Using Logger to Save Error Exception in log file

Three step to create log file 

Step 1-

 On root folder create following folder structure

/data/log/

Step 2-

Module.php file insert following function

public function onBootstrap(MvcEvent $e)
{
    $eventManager = $e->getApplication()->getEventManager();
    $moduleRouteListener = new ModuleRouteListener();
    $moduleRouteListener->attach($eventManager);
    /**
     * Log any Uncaught Exceptions, including all Exceptions in the stack
     */
    $sharedManager = $e->getApplication()->getEventManager()->getSharedManager();
    $sm = $e->getApplication()->getServiceManager();
    $sharedManager->attach('Zend\Mvc\Application', 'dispatch.error',
         function($e) use ($sm) {
            if ($e->getParam('exception')){
                $ex = $e->getParam('exception');
                do {
                    $sm->get('Logger')->crit(
                        sprintf(
                           "%s:%d %s (%d) [%s]\n", 
                            $ex->getFile(), 
                            $ex->getLine(), 
                            $ex->getMessage(), 
                            $ex->getCode(), 
                            get_class($ex)
                        )
                    );
                }
                while($ex = $ex->getPrevious());
            }
         }
    );
}

Step 3-

global.php file insert following code

'factories' => array(
    'Logger' => function($sm){
        $logger = new \Zend\Log\Logger;
        $writer = new \Zend\Log\Writer\Stream('./data/log/'.date('Y-m-d').'-error.log');
        $logger->addWriter($writer);  

        return $logger;
    },