Q:

How enable debugging toolbar in prod environment of a Symfony2 project?

I have an existing project and just would like to know which files and what should I change to make visible the debug toolbar in the prod environment

A:

You should change in the AppKernel.php file in order to enable the bundle in the prod environment also and change the route moving from the routing_dev.yml to the routing.yml the bundle definition route. Then add the configuration in the config.yml also.
As Example:
AppKernel.php
        // Move this outside the if statement
        $bundles[] = new Symfony\Bundle\DebugBundle\DebugBundle();
        $bundles[] = new Symfony\Bundle\WebProfilerBundle\WebProfilerBundle();

    if (in_array($this->getEnvironment(), array('dev', 'test'), true)) {
        $bundles[] = new Sensio\Bundle\DistributionBundle\SensioDistributionBundle();
        $bundles[] = new Sensio\Bundle\GeneratorBundle\SensioGeneratorBundle();
    }

routing.yml
#add this

_wdt:
    resource: "@WebProfilerBundle/Resources/config/routing/wdt.xml"
    prefix:   /_wdt

_profiler:
    resource: "@WebProfilerBundle/Resources/config/routing/profiler.xml"
    prefix:   /_profiler

config.yml
web_profiler:
    toolbar: true

Hope this help

