grandchamp/commandscaler

A simple command handler pattern implementation, but fully scalable with RabbitMQ

CommandScaler

A simple command handler pattern implementation, but fully scalable with RabbitMQ (maybe more?).

This app was heavily inspired by the amazing https://github.com/jbogard/MediatR.

With this app is possible to scale your command handlers to multiple machines (or processes) by using RabbitMQ as the responsible to distribute your commands.

Configuring

1. Configure RabbitConfiguration class on your Startup.cs

services.Configure<RabbitConfiguration>(Configuration.GetSection("RabbitMQ"));

JSON

{
  "RabbitMQ": {
    "Host": "127.0.0.1",
    "User": "admin",
    "Password": "123456"
  }
}

2. Add CommandScaler stuff

services.AddCommandScaler(new[] { typeof(YourCommand).Assembly })
        .AddRabbitMQCommandScaler()
        .ConfigureRabbitMQHandler();

For AddCommandScaler method you should pass the assemblies where your ICommandHandler are defined (you can have multiple here), so the lib will be able to scan and register them.

3. Start the CommandScaler handler

3.1 Start just the IBus

On your Configure method on Startup.cs add:

await app.StartCommandScaler();

3.2 Start IBus and RabbitGenericHandler

await app.StartRabbitMQHandler();

This will start the listener.

Using

To start using, you should inject IBus interface when you need to send commands:

    public class TestController : Controller
    {
        private readonly IBus _bus;
        public TestController(IBus bus)
        {
            _bus = bus;
        }

        [HttpGet]
        public async Task<IHttpActionResult> Test()
        {
            var result = await _bus.Send(new TestCommand { MyValue = 1 });
            return Ok(result);
        }
    }

    public class TestCommand
    {
        public int MyValue { get; set; }
    }

    public class TestCommandHandler : ICommandHandler<TestCommand, int>
    {
        public Task<int> Handle(TestCommand command)
        {
            return command.MyValue;
        }
    }

On result you'll have the value returned from the Handle method of your ICommandHandler.

Check the samples if you have any doubt.