register custom config namespace for Symfony MicroKernel

Question

I have an app with a MicroKernel and would like to use Symfony's TreeBuilder with a custom config because the app will be quite generic and I would like to have as much as possible configured externally. My problem is, I can't get my custom namespace registered for symfony:

There is no extension able to load the configuration for "research" 
(in /var/www/html/src/app/config/config.yml). Looked for 
namespace "research", found "framework", "twig", 
"sensio_framework_extra", "web_profiler"

I have this Configuration class:

<?php
namespace App\DependencyInjection;

use Symfony\Component\Config\Definition\Builder\TreeBuilder;
use Symfony\Component\Config\Definition\ConfigurationInterface;

class Configuration implements ConfigurationInterface
{
    public function getConfigTreeBuilder()
    {
        $treeBuilder = new TreeBuilder();
        $rootNode    = $treeBuilder->root('research');

        // @formatter:off
        $rootNode
            ->children()
                ->arrayNode('questions')
                    ->children()
                        ->integerNode('client_id')->end()
                        ->scalarNode('client_secret')->end()
                    ->end()
                ->end()// twitter
            ->end();
        // @formatter:on

        return $treeBuilder;
    }
}

and my AppExtension:

<?php
namespace App\DependencyInjection;

use Symfony\Component\DependencyInjection\ContainerBuilder;
use Symfony\Component\HttpKernel\DependencyInjection\ConfigurableExtension;

class AppExtension extends ConfigurableExtension
{
    // note that this method is called loadInternal and not load
    protected function loadInternal(array $mergedConfig, ContainerBuilder $container)
    {
        dump($mergedConfig);
    }

    public function getAlias()
    {
        return 'research';
    }
}

In my AppKernel class, I'm initializing the extension like this and as a result I also get an output from the dump($mergedConfig) call in my AppExtension from my original research.yml

<?php
namespace App;

use App\DependencyInjection\AppExtension;
use Doctrine\Common\Annotations\AnnotationRegistry;
use Symfony\Bundle\FrameworkBundle\Kernel\MicroKernelTrait;
use Symfony\Component\Config\Loader\LoaderInterface;
use Symfony\Component\DependencyInjection\ContainerBuilder;
use Symfony\Component\HttpKernel\Kernel;
use Symfony\Component\Routing\RouteCollectionBuilder;
use Symfony\Component\Yaml\Exception\ParseException;
use Symfony\Component\Yaml\Yaml;

$loader = require __DIR__ . '/../vendor/autoload.php';

// auto-load annotations
AnnotationRegistry::registerLoader(array($loader, 'loadClass'));

/**
 * Class AppKernel
 */
class AppKernel extends Kernel
{
    use MicroKernelTrait;

    ...

    protected function configureContainer(ContainerBuilder $c, LoaderInterface $loader)
    {
        $researchConfig = Yaml::parse(file_get_contents(__DIR__ . '/config/research.yml'));
        $appExtension = new AppExtension();
        $appExtension->load(researchConfig, $c);

        $loader->load(__DIR__ . '/config/config.yml');
    }

    ...
}

nevertheless, when my config.yml looks like this, I get the error mentioned above:

framework:
    secret: S0ME_SUPER_SECRET
    profiler: { only_exceptions: false }


research:
    questions:
       client_id: 2342323423
       clent_secret: mysecret

so what do I need to do, to actually register my namespace research so I can properly overwrite it? Or does it have to an external vendor bundle?

Answer 1

You get the error because you dont register a bundle and so symfony doesnt know the bundle config namespace.

I cant say how you could fix this with your approach but i would suggest to make a AppBundle instead of the App and register AppBundle in public function registerBundles().

See f.E. in some boilerplates like https://github.com/ikoene/symfony-micro.

Alternativly you could try to set up your project with the new symfony Flex.
This already uses MicroKernel, is bundleless and also supports latest stable symfony version (sf3.3).
https://symfony.com/doc/current/setup/flex.html#using-symfony-flex-in-new-applications

So no need to build something off the track yourself.

Answer 2

Since Symfony does not recommend the usage of Bundles anymore (), to create a Bundle is NOT the way to solve this.

@see [https://symfony.com/doc/current/bundles.html][1]

In Symfony versions prior to 4.0, it was recommended to organize your own application code using bundles. This is no longer recommended and bundles should only be used to share code and features between multiple applications.

[1]: Symfony Bundle Documentation