CODEWITHSUNDEEP
c#castle-windsorrebus
pete the pagan-gerbil
pete the pagan-gerbil

Reputation: 3166

Publishing to multiple Rebus queues with different stores

We have one application that publishes messages - PublishApp.

The messages (MessageA and MessageB) are picked up by two different consumer apps (ConsumerA and ConsumerB).

All applications use SQL Server as a transport and Windsor configuration, but the two Consumers have different databases in SQL Server.

How can we configure PublishApp to publish MessageA for ConsumerA and MessageB for ConsumerB?

I have tried using DetermineMessageOwnership as described here, but that doesn't seem to actually be called (no breakpoints hit). I'm a little mystified as to what the string endpoints returned should be.

I was hoping that I could set up an IBus component in Windsor with a specific name, then reference that by name when setting up my MessageB-publishing class. However it's not clear how to set up an IBus in Windsor outside of the magic box that does it all for me.

Fiddling with Windsor configuration leads me to a Windsor error if I try to call Configure.With(new WindsorContainerAdapter(container)) twice, as it is interpreted as registering the IBus interface twice. I can't see an extension point here to give one of the IBus instances a name, and hence differentiate them in Windsor.

Alternatively, trying to reuse the Configure.With... call throws an error telling me I have called .Transport() on the configurer twice, which is also not allowed (but which would let me use a different connection string...)

Adding XML configuration will let me specify different endpoints for my different messages, but not different SQL connection strings.

What I would really like to end up with is something like:

// Set up Bus A
var busA = Configure.With(new WindsorContainerAdapter(container))
    .Transport(tc => tc.UseSqlServerInOneWayClientMode("ConnectionStringA"))
    .Subscriptions(sc => sc.StoreInSqlServer("ConnectionStringA", "RebusSubscriptions"))
    .CreateBus()
    .Start();

// Set up Bus B
var busB = Configure.With(new WindsorContainerAdapter(container))
    .Transport(tc => tc.UseSqlServerInOneWayClientMode("ConnectionStringB"))
    .Subscriptions(sc => sc.StoreInSqlServer("ConnectionStringB", "RebusSubscriptions"))
    .CreateBus()
    .Start();

// Register Bus A in Windsor
container.Register(Component.For<IBus>()
    .Named("BusA")
    .Instance(busA));

// Register a class that depends on IBus, and set it to use Bus A
container.Register(Component.For<IPublishA>()
    .ImplementedBy<PublishA>()
    .DependsOn(Dependency.OnComponent(typeof(IBus), "BusA"));

// And a registration also for IBus B, and for IPublishB to reference named "BusB"

Note: I do not want to listen to multiple buses, only publish events to them. Other applications are monitoring the queues, and each application only listens for one event on one queue.

Upvotes: 1

Views: 1366

Answers (2)

pete the pagan-gerbil
pete the pagan-gerbil

Reputation: 3166

We resolved this in the end by dropping the WindsorContainerAdaptor. Since we're not handling any messages, only publishing/sending, we don't need any of the 'handler' stuff in the container adaptor and we can switch the registration of the IBus component around to happen outside of the configuration/starting, rather than inside it. This gives us the control to name the IBus registration.

    public static void ConfigureAndStartBus(IWindsorContainer container)
    {
        _RegisterBus(container, "ConnectionStringA" "BusA");
        _RegisterBus(container, "ConnectionStringB" "BusB");
    }

    private static void _RegisterBus(IWindsorContainer container, string connectionString, string busName)
    {
        var bus = Configure.With(new BuiltinContainerAdapter())
            .Transport(tc => tc.UseSqlServerInOneWayClientMode(connectionString))
            .Subscriptions(sc => sc.StoreInSqlServer(connectionString, "RebusSubscriptions"))
            .CreateBus()
            .Start();

        container.Register(
            Component.For<IBus>()
                .Named(busName)
                .LifestyleSingleton()
                .Instance(bus));
    }

Then in class PublishA, we can register it with a dependency on BusA, and PublishB can be registered with a dependency on BusB. The messages go to separate databases, and are picked up by separate subscribers to do work in those different databases.

Upvotes: 3

mookid8000
mookid8000

Reputation: 18628

First off: There's no way (at least at the moment) to ship messages between two SQL Server databases. In order for messages to be sent/published between endpoints, you need to use one single table in one shared database.

Your setup hints at something being off there, since you're using "ConnectionStringA" and "ConnectionStringB" for the transports.

It's not clear to me whether you actually want/need to do pub/sub messaging - pub/sub is what you would usually use when you want multiple recipients of each message, which would usually be some kind of event (i.e. a message whose name is in the past tense, as in: "this and that happened").

If you want one specific recipient for a message, you want to bus.Send that message, and that is when your endpoint mappings will be hit in order to get a destination for the message.

If you tell me some more about exactly what you're trying to achieve, I am sure I can help you :)

Upvotes: 0

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