Create or extend configuration types | Magento 2 Developer Documentation

Extend configuration types

To extend an existing configuration type, you need only create a configuration file in your module.

For example, to add an event observer, you create app/code/{VendorName}/{ModuleName}/etc/events.xml and declare a new observer.

Because the event configuration type already exists in Magento, the loader and the events.xsd validating schema are already present and functional.

Your new events.xml is automatically collected from your module and merged with other events.xml files for other modules.

Create configuration types

To create new configuration type, you must add at minimum:

A loader
XSD validation schema
XML configuration files

For example, to introduce an adapter for a new search server that enables extensions to configure how its entities are indexed in that server, create:

A loader
An XSD schema file
An appropriately named configuration file. For example, search.xml. This file is read and validated against your schema.
Any other classes required for your work.

If new modules have a search.xml file, they will be merged with your file when it loads.

Examples of use

To create a new configuration type:

Create your XSD file.
Create your XML file.

Define your configuration object in your di.xml.

The following example from the Magento_Sales module’s di.xml illustrates how a configuration object should look like.

 <config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">

     <type name="Magento\Sales\Model\Order\Pdf\Config\Reader">
         <arguments>
             <argument name="fileName" xsi:type="string">pdf.xml</argument>
             <argument name="converter" xsi:type="object">Magento\Sales\Model\Order\Pdf\Config\Converter</argument>
             <argument name="schemaLocator" xsi:type="object">Magento\Sales\Model\Order\Pdf\Config\SchemaLocator</argument>
         </arguments>
     </type>

     <virtualType name="pdfConfigDataStorage" type="Magento\Framework\Config\Data">
         <arguments>
             <argument name="reader" xsi:type="object">Magento\Sales\Model\Order\Pdf\Config\Reader</argument>
             <argument name="cacheId" xsi:type="string">sales_pdf_config</argument>
         </arguments>
     </virtualType>

     <type name="Magento\Sales\Model\Order\Pdf\Config">
         <arguments>
             <argument name="dataStorage" xsi:type="object">pdfConfigDataStorage</argument>
         </arguments>
     </type>
 </config>

The first type node sets the Reader’s filename, associated Converter and SchemaLocator classes.
Then, the pdfConfigDataStorage virtual type node attaches the reader class to an instance of Magento\Framework\Config\Data.
And finally, the last type node attaches that config data virtual type to the Magento\Sales\Model\Order\Pdf\Config class, which is used for actually reading values in from those pdf.xml files.

Define a reader by extending Magento\Framework\Config\Reader\Filesystem class and rewrite the following parameters:

$_idAttributes // Array of node attribute IDs.

Example:

namespace Vendor\ModuleName\Model\Config;

class Reader extends \Magento\Framework\Config\Reader\Filesystem
{
    /**
     * List of identifier attributes for merging
     *
     * @var array
     */
    protected $_idAttributes = [
         '</path/to/node_in_your_xml_file>'        => '<identifierAttributeName>',
         '</path/to/other/node_in_your_xml_file>'  => '<identifierAttributeName>',
    ];
}

If you prefer to create your own version of the reader you can do so by implementing \Magento\Framework\Config\ReaderInterface. For reference see Magento_Analytics config reader

After defining your reader, use it to collect, merge, validate, and convert the configuration files to an internal array representation.

Validate a configuration type

Each configuration file is validated against a schema specific to its configuration type. Example: events, which, in earlier Magento versions, were configured in config.xml, are now configured in events.xml.

Configuration files can be validated both before (optional) and after any merge of multiple files affecting the same configuration type. Unless the validation rules for the individual and merged files are identical, you should provide two schemas for validating the configuration files:

Schema to validate an individual
Schema to validate a merged file

New configuration files must be accompanied by XSD validation schemas. An XML configuration file and its XSD validation file must have the same name.

If you must use two XSD files for a single XML file, the names of the schemas should be recognizable and associated with the XML file. If you have an events.xml file and a first events.xsd file, the XSD files for the merged events.xml file could be named events_merged.xsd. To ensure validation of an XML file by appropriate XSD file, you must add the Uniform Resource Name (URN) to the XSD file in the XML file. For example:

<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager:etc/config.xsd">

Your IDE can validate your configuration files at both runtime and during development.