[What's new in WCF4] Protocol bridging & fault tolerance with the Routing Service - or: "Look ma: Really just one service to talk to!"

[Note: all the information was gathered based on a close-to-Beta 1 build of .NET Framework 4.0 and Visual Studio 2010. Details may vary and change]

Let's look at some more features of the new RoutingService in WCF4.
We are going to expose our RoutingService via an basicHttpBinding-based request-reply endpoint:

<service behaviorConfiguration="routingData"
  name="System.ServiceModel.Routing.RoutingService">
    <host>
      <baseAddresses>
        <add  baseAddress="http://localhost:7777/Services/Universal"/>
      </baseAddresses>
    </host>

    <endpoint address=""
              binding="basicHttpBinding"
              name="requestReplyEndpoint"
              contract="System.ServiceModel.Routing.IRequestReplyRouter" />
</service>

Then 'internally' we have two business services, HelloService1 and HelloService2 :)
One of them is exposed via a basicHttpBinding-based endpoint, the other one uses netTcpBinding.

We can now configure our router in such a way that it still accepts incoming messages via basicHttpBinding (actually we just did that and do not need to change anything) but can route messages to the netTcpBinding-based service.

<client>
  <endpoint name="HelloService1"
            address="net.tcp://localhost:7778/Services/Hello"
            binding="netTcpBinding"
            contract="*" />
  <endpoint name="HelloService2"
            address="http://localhost:7777/Services/Hello"
            binding="basicHttpBinding"
            contract="*" />
</client>

OK, great.
Our routing table looks like this, which means we will always (try to) route to the netTcpBinding-based service.

<routingTables>
    <table name="mainRoutingTable">
      <entries>
        <add filterName="xPath1" endpointName="HelloService1" />
      </entries>
    </table>
</routingTables>

But what happens if *** happens?
We can specify alternate endpoints which will be called when a CommunicationException or TimeoutException occurs in the RoutingService while calling the original target endpoint.

<routingTables>
    <table name="mainRoutingTable">
      <entries>
        <add filterName="xPath1" endpointName="HelloService1" alternateEndpoints="endpointsList" />
      </entries>
    </table>
</routingTables>
<alternateEndpoints>
<list name="endpointsList">
    <endpoints>
        <add endpointName="HelloService2" />
        <!--<add endpointName="HelloService3" />-->
    </endpoints>
</list>
</alternateEndpoints>

We can have as many alternate endpoints as we like, in this sample it is just one active one, namely our HelloService2 which is exposed via a basicHttpBinding endpoint.

That's it: protocol bridging & fault tolerance with the Routing Service in WCF4.

Comments

[Michel Girard]

Can you add the app.config of the client !

[company logo design]

Well don't know whats going on but its not a Good way to do this. in my opinion we have to look again about this issue