Call container inside ExceptionListener - symfony

Question

I am using Symfony and i have created custom ExceptionListener to handle error.
class ExceptionListener
{
protected $templating;
protected $kernel;
public function __construct(EngineInterface $templating, $kernel)
{
$this->templating = $templating;
$this->kernel = $kernel;
}
public function onKernelException(GetResponseForExceptionEvent $event)
{
// exception object
$exception = $event->getException();
// new Response object
$response = new Response();
$response->setContent(
// create you custom template AcmeFooBundle:Exception:exception.html.twig
$this->templating->render(
'Exception/exception.html.twig',
array('exception' => $exception)
)
);
// HttpExceptionInterface is a special type of exception
// that holds status code and header details
if ($exception instanceof HttpExceptionInterface) {
$response->setStatusCode($exception->getStatusCode());
$response->headers->replace($exception->getHeaders());
} else {
$this->container->get('monolog.logger.db')->info('something happened 34', [
'foo' => 'bar'
]);
$response->setStatusCode(500);
}
if($exception instanceof FatalThrowableError){
return $this->templating->render(
'Exception/exception.html.twig'
);
}
// set the new $response object to the $event
$event->setResponse($response);
}
}
and in service
kernel.listener.acme_foo_exception_listener:
class: AppBundle\Listener\ExceptionListener
arguments: [#templating, #kernel]
tags:
- { name: kernel.event_listener, event: kernel.exception, method: onKernelException }
My aim is to when symfony throws exception i need to log error in database so i have created Logger event as per below link and it works fine when i called in controller but this event doesn't work when i called inside ExceptionListener.
I got following error
Notice: Undefined property:
AppBundle\Listener\ExceptionListener::$container in
can any one help me how i can pass container inside Listener

Answer 1

As said by geoforce your service doesn't know about the container. Quick fix for this by changing the service arguments:
arguments: [#templating, #container]
While changing the listener constructor to:
public function __construct(EngineInterface $templating, ContainerInterface $container)
{
$this->container = $container;
// ...
This should work, but injecting the entire container is quite an overkill and should definitely be done differently. Inject just what you need:
arguments: [#templating, '#monolog.logger.db']
And your constructor:
public function __construct(EngineInterface $templating,
LoggerInterface $logger)
{
$this->logger = $logger;
// ...
Log with $this->logger->info(...).
Since you've said that you're new to Symfony, I'd heavily recommend reading the DI component (http://symfony.com/doc/current/components/dependency_injection.html) docs. Understanding what DI does and how it works is mandatory to work with MVC frameworks like Symfony.

Answer 2

Like the error says, you are trying to access a property that does not exist:
$this->container->get('monolog.logger.db')->info('something happened 34', [
'foo' => 'bar'
]);
The container property is never declared nor assigned. If you want to access your logging service inject it in your service definition, like you did with the templating and kernel services.
Updated service definition:
kernel.listener.acme_foo_exception_listener:
class: AppBundle\Listener\ExceptionListener
arguments: [#templating, #kernel, #monolog.logger.db]
tags:
- { name: kernel.event_listener, event: kernel.exception, method: onKernelException }
And update your class constructor to accept the log service as the third argument.