在Symfony 4应用程序中，如何将环境变量传递给服务类？

Question

I am creating an app using Symfony 4 and Docker. In my .env file, I have the following line:

DEVICE_CREATION_SECRET=123456

... and in my services.yaml file, I have the following definition:

VMS\Application\DigitalRetail\Handler\DeviceForwardHandler:
    arguments:
        - env(DEVICE_CREATION_SECRET)

... which I expect to hand off my secret (123456) to my class, since I have this in that class:

public function __construct(string $deviceCreationSecret)
{
    $this->deviceCreationSecret = $deviceCreationSecret;
}

But when I run my app and dump out the value, I get env(DEVICE_CREATION_SECRET) rather then my secret (123456). What do I need to get access to that secret?

Answer 1

I think this way should work:

VMS\Application\DigitalRetail\Handler\DeviceForwardHandler:
    arguments:
        - '%env(DEVICE_CREATION_SECRET)%'

https://symfony.com/doc/current/configuration/external_parameters.html

Answer 2

Go to services.yml:

parameters:
    DEVICE_CREATION_SECRET: '%env(DEVICE_CREATION_SECRET)%'

After this, on the class, inject parameterBagInterface:

use Symfony\Component\DependencyInjection\ParameterBag\ParameterBagInterface;

private $deviceCreationSecret;
private $params;

public function __construct(
    string $deviceCreationSecret,
    ParameterBagInterface $params
)
{
    $this->deviceCreationSecret = $deviceCreationSecret;
    $this->params = $params;
}

And then, for get parameter:

$this->params->get('DEVICE_CREATION_SECRET');