emit问题

$io = new SocketIO(3120);

$io->on('workerStart', function(){
    Timer::add(2, function() {
        global $io;
//        $componentLatest = shell_exec('cd ../index_web && php artisan componentLatest');
//        $io->emit('getComponentLatest', $componentLatest);
        $latest = shell_exec('cd ../index_web && php artisan latest');
        $io->emit('getLatest', $latest);
    });
});