Hugo Soltys

Symfony developer

Since 2013

How to make a maintenance mode for your Symfony website

Posted on by Hugo - 454 views - 0 comments

Developing a website is synonymous of multiple releases which can cause some undesirables critical errors.

In this tutorial, we will learn how to make a simple and efficient maintenance mode with Symfony.

Furthermore, you'll still be able to access your website while maintenance mode is active.

Read more

Let's go. 


First of all, we need to define a new parameter with a boolean value you will use to toggle maintenance on or off.


Do the following in your parameters.yml file :


    maintenance: false


Keep it to false for now.


Then, we will create the listener class that will detect if maintenance is enabled. We will name it MaintenanceListener.php


namespace AcmeBundle\EventListener;

use Symfony\Component\HttpKernel\Event\GetResponseEvent;
use Symfony\Component\DependencyInjection\ContainerInterface;
use Symfony\Component\HttpFoundation\Response;

class MaintenanceListener
    private $container;

    public function __contruct(ContainerInterface $container)
        $this->container = $container;

    public function onKernelRequest(GetResponseEvent $event)
        // This will get the value of our maintenance parameter
        $maintenance = $this->container->hasParameter('maintenance') ? $this->container->getParameter('maintenance') : false;

        // This will detect if we are in dev environment (app_dev.php)
        $debug = in_array($this->container->get('kernel')->getEnvironment(), ['dev']);

        // If maintenance is active and in prod environment
        if ($maintenance && !$debug) {
            // We load our maintenance template
            $engine = $this->container->get('templating');
            $template = $engine->render('::maintenance.html.twig');

            // We send our response with a 503 response code (service unavailable)
            $event->setResponse(new Response($template, 503));


And now the service declaration :


<service id="acme.maintenance_mode" class="AcmeBundle\EventListener\MaintenanceListener">
    <argument type="service" id="service_container" />
    <tag name="kernel.event_listener" event="kernel.request" method="onKernelRequest" />


So we have now a MaintenanceListener class which will disable your website in a production environment if you set it to true. Cool isn't it ? smile

Don't forget to create your own maintenance template in app/Resources/views/maintenance.html.twig

<!DOCTYPE html>
    <meta charset="utf-8">
    <title>Site temporarily under maintenance</title>
    <h1>Site temporarily under maintenance</h1>
    <p>Sorry for the inconvenience, we will get back soon !</p>


That's all folks, I hope this tutorial helped you ! :) 

Do not hesitate to give me your feedback or asking some questions !


Hugo Soltys

My name is Hugo, I'm 25 and I'm a Symfony developer since 2013. I love to create websites by myself to learn new technologies or increase my skills.
I love movies, books, music and video games. I also like to drink a few beers with my friends. I'm from Lille (France) and I currently work as Symfony developer at Decathlon since 2016. Before that, I worked as Symfony developer for the IT Room company, in Roubaix, France.