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How to Set external Parameters in the Service Container
How to Set external Parameters in the Service Container¶
In Configuring Symfony (and Environments), you learned how to manage your application configuration. At times, it may benefit your application to store certain credentials outside of your project code. Database configuration is one such example. The flexibility of the Symfony service container allows you to easily do this.
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:
1 2 | # .env
DATABASE_URL="mysql://db_user:[email protected]:3306/db_name"
|
This variable is referenced in the service container configuration using
%env(DATABASE_URL)%
:
- YAML
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# config/packages/doctrine.yaml doctrine: dbal: url: '%env(DATABASE_URL)%' # ...
- XML
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<!-- config/packages/doctrine.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:doctrine="http://symfony.com/schema/dic/doctrine" xsi:schemaLocation="http://symfony.com/schema/dic/services http://symfony.com/schema/dic/services/services-1.0.xsd http://symfony.com/schema/dic/doctrine http://symfony.com/schema/dic/doctrine/doctrine-1.0.xsd"> <doctrine:config> <doctrine:dbal url="%env(DATABASE_URL)%" /> </doctrine:config> </container>
- PHP
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// config/packages/doctrine.php $container->loadFromExtension('doctrine', array( 'dbal' => array( 'url' => '%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:
- YAML
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# config/services.yaml parameters: env(DATABASE_HOST): localhost
- XML
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<!-- config/services.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(DATABASE_HOST)">localhost</parameter> </parameters> </container>
- PHP
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// config/services.php $container->setParameter('env(DATABASE_HOST)', 'localhost');
Configuring Environment Variables in Production¶
During development, you’ll use the .env
file to configure your environment
variables. On your production server, it is recommended to configure these at
the web server level. If you’re using Apache or Nginx, you can use e.g. one of
the following:
- Apache
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<VirtualHost *:80> # ... SetEnv DATABASE_URL "mysql://db_user:[email protected]:3306/db_name" </VirtualHost>
- Nginx
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fastcgi_param DATABASE_URL "mysql://db_user:[email protected]:3306/db_name";
Caution
Beware that dumping the contents of the $_SERVER
and $_ENV
variables
or outputting the phpinfo()
contents will display the values of the
environment variables, exposing sensitive information such as the database
credentials.
The values of the env vars are also exposed in the web interface of the Symfony profiler. In practice this shouldn’t be a problem because the web profiler must never be enabled in production.
Environment Variable Processors¶
New in version 3.4: Environment variable processors were introduced in Symfony 3.4.
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:
- YAML
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# config/packages/framework.yaml framework: router: http_port: env(int:HTTP_PORT)
- 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"> <framework:config> <framework:router http-port="%env(int:HTTP_PORT)%" /> </framework:config> </container>
- PHP
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// config/packages/framework.php $container->loadFromExtension('framework', array( 'router' => array( 'http_port' => '%env(int:HTTP_PORT)%', ), ));
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)%', ));
- YAML
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'); $container->loadFromExtension('framework', array( 'http_method_override' => '%env(bool:HTTP_METHOD_OVERRIDE)%', ));
- YAML
env(int:FOO)
- Casts
FOO
to an int. env(float:FOO)
- Casts
FOO
to a float. env(const:FOO)
Finds the const value named in
FOO
:- YAML
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# config/packages/security.yaml parameters: env(HEALTH_CHECK_METHOD): 'Symfony\Component\HttpFoundation\Request::METHOD_HEAD' security: access_control: - { path: '^/health-check$', 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)%', ), ), ));
- YAML
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 ornull
:- 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)%', ));
- YAML
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)%', ));
- YAML
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)%', ));
- YAML
It is also possible to combine any number of processors:
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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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Custom Environment Variable Processors¶
It’s also possible to add your own processors for environment variables. First,
create a class that implements
Symfony\Component\DependencyInjection\EnvVarProcessorInterface
and
then, define a service for that class:
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:
// 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);
This work, including the code samples, is licensed under a Creative Commons BY-SA 3.0 license.