Revision: Sat, 01 Aug 2020 19:23:52 GMT

Framework - Kernel and Environment

Each spiral build will contain a kernel object with a set of application-specific services. Unlike Symfony, The Spiral needs only one Kernel for all the dispatching methods (HTTP, Queue, GRPC, Console). The kernel will select the dispatching method automatically, based on connected Spiral\Boot\DispatcherInterface instances.

The base kernel implementation located in spiral/boot repository.

Kernel Responsibilities

The Spiral\Boot\AbstractKernel class only responsible for the following aspects of your application:

  • container initialization via a set of application-specific bootloaders
  • environment and directory structure initialization
  • selection of appropriate dispatching method

To create your kernel extends Spiral\Boot\AbstractKernel.

namespace App;

use Spiral\Boot\AbstractKernel;
use Spiral\Boot\Exception\BootException;

class MyApp extends AbstractKernel
{
    protected const LOAD = [
        // bootloaders to initialize
    ];

    public function get(string $service)
    {
        return $this->container->get($service);
    }

    protected function bootstrap()
    {
        // custom initialization code
        // invoked after all bootloaders are loaded
    }

    protected function mapDirectories(array $directories): array
    {
        if (!isset($directories['root'])) {
            throw new BootException('Missing required directory `root`');
        }

        if (!isset($directories['app'])) {
            $directories['app'] = $directories['root'] . '/app/';
        }

        return array_merge(
            [
                // public root
                'public'    => $directories['root'] . '/public/',

                // vendor libraries
                'vendor'    => $directories['root'] . '/vendor/',

                // data directories
                'runtime'   => $directories['root'] . '/runtime/',
                'cache'     => $directories['root'] . '/runtime/cache/',

                // application directories
                'config'    => $directories['app'] . '/config/',
                'resources' => $directories['app'] . '/resources/',
            ],
            $directories
        );
    }
}

The Spiral\Framework\Kernel defines the default directory map.

To init the kernel invoke static method init:

$myapp = MyApp::init(
    [
        'root' => __DIR__
    ],
    null, // use default env 
    false // do not mount error handler
);      

dump($myapp->get(\Spiral\Boot\DirectoriesInterface::class)->getAll());

Environment

Use Spiral\Boot\EnvironmentInterface to access the list of ENV variables. By default, the framework relies on system-level environment values. To redefine env values while initializing the kernel pass custom EnvironmentInterface to the init method.

$myapp = MyApp::init(
    [
        'root' => __DIR__
    ],
    new Environment(['key' => 'value']),
    false // do not mount error handler
);

dump($myapp->get(\Spiral\Boot\EnvironmentInterface::class)->getAll());

Such an approach can be used to bootstrap the application for testing purposes.

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