Bootstrap

Initializing Gacela

Gacela should be bootstrapped using the Gacela::bootstrap function.

• The first parameter is the application root directory and is mandatory
• The second one is an optional Closure(GacelaConfig) configuration

<?php # index.php

Gacela::bootstrap($appRootDir, function (GacelaConfig $config): void { ... });

The gacela.php file

You can define the configuration as the second parameter in the Gacela::bootstrap() in your index.php or, alternatively, you can create a gacela.php file in your application root directory which returns a Closure(GacelaConfig) function.

<?php # gacela.php

return function (GacelaConfig $config): void { ... };

Different environments

You can define a gacela configuration file for different environments using the APP_ENV environment variable. Where you have a Gacela file with the suffix of the environment in the file name, it will load that configuration.

For example:

• APP_ENV=dev -> will load gacela-dev.php
• APP_ENV=prod -> will load gacela-prod.php
• APP_ENV=anything -> will load gacela-anything.php

The loading of this particular file will happen after the default gacela.php (if exists). So it will override (or add) the possible values you might have defined in the default gacela.php file.

(A similar behaviour already exists for your app config files. See: Config files for diff env.)

Note: If you are working "on top" of another project which is using gacela, you can always define your custom gacela.php file and define your GacelaConfig configuration, which will be combined with the gacela.php of the vendor project itself.

GacelaConfig

As we just mentioned, you can customize some Gacela behaviours while bootstrapping without the need of a gacela.php in the root of your project, however, if this file exists, it will be combined with the configuration from Gacela::bootstrap().
It is not mandatory but recommended having a gacela.php file in order to decouple and centralize the custom Gacela configuration.

In other words, you can modify some Gacela behaviour from two different places:

1. Directly with Gacela::bootstrap()
2. Or using gacela.php

Application Config

Using the GacelaConfig object you can add different paths and use different config file types, even with custom config readers. The PhpConfigReader is used by default.

Config PHP files

<?php # gacela.php
return function (GacelaConfig $config): void {
    $config->addAppConfig(
        path: 'config/*.php',
        pathLocal: 'config/local.php',
        reader: PhpConfigReader::class 
    );
};

You can add to addAppConfig() method as many config locations as you want.

• path: this is the path of the folder which contains your application configuration. You can use ? or * in order to match 1 or multiple characters. Check glob() function for more info.
• pathLocal: this is the last file loaded, which means, it will override the previous configuration, so you can easily add it to your .gitignore and set your local config values in case you want to have something different for some cases.
• reader: Define the reader class which will read and parse the config files. It must implement ConfigReaderInterface.

Multiple and different environment config files

<?php # gacela.php
return function (GacelaConfig $config): void {
    $config->addAppConfig('config/.env', '', EnvConfigReader::class);
    $config->addAppConfig('config/*.custom', '', CustomConfigReader::class);
    $config->addAppConfig('config/*.php', 'config/local.php');
};

Mapping Interfaces

You can define a map between an interface and the concrete class that you want to create (or use) when that interface is found during the process of auto-wiring in any Factory's Module dependencies via its constructor. Let's see an example:

The addMappingInterface() method will let you bind a class with another class interface => concreteClass|callable|string-class that you want to resolve. For example:

<?php # gacela.php
return function (GacelaConfig $config): void {
    $config->addMappingInterface(AbstractString::class, StringClass::class);
    $config->addMappingInterface(ClassInterface::class, new ConcreteClass(/*args*/));
    $config->addMappingInterface(ComplexInterface::class, new class() implements Foo { /** logic */ });
    $config->addMappingInterface(FromCallable::class, fn() => new StringClass('From callable'));
};

In the example above, whenever OneInterface::class is found then OneConcrete::class will be resolved.

Using externalServices

First, we set a global service using GacelaConfig->addExternalService(string, class-string|object|callable) (you can set as many as you need). In this example 'concreteClass':

<?php # gacela.php
return function (GacelaConfig $config): void {
    $config->addExternalService('concreteClass', ConcreteClass::class);
}

This way we can access the value of that key 'concreteClass' in the gacela.php from $config->getExternalService(string). For example:

<?php # gacela.php
return function (GacelaConfig $config): void {
    $config->addMappingInterface(
        AnInterface::class,
        $config->getExternalService('concreteClass')
    );
}

In the example above, whenever AnInterface::class is found then ConcreteClass::class will be resolved.

Suffix Types

Apart from the known Gacela suffix classes: Factory, Config, and DependencyProvider, you can define other suffixes to be resolved for your different modules. You can do this by adding custom gacela resolvable types.

<?php # gacela.php
return function (GacelaConfig $config): void {
    $config->addSuffixTypeFacade('EntryPoint');
    $config->addSuffixTypeFactory('Creator');
    $config->addSuffixTypeConfig('Conf');
    $config->addSuffixTypeDependencyProvider('Binder');
};

In the example above, you'll be able to create a gacela module with these file names:

ExampleModule
├── Domain
│   └── YourLogicClass.php
├── EntryPoint.php  # this is the `Facade`
├── Creator.php     # this is the `Factory`
└── Conf.php        # this is the `Config`
└── Binder.php      # this is the `DependencyProvider` 

Project Namespaces

You can add your project namespaces to be able to resolve gacela classes with priorities.

Gacela will start looking on your project namespaces when trying to resolve any gacela resolvable classes, eg: Facade, Factory, Config, or DependencyProvider.

Let's visualize it with an example. Consider this structure:

├── gacela.php
├── index.php # entry point
├── src
│   └── Main
│       └── ModuleA
│           └── Factory.php
└── vendor
    └── third-party
        └── ModuleA
            ├── Facade.php
            └── Factory.php

<?php # gacela.php
return function (GacelaConfig $config): void {
    $config->setProjectNamespaces(['Main']);
};

Because you have defined Main as your project namespace, when you use the ModuleA\Facade from vendor, that Facade will load the Factory from src/Main/ModuleA/Factory and not vendor/third-party/ModuleA/Factory because Main has priority (over third-party, in this case).

TL;DR: You can override gacela resolvable classes by copying the directory structure from vendor modules in your project namespaces.

Gacela File Cache

When the method setFileCacheEnabled() is true, a new .gacela/cache folder will be created in the root of your project with the resolved classes.

You can customize the file cache directory name considering the root app directory. This is the first argument you pass when bootstrapping gacela: Gacela::bootstrap(__DIR__).

<?php # gacela.php
return function (GacelaConfig $config): void {
    $config->setFileCacheEnabled(true);
    $config->setFileCacheDirectory('.gacela/cache');
};

You can also enable or disable the gacela file cache system via your project config values.

<?php # config/default.php
use Gacela\Framework\ClassResolver\Cache\GacelaFileCache;

return [
    GacelaFileCache::KEY_ENABLED => true|false,
];

Listening internal gacela events

Gacela has an internal event-listener system that dispatches a variety of events. These are read-only events interesting for tracing, debugging or act on them as you want.

Register a generic listener to all internal gacela events

<?php # gacela.php
return function (GacelaConfig $config): void {
    $config->registerGenericListener(
        function (GacelaEventInterface $event): void {
            echo $event->toString();
        }
    );
};

Register a specific listener to one internal gacela event

<?php # gacela.php
return function (GacelaConfig $config): void {
    $config->registerSpecificListener(
        ResolvedClassCreatedEvent::class, 
        function (GacelaEventInterface $event): void {
            echo $event->toString();
        }
    );
};

List of supported events

Gacela\Framework\Event\ClassResolver\ClassNameFinder

• ClassNameInvalidCandidateFoundEvent
• ClassNameNotFoundEvent
• ClassNameCachedFoundEvent
• ClassNameValidCandidateFoundEvent

Gacela\Framework\Event\ConfigReader

• ReadPhpConfigEvent

Gacela\Framework\Event\ClassResolver

• AbstractGacelaClassResolverEvent
• ResolvedClassCachedEvent
• ResolvedClassCreatedEvent
• ResolvedCreatedDefaultClassEvent
• ResolvedClassTriedFromParentEvent

Gacela\Framework\Event\ClassResolver\Cache

• ClassNameCacheCachedEvent
• ClassNamePhpCacheCreatedEvent
• ClassNameInMemoryCacheCreatedEvent
• CustomServicesCacheCachedEvent
• CustomServicesPhpCacheCreatedEvent
• CustomServicesInMemoryCacheCreatedEvent

Reset internal InMemoryCache

If you are working with integration tests, this option can be helpful to avoid false-positives, as Gacela works as a global singleton pattern to store the resolved dependencies. This value by default is false.

<?php # gacela.php
$configFn = function (GacelaConfig $config): void {
    $config->shouldResetInMemoryCache();
};
Gacela::bootstrap(__DIR__, $configFn);

Extend Service

You are able to extend any service functionality. The extendService() receives the service name that will be defined in any DependencyProvider, and a callable which receives the service itself as 1st arg, and the Container as 2nd arg.

<?php # gacela.php
Gacela::bootstrap(__DIR__, static function (GacelaConfig $config): void {
    $config->extendService(
        DependencyProvider::ARRAY_AS_OBJECT,
        static function (ArrayObject $arrayObject, Container $container): void {
            $arrayObject->append(3);
        }
    );
});
/************************************************************************/
final class DependencyProvider extends AbstractDependencyProvider
{
    public const ARRAY_AS_OBJECT = 'ARRAY_AS_OBJECT';

    public function provideModuleDependencies(Container $container): void
    {
        $container->set(self::ARRAY_AS_OBJECT, new ArrayObject([1, 2]));
    }
}
/************************************************************************/
final class Factory extends AbstractFactory
{
    public function getArrayAsObject(): ArrayObject
    {
        return $this->getProvidedDependency(DependencyProvider::ARRAY_AS_OBJECT);
    }
}
/************************************************************************/
final class Facade extends AbstractFacade
{
    public function getArrayAsObject(): ArrayObject
    {
        return $this->getFactory()->getArrayAsObject();
    }
}

/************************************************************************/
$facade = new Module\Facade();
$facade->getArrayAsObject(); // === new ArrayObject([1, 2, 3])

A complete example using gacela.php

<?php # gacela.php
return function (GacelaConfig $config): void {
    $config
        // Define different config sources.
        ->addAppConfig('config/*.php', 'config/override.php')

        // Allow overriding gacela resolvable types.
        ->addSuffixTypeFacade('FacadeFromBootstrap')
        ->addSuffixTypeFactory('FactoryFromBootstrap')
        ->addSuffixTypeConfig('ConfigFromBootstrap')
        ->addSuffixTypeDependencyProvider('DependencyProviderFromBootstrap')

        // Define the mapping between interfaces and concretions,
        // so Gacela services will auto-resolve them automatically.
        ->addMappingInterface(GeneratorInterface::class, ConcreteGenerator::class)
        ->addMappingInterface(
            CustomInterface::class,
            $config->getExternalService('CustomClassKey')
        )
        
        // Define your project namespace resolve gacela classes with priorities.
        ->setProjectNamespaces(['App'])
        
        // Enable Gacela file cache system with a custom cache directory.
        ->setFileCacheEnabled(true)
        ->setFileCacheDirectory('.gacela/cache')
        
        // Listening all internal gacela events
        ->registerGenericListener(
            function (GacelaEventInterface $event): void {
                echo $event->toString();
            }
        )
        // Listening a concrete internal gacela event
        ->registerSpecificListener(
            ResolvedClassCreatedEvent::class, 
            function (GacelaEventInterface $event): void {
                echo $event->toString();
            }
        )
        // Extending the functionality of a particular service
        ->extendService(
            'any-service-name',
            static function (ServiceType $service): void {
                // you can retrieve/alter any functionality of the $service  
            }
        );
};

Accessing a Doctrine-Repository from a Gacela-Factory

The Gacela Factory has auto-wiring that will resolve its dependencies. The only exception is for interfaces, because there is no way to discover what want to inject there. For this purpose, you need to define the mapping between the interfaces and to what do you want them to be resolved.

<?php # index.php

namespace Symfony\Component\HttpKernel\Kernel;
# ...
$kernel = new Kernel($_SERVER['APP_ENV'], (bool)$_SERVER['APP_DEBUG']);

$configFn = function (GacelaConfig $config) use ($kernel): void {
    $config->addExternalService('symfony/kernel', $kernel);
}

Gacela::bootstrap($appRootDir, $configFn);

<?php # gacela.php

return function (GacelaConfig $config): void {
    $config->addAppConfig('.env*', '.env.local', EnvConfigReader::class);

    $config->addMappingInterface(
        ProductRepositoryInterface::class,
        ProductRepository::class
    );

    /** 
     * Using $config we can get the service that we added in `index.php`
     * 
     * @var Kernel $kernel
     */
    $kernel = $config->getExternalService('symfony/kernel');

    $config->addMappingInterface(
        EntityManagerInterface::class,
        fn () => $kernel->getContainer()->get('doctrine.orm.entity_manager')
    );
};

In our current example (using Symfony) we want to use the doctrine service from the kernel.container and not just "a new one". A new one wouldn't have all services and stuff already defined as the original one would have.

Extra: using the fn() => ... as value when doing addMappingInterface() allows us to delay the execution of getContainer() to when it is really needed i.e. "lazy loading".