Kernel.php

<?php

namespace App;

use Symfony\Bundle\FrameworkBundle\Kernel\MicroKernelTrait;
use Symfony\Component\Config\Definition\Builder\TreeBuilder;
use Symfony\Component\Config\Definition\ConfigurationInterface;
use Symfony\Component\Config\Loader\LoaderInterface;
use Symfony\Component\DependencyInjection\ContainerBuilder;
use Symfony\Component\DependencyInjection\Extension\ConfigurationExtensionInterface;
use Symfony\Component\DependencyInjection\Extension\ExtensionInterface;
use Symfony\Component\HttpKernel\Kernel as BaseKernel;
use Symfony\Component\Routing\RouteCollectionBuilder;

class Kernel extends BaseKernel implements ExtensionInterface, ConfigurationExtensionInterface
{
    use MicroKernelTrait;

    private const CONFIG_EXTS = '.{php,xml,yaml,yml}';

    public function getCacheDir(): string
    {
        return dirname(__DIR__).'/var/cache/'.$this->environment;
    }

    public function getLogDir(): string
    {
        return dirname(__DIR__).'/var/log';
    }

    public function registerBundles(): iterable
    {
        $contents = require dirname(__DIR__).'/config/bundles.php';
        foreach ($contents as $class => $envs) {
            if (isset($envs['all']) || isset($envs[$this->environment])) {
                yield new $class();
            }
        }
    }

    protected function configureContainer(ContainerBuilder $container, LoaderInterface $loader): void
    {
        $confDir = dirname(__DIR__).'/config';
        $loader->load($confDir.'/packages/*'.self::CONFIG_EXTS, 'glob');
        if (is_dir($confDir.'/packages/'.$this->environment)) {
            $loader->load($confDir.'/packages/'.$this->environment.'/**/*'.self::CONFIG_EXTS, 'glob');
        }
        $loader->load($confDir.'/services'.self::CONFIG_EXTS, 'glob');
        $loader->load($confDir.'/services_'.$this->environment.self::CONFIG_EXTS, 'glob');

        $container->setParameter('foobar', 123);
    }

    protected function configureRoutes(RouteCollectionBuilder $routes): void
    {
        $confDir = dirname(__DIR__).'/config';
        if (is_dir($confDir.'/routes/')) {
            $routes->import($confDir.'/routes/*'.self::CONFIG_EXTS, '/', 'glob');
        }
        if (is_dir($confDir.'/routes/'.$this->environment)) {
            $routes->import($confDir.'/routes/'.$this->environment.'/**/*'.self::CONFIG_EXTS, '/', 'glob');
        }
        $routes->import($confDir.'/routes'.self::CONFIG_EXTS, '/', 'glob');
    }

    protected function build(ContainerBuilder $container)
    {
        $container->registerExtension($this);
    }

    /**
     * {@inheritdoc}
     */
    public function getConfiguration(array $config, ContainerBuilder $container)
    {
        return new class implements ConfigurationInterface
        {
            /**
             * {@inheritdoc}
             */
            public function getConfigTreeBuilder()
            {
                $treeBuilder = new TreeBuilder();

                $rootNode = $treeBuilder->root('app');
                $rootNode
                    ->children()
                    ->scalarNode('foobar')
                    ->isRequired()
                    ->end();

                return $treeBuilder;
            }
        };
    }

    /**
     * Loads a specific configuration.
     *
     * @param array            $configs   An array of configuration values
     * @param ContainerBuilder $container A ContainerBuilder instance
     *
     * @throws \InvalidArgumentException When provided tag is not defined in this extension
     */
    public function load(array $configs, ContainerBuilder $container)
    {
        var_dump('dsf');
    }

    /**
     * Returns the namespace to be used for this extension (XML namespace).
     *
     * @return string The XML namespace
     */
    public function getNamespace()
    {
        return '';
    }

    /**
     * Returns the base path for the XSD files.
     *
     * @return string The XSD base path
     */
    public function getXsdValidationBasePath()
    {
        return '';
    }

    /**
     * Returns the recommended alias to use in XML.
     *
     * This alias is also the mandatory prefix to use when using YAML.
     *
     * @return string The alias
     */
    public function getAlias()
    {
        return 'app';
    }
}