts.

Related errors

• failed to close logger
• unable to get logger instance
• failed to initialize access logger
• failed to initialize error logger
• unsupported router implementation

AI-assisted analysis of XTLS/Xray-core@7d214f8b09 (2026-08-15). Data as JSON: /api/errors/5eaeb4b6aee108ae. Report an issue: GitHub.