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, when installing the doctrine recipe, database configuration is put in a DATABASE_URL environment variable:

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# .env
DATABASE_URL="mysql://db_user:db_password@127.0.0.1:3306/db_name"

This variable is referenced in the service container configuration using %env(DATABASE_URL)%:

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

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:

• YAML

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

• XML

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  <!-- config/packages/framework.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 http://symfony.com/schema/dic/services/services-1.0.xsd http://symfony.com/schema/dic/symfony http://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>

• PHP

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

env(bool:FOO)

Casts FOO to a bool:

• YAML

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

• XML

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  <!-- config/packages/framework.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 http://symfony.com/schema/dic/services/services-1.0.xsd http://symfony.com/schema/dic/symfony http://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>

• PHP

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  // config/packages/framework.php $container->setParameter('env(HTTP_METHOD_OVERRIDE)', 'true'); $container->loadFromExtension('framework', array( '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 const value named in FOO:

• YAML

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

• XML

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  <!-- config/packages/security.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 http://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>

• PHP

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  // config/packages/security.php $container->setParameter('env(HEALTH_CHECK_METHOD)', 'Symfony\Component\HttpFoundation\Request::METHOD_HEAD'); $container->loadFromExtension('security', array( 'access_control' => array( array( 'path' => '^/health-check$', '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:

• YAML

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

• XML

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  <!-- config/packages/framework.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 http://symfony.com/schema/dic/services/services-1.0.xsd http://symfony.com/schema/dic/symfony http://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>

• PHP

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

env(resolve:FOO)

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

• YAML

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  # config/packages/sentry.yaml parameters: env(HOST): '10.0.0.1' env(SENTRY_DSN): 'http://%env(HOST)%/project' sentry: dsn: '%env(resolve:SENTRY_DSN)%'

• XML

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  <!-- config/packages/sentry.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 http://symfony.com/schema/dic/services/services-1.0.xsd"> <parameters> <parameter key="env(HOST)">10.0.0.1</parameter> <parameter key="env(SENTRY_DSN)">http://%env(HOST)%/project</parameter> </parameters> <sentry:config dsn="%env(resolve:SENTRY_DSN)%" /> </container>

• PHP

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  // config/packages/sentry.php $container->setParameter('env(HOST)', '10.0.0.1'); $container->setParameter('env(SENTRY_DSN)', 'http://%env(HOST)%/project'); $container->loadFromExtension('sentry', array( 'dsn' => '%env(resolve:SENTRY_DSN)%', ));

env(file:FOO)

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

• YAML

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  # config/packages/framework.yaml parameters: env(AUTH_FILE): '../config/auth.json' google: auth: '%env(file:AUTH_FILE)%'

• XML

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  <!-- config/packages/framework.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 http://symfony.com/schema/dic/services/services-1.0.xsd http://symfony.com/schema/dic/symfony http://symfony.com/schema/dic/symfony/symfony-1.0.xsd"> <parameters> <parameter key="env(AUTH_FILE)">../config/auth.json</parameter> </parameters> <google auth="%env(file:AUTH_FILE)%" /> </container>

• PHP

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  // config/packages/framework.php $container->setParameter('env(AUTH_FILE)', '../config/auth.json'); $container->loadFromExtension('google', array( '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"
google:
    # 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)%'

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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¶

You can mix whatever configuration format you like (YAML, XML and PHP) in config/packages/. Importing a PHP file gives you the flexibility to add whatever is needed in the container. For instance, you can create a drupal.php file in which you set a database URL based on Drupal's database configuration:

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// config/packages/drupal.php

// import Drupal's configuration
include_once('/path/to/drupal/sites/default/settings.php');

// set a app.database_url parameter
$container->setParameter('app.database_url', $db_url);