How to execute a Symfony command in background from a controller - symfony

Question

I have a command which take a long time to run (it generates a big file).
I would like to use a controller to start it in background and don't wait for the end of its execution to render a view.
Is it possible? If yes, how?
I though the Process class would be useful but the documentation says:
If a Response is sent before a child process had a chance to complete, the server process will be killed (depending on your OS). It means that your task will be stopped right away. Running an asynchronous process is not the same as running a process that survives its parent process.

Answer 1

I solved my problem using the Messenger component as #msg suggested in comments.
To do so, I had to:
install the Messenger component by doing composer require symfony/messenger
create a custom log entity to track the file generation
create a custom Message and a custom MessageHandler for my file generation
dispatch the Message in my controller view
move my command code to a service method
call the service method in my MessageHandler
run bin/console messenger:consume -vv to handle the messages
Here is my code:
Custom log entity
I use it to show in my views if a file is being generated and to let the user download the file if its generation is complete
namespace App\Entity;
use Doctrine\ORM\Mapping as ORM;
/**
* #ORM\Entity(repositoryClass="App\Repository\MyLogForTheBigFileRepository")
*/
class MyLogForTheBigFile
{
/**
* #ORM\Id()
* #ORM\GeneratedValue()
* #ORM\Column(type="integer")
*/
private $id;
/**
* #ORM\Column(type="datetime")
*/
private $generationDateStart;
/**
* #ORM\Column(type="datetime", nullable=true)
*/
private $generationDateEnd;
/**
* #ORM\Column(type="string", length=200, nullable=true)
*/
private $filename;
/**
* #ORM\ManyToOne(targetEntity="App\Entity\User")
* #ORM\JoinColumn(nullable=false)
*/
private $generator;
public function __construct() { }
// getters and setters for the attributes
// ...
// ...
}
Controller
I get the form submission and dispatch a message which will run the file generation
/**
* #return views
* #param Request $request The request.
* #Route("/generate/big-file", name="generate_big_file")
*/
public function generateBigFileAction(
Request $request,
MessageBusInterface $messageBus,
MyFileService $myFileService
)
{
// Entity manager
$em = $this->getDoctrine()->getManager();
// Creating an empty Form Data Object
$myFormOptionsFDO = new MyFormOptionsFDO();
// Form creation
$myForm = $this->createForm(
MyFormType::class,
$myFormOptionsFDO
);
$myForm->handleRequest($request);
// Submit
if ($myForm->isSubmitted() && $myForm->isValid())
{
$myOption = $myFormOptionsFDO->getOption();
// Creating the database log using a custom entity
$myFileGenerationDate = new \DateTime();
$myLogForTheBigFile = new MyLogForTheBigFile();
$myLogForTheBigFile->setGenerationDateStart($myFileGenerationDate);
$myLogForTheBigFile->setGenerator($this->getUser());
$myLogForTheBigFile->setOption($myOption);
// Save that the file is being generated using the custom entity
$em->persist($myLogForTheBigFile);
$em->flush();
$messageBus->dispatch(
new GenerateBigFileMessage(
$myLogForTheBigFile->getId(),
$this->getUser()->getId()
));
$this->addFlash(
'success', 'Big file generation started...'
);
return $this->redirectToRoute('bigfiles_list');
}
return $this->render('Files/generate-big-file.html.twig', [
'form' => $myForm->createView(),
]);
}
Message
Used to pass data to the service
namespace App\Message;
class GenerateBigFileMessage
{
private $myLogForTheBigFileId;
private $userId;
public function __construct(int $myLogForTheBigFileId, int $userId)
{
$this->myLogForTheBigFileId = $myLogForTheBigFileId;
$this->userId = $userId;
}
public function getMyLogForTheBigFileId(): int
{
return $this->myLogForTheBigFileId;
}
public function getUserId(): int
{
return $this->userId;
}
}
Message handler
Handle the message and run the service
namespace App\MessageHandler;
use App\Service\MyFileService;
use App\Message\GenerateBigFileMessage;
use Symfony\Component\Messenger\Handler\MessageHandlerInterface;
class GenerateBigFileMessageHandler implements MessageHandlerInterface
{
private $myFileService;
public function __construct(MyFileService $myFileService)
{
$this->myFileService = $myFileService;
}
public function __invoke(GenerateBigFileMessage $generateBigFileMessage)
{
$myLogForTheBigFileId = $generateBigFileMessage->getMyLogForTheBigFileId();
$userId = $generateBigFileMessage->getUserId();
$this->myFileService->generateBigFile($myLogForTheBigFileId, $userId);
}
}
Service
Generate the big file and update the logger
public function generateBigFile($myLogForTheBigFileId, $userId)
{
// Get the user asking for the generation
$user = $this->em->getRepository(User::class)->find($userId);
// Get the log object corresponding to this generation
$myLogForTheBigFile = $this->em->getRepository(MyLogForTheBigFile::class)->find($myLogForTheBigFileId);
$myOption = $myLogForTheBigFile->getOption();
// Generate the file
$fullFilename = 'my_file.pdf';
// ...
// ...
// Update the log
$myLogForTheBigFile->setGenerationDateEnd(new \DateTime());
$myLogForTheBigFile->setFilename($fullFilename);
$this->em->persist($myLogForTheBigFile);
$this->em->flush();
}