Learn how to build a microservices event bus architecture using CAP, which offers advantages over direct integration of message queues, and what out-of-the-box features it provides.
PM> Install-Package DotNetCore.CAP
For quick start, we use memory-based event storage and message transport.
PM> Install-Package DotNetCore.CAP.InMemoryStorage
PM> Install-Package Savorboard.CAP.InMemoryMessageQueue
In Startup.cs
,add the following configuration:
public void ConfigureServices(IServiceCollection services)
{
services.AddCap(x =>
{
x.UseInMemoryStorage();
x.UseInMemoryMessageQueue();
});
}
public class PublishController : Controller
{
[Route("~/send")]
public IActionResult SendMessage([FromService]ICapPublisher capBus)
{
capBus.Publish("test.show.time", DateTime.Now);
return Ok();
}
}
public class ConsumerController : Controller
{
[NonAction]
[CapSubscribe("test.show.time")]
public void ReceiveMessage(DateTime time)
{
Console.WriteLine("message time is:" + time);
}
}
One of the most powerful advantages of asynchronous messaging over direct integrated message queues is reliability, where failures in one part of the system do not propagate or cause the entire system to crash. Messages are stored inside the CAP to ensure the reliability of the message, and strategies such as retry are used to achieve the final consistency of data between services.