In Magento 2, the configuration layer is a critical component of the system that allows developers and store owners to manage various settings for their store. The configuration layer is implemented using the Configuration module, which is part of the Magento\Framework\App namespace.

The configuration layer is designed to provide a hierarchical structure for managing different configuration settings. The hierarchy starts at the default level and extends to the store level. This hierarchical structure allows the settings to be inherited from the default level to the store level, making it easy to manage settings for multiple stores.

The configuration settings are stored in the database in the core_config_data table. This table contains a row for each configuration setting and stores information such as the configuration path, the value of the configuration, and the scope of the configuration (i.e. website, store view, or default).

The Configuration module also provides an API for retrieving and modifying configuration settings. This API can be used by developers to read and modify configuration settings programmatically.

The configuration layer is used extensively throughout Magento 2, and it is an integral part of the system architecture. It is used to manage a wide range of settings, including store-specific settings, system-wide settings, and module-specific settings.

Overall, the configuration layer in Magento 2 is a critical component of the system architecture, and it provides a flexible and hierarchical structure for managing configuration settings.

Here is some more information about the configuration layer in Magento 2:

1. Configuration Scope:

The configuration layer in Magento 2 allows developers to set configuration settings at different levels of scope. The available scopes are “Default”, “Website”, and “Store View”. This means that a configuration setting can be applied to the entire Magento installation (Default scope), to a specific website, or to a specific store view. When a setting is applied at a higher scope, it is inherited by lower scopes. For example, if a configuration setting is set at the website level, all store views under that website will inherit that setting.

2. Configuration Path:

Each configuration setting in Magento 2 has a unique configuration path. This path is used to identify the setting and to retrieve or modify its value. The configuration path is a combination of a group name, a field name, and (optionally) a website code or a store code. For example, the configuration path for the store name setting is “general/store_information/name”.

3. Configuration Structure:

The configuration settings in Magento 2 are organized into different groups based on their functionality. For example, there are groups for General Settings, Catalog Settings, Sales Settings, etc. These groups are defined in XML files located in the etc/adminhtml/system.xml and etc/frontend/system.xml files of each module. Each group contains one or more fields, which are the individual configuration settings.

4. Configuration Override:

The configuration layer in Magento 2 allows developers to override the default configuration settings by creating custom XML files. These files can be placed in the app/code/[Vendor]/[Module]/etc directory of a custom module, and they can be used to set custom values for specific configuration settings. When Magento 2 loads the configuration settings, it will merge the custom XML files with the default XML files, and apply the custom values for any overridden settings.

Overall, the configuration layer in Magento 2 provides a flexible and hierarchical structure for managing configuration settings, and it is an essential component of the system architecture. It allows developers to customize the behavior of the system and provides store owners with the ability to manage their stores efficiently.

Example of how to use the configuration layer in Magento 2:

Let’s say you want to change the maximum order amount allowed for your store. By default, Magento 2 sets the maximum order amount to 10,000. To change this setting, follow these steps:

1. Log in to the Magento 2 admin panel and navigate to “Stores” > “Configuration” > “Sales”.
2. Click on the “Payment Methods” tab and then click on the “Credit Card” section to expand it.
3. Scroll down to the “Maximum Order Total” setting and change the value to your desired maximum order amount (e.g. 20,000).
4. Click the “Save Config” button to save your changes.

Now, let’s say you want to change the maximum order amount for a specific website. To do this, follow these steps:

1. Log in to the Magento 2 admin panel and navigate to “Stores” > “Configuration”.
2. From the “Scope” dropdown menu, select the website for which you want to change the maximum order amount.
3. Follow the same steps as above to locate the “Maximum Order Total” setting under the “Credit Card” section, and update the value to your desired maximum order amount (e.g. 30,000).
4. Click the “Save Config” button to save your changes.

These changes will now apply to the specific website you selected, and any store views under that website. If you want to apply the same changes to all websites or store views, you can follow the same steps and select the “Default Config” scope from the dropdown menu in step 2.

Alternatively, you can use the configuration override feature to set a custom value for the “Maximum Order Total” setting in a custom module. To do this, you can create an XML file with the following content:

<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:module:Magento_Store:etc/config.xsd">
    <default>
        <payment>
            <ccsave>
                <order_total>40000</order_total>
            </ccsave>
        </payment>
    </default>
</config>

This XML file sets the “Maximum Order Total” value for the “ccsave” payment method to 40,000. You can place this file in the app/code/[Vendor]/[Module]/etc directory of your custom module and enable the module in the Magento 2 admin panel.