Symfony Bundle Plugins

By Matthias Noback

This package helps you create extensible bundles, by introducing a plugin system for bundles. Each bundle plugin can define its own services and configuration. This basically makes your bundles conform to the open/closed principle.

Setup

Install this library in your project by running

composer require matthiasnoback/symfony-bundle-plugins

Example

First, your bundle should extend BundleWithPlugins. You need to implement the getAlias method. It should return the name of your bundle's configuration key (as it will be used in config.yml for instance).

use Matthias\BundlePlugins\BundleWithPlugins;

class DemoBundle extends BundleWithPlugins
{
    protected function getAlias()
    {
        return 'demo';
    }
}

Each plugin for the bundle should implement BundlePlugin:

use Matthias\BundlePlugins\BundlePlugin;
use Symfony\Component\Config\Definition\Builder\ArrayNodeDefinition;
use Symfony\Component\Config\FileLocator;
use Symfony\Component\DependencyInjection\ContainerBuilder;
use Symfony\Component\DependencyInjection\ContainerInterface;
use Symfony\Component\DependencyInjection\Loader\YamlFileLoader;

class FooPlugin implements BundlePlugin
{
    public function name()
    {
        return 'foo';
    }

    public function load(
        array $pluginConfiguration, 
        ContainerBuilder $container
    ) {
        // load specific service definitions for this plugin,
        // just like you would do in a bundle extension
        
        $loader = new YamlFileLoader($container, new FileLocator(__DIR__));
        $loader->load('foo.yml');
        
        // $pluginConfiguration contains just the values that are relevant 
        // for this plugin
    }

    public function addConfiguration(ArrayNodeDefinition $pluginNode)
    {
        // add plugin-specific configuration nodes, 
        // just like you would do in a bundle extension
    
        $pluginNode
            ->children()
                ->scalarNode('foo')
                ->isRequired()
            ->end();
    }
}

When instantiating this bundle in your AppKernel class, you can provide any number of BundlePlugin instances:

class AppKernel extends Kernel
{
    public function registerBundles()
    {
        return array(
            ...,
            new DemoBundle(array(new FooPlugin()))
        );
    }
}

If some of the plugins are required, just introduce a CorePlugin and make sure it is always registered by overriding your bundle's alwaysRegisteredPlugins() method:

class DemoBundle
{
    ...
    
    protected function alwaysRegisteredPlugins()
    {
        return array(new CorePlugin());
    }
}

Register compiler passes

When a bundle plugin needs to register a compiler pass, it can do so in its build() method.

class FooPlugin implements BundlePlugin
{
    ...
    
    public function build(ContainerBuilder $container)
    {
        $container->addCompilerPass(...);
    }
}

Booting a plugin

Whenever the main bundle is booted, plugins are allowed to do some runtime initialization as well. They can do this in their boot() method. At that time, the fully initialized service container is available:

class FooPlugin implements BundlePlugin
{
    ...
    
    public function boot(ContainerInterface $container)
    {
        // runtime initialization (will run when the kernel itself is 
        // booted)
    }
}

Simple plugins

If your plugin is quite simple (i.e. only needs a load() method), just make the plugin class extend SimpleBundlePlugin which contains stub implementations for the interface methods that you won't need.

Thanks

To @dennisdegreef for reviving the test suite of this project.