Shuttle Bus之Request/Response模式簡單示例

小弟季義欽發表於2013-08-02
模式

建立類庫工程RequestResponse.Messages：

namespace RequestResponse.Messages
{
    public class MyMessage 
    {
        public string Text { get; set; }
    }
}

建立類庫工程RequestResponse.Server：

using System;
using log4net;
using log4net.Config;
using Shuttle.Core.Host;
using Shuttle.Core.Infrastructure;
using Shuttle.Core.Infrastructure.Log4Net;
using Shuttle.ESB.Core;
using Shuttle.ESB.Modules.ActiveTimeRange;

namespace RequestResponse.Server
{
	public class ServiceBusHost : IHost, IDisposable
	{
		private static IServiceBus bus;

		public void Start()
		{
			Log.Assign(new Log4NetLog(LogManager.GetLogger(typeof(ServiceBusHost))));

			bus = ServiceBus.Create().Start();

            Console.WriteLine("#########server-end bus instance has started");
		}

		public void Dispose()
		{
			bus.Dispose();
			LogManager.Shutdown();
		}
	}
}

　　

using System;
using System.Text;
using RequestResponse.Messages;
using Shuttle.Core.Infrastructure;
using Shuttle.ESB.Core;

namespace RequestResponse.Server
{
    public class ServerMessageHandler : IMessageHandler<MyMessage>
	{
		private int received;

        public void ProcessMessage(HandlerContext<MyMessage> context)
		{
            //伺服器端接受到訊息
            Console.WriteLine("【SERVER-END RECEIVE A MSG，Content："+ context.Message.Text+ "】");
           
            //伺服器端傳送迴應訊息
			context.Bus.SendReply(new MyMessage
					{
						Text = "I have recwived your msg"
					});
		}

        public bool IsReusable
        {
            get { return true; }
        }
	}
}

　

<?xml version="1.0"?>
<configuration>
	<configSections>
		<section name="serviceBus" type="Shuttle.ESB.Core.ServiceBusSection, Shuttle.ESB.Core"/>
    <section name="log4net" type="log4net.Config.Log4NetConfigurationSectionHandler, log4net"/>
	</configSections>

	<serviceBus>
    <control workQueueUri="msmq://./requestresponse-server-control-inbox-work" errorQueueUri="msmq://./shuttle-samples-error" durationToSleepWhenIdle="250ms*25,500ms*10,1s" threadCount="1"/>
    <inbox workQueueUri="msmq://./requestresponse-server-inbox-work" errorQueueUri="msmq://./shuttle-samples-error" durationToSleepWhenIdle="250ms,1s" durationToIgnoreOnFailure="1s" threadCount="1"/>
	</serviceBus>

  <log4net>
    <appender name="ConsoleAppender" type="log4net.Appender.ColoredConsoleAppender">
      <layout type="log4net.Layout.PatternLayout">
        <conversionPattern value="%d [%t] %-5p %c - %m%n"/>
      </layout>
    </appender>
    <appender name="RollingFileAppender" type="log4net.Appender.RollingFileAppender">
      <file value="logs\request-response-server"/>
      <appendToFile value="true"/>
      <rollingStyle value="Date"/>
      <maxSizeRollBackups value="10"/>
      <maximumFileSize value="100000KB"/>
      <datePattern value="-yyyyMMdd.'log'"/>
      <param name="StaticLogFileName" value="false"/>
      <layout type="log4net.Layout.PatternLayout">
        <conversionPattern value="%d [%t] %-5p %c - %m%n"/>
      </layout>
    </appender>
    <root>
      <level value="TRACE"/>
      <appender-ref ref="ConsoleAppender"/>
      <appender-ref ref="RollingFileAppender"/>
    </root>
  </log4net>

<startup><supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.0"/></startup></configuration>

　　　建立控制檯應用程式RequestResponse.Client：

using System;
using log4net;
using RequestResponse.Messages;
using Shuttle.Core.Infrastructure;
using Shuttle.Core.Infrastructure.Log4Net;
using Shuttle.ESB.Core;

namespace RequestResponse.Client
{
	internal class Program
	{
		private static void Main()
		{
            Log.Assign(new Log4NetLog(LogManager.GetLogger(typeof(Program))));

			var bus = ServiceBus.Create().Start();

            Console.WriteLine("###### Client bus started. Press CTRL+C to stop.");
            Console.WriteLine();
			Console.WriteLine("@Press enter to send a message to the server.");
			Console.WriteLine();

            while (true)
            {
                Console.ReadLine();
                //將訊息傳送出去
                bus.Send(new MyMessage{Text = "Client Massage"});
            }
		}
	}
}

　　

using System;
using RequestResponse.Messages;
using Shuttle.Core.Infrastructure;
using Shuttle.ESB.Core;

namespace RequestResponse.Client
{
    public class ClientMessageHandler : IMessageHandler<MyMessage>
    {
		public void ProcessMessage(HandlerContext<MyMessage> context)
    	{
            //客戶端接收到訊息
            Console.WriteLine("【Client-END RECEIVE A MSG, Content:"+ context.Message.Text +"】");
		}

        public bool IsReusable
        {
            get { return true; }
        }
    }
}

<?xml version="1.0"?>
<configuration>
	<configSections>
		<section name="serviceBus" type="Shuttle.ESB.Core.ServiceBusSection, Shuttle.ESB.Core"/>
    <section name="log4net" type="log4net.Config.Log4NetConfigurationSectionHandler, log4net"/>
  </configSections>

  <serviceBus>
		<messageRoutes>
			<messageRoute uri="msmq://./requestresponse-server-inbox-work">
				<add specification="StartsWith" value="RequestResponse"/>
			</messageRoute>
		</messageRoutes>
		<inbox workQueueUri="msmq://./requestresponse-client-inbox-work" journalQueueUri="msmq://./requestresponse-client-inbox-journal" errorQueueUri="msmq://./shuttle-samples-error"/>
		<outbox workQueueUri="msmq://./requestresponse-client-outbox-work" errorQueueUri="msmq://./shuttle-samples-error"/>
	</serviceBus>

  <log4net>
    <appender name="ConsoleAppender" type="log4net.Appender.ColoredConsoleAppender">
      <layout type="log4net.Layout.PatternLayout">
        <conversionPattern value="%d [%t] %-5p %c - %m%n"/>
      </layout>
    </appender>
    <appender name="RollingFileAppender" type="log4net.Appender.RollingFileAppender">
      <file value="logs\request-response-server"/>
      <appendToFile value="true"/>
      <rollingStyle value="Date"/>
      <maxSizeRollBackups value="10"/>
      <maximumFileSize value="100000KB"/>
      <datePattern value="-yyyyMMdd.'log'"/>
      <param name="StaticLogFileName" value="false"/>
      <layout type="log4net.Layout.PatternLayout">
        <conversionPattern value="%d [%t] %-5p %c - %m%n"/>
      </layout>
    </appender>
    <root>
      <level value="TRACE"/>
      <appender-ref ref="ConsoleAppender"/>
      <appender-ref ref="RollingFileAppender"/>
    </root>
  </log4net>

<startup><supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.0"/></startup></configuration>

　　一切就緒。

然後設定解決方案的啟動順序，將server放在client前面。

然後右擊專案RequestResponse.Server，生成，再右擊其屬性，在啟動外部程式中選擇host.exe

然後便可以執行這個解決方案了。

三個問題：

1 內部執行原理？

2 適用場景？

If there is one thing that a service bus should never be used for it is querying. A service bus is geared towards instructing systems what to do (command message); notifying systems of events that have taken place using a publish / subscribe mechanism (event message); and, less frequently, transferring data (document message).

It is perfectly valid to send a command to a system to perform some calculation. The result could then be stored a result store and a notification sent that the calculation has been completed. This is quite different from sending a request for data.

Autonomous Components

With any system it is advisable to isolate tasks and decouple them. In this way each can be implemented independently and versioned independently. By using a specific endpoint / queue to handle a particular message type you have the ability to send a relevant message for processing at any time.

For example, in a tightly-coupled system you may have a process that registers a new user. So after gathering the user information from some front-end the information is submitted for processing:

  • check if the user is blacklisted
  • register the user in the database
  • send an activation e-mail


If this is done in a synchronous fashion the user presses thesubmitbutton and waits. Let's assume our mail server has gone down. Now the user cannot register. What's more is that sending e-mail by using our shared smtp server takes a couple of seconds so during periods of heavy traffic this process takes quite some time.

We could change this process to gather the user information from the front-end and submit it for registration by sending aRegisterUserCommandto our user service. The call returns immediately informing the user that there registration request has been received and they will be contact with the result via e-mail. Now our process will be as follows (autonomous components indicated byAC):

  • User Registration Service (AC) - handlesRegisterUserCommand
    • check blacklisting
      • if user blacklisted sendSendEMailCommandto then e-mail service (AC) to notify user that the details provided (user name / e-mail address / contact numbers) have been blacklisted.
      • if not blacklisted register user in database and sendSendEMailCommandto the e-mail server (AC) and publishesUserRegisteredEvent.
  • E-Mail Service (AC) - handlesSendEMailCommand
    • sends the requested e-mail via our smtp server; if the server is down the message will simply be retried until it goes through
  • CRM User Registration Service (AC) - subscribes toUserRegisteredEvent
    • registers the new user in our CRM


In this way each component can be developed, versioned, and deployed in isolation. Stopping any of the services for deployment would not result in any process breaking since the queues will continue receiving work. Even if the entire machine is brought down Shuttle ESB will still store message on the sending machine when using anoutbox.

3 與MSMQ In WCF的異同？

Web Services / WCF

Some may argue that they use web services and therefore have a service oriented architecture. They would be correct in that they have exposed a service of some sort. There are however many properties of a SOA that are not present when using only web services:

  • Noevent driven architecture(EDA)
    • WS / WCF cannot subscribe to events
  • No durability of messages
    • A message goes across the wire and is not stored anywhere
  • No recoverability
    • Once a message is lost it is gone
  • No lowtemporal coupling
    • A WS must be running in order to invoke it
  • No lowbehavioural coupling
    • We have to know what the service will do in order to invoke it
  • Nomessage routing
    • We send messages to a specific WS to invoke some action
  • No queuing
    • Calls are synchronous and blocking


These are not necessarily bad but do represent some of the properties of a WS.

This does not mean that web services have no place in a SOA. In fact, there are instances where we definitely need them. For external integration they are fine; serving as an entry point into our systems.

這裡是NServiceBus與WCF的對比：http://support.nservicebus.com/customer/portal/articles/861164-nservicebus-and-wcf

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