How to Set external Parameters in the Service Container
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How to Set external Parameters in the Service Container
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 easily 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
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
host="%env(DATABASE_HOST)%"
/>
</doctrine:config>
</container>
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// app/config/config.php
$container->loadFromExtension('doctrine', array(
'dbal' => array(
'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 http://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
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.
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
http://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);