Remember to download the samples from the GitHub repository.

Running

When using Visual Studio 2017 the NuGet packages should be restored automatically. If you find that they do not or if you are using an older version of Visual Studio please execute the following in a Visual Studio command prompt:

cd {extraction-folder}\Shuttle.Esb.Samples\Shuttle.Distribution
nuget restore

Once you have opened the Shuttle.Distribution.sln solution in Visual Studio set the following projects as startup projects:

  • Shuttle.Distribution.Client
  • Shuttle.Distribution.Server
  • Shuttle.Distribution.Worker

Implementation

When you find that a single endpoint, even with ample threads, cannot keep up with the required processing and is falling behind you can opt for message distribution.

When using a broker architecture (such as RabbitMQ) you do not need to use message distribution as workers can all access the same inbox work queue.

Plesae note that the project structure here is used as a sample to facilitate the execution of the solution. In a real-world scenario the endpoint project would not be separated into a distributor and a worker; rather, there would be a single implementation and you would simply install the service multiple times on, possibly, multiple machines and then configure the workers and distributor as such. When using shuttle as the distribution mechanism there is always a 1 to N relationship between the distribution endpoint and the worker(s).

However, for a broker-style queueing mechanism such as RabbitMQ you do not need to use shuttle to perform any distribution as RabbitMQ would have a consumer for each thread irrespective of where it originates from.

In this guide we’ll create the following projects:

  • a Console Application called Shuttle.Distribution.Client
  • a Console Application called Shuttle.Distribution.Server
  • a Console Application called Shuttle.Distribution.Worker
  • a Class Library called Shuttle.Distribution.Messages that will contain all our message classes

Messages

Create a new class library called Shuttle.Distribution.Messages with a solution called Shuttle.Distribution

Note: remember to change the Solution name.

RegisterMemberCommand

Rename the Class1 default file to RegisterMemberCommand and add a UserName property.

namespace Shuttle.Distribution.Messages
{
	public class RegisterMemberCommand
	{
		public string UserName { get; set; }
	}
}

Client

Add a new Console Application to the solution called Shuttle.Distribution.Client.

Install the Shuttle.Esb.Msmq nuget package.

This will provide access to the Msmq IQueue implementation and also include the required dependencies.

Install the Shuttle.Core.Unity nuget package.

This will provide access to the Unity dependency container implementation.

Add a reference to the Shuttle.Distribution.Messages project.

Program

Implement the main client code as follows:

using System;
using Shuttle.Core.Unity;
using Shuttle.Distribution.Messages;
using Shuttle.Esb;
using Unity;

namespace Shuttle.Distribution.Client
{
    internal class Program
    {
        private static void Main(string[] args)
        {
            var container = new UnityComponentContainer(new UnityContainer());

            ServiceBus.Register(container);

            using (var bus = ServiceBus.Create(container).Start())
            {
                string userName;

                while (!string.IsNullOrEmpty(userName = Console.ReadLine()))
                {
                    bus.Send(new RegisterMemberCommand
                    {
                        UserName = userName
                    });
                }
            }
        }
    }
}

App.config

Create the shuttle configuration as follows:

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
	<configSections>
		<section name='serviceBus' type="Shuttle.Esb.ServiceBusSection, Shuttle.Esb"/>
	</configSections>

	<serviceBus>
		<messageRoutes>
			<messageRoute uri="msmq://./shuttle-server-work">
				<add specification="StartsWith" value="Shuttle.Distribution.Messages" />
			</messageRoute>
		</messageRoutes>		
	</serviceBus>
</configuration>

This tells Shuttle that all messages that are sent and have a type name starting with Shuttle.Distribution.Messages should be sent to endpoint msmq://./shuttle-server-work.

Server

Add a new Console Application to the solution called Shuttle.Distribution.Server.

Install the Shuttle.Esb.Msmq and Shuttle.Core.Unity nuget packages.

This will provide access to the Msmq IQueue implementation and also include the required dependencies.

Install the Shuttle.Core.ServiceHost nuget package.

The default mechanism used to host an endpoint is by using a Windows service. However, by using the Shuttle.Core.ServiceHost we are able to run the endpoint as a console application or register it as a Windows service for deployment.

Program

Implement the Program class as follows:

using Shuttle.Core.ServiceHost;

namespace Shuttle.Distribution.Server
{
    public class Program
    {
        public static void Main()
        {
            ServiceHost.Run<Host>();
        }
    }
}

Host

Add a Host class and implement the IServiceHost interface as follows:

using Shuttle.Core.ServiceHost;
using Shuttle.Core.Unity;
using Shuttle.Esb;
using Unity;

namespace Shuttle.Distribution.Server
{
    public class Host : IServiceHost
    {
        private IServiceBus _bus;

        public void Start()
        {
            var container = new UnityComponentContainer(new UnityContainer());

            ServiceBus.Register(container);

            _bus = ServiceBus.Create(container).Start();
        }

        public void Stop()
        {
            _bus.Dispose();
        }
    }
}

App.config

Add an Application Configuration File item to create the App.config and populate as follows:

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
	<configSections>
		<section name='serviceBus' type="Shuttle.Esb.ServiceBusSection, Shuttle.Esb"/>
	</configSections>

	<serviceBus>
		<control 
			workQueueUri="msmq://./shuttle-server-control-inbox-work" 
			errorQueueUri="msmq://./shuttle-samples-error" />

		<inbox
		   distribute="true"
		   workQueueUri="msmq://./shuttle-server-work"
		   errorQueueUri="msmq://./shuttle-error" />
	</serviceBus>
</configuration>

This will instruct the endpoint to *only distribute messages since the distribute attribute is set to true. If it is set to false then the endpoint will process an incoming message if a worker thread is not available.

It also configures the control inbox that the endpoint will use to process administrative messages.

Worker

Add a new Console Application to the solution called Shuttle.Distribution.Worker.

Install the Shuttle.Esb.Msmq and Shuttle.Core.Unity nuget packages.

This will provide access to the Msmq IQueue implementation and also include the required dependencies.

Install the Shuttle.Core.ServiceHost nuget package.

The default mechanism used to host an endpoint is by using a Windows service. However, by using the Shuttle.Core.ServiceHost we are able to run the endpoint as a console application or register it as a Windows service for deployment.

Add a reference to the Shuttle.Distribution.Messages project.

Program

Implement the Program class as follows:

using Shuttle.Core.ServiceHost;

namespace Shuttle.Distribution.Worker
{
    public class Program
    {
        public static void Main()
        {
            ServiceHost.Run<Host>();
        }
    }
}

Host

Add a Host class and implement the IServiceHost interface as follows:

using Shuttle.Core.ServiceHost;
using Shuttle.Core.Unity;
using Shuttle.Esb;
using Unity;

namespace Shuttle.Distribution.Worker
{
    public class Host : IServiceHost
    {
        private IServiceBus _bus;

        public void Start()
        {
            var container = new UnityComponentContainer(new UnityContainer());

            ServiceBus.Register(container);

            _bus = ServiceBus.Create(container).Start();
        }

        public void Stop()
        {
            _bus.Dispose();
        }
    }
}

App.config

Add an Application Configuration File item to create the App.config and populate as follows:

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
	<configSections>
		<section name='serviceBus' type="Shuttle.Esb.ServiceBusSection, Shuttle.Esb"/>
	</configSections>

	<serviceBus>
		<worker 
			distributorControlWorkQueueUri="msmq://./shuttle-server-control-inbox-work" />
			
		<inbox
			workQueueUri="msmq://./shuttle-worker-work"
			errorQueueUri="msmq://./shuttle-error" />
	</serviceBus>
</configuration>

This configures the endpoint as a worker and specifies the control inbox of the distributor to notify when a thread is available to perform work.

RegisterMemberHandler

Add a new class called RegisterMemberHandler that implements the IMessageHandler<RegisterMemberCommand> interface as follows:

using System;
using Shuttle.Esb;
using Shuttle.Distribution.Messages;

namespace Shuttle.Distribution.Worker
{
	public class RegisterMemberHandler : IMessageHandler<RegisterMemberCommand>
	{
		public void ProcessMessage(IHandlerContext<RegisterMemberCommand> context)
		{
			Console.WriteLine();
			Console.WriteLine("[MEMBER REGISTERED --- WORKER] : user name = '{0}'", context.Message.UserName);
			Console.WriteLine();
		}
	}
}

This will write out some information to the console window.

Run

Set both the client and server projects as the startup.

Execute

Execute the application.

The client application will wait for you to input a user name. For this example enter my user name and press enter:

You will observe that the server application forwards the message to the worker.
The worker application will perform the actual processing.

You have now implemented message distribution.