Symfony configuration

Configuration files

Symfony applications are configured using the files stored in the config/ directory which has the following default structure:

your-project/
├─ config/
│  ├─ packages/
│  ├─ bundles.php
│  ├─ routes.yaml
│  └─ services.yaml

• The config/packages directory stores the configuration of every package installed in your application;
• The bundles.php file enables/disables packages in your application;
• The routes.yaml file defines the routing configuration;
• The services.yaml file configures the services of the service container.

When using Symfony Flex (enabled by default in Symfony applications), Symfony packages will automatically update the config/bundles.php file and create a new file in config/packages/ to contains its configuration.

For example, the API Platform package creates this file:

# config/packages/api_platform.yaml
api_platform:
    mapping:
        paths: ['%kernel.project_dir%/src/Entity']

Configuration parameters

If you have configuration values that need to be reused in several configuration files, you can define it as a “parameter”. You can think of a configuration parameter as a reusable configuration value.

Define a parameter

By convention, parameters are defined under the parameters key in the config/services.yaml file. For example:

# config/services.yaml
parameters:
    # the parameter name is an arbitrary string (the 'app.' prefix is recommended
    # to better differentiate your parameters from Symfony parameters).
    app.admin_email: 'something@example.com'

    # boolean parameters
    app.enable_v2_protocol: true

    # array/collection parameters
    app.supported_locales: ['en', 'es', 'fr']

    # binary content parameters (encode the contents with base64_encode())
    app.some_parameter: !!binary VGhpcyBpcyBhIEJlbGwgY2hhciAH

    # PHP constants as parameter values
    app.some_constant: !php/const GLOBAL_CONSTANT
    app.another_constant: !php/const App\Entity\BlogPost::MAX_ITEMS

    # Enum case as parameter values
    app.some_enum: !php/enum App\Enum\PostState::Published

# ...

Use a parameter in another configuration file

You can wrap the parameter name in two % symbols to reference it from other configuration files:

# config/packages/some_package.yaml
some_package:
    # any string surrounded by two % is replaced by that parameter value
    email_address: '%app.admin_email%'

Note that due to the way parameters are resolved, you cannot concatenate parameters in the following way:

# config/services.yaml
imports:
    - { resource: '%kernel.project_dir%/somefile.yaml' }

List all config parameters

bin/console debug:container --parameters

Use a parameter in a service or controller

See here.