Inject configuration in Symfony - php

Question

I'm using Symfony 4 and there is a configuration file which needs to be injected into the command App\Command\FooCommand in the form of an array. I have a custom DI extension registered at App\Kernel::configureContainer(), which's used to validate the custom configuration file (for the convenience of the development, the config is big and going to be changed frequently during the dev). The constructor of the command is public function __construct(Foo $foo, array $config), I'm expecting the config as the second argument.
Now how do I put this config there? The documentation says about parameters, but it's not a parameter. I was thinking of changing the definition of the command and adding this argument in the Extension::load method like this:
class FooExtension extends Extension
{
public function load(array $configs, ContainerBuilder $container)
{
$configuration = $this->getConfiguration($configs, $container);
$config = $this->processConfiguration($configuration, $configs);
//inject the configuration into the command
$fooCmdDef = $container->getDefinition(FooCommand::class);
$fooCmdDef->addArgument($config);
}
}
but it ends up with the error
You have requested a non-existent service "App\Command\FooCommand".
However the command must have been registered as a service automatically.
What am I doing wrong and how to inject this config?

Answer 1

You cannot access any service in a DI extension Class because the container was not yet compiled. For your case is common to create a Compiler Pass where you will be able to retrieve the needed service and apply any modification to it.
For example you can create a parameter in the container extension on where store the configuration:
class FooExtension extends Extension
{
public function load(array $configs, ContainerBuilder $container)
{
$configuration = $this->getConfiguration($configs, $container);
$config = $this->processConfiguration($configuration, $configs);
//create a container parameter
$container->setParameter('your_customized_parameter_name', $config);
}
}
Then retrieve what you need in the compiler pass and then apply some modification:
use Symfony\Component\DependencyInjection\Compiler\CompilerPassInterface;
use Symfony\Component\DependencyInjection\ContainerBuilder;
use Symfony\Component\DependencyInjection\Definition;
use Symfony\Component\DependencyInjection\Reference;
class YourCompilerPass implements CompilerPassInterface
{
/**
* {#inheritdoc}
*/
public function process(ContainerBuilder $container)
{
# retrieve the parameter
$config = $container->getParameter('your_customized_parameter_name');
# retrieve the service
$fooCmdDef = $container->getDefinition(FooCommand::class);
# inject the configuration
$fooCmdDef->addArgument($config);
# or you can also replace an argument
$fooCmdDef->replaceArgument('$argument', $config);
}
}