Overview

This guide serves as an entry point for developers familiar with the concepts of Symfony bundles.

Prerequisites

This guide handles some base concepts of Shopware plugins. Therefore, you may want to have a look at plugin base guide first.

As this guide also references the functionality of Symfony bundles, you should have at least a basic knowledge of it. You may want to have a look or refresh your knowledge with help of Symfony's bundle documentation.

Symfony bundles

A bundle is the Symfony's preferred way to provide additional third-party features to any Symfony application. Those bundles are everywhere: Symfony even outsources many of its core features into external bundles. The template engine Twig, the Security bundle, the WebProfiler, as well as many other third-party bundles can be installed on demand to extend your Symfony application in any way. The Bundle System is Symfony's way of providing an extendable framework with plugin capabilities.

Shopware plugins

Shopware is building upon the Symfony Bundle System to extend its functionality even more. This allows the Shopware Plugin System to function as a traditional plugin system with features like plugin lifecycles and more.

Whenever you create a Shopware plugin, you have to extend the Shopware\Core\Framework\Plugin class. If you investigate this class, you will see that this class extends Shopware\Core\Framework\Bundle, which in return extends the Symfony's Bundle class:

class YourNamespace\PluginName extends
​
    // plugin lifecycles
    abstract class Shopware\Core\Framework\Plugin extends
​
        // adds support for migrations, filesystem, events, themes
        abstract class Shopware\Core\Framework\Bundle extends
​
            // Symfony base bundle
            abstract class Symfony\Component\HttpKernel\Bundle

As you can see, any Shopware plugin is also a Symfony bundle internally as well, and will be handled as such by Symfony. A plugin adds support for some cases, specific to the Shopware environment. These include, for example, handling plugin migrations and registering Shopware business events.

Plugin lifecycle

As mentioned before, Shopware extends the Symfony Bundle System with some functionality to adjust its use for the Shopware ecosystem. For you as plugin developer, the most important addition is the extended plugin lifecycle.

A Shopware plugin runs through a lifecycle. Your plugin's base class can implement the following methods to execute any sort of installation or maintenance tasks.

Next steps

Now that you know about the differences between a Symfony bundle and a Shopware plugin, you might also want to have a look into the following Symfony-specific topics and how they are integrated in Shopware 6:

• ​Dependency Injection​

• ​Listening to events​

Here are some useful videos explaining the basics of bundle methods and Symfony services taken from our free online training ["Backend Development"](https://academy.shopware.com/courses/shopware-6-backend-development-with-jisse-reitsma).