How to access dynamic references from other container items? - php

Question

How can I pass a dynamic dependency from one registered container definition to another? In this case, a generic Database object wants to inherit from a generic Config object. The twist is config is not static, but loaded depending on a given environment variable.
Config pertinent methods
public function __construct()
{
$configFile = 'example.config.yml';
$yamlParser = new Parser();
$reader = new Config\Reader($yamlParser);
$configYaml = $reader->parse(file_get_contents($configFile));
$config = new Config\Environment(getenv('SITE'), $configYaml);
$this->config = $config;
}
public function getEnvironmentConfig()
{
return $this->config;
}
Registering config is as simple as
$container->register('config', 'Config');
Database is currently added to the container as follows:
$container
->register('database', 'Database')
->addArgument($config->getEnvironmentConfig('Database', 'db.username'))
->addArgument($config->getEnvironmentConfig('Database', 'db.password'))
;
But I want to do something like
$container
->register('database', 'Database')
->addArgument(new Reference('config')->getEnvironmentConfig('Database', 'db.username'))
->addArgument(new Reference('config')->getEnvironmentConfig('Database', 'db.password'))
;
The $config in-PHP variable makes migrating from a PHP-built config impossible. I want to define the services in yaml force the container to:
Instantiate Config
Parse the config yaml file and create an environment-specific version
Return this on a call to getEnvironmentConfig
Is this possible?

Answer 1

This was solved by using the Expression Language Component
So you can easily chain method calls, for example:
use Symfony\Component\ExpressionLanguage\Expression;
$container->register('database', 'Database')
->addArgument(new Expression('service("config").getEnvironmentConfig("Database", "db.username")'));