Injecting Services into a Service - php

Question

I am trying to inject public services like entityManager in the constructor of a service I created but I keep having this error :
Too few arguments to function App\Services\BillingInterface::__construct(), 0 passed in /var/www/.../src/Controller/TestController.php on line 144 and exactly 1 expected.
In my controllers, services are correctly injected in different methods but in the service I created it's not injected in the constructor.
I didn't change anything in the services.yaml as the documentation says autowire is automatic in Symfony 4.2
PS : I recently updated from Symfony 4.1 to 4.2 and I'm not sure but I think it worked before.
Maybe a library didn't updated correctly but I don't find any errors.
Here are the informations for the service
Service code :
#/src/Services/BillingInterface
namespace App\Services;
use Doctrine\ORM\EntityManagerInterface;
class BillingInterface {
private $em;
public function __construct(EntityManagerInterface $entityManager)
{
$this->em = $entityManager;
}
}
Controller code :
namespace App\Controller;
use App\Services\BillingInterface;
use Doctrine\ORM\EntityManagerInterface;
use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
class TestController extends AbstractController {
public function teest(EntityManagerInterface $entityManager)
{
$billing = new BillingInterface();
}
}
And If I instantiate BillingInterface with $entityManager parameter of Controller, it works but I would like it injected directly in the BillingInterface class constructor.
And finally, here is what is written in Symfony's documentation :
// src/Service/MessageGenerator.php
// ...
use Psr\Log\LoggerInterface;
class MessageGenerator
{
private $logger;
public function __construct(LoggerInterface $logger)
{
$this->logger = $logger;
}
public function getHappyMessage()
{
$this->logger->info('About to find a happy message!');
// ...
}
}
Link : https://symfony.com/doc/current/service_container.html
Chapter : Injecting Services/Config into a Service
So, I don't know what's wrong with my Service.
Thank you for your answers.

Answer 1

Since your BillingInterface is a service - you need to use its instance that is provided by Symfony container instead of attempting to instantiate it by yourself. Your controller needs to inject this service in order to be able to use it:
namespace App\Controller;
use App\Services\BillingInterface;
use Doctrine\ORM\EntityManagerInterface;
use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
class TestController extends AbstractController
{
/**
* #var BillingInterface
*/
private $billing;
/**
* #param BillingInterface $billing
*/
public function __construct(BillingInterface $billing)
{
$this->billing = $billing;
}
public function teest(EntityManagerInterface $entityManager)
{
// Use $this->billing ...
}
}