Jetpack Configuration

Allows for enabling and initializing of Jetpack features provided by other packages.

Usage

Add this package as a dependency to your project:

composer require automattic/jetpack-config

Add every other package you're planning to configure:

composer require automattic/jetpack-sync
composer require automattic/jetpack-tracking
composer require automattic/jetpack-terms-of-service

In your code initialize the configuration package at or before plugins_loaded priority 1:

use Automattic/Jetpack/Config;

// Configuring Jetpack as early as plugins_loaded priority 1
// to make sure every action handler gets properly set.
add_action( 'plugins_loaded', 'configure_jetpack', 1 );

function configure_jetpack() {
    $config = new Config();

    foreach (
        array(
            'sync',
            'tracking',
            'tos',
        )
        as $feature
    ) {
        $config->ensure( $feature );
    }
}

Adding your package to the config class

You can have your package initialized using the Config class by adding several things.

The configure method

It's better to have one static configure method in your package class. That method will be called early on the plugins_loaded hook. This way you can add your own plugins_loaded handlers with standard priority and they will get executed:

class Configurable_Package {

    public static function configure() {
        add_action( 'plugins_loaded', array( __CLASS__, 'on_plugins_loaded' );
    }

    public static function on_plugins_loaded() {
        self::do_interesting_stuff();
    }

}

The feature enabling method

An enabling method should be added to the Config class and should only contain your configuration method call.

public function enable_configurable_package() {
    Configurable_Package::configure();

    return true;
}

Note that the method name should use the feature slug, in this case your feature slug is configurable_package for the sake of simplicity. When you're adding your feature it should be unique and recognizable, like sync or tracking.

The feature slug

To make sure the feature is supported by the Config class, you need to add its slug to the config class property:

    /**
     * The initial setting values.
     *
     * @var Array
     */
    protected $config = array(
        // ...
        'configurable_package' => false,
        // ...
    );

The ensure call

Finally you need to add a block that will check if your package is loaded and mark it to be initialized:

if ( $this->config['configurable_package'] ) {
    $this->ensure_class( 'Configurable_Package' ) && $this->ensure_feature( 'configurable_package' );
}

This code does three things: it checks whether the current setup has requested your package to be loaded. Next it checks if the class that you need for the package to run is present, and then it adds the hook handlers that initialize your class. After that you can use the config package's interface in a Jetpack package consumer application and load your package as shown in the first section of this README.

Config Package Dependencies

The Config package does not have any composer package dependencies. The consumer plugins must require the packages that they need.

Before using a package class, the Config package will verify that the class exists using the Config::ensure_class() method. This allows the consumer plugins to use the Config package to enable and initialize Jetpack features while requiring only the packages that they need.