A reference Symfony services.yaml file that has many different examples

services.yaml

# config/services.yaml

services:
  # default configuration for services in *this* file
  _defaults:
    autowire: true      # Automatically injects dependencies in your services.
    autoconfigure: true # Automatically registers your services as commands, event subscribers, etc.
  bind:
    # pass this value to any $adminEmail argument
    $adminEmail: 'manager@example.com'

    # pass this service to any $requestLogger argument
    $requestLogger: '@monolog.logger.request'

    # pass this service for any LoggerInterface type-hint argument
    Psr\Log\LoggerInterface: '@monolog.logger.request'

    # optionally you can define both the name and type of the argument to match
    string $adminEmail: 'manager@example.com'
    Psr\Log\LoggerInterface $requestLogger: '@monolog.logger.request'
    iterable $rules: !tagged_iterator app.foo.rule

  # makes classes in src/ available to be used as services
  # this creates a service per class whose id is the fully-qualified class name
  App\:
    resource: '../src/*'
    exclude: '../src/{DependencyInjection,Entity,Migrations,Tests,Kernel.php}'

  # explicitly configure the service by name
  App\Updates\SiteUpdateManager:	# use the FQCN as the service id (recommended)
    arguments:
      $adminEmail: 'manager@example.com'

  App\Service\MessageGenerator:
    arguments: ['@logger']  # Reference to a service called 'logger'
    mailer_password: '@@securepassword'	# Use @@ to escape literal @

  Acme\PublicService:
    public: true  # allow the service to be obtained via Container::get()

  # Multiple services in the same namespace requires custom service ids
  command_handlers:
    namespace: App\Domain\
    resource: '../src/Domain/*/CommandHandler'
    tags: [command_handler]	# Add tags

  event_subscribers:
    namespace: App\Domain\
    resource: '../src/Domain/*/EventSubscriber'
    tags: [event_subscriber]


  # Alias
  App\Updates\SiteUpdateManager: '@site_update_manager.superadmin'

  # Specify a single FQCN as a service.  Use all defaults
  App\Service\MarkdownTransformer: ~

  # Single service, with custom service id.  Using all defaults.
  app.github_notifier:
    class: App\Service\GitHubNotifier

  # Import service definitions from another file
  imports:
    - { resource: legacy_aliases.yaml }


  # Factory Service

  App\Email\NewsletterManager:
    # the first argument is the class and the second argument is the static method
    factory: ['App\Email\NewsletterManagerStaticFactory', 'createNewsletterManager']

  App\Email\NewsletterManager:
    # first argument: factory service id, second argument: method
    factory: ['@App\Email\NewsletterManagerFactory', 'createNewsletterManager']

  App\Email\NewsletterManager:
    class:   App\Email\NewsletterManager
    factory: '@App\Email\NewsletterManagerFactory'

  App\Email\NewsletterManager:
    factory:   ['@App\Email\NewsletterManagerFactory', createNewsletterManager]
    arguments: ['@templating']

  App\Twig\AppExtension:
    lazy: true	# Creates a proxy service that will instantiate real service upon first member function call

  # Legacy
  site_update_manager.superadmin:
    class: App\Updates\SiteUpdateManager
    autowire: false
    arguments:
      - '@App\Service\MessageGenerator'
      - '@mailer'
      - 'superadmin@example.com'