The container — Tempest

In contrast to other frameworks, Tempest doesn't have a concept of service provider. Instead, the instantiation process of dependencies is specified in initializer classes, which are automatically discovered.

Additionally, the container will also autowire dependencies as much as possible, so initializer classes may only be used when there is the need for specific, manual set-up code.

The following is an example of an initializer:

LoggerInitializer.php

#[Singleton]
final readonly class LoggerInitializer implements Initializer
{
    public function initialize(Container $container): LoggerInterface|Logger
    {
        return new GenericLogger(
            $container->get(LogConfig::class),
        );
    }
}

Tempest knows that this initializer produces a Logger or LoggerInterface thanks to the return type of the initialize() method. The first time one of these objects is injected as a dependency, the container will call this initializer class.

Additionally, thanks to the #[Singleton] attribute, the logger instance will be registered as a singleton—which means this initializer will be called only once by the container.