Enterprise Service Bus libraries for .NET – Shuttle ESB

One in a series of posts giving a quick overview of ESB libraries for .NET

Shuttle ESB describes itself as a “free .NET open-source enterprise service bus”. It supports a good range of transports and integrates with a number of IoC containers.

https://github.com/Shuttle/shuttle-esb

Messages

A POCO class

Publishing

Publish using IServiceBus. You’ll also make use of static methods from the ServiceBus class.

using (var bus = ServiceBus.Create(resolver).Start())
{
    bus.Publish(new MemberRegisteredEvent
    {
        UserName = "Mr Resistor"
    });
}

Subscribing

A handler implements IMessageHandler

public class MemberRegisteredHandler : IMessageHandler<MemberRegisteredEvent>
{
    public void ProcessMessage(IHandlerContext<MemberRegisteredEvent> context)

    {
        Console.WriteLine();
        Console.WriteLine("[EVENT RECEIVED] : user name = ‘{0}’", context.Message.UserName);
        Console.WriteLine();
    }
}

You also need to tell the subscription manager that you want to subscribe to a particular event. resolver is a wrapper class for your specific container.

resolver.Resolve<ISubscriptionManager>().Subscribe<MemberRegisteredEvent>();

Enterprise Service Bus libraries for .NET – Nimbus

One in a series of posts giving a quick overview of ESB libraries for .NET

Nimbus primarily supports the Azure Service Bus as a transport, so if your application is going to run in Azure, then this could be a good choice.

https://github.com/NimbusAPI/Nimbus/wiki/Publishing-an-Event-on-the-Bus

Messages

Event messages should implement IBusEvent

Publishing

Publish with an instance of IBus

_bus.Publish(new NewOrderReceived {CustomerName = "Ricky Bobby"});

Subscribing

Handle events by implementing IHandleMulticastEvent

public class ListenForNewOrders : IHandleMulticastEvent
{

    public async Task Handle(NewOrderReceived busEvent)
    {
        Console.WriteLine("I heard about a new order from " + busEvent.CustomerName);

        //Do more stuff
    }
}

Enterprise Service Bus libraries for .NET – MassTransit

One in a series of posts giving a quick overview of ESB libraries for .NET

MassTransit is an open-source library which apparently began as a response to some perceived deficiencies in the version of NServiceBus that was around in 2007. The project did a major rewrite in 2014, introducing async support and switching from MSMQ to RabbitMQ as the preferred transport.

Messages

Messages are POCO classes. There is no requirement to inherit from any base class or implement a specific interface.

Publishing

http://masstransit-project.com/MassTransit/usage/producing-messages.html

Messages are published using IPublishEndpoint, which is provided by ConsumeContext for consumers or by the IBus interface

public async Task NotifyOrderSubmitted(IPublishEndpoint publishEndpoint)
{
    await publishEndpoint.Publish<OrderSubmitted>(new
    {
        OrderId = "27",
        OrderDate = DateTime.UtcNow,
    });
}

Subscribing

http://masstransit-project.com/MassTransit/usage/message-consumers.html

A subscribing class (or consumer) implements the IConsumer<T> interface.

public class UpdateCustomerConsumer :
    IConsumer<UpdateCustomerAddress>
{
    public async Task Consume(ConsumeContext<UpdateCustomerAddress> context)
    {
        await Console.Out.WriteLineAsync($"Updating customer: {context.Message.CustomerId}");

        // update the customer address
    }
}

A consumer needs to be connected to an endpoint to receive messages

var busControl = Bus.Factory.CreateUsingRabbitMq(cfg =>
{
    var host = cfg.Host(new Uri("rabbitmq://localhost/"), h =>
    {
        h.Username("guest");
        h.Password("guest");
    });

    cfg.ReceiveEndpoint(host, "customer_update_queue", e =>
    {
        e.Consumer<UpdateCustomerConsumer>();
    });
});