How to use EntityManager as a service? - symfony

Question

I use Doctrine and try to use [DependencyInjection Component][1] without Symfony (outside of a Symfony application).
I have [bootstrap.php for doctrine][2]:
use Doctrine\ORM\Tools\Setup;
use Doctrine\ORM\EntityManager;
require_once "vendor/autoload.php";
$isDevMode = false;
$paths = ["src/Project/Infrastructure/Persistence/Doctrine/Mapping/"];
$config = Setup::createXMLMetadataConfiguration($paths, $isDevMode);
$dbParams = array(
'driver' => 'pdo_mysql',
'user' => 'root',
'password' => 'root',
'dbname' => 'project',
);
$entityManager = EntityManager::create($dbParams, $config);
And I have a file to configure the container:
$containerBuilder = new ContainerBuilder();
$loader = new XmlFileLoader($containerBuilder, new FileLocator(__DIR__));
$loader->load(dirname(__DIR__) . '/config/services.xml');
And I want to get EntityManager from container such as:
$entityManager = $containerBuilder->get('doctrine.orm.entity_manager')->getManager();
But what should I do here I don't understand:
//config/services.xml
<services>
<defaults autowire="true" autoconfigure="true"/>
<service id="Doctrine\ORM\EntityManagerInterface" alias="doctrine.orm.entity_manager" public="false" />
</services>
How I can register EntityManager as a service? (I don't use Symfony just DI component)
[1]: https://symfony.com/doc/current/components/dependency_injection.html
[2]: https://www.doctrine-project.org/projects/doctrine-orm/en/2.8/reference/configuration.html#obtaining-an-entitymanager

Answer 1

This is basically a 'how do I use the DI component without reading the documentation' sort of question. But it is kind of interesting so here are some hints.
You need to configure a Doctrine configuration service and then inject it into the entity manager service. Both services use a static factory method so something like:
parameters:
isDevMode: true
services:
doctrine.orm.config:
public: false
class: 'Doctrine\ORM\Configuration'
factory:
- 'Doctrine\ORM\Tools\Setup'
- 'createYAMLMetadataConfiguration'
arguments:
- ['src/Entity']
- '%isDevMode%'
doctrine.orm.entity_manager:
public: true
class: 'Doctrine\ORM\EntityManager'
factory:
- 'Doctrine\ORM\EntityManager'
- 'create'
arguments:
-
driver: 'pdo_mysql'
user: db_user
password: db_password
dbname: db_name
- '#doctrine.orm.config'
I used yaml here because it's easier for me to understand. You of course can convert to xml. You never want to check in your database credentials but I'll leave that for the student to figure out. This is the sort of thing that the Doctrine bundle deals with and is why you should probably use the framework.
The test application looks like:
use Symfony\Component\Config\FileLocator;
use Symfony\Component\DependencyInjection\ContainerBuilder;
use Symfony\Component\DependencyInjection\Loader\YamlFileLoader;
require_once 'vendor/autoload.php';
$container = new ContainerBuilder();
$loader = new YamlFileLoader($container, new FileLocator(__DIR__));
$loader->load('config/services.yaml');
$container->compile();
$em = $container->get('doctrine.orm.entity_manager');
echo get_class($em) . "\n";
I tested it and it all works.
Enjoy.