How to Set external Parameters in the Service Container
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Read the updated version of this page for Symfony 7.1 (the current stable version).
In the article 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 do this.
Environment Variables
3.2
env()
parameters were introduced in Symfony 3.2.
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:
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# app/config/config.yml
doctrine:
dbal:
host: '%env(DATABASE_HOST)%'
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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:doctrine="http://symfony.com/schema/dic/doctrine"
xsi:schemaLocation="http://symfony.com/schema/dic/services
https://symfony.com/schema/dic/services/services-1.0.xsd
http://symfony.com/schema/dic/doctrine
https://symfony.com/schema/dic/doctrine/doctrine-1.0.xsd">
<doctrine:config>
<doctrine:dbal host="%env(DATABASE_HOST)%"/>
</doctrine:config>
</container>
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// app/config/config.php
$container->loadFromExtension('doctrine', [
'dbal' => [
'host' => '%env(DATABASE_HOST)%',
],
]);
You can also give the env()
parameters a default value: the default value
will be used whenever the corresponding environment variable is not found:
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# app/config/parameters.yml
parameters:
database_host: '%env(DATABASE_HOST)%'
env(DATABASE_HOST): localhost
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<!-- app/config/parameters.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">
<parameters>
<parameter key="database_host">%env(DATABASE_HOST)%</parameter>
<parameter key="env(DATABASE_HOST)">localhost</parameter>
</parameters>
</container>
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// app/config/parameters.php
$container->setParameter('database_host', '%env(DATABASE_HOST)%');
$container->setParameter('env(DATABASE_HOST)', 'localhost');
Setting environment variables is generally done at the web server level or in the terminal. If you're using Apache, nginx or just the console, you can use e.g. one of the following:
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<VirtualHost *:80>
# ...
SetEnv DATABASE_USER user
SetEnv DATABASE_PASSWORD secret
</VirtualHost>
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fastcgi_param DATABASE_USER user;
fastcgi_param DATABASE_PASSWORD secret;
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$ export DATABASE_USER=user
$ export DATABASE_PASSWORD=secret
Tip
3.3
The support of the special SYMFONY__
environment variables was
deprecated in Symfony 3.3 and will be removed in 4.0. Instead of
using those variables, define regular environment variables and get
their values using the %env(...)%
syntax in your config files.
You can also define the default value of any existing parameters using
special environment variables named after their corresponding parameter
prefixed with SYMFONY__
after replacing dots by double underscores
(e.g. SYMFONY__KERNEL__CHARSET
to set the default value of the
kernel.charset
parameter). These default values are resolved when
compiling the service container and won't change at runtime once dumped.
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
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:
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# app/config/config.yml
framework:
router:
http_port: '%env(int:HTTP_PORT)%'
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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">
<framework:config>
<framework:router http-port="%env(int:HTTP_PORT)%"/>
</framework:config>
</container>
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// app/config/config.php
$container->loadFromExtension('framework', [
'router' => [
'http_port' => '%env(int:HTTP_PORT)%',
],
]);
Symfony provides the following env var processors:
env(string:FOO)
-
Casts
FOO
to a string:1 2 3 4 5
# 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:1 2 3 4 5
# 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 ornull
:1 2 3 4 5
# 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:1 2 3 4 5 6 7
# 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:1 2 3 4 5 6 7 8
# 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)%'
Custom Environment Variable Processors
It's also possible to add your own processors for environment variables. First, create a class that implements EnvVarProcessorInterface and then, define a service for that class:
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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 Introduction to 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
.
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# app/config/config.yml
imports:
- { resource: parameters.php }
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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">
<imports>
<import resource="parameters.php"/>
</imports>
</container>
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// app/config/config.php
$loader->import('parameters.php');
Note
A resource file can be one of many types. PHP, XML, YAML, INI, and
closure resources are all supported by the imports
directive.
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:
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// app/config/parameters.php
include_once('/path/to/drupal/sites/default/settings.php');
$container->setParameter('drupal.database.url', $db_url);