Environment Variables¶

You can reference environment variables by using special parameters named after the variables you want to use enclosed between env(). Their actual values will be resolved at runtime (once per request), so that dumped containers can be reconfigured dynamically even after being compiled.

For example, if you want to use the value of the DATABASE_HOST environment variable in your service container configuration, you can reference it using %env(DATABASE_HOST)% in your configuration files:

You can also give the env() parameters a default value: the default value will be used whenever the corresponding environment variable is not found:

Setting environment variables is generally done at the web server level or in the terminal. If you’re using Apache, nginx or just the console, you can use e.g. one of the following:

Environment Variable Processors¶

The values of environment variables are considered strings by default. However, your code may expect other data types, like integers or booleans. Symfony solves this problem with processors, which modify the contents of the given environment variables. The following example uses the integer processor to turn the value of the HTTP_PORT env var into an integer:

Symfony provides the following env var processors:

env(string:FOO)

Casts FOO to a string:

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  # app/config/config.yml parameters: env(SECRET): 'some_secret' framework: secret: '%env(string:SECRET)%'

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  <!-- app/config/config.xml --> <?xml version="1.0" encoding="UTF-8" ?> <container xmlns="http://symfony.com/schema/dic/services" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:framework="http://symfony.com/schema/dic/symfony" xsi:schemaLocation="http://symfony.com/schema/dic/services https://symfony.com/schema/dic/services/services-1.0.xsd http://symfony.com/schema/dic/symfony https://symfony.com/schema/dic/symfony/symfony-1.0.xsd"> <parameters> <parameter key="env(SECRET)">some_secret</parameter> </parameters> <framework:config secret="%env(string:SECRET)%"/> </container>

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  // app/config/config.php $container->setParameter('env(SECRET)', 'some_secret'); $container->loadFromExtension('framework', [ 'secret' => '%env(string:SECRET)%', ]);

env(bool:FOO)

Casts FOO to a bool:

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  # app/config/config.yml parameters: env(HTTP_METHOD_OVERRIDE): 'true' framework: http_method_override: '%env(bool:HTTP_METHOD_OVERRIDE)%'

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  <!-- app/config/config.xml --> <?xml version="1.0" encoding="UTF-8" ?> <container xmlns="http://symfony.com/schema/dic/services" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:framework="http://symfony.com/schema/dic/symfony" xsi:schemaLocation="http://symfony.com/schema/dic/services https://symfony.com/schema/dic/services/services-1.0.xsd http://symfony.com/schema/dic/symfony https://symfony.com/schema/dic/symfony/symfony-1.0.xsd"> <parameters> <parameter key="env(HTTP_METHOD_OVERRIDE)">true</parameter> </parameters> <framework:config http-methode-override="%env(bool:HTTP_METHOD_OVERRIDE)%"/> </container>

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  // app/config/config.php $container->setParameter('env(HTTP_METHOD_OVERRIDE)', 'true'); $container->loadFromExtension('framework', [ 'http_method_override' => '%env(bool:HTTP_METHOD_OVERRIDE)%', ]);

env(int:FOO)

Casts FOO to an int.

env(float:FOO)

Casts FOO to a float.

env(const:FOO)

Finds the constant value named in FOO:

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  # app/config/config.yml parameters: env(HEALTH_CHECK_METHOD): 'Symfony\Component\HttpFoundation\Request::METHOD_HEAD' security: access_control: - { path: '^/health-check$', methods: '%env(const:HEALTH_CHECK_METHOD)%' }

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  <!-- app/config/config.xml --> <?xml version="1.0" encoding="UTF-8" ?> <container xmlns="http://symfony.com/schema/dic/services" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:security="http://symfony.com/schema/dic/security" xsi:schemaLocation="http://symfony.com/schema/dic/services https://symfony.com/schema/dic/services/services-1.0.xsd"> <parameters> <parameter key="env(HEALTH_CHECK_METHOD)">Symfony\Component\HttpFoundation\Request::METHOD_HEAD</parameter> </parameters> <security:config> <rule path="^/health-check$" methods="%env(const:HEALTH_CHECK_METHOD)%"/> </security:config> </container>

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  // app/config/config.php $container->setParameter('env(HEALTH_CHECK_METHOD)', 'Symfony\Component\HttpFoundation\Request::METHOD_HEAD'); $container->loadFromExtension('security', [ 'access_control' => [ [ 'path' => '^/health-check$', 'methods' => '%env(const:HEALTH_CHECK_METHOD)%', ], ], ]);

env(base64:FOO)

Decodes the content of FOO, which is a base64 encoded string.

env(json:FOO)

Decodes the content of FOO, which is a JSON encoded string. It returns either an array or null:

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  # app/config/config.yml parameters: env(TRUSTED_HOSTS): '["10.0.0.1", "10.0.0.2"]' framework: trusted_hosts: '%env(json:TRUSTED_HOSTS)%'

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  <!-- app/config/config.xml --> <?xml version="1.0" encoding="UTF-8" ?> <container xmlns="http://symfony.com/schema/dic/services" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:framework="http://symfony.com/schema/dic/symfony" xsi:schemaLocation="http://symfony.com/schema/dic/services https://symfony.com/schema/dic/services/services-1.0.xsd http://symfony.com/schema/dic/symfony https://symfony.com/schema/dic/symfony/symfony-1.0.xsd"> <parameters> <parameter key="env(TRUSTED_HOSTS)">["10.0.0.1", "10.0.0.2"]</parameter> </parameters> <framework:config trusted-hosts="%env(json:TRUSTED_HOSTS)%"/> </container>

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  // app/config/config.php $container->setParameter('env(TRUSTED_HOSTS)', '["10.0.0.1", "10.0.0.2"]'); $container->loadFromExtension('framework', [ 'trusted_hosts' => '%env(json:TRUSTED_HOSTS)%', ]);

env(resolve:FOO)

Replaces the string FOO by the value of a config parameter with the same name:

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  # app/config/config.yml parameters: env(HOST): '10.0.0.1' sentry_host: '%env(HOST)%' env(SENTRY_DSN): 'https://%sentry_host%/project' sentry: dsn: '%env(resolve:SENTRY_DSN)%'

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  <!-- app/config/config.xml --> <?xml version="1.0" encoding="UTF-8" ?> <container xmlns="http://symfony.com/schema/dic/services" xmlns:sentry="http://symfony.com/schema/dic/sentry" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://symfony.com/schema/dic/services https://symfony.com/schema/dic/services/services-1.0.xsd"> <parameters> <parameter key="env(HOST)">10.0.0.1</parameter> <parameter key="sentry_host">%env(HOST)%</parameter> <parameter key="env(SENTRY_DSN)">https://%sentry_host%/project</parameter> </parameters> <sentry:config dsn="%env(resolve:SENTRY_DSN)%"/> </container>

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  // app/config/config.php $container->setParameter('env(HOST)', '10.0.0.1'); $container->setParameter('sentry_host', '%env(HOST)%'); $container->setParameter('env(SENTRY_DSN)', 'https://%sentry_host%/project'); $container->loadFromExtension('sentry', [ 'dsn' => '%env(resolve:SENTRY_DSN)%', ]);

env(file:FOO)

Returns the contents of a file whose path is the value of the FOO env var:

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  # app/config/config.yml parameters: env(AUTH_FILE): '../auth.json' services: some_authenticator: arguments: $auth: '%env(file:AUTH_FILE)%'

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  <!-- app/config/config.xml --> <?xml version="1.0" encoding="UTF-8" ?> <container xmlns="http://symfony.com/schema/dic/services" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://symfony.com/schema/dic/services https://symfony.com/schema/dic/services/services-1.0.xsd http://symfony.com/schema/dic/symfony https://symfony.com/schema/dic/symfony/symfony-1.0.xsd"> <parameters> <parameter key="env(AUTH_FILE)">../auth.json</parameter> </parameters> <services> <service id="some_authenticator"> <argument key="$auth">"%env(file:AUTH_FILE)%"<argument/> <service> </services> </container>

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  // app/config/config.php $container->setParameter('env(AUTH_FILE)', __DIR__.'/../auth.json'); $container->register('some_authenticator') ->setArgument('$auth', '%env(file:AUTH_FILE)%') ;

It is also possible to combine any number of processors:

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parameters:
    env(AUTH_FILE): "%kernel.project_dir%/config/auth.json"

services:
    some_authenticator:
        arguments:
            # 1. gets the value of the AUTH_FILE env var
            # 2. replaces the values of any config param to get the config path
            # 3. gets the content of the file stored in that path
            # 4. JSON-decodes the content of the file and returns it
            $auth: '%env(json:file:resolve:AUTH_FILE)%'

class LowercasingEnvVarProcessor implements EnvVarProcessorInterface
{
    private $container;

    public function __construct(ContainerInterface $container)
    {
        $this->container = $container;
    }

    public function getEnv($prefix, $name, \Closure $getEnv)
    {
        $env = $getEnv($name);

        return strtolower($env);
    }

    public static function getProvidedTypes()
    {
        return [
            'lowercase' => 'string',
        ];
    }
}

Constants¶

The container also has support for setting PHP constants as parameters. See Constants as Parameters for more details.

Miscellaneous Configuration¶

The imports directive can be used to pull in parameters stored elsewhere. Importing a PHP file gives you the flexibility to add whatever is needed in the container. The following imports a file named parameters.php.

In parameters.php, tell the service container the parameters that you wish to set. This is useful when important configuration is in a non-standard format. The example below includes a Drupal database configuration in the Symfony service container:

// app/config/parameters.php
include_once('/path/to/drupal/sites/default/settings.php');
$container->setParameter('drupal.database.url', $db_url);