Environment Variable Processors
Environment Variable Processors
Using env vars to configure Symfony applications is a common practice to make your applications truly dynamic.
The main issue of env vars is that their values can only be strings and your application may need other data types (integer, boolean, etc.). Symfony solves this problem with “env var processors”, which transform the original 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
# config/packages/framework.yaml
framework:
router:
http_port: '%env(int:HTTP_PORT)%'
XML
<!-- 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
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>
PHP
// config/packages/framework.php
$container->loadFromExtension('framework', [
'router' => [
'http_port' => '%env(int:HTTP_PORT)%',
],
]);
Built-In Environment Variable Processors
Symfony provides the following env var processors:
env(string:FOO)
Casts FOO
to a string:
YAML
# config/packages/framework.yaml
parameters:
env(SECRET): 'some_secret'
framework:
secret: '%env(string:SECRET)%'
XML
<!-- 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
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>
PHP
// config/packages/framework.php
$container->setParameter('env(SECRET)', 'some_secret');
$container->loadFromExtension('framework', [
'secret' => '%env(string:SECRET)%',
]);
env(bool:FOO)
Casts FOO
to a bool (true
values are 'true'
, 'on'
, 'yes'
and all numbers except 0
and 0.0
; everything else is false
):
YAML
# config/packages/framework.yaml
parameters:
env(HTTP_METHOD_OVERRIDE): 'true'
framework:
http_method_override: '%env(bool:HTTP_METHOD_OVERRIDE)%'
XML
<!-- 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
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-method-override="%env(bool:HTTP_METHOD_OVERRIDE)%"/>
</container>
PHP
// config/packages/framework.php
$container->setParameter('env(HTTP_METHOD_OVERRIDE)', 'true');
$container->loadFromExtension('framework', [
'http_method_override' => '%env(bool:HTTP_METHOD_OVERRIDE)%',
]);
env(int:FOO)
Casts FOO
to an int.
env(float:FOO)
Casts FOO
to a float.
env(const:FOO)
Finds the const value named in FOO
:
YAML
# config/packages/security.yaml
parameters:
env(HEALTH_CHECK_METHOD): 'Symfony\Component\HttpFoundation\Request::METHOD_HEAD'
security:
access_control:
- { path: '^/health-check$', methods: '%env(const:HEALTH_CHECK_METHOD)%' }
XML
<!-- 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
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>
PHP
// config/packages/security.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
:
YAML
# config/packages/framework.yaml
parameters:
env(TRUSTED_HOSTS): '["10.0.0.1", "10.0.0.2"]'
framework:
trusted_hosts: '%env(json:TRUSTED_HOSTS)%'
XML
<!-- 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
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>
PHP
// config/packages/framework.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)
If the content of FOO
includes container parameters (with the syntax %parameter_name%
), it replaces the parameters by their values:
YAML
# config/packages/sentry.yaml
parameters:
env(HOST): '10.0.0.1'
sentry_host: '%env(HOST)%'
env(SENTRY_DSN): 'http://%sentry_host%/project'
sentry:
dsn: '%env(resolve:SENTRY_DSN)%'
XML
<!-- 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
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)">http://%sentry_host%/project</parameter>
</parameters>
<sentry:config dsn="%env(resolve:SENTRY_DSN)%"/>
</container>
PHP
// config/packages/sentry.php
$container->setParameter('env(HOST)', '10.0.0.1');
$container->setParameter('sentry_host', '%env(HOST)%');
$container->setParameter('env(SENTRY_DSN)', 'http://%sentry_host%/project');
$container->loadFromExtension('sentry', [
'dsn' => '%env(resolve:SENTRY_DSN)%',
]);
env(csv:FOO)
Decodes the content of FOO
, which is a CSV-encoded string:
YAML
# config/packages/framework.yaml
parameters:
env(TRUSTED_HOSTS): "10.0.0.1,10.0.0.2"
framework:
trusted_hosts: '%env(csv:TRUSTED_HOSTS)%'
XML
<!-- 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
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(csv:TRUSTED_HOSTS)%"/>
</container>
PHP
// config/packages/framework.php
$container->setParameter('env(TRUSTED_HOSTS)', '10.0.0.1,10.0.0.2');
$container->loadFromExtension('framework', [
'trusted_hosts' => '%env(csv:TRUSTED_HOSTS)%',
]);
env(file:FOO)
Returns the contents of a file whose path is the value of the FOO
env var:
YAML
# config/packages/framework.yaml
parameters:
env(AUTH_FILE): '../config/auth.json'
google:
auth: '%env(file:AUTH_FILE)%'
XML
<!-- 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
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)">../config/auth.json</parameter>
</parameters>
<google auth="%env(file:AUTH_FILE)%"/>
</container>
PHP
// config/packages/framework.php
$container->setParameter('env(AUTH_FILE)', '../config/auth.json');
$container->loadFromExtension('google', [
'auth' => '%env(file:AUTH_FILE)%',
]);
env(require:FOO)
require()
the PHP file whose path is the value of the FOO
env var and return the value returned from it.
YAML
# config/packages/framework.yaml
parameters:
env(PHP_FILE): '../config/.runtime-evaluated.php'
app:
auth: '%env(require:PHP_FILE)%'
XML
<!-- 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
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(PHP_FILE)">../config/.runtime-evaluated.php</parameter>
</parameters>
<app auth="%env(require:PHP_FILE)%"/>
</container>
PHP
// config/packages/framework.php
$container->setParameter('env(PHP_FILE)', '../config/.runtime-evaluated.php');
$container->loadFromExtension('app', [
'auth' => '%env(require:PHP_FILE)%',
]);
New in version 4.3: The require
processor was introduced in Symfony 4.3.
env(trim:FOO)
Trims the content of FOO
env var, removing whitespaces from the beginning and end of the string. This is especially useful in combination with the file
processor, as it’ll remove newlines at the end of a file.
YAML
# config/packages/framework.yaml
parameters:
env(AUTH_FILE): '../config/auth.json'
google:
auth: '%env(trim:file:AUTH_FILE)%'
XML
<!-- 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
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)">../config/auth.json</parameter>
</parameters>
<google auth="%env(trim:file:AUTH_FILE)%"/>
</container>
PHP
// config/packages/framework.php
$container->setParameter('env(AUTH_FILE)', '../config/auth.json');
$container->loadFromExtension('google', [
'auth' => '%env(trim:file:AUTH_FILE)%',
]);
New in version 4.3: The trim
processor was introduced in Symfony 4.3.
env(key:FOO:BAR)
Retrieves the value associated with the key FOO
from the array whose contents are stored in the BAR
env var:
YAML
# config/services.yaml
parameters:
env(SECRETS_FILE): '/opt/application/.secrets.json'
database_password: '%env(key:database_password:json:file:SECRETS_FILE)%'
# if SECRETS_FILE contents are: {"database_password": "secret"} it returns "secret"
XML
<!-- 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"
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(SECRETS_FILE)">/opt/application/.secrets.json</parameter>
<parameter key="database_password">%env(key:database_password:json:file:SECRETS_FILE)%</parameter>
</parameters>
</container>
PHP
// config/services.php
$container->setParameter('env(SECRETS_FILE)', '/opt/application/.secrets.json');
$container->setParameter('database_password', '%env(key:database_password:json:file:SECRETS_FILE)%');
env(default:fallback_param:BAR)
Retrieves the value of the parameter fallback_param
when the BAR
env var is not available:
YAML
# config/services.yaml
parameters:
# if PRIVATE_KEY is not a valid file path, the content of raw_key is returned
private_key: '%env(default:raw_key:file:PRIVATE_KEY)%'
raw_key: '%env(PRIVATE_KEY)%'
XML
<!-- 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"
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>
<!-- if PRIVATE_KEY is not a valid file path, the content of raw_key is returned -->
<parameter key="private_key">%env(default:raw_key:file:PRIVATE_KEY)%</parameter>
<parameter key="raw_key">%env(PRIVATE_KEY)%</parameter>
</parameters>
</container>
PHP
// config/services.php
// if PRIVATE_KEY is not a valid file path, the content of raw_key is returned
$container->setParameter('private_key', '%env(default:raw_key:file:PRIVATE_KEY)%');
$container->setParameter('raw_key', '%env(PRIVATE_KEY)%');
When the fallback parameter is omitted (e.g. env(default::API_KEY)
), the value returned is null
.
New in version 4.3: The default
processor was introduced in Symfony 4.3.
env(url:FOO)
Parses an absolute URL and returns its components as an associative array.
# .env
MONGODB_URL="mongodb://db_user:[email protected]:27017/db_name"
YAML
# config/packages/mongodb.yaml
mongo_db_bundle:
clients:
default:
hosts:
- { host: '%env(key:host:url:MONGODB_URL)%', port: '%env(key:port:url:MONGODB_URL)%' }
username: '%env(key:user:url:MONGODB_URL)%'
password: '%env(key:pass:url:MONGODB_URL)%'
connections:
default:
database_name: '%env(key:path:url:MONGODB_URL)%'
XML
<!-- config/packages/mongodb.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">
<mongodb:config>
<mongodb:client name="default" username="%env(key:user:url:MONGODB_URL)%" password="%env(key:pass:url:MONGODB_URL)%">
<mongodb:host host="%env(key:host:url:MONGODB_URL)%" port="%env(key:port:url:MONGODB_URL)%"/>
</mongodb:client>
<mongodb:connections name="default" database_name="%env(key:path:url:MONGODB_URL)%"/>
</mongodb:config>
</container>
PHP
// config/packages/mongodb.php
$container->loadFromExtension('mongodb', [
'clients' => [
'default' => [
'hosts' => [
[
'host' => '%env(key:host:url:MONGODB_URL)%',
'port' => '%env(key:port:url:MONGODB_URL)%',
],
],
'username' => '%env(key:user:url:MONGODB_URL)%',
'password' => '%env(key:pass:url:MONGODB_URL)%',
],
],
'connections' => [
'default' => [
'database_name' => '%env(key:path:url:MONGODB_URL)%',
],
],
]);
Caution
In order to ease extraction of the resource from the URL, the leading /
is trimmed from the path
component.
New in version 4.3: The url
processor was introduced in Symfony 4.3.
env(query_string:FOO)
Parses the query string part of the given URL and returns its components as an associative array.
# .env
MONGODB_URL="mongodb://db_user:[email protected]:27017/db_name?timeout=3000"
YAML
# config/packages/mongodb.yaml
mongo_db_bundle:
clients:
default:
# ...
connectTimeoutMS: '%env(int:key:timeout:query_string:MONGODB_URL)%'
XML
<!-- config/packages/mongodb.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">
<mongodb:config>
<mongodb:client name="default" connectTimeoutMS="%env(int:key:timeout:query_string:MONGODB_URL)%"/>
</mongodb:config>
</container>
PHP
// config/packages/mongodb.php
$container->loadFromExtension('mongodb', [
'clients' => [
'default' => [
// ...
'connectTimeoutMS' => '%env(int:key:timeout:query_string:MONGODB_URL)%',
],
],
]);
New in version 4.3: The query_string
processor was introduced in Symfony 4.3.
It is also possible to combine any number of processors:
YAML
# config/packages/framework.yaml
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)%'
XML
<!-- 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
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)">%kernel.project_dir%/config/auth.json</parameter>
</parameters>
<!-- 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 -->
<google auth="%env(json:file:resolve:AUTH_FILE)%"/>
</container>
PHP
// config/packages/framework.php
$container->setParameter('env(AUTH_FILE)', '%kernel.project_dir%/config/auth.json');
// 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
$container->loadFromExtension('google', [
'auth' => '%env(json:file:resolve:AUTH_FILE)%',
]);
Custom Environment Variable Processors
It’s also possible to add your own processors for environment variables. First, create a class that implements Symfony\Component\DependencyInjection\EnvVarProcessorInterface
:
use Symfony\Component\DependencyInjection\EnvVarProcessorInterface;
class LowercasingEnvVarProcessor implements EnvVarProcessorInterface
{
public function getEnv($prefix, $name, \Closure $getEnv)
{
$env = $getEnv($name);
return strtolower($env);
}
public static function getProvidedTypes()
{
return [
'lowercase' => 'string',
];
}
}
To enable the new processor in the app, register it as a service and tag it with the container.env_var_processor
tag. If you’re using the default services.yaml configuration, this is already done for you, thanks to autoconfiguration.
This work, including the code samples, is licensed under a Creative Commons BY-SA 3.0 license.