Sulu Messenger
This library provides the stamps and middlewares which configures the Sulu message bus.
It can be used independently in any Symfony installation.
## Installation
Make sure Composer is installed globally, as explained in the
[installation chapter](https://getcomposer.org/doc/00-intro.md)
of the Composer documentation.
Open a command console, enter your project directory and execute:
```bash
composer require sulu/messenger
```
Then, enable the bundle by adding it to the list of registered bundles
in the `config/bundles.php` file of your project:
```php
// config/bundles.php
return [
// ...
Sulu\Messenger\Infrastructure\Symfony\HttpKernel\SuluMessengerBundle::class => ['all' => true],
];
```
## Middlewares
### UnpackExceptionMiddleware
The `UnpackExceptionMiddleware` will unpack the `HandlerFailedException` which
is created by the Symfony [`HandleMessageMiddleware`](https://github.com/symfony/symfony/blob/c7dbcc954366f92f66360f3960a10dc1ef5f2584/src/Symfony/Component/Messenger/Middleware/HandleMessageMiddleware.php#L129).
This way we make sure that the real exception is thrown out by this message
bus, and a controller can catch or convert it to a specific http status code.
This middleware is always activated in the Sulu message bus.
### LockMiddleware
The `LockMiddleware` will allow to lock specific resources by a given key. This is commonly
used to prevent concurrent access to the same resource and avoid race conditions.
The locking can be activated and controlled via the `LockStamp` which supports the same parameters
as the Symfony `LockFactory` to create the Lock.
```php
use Sulu\Messenger\Infrastructure\Symfony\Messenger\LockMiddleware\LockStamp;
$this->handle(new Envelope(new YourMessage(), [new LockStamp('lock-key')]));
# set ttl and autorelease
$this->handle(new Envelope(new YourMessage(), [new LockStamp('lock-key', 300.0, true)]));
# multiple locks possible all locks need to be acquired before processing the message
$this->handle(new Envelope(new YourMessage(), [new LockStamp('lock-key-1'), new LockStamp('lock-key-2')]));
```
This middleware is always activated in the Sulu message bus.
### DoctrineFlushMiddleware
The `DoctrineFlushMiddleware` is a Middleware which let us flush the Doctrine
EntityManager by an opt-in flag via the `EnableFlushStamp`. It can be used this way:
```php
use Sulu\Messenger\Infrastructure\Symfony\Messenger\FlushMiddleware\EnableFlushStamp;
$this->handle(new Envelope(new YourMessage(), [new EnableFlushStamp()]));
```
This middleware is always activated in the Sulu message bus.