alexbowers / laravel-app-events

App-wide events for SOA applications using Laravel

Laravel App Events for Google Cloud PubSub

Installation

Install through Composer with composer require decahedron/laravel-app-events

Usage

The App Event as implemented in this package is just a regular Laravel job class that gets dispatched as usual with the dispatch method.

Dispatching ("broadcasting") events

When you dispatch an app event, you must provide an event name, and a payload in the form of a protobuf message.

dispatch(new AppEvent('user.created', new User(['name' => $user->name])));

In order for this to get properly encoded, you also need to provide a mapping from a name to the class implementation. This allows the package to encode the message in a way that is not bound exclusively to PHP, and thus allows decoding the message into a protobuf structure in any language that protobuf supports.

Configuration for broadcasting

return [
    'enabled' => true,
    'project_id' => 'your-google-project',
    'topic' => 'app-events',
    'subscription' => 'login-handler'

    'mappings' => [
        'User' => App\Proto\User::class,
    ],
];

Handling events

Events can be handled by any application that is able to communicate with Google Cloud PubSub, and is written in a language that can use protobuf.

To handle events with this package, your handling application (which may be the same as the dispatching one) must contain the following configuration.

return [
    'enabled' => true,
    'project_id' => 'your-google-project',
    'topic' => 'app-events',
    'subscription' => 'user-registrator',

    'mappings' => [
        'User' => App\Proto\User::class,
    ],
    
    'handlers' => [
        'user.created' => App\Auth\RegisterUser::class,
    ],
];

The handler specified here must be a class with a handle method, which accepts the protobuf message as an argument. This class gets resolved through the Laravel container, so you may use constructor injection:

class RegisterUser
{
    protected $registrator;

    public function __construct(Registrator $registrator)
    {
        $this->registrator = $registrator;
    }

    public function handle(User $user)
    {
        $this->registrator->register(
            $user->getName(),
            $user->getEmail(),
        );
    }
}

Note that the mappings are still required here, in order to convert the data back into the correct protobuf message. Therefore, it might be beneficial to place your base configuration (not including the subscription name and handlers) in a shared location so it can be updated in all places at once.