How to Import Configuration Files/Resources
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How to Import Configuration Files/Resources
Tip
In this section, service configuration files are referred to as resources. While most configuration resources are files (e.g. YAML, XML, PHP), Symfony is able to load configuration from anywhere (e.g. a database or even via an external web service).
The service container is built using a single configuration resource
(config/services.yaml by default). This gives you absolute flexibility over
the services in your application.
External service configuration can be imported in two different ways. The first
method, commonly used to import other resources, is via the imports
directive. The second method, using dependency injection extensions, is used by
third-party bundles to load the configuration. Read on to learn more about both
methods.
Importing Configuration with imports
By default, service configuration lives in config/services.yaml. But if that
file becomes large, you're free to organize into multiple files. For suppose you
decided to move some configuration to a new file:
- YAML
- XML
- PHP
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# config/services/mailer.yaml
parameters:
# ... some parameters
services:
# ... some servicesTo import this file, use the imports key from a file that is loaded:
- YAML
- XML
- PHP
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# config/services.yaml
imports:
- { resource: services/mailer.yaml }The resource location, for files, is either a relative path from the
current file or an absolute path.
Note
Due to the way in which parameters are resolved, you cannot use them to build paths in imports dynamically. This means that something like the following doesn't work:
- YAML
- XML
- PHP
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# config/services.yaml
imports:
- { resource: '%kernel.project_dir%/somefile.yaml' }Importing Configuration via Container Extensions
Third-party bundle container configuration, including Symfony core services, are usually loaded using another method: a container extension.
Internally, each bundle defines its services in files like you've seen so far.
However, these files aren't imported using the import directive. Instead, bundles
use a dependency injection extension to load the files automatically. As soon
as you enable a bundle, its extension is called, which is able to load service
configuration files.
In fact, each configuration file in config/packages/ is passed to the
extension of its related bundle - e.g. FrameworkBundle or TwigBundle -
and used to configure those services further.
