Messaging and redis

Redis MQ Client/Server

A redis-based message queue client/server that can be hosted in any .NET or ASP.NET application. The RedisMqHost lives in the ServiceStack.Redis project and brings the many benefits of using a Message Queue. The current unoptimized version uses only a single background thread although initial benchmarks shows it can send/receive a promising 5k messages /sec when accessing a local redis instance (on my dev workstation).

Major kudos goes to Redis which thanks to its versatility, has Pub/Sub and Lists primitives that makes implementing a Queue trivial.

The first version already sports the major features you've come to expect from a MQ:

Each service maintains its own Standard and Priority MQ's Automatic Retries on messages generating errors with Failed messages sent to a DLQ (Dead Letter Queue) when its Retry threshold is reached. Each message can have a ReplyTo pointing to any Queue, alternatively you can even provide a ServiceStack endpoint URL which will send the response to a Web Service instead. If the web service is not available it falls back into publishing it in the default Response Queue so you never lose a message! MQ/Web Services that don't return any output have their Request DTOs sent to a rolling Out queue which can be monitored by external services (i.e. the publisher/callee) to determine when the request has been processed. Although you can host RedisMqHost in any ASP.NET web app, the benefit of hosting inside ServiceStack is that your web services are already capaable of processing Redis MQ messages without any changes required since they're already effectively designed to work like a Message service to begin with, i.e. C# POCO-in -> C# POCO-out.

This is another example of ServiceStack's prescribed DTO-first architecture continues to pay dividends since each web service is a DI clean-room allowing your C# logic to be kept pure as it only has to deal with untainted POCO DTOs, allowing your same web service to be re-used in: SOAP, REST (JSON,XML,JSV,CSV,HTML) web services, view models for dynamic HTML pages and now as a MQ service!

Eventually (based on feedback) there will be posts/documentation/examples forthcoming covering how to use it, in the meantime you can Check out the Messaging API to see how simple it is to use. To see some some working code showing some of the capabilities listed above, view the tests.

Hooking up a basic send/reply example is as easy as:

//DTO messages:
public class Hello { public string Name { get; set; } }
public class HelloResponse { public string Result { get; set; } }

var redisFactory = new PooledRedisClientManager("localhost:6379");
var mqHost = new RedisMqHost(redisFactory, noOfRetries:2, null);

//Server - MQ Service Impl:
mqHost.RegisterHandler<Hello>(m =>
    new HelloResponse { Result = "Hello, " + m.GetBody().Name });
mqHost.Start();

...

//Client - Process Response:
mqHost.RegisterHandler<HelloResponse>(m => {
    Consle.Log("Received: " + m.GetBody().Result);
});
mqHost.Start();

...

//Producer - Start publishing messages:
var mqClient = mqHost.CreateMessageQueueClient();
mqClient.Publish(new Hello { Name = "ServiceStack" });