Symfony index.php front controller switches on ENVIRONMENT

index.php

<?php

use Symfony\Component\Debug\Debug;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\ClassLoader\ApcClassLoader;

$env = getenv('ENVIRONMENT');
if (!isset($env) || empty($env)) {
    die('Please set environment variable in nginx like so: fastcgi_param ENVIRONMENT prod;');
}

if ($env == 'production' || $env == 'qa') {

    $loader = require(__DIR__ . '/../app/bootstrap.php.cache');
    require(__DIR__ . '/../app/AppKernel.php');
    require(__DIR__ . '/../app/AppCache.php');

    $apcLoader = new ApcClassLoader('WFM_APC', $loader);
    $loader->unregister();
    $apcLoader->register(true);

    $kernel = new AppKernel($env, $debug = false);
    $kernel->loadClassCache();
    $kernel = new AppCache($kernel);

    // When using the HttpCache, you need to call the method in your front controller
    // instead of relying on the configuration parameter
    Request::enableHttpMethodParameterOverride();

    $request = Request::createFromGlobals();
    $response = $kernel->handle($request);
    $response->send();

    $kernel->terminate($request, $response);

} elseif ($env == 'development' || $env == 'integration') {

    $loader = require_once __DIR__.'/../app/autoload.php';
    require(__DIR__ . '/../app/AppKernel.php');

    Debug::enable();
    $kernel = new AppKernel($env, $debug = true);
    $request = Request::createFromGlobals();
    $response = $kernel->handle($request);
    $response->send();
    $kernel->terminate($request, $response);
} else {
    die($env . ' has no valid code path');
}