ServiceStack Message Filtering - servicestack

Question

I have been using the ServiceStack MQ Server/Client to empower a message based architecture in my platform and it has been working flawlessly. I am now trying to do something that I do not believe is supported by the SS Message Producer/Consumer.
Essentially I am firing off messages (events) at a centralized data center and I have ~2000 decentralized nodes all over the US over a non reliable network that need to potentially know about about this event BUT the event needs to be targeted to only one of the ~2000 nodes. I need the flexibility of the arbitrarily named channels with Pub/Sub but the durability of the MQ. I started off with Pub/Sub but the network is too unreliable so I have moved the solution to use the RedisMQServer. I have it working but wanted to make sure I am not missing something in the interface. I am curious if the creators of SS have thought through this use case and if so what the outcome of that discussion was? This does fight the concept of using the POCO's to drive the outcomes/actions of the message consumption. Maybe that is the reason?
Here is my producer
public ExpressLightServiceResponse Get(ExpressLightServiceRequest query)
{
var result = new ExpressLightServiceResponse();
var assemblyBuilder = Thread.GetDomain().DefineDynamicAssembly(new AssemblyName("ArbitaryNamespace"), AssemblyBuilderAccess.Run);
var moduleBuilder = assemblyBuilder.DefineDynamicModule("ModuleName");
var typeBuilder = moduleBuilder.DefineType(string.Format("EventA{0}", query.Store), TypeAttributes.Public);
typeBuilder.DefineDefaultConstructor(MethodAttributes.Public);
var newType = typeBuilder.CreateType();
using (var messageProducer = _messageService.CreateMessageProducer())
{
var message = MessageFactory.Create(newType.CreateInstance());
messageProducer.Publish(message);
}
return result;
}
Here is my consumer
public class ServerAppHost : AppHostHttpListenerBase
{
private readonly string _store;
public string StoreQueue => $"EventA{_store}";
public ServerAppHost(string store) : base("Express Light Server", typeof(PubSubServiceStatsService).Assembly)
{
_store = store;
}
public override void Configure(Container container)
{
container.Register<IRedisClientsManager>(new PooledRedisClientManager(ConfigurationManager.ConnectionStrings["Redis"].ConnectionString));
var assemblyBuilder = Thread.GetDomain().DefineDynamicAssembly(new AssemblyName("ArbitaryNamespace"), AssemblyBuilderAccess.Run);
var moduleBuilder = assemblyBuilder.DefineDynamicModule("ModuleName");
var typeBuilder = moduleBuilder.DefineType(StoreQueue, TypeAttributes.Public);
typeBuilder.DefineDefaultConstructor(MethodAttributes.Public);
var newType = typeBuilder.CreateType();
var mi = typeof(Temp).GetMethod("Foo");
var fooRef = mi.MakeGenericMethod(newType);
fooRef.Invoke(new Temp(container.Resolve<IRedisClientsManager>()), null);
}
}
public class Temp
{
private readonly IRedisClientsManager _redisClientsManager;
public Temp(IRedisClientsManager redisClientsManager)
{
_redisClientsManager = redisClientsManager;
}
public void Foo<T>()
{
var mqService = new RedisMqServer(_redisClientsManager);
mqService.RegisterHandler<T>(DoWork);
mqService.Start();
}
private object DoWork<T>(IMessage<T> arg)
{
//Do work
return null;
}
}
What this gives me is the flexibility of Pub/Sub with the durability of a Queue. Does anyone see/know of a more "native" way to achieve this?

Answer 1

There should only be 1 MQ Host registered in your AppHost so I'd firstly remove it out of your wrapper class and have it just register the handler, e.g:
public override void Configure(Container container)
{
//...
container.Register<IMessageService>(
c => new RedisMqServer(c.Resolve<IRedisClientsManager>());
var mqServer = container.Resolve<IMessageService>();
fooRef.Invoke(new Temp(mqServer), null);
mqServer.Start();
}
public class Temp
{
private readonly IMessageService mqServer;
public Temp(IMessageService mqServer)
{
this.mqServer = mqServer;
}
public void Foo<T>() => mqService.RegisterHandler<T>(DoWork);
}
But this approach isn't good fit for ServiceStack which encourages the use of code-first Messages which defines the Service Contract that client/servers use to process the messages that are sent and received. So if you want to use ServiceStack for sending custom messages I'd recommend either having a separate class per message otherwise have a generic Type like SendEvent where the message or event type is a property on the class.
Otherwise if you want to continue with custom messages don't use RedisMqServer, you can just use a dedicated MQ like Rabbit MQ or if you prefer use a Redis List directly - which is the data structure that all Redis MQ's use underneath.