Rezzza\CommandBus

Light command bus.

Installation

composer.json:

    "rezzza/command-bus": "~2.0"

Command

Commands must implements an interface Rezzza\CommandBus\Domain\CommandInterface, it should be value object, example:

class ShortenUrlCommand
{
    private $longUrl;

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

    public function getLongUrl()
    {
        return $this->longUrl;
    }
}

Command Handlers

A command handler will be called by the command bus when it handle command.

The handler could be:

- A callable (\Closure or a callback)
- An object. In example of ShortenUrlCommand, the bus will execute `$object->shortenUrl($command)`

Command bus

It'll find a command handler then handle the command. We provide at this moment three command bus:

- Direct (synchronous)
- Redis (asynchronous)
- Rabbit (asynchronous)
- Implement your own command bus with `\Rezzza\CommandBus\Domain\CommandBusInterface`

You can see examples to see them in action.

Fail Strategies

When the bus handle the command, and the command handler fail, you may want to re-queue the command to be executed later.

- RetryThenFailStrategy: The command is requeued in a `Retry` queue, you'll be able to consume this queue and configure how many time you want to execute it before it goes to a `Fail` queue. Look at `examples/redis_worker.php` example to understand how it work.
- RequeueStrategy: The command is requeued
- NoneStrategy: The command will not being requeued.
- Your own strategy with `Rezzza\CommandBus\Domain\Consumer\FailStrategy\FailStrategyInterface`

Consumer

In your console command, you can use a consumer to handle asynchronous commands. For example with redis, you'll do

do {
    $redis    = new \Redis();
    $redis->connect('......');

    $handlerLocator = new Rezzza\CommandBus\Infra\Handler\MemoryHandlerLocator();
    // add some handlers ...
    $directBus         = new Rezzza\CommandBus\Infra\Provider\Direct\DirectBus($handlerLocator);
    $failStrategy      = new Rezzza\CommandBus\Domain\Consumer\FailStrategy\NoneStrategy();
    $redisKeyGenerator = new CommandBus\Infra\Provider\Redis\RedisKeyGenerator();
    $serializer        = new CommandBus\Infra\Serializer\NativeSerializer();

    $consumer = new Rezzza\CommandBus\Domain\Consumer\Consumer(
        new Rezzza\CommandBus\Infra\Provider\Redis\RedisConsumerProvider($redis, $redisKeyGenerator, $serializer),
        $directBus,
        $failStrategy
    );

    $consumer->consume('FooCommand');
    sleep(1); // yep ...
} while (true);

Examples are the best documentation, look at examples directory.