Update 15th June 2010: Downloads are now available:

• Udi Dahan on NServiceBus – Part 1.wmv (640x480, BitRate=815, ~400MB)
• Udi Dahan on NServiceBus – Part 1.wmv (560x416, BitRate=643, ~300MB)
• Udi Dahan on NServiceBus – Part 1.wmv (464x352, BitRate=507, ~240MB)
• Udi Dahan on NServiceBus – Part 1.wmv (384x288, BitRate=400, ~220MB)

• Udi Dahan on NServiceBus – Part 2.wmv (1024x768, BitRate=727, ~240MB)
• Udi Dahan on NServiceBus – Part 2.wmv (768x576, BitRate=473, ~175MB)
• Udi Dahan on NServiceBus – Part 2.wmv (560x416, BitRate=308, ~150MB)

I've finally found the time to encode the recording we did when Udi Dahan visited us at NNUG Bergen and presented NServiceBus. In the first video, Udi talks about why or why not you should use a bus. The second video demos NServiceBus in action.

The original plan was to have a screen recording as well as video, but because of some network problems that plan failed. In the first video you can see me hacking on Udi’s computer to try and get the internet connection to work Sorry about that.

We plan to get a permanent solution in place for publishing videos (not my blog ), but for now I’ve posted them here and we'll see how long my server/broadband can withstand the traffic I used IIS Smooth Streaming for this one, so that should help a lot. Let me know if you have any problems. The quality should be quite good so full screen viewing is probably a good option (especially on the second video).

Udi Dahan on NServiceBus – Part 1

Udi Dahan on NServiceBus – Part 2

In my previous post about Azure Services Platform I linked to where you could find David Chappell’s presentation that I attended. Now Børge Hansen have made Clemens Vasters slide decks available too. You can find them all here:

David Chappell (Azure Services Platform): https://cid-88b5769d9bbdf846.skydrive.live.com/self.aspx/Offentlig/Azure%20Services%20Platform--Chappell.pdf

Clemens Vasters (.Net Services overview): https://cid-88b5769d9bbdf846.skydrive.live.com/self.aspx/Offentlig/NETServicesOverview-v2.pptx

Clemens Vasters (.Net Services drilldown): https://cid-88b5769d9bbdf846.skydrive.live.com/self.aspx/Offentlig/NETServicesDrilldown-v2.pptx

If everything goes as planned NNUG Bergen will in August have two great speakers. Dan North from ThoughtWorks and Christian Weyer from Thinktecture! Is that a great lineup or what?! And the best part... it's FREE!

Currently the plan is to have Dan North on stage the 25th of August and Christian Weyer the 27th (Monday and Wednesday). Here's a bit about the two speakers and what they're going to talk about:

Dan is a principal consultant with ThoughtWorks, where he writes software and coaches teams in agile and lean methods. He believes in putting people first and writing simple, pragmatic software. He believes that most problems that teams face are about communication, and all the others are too. This is why he puts so much emphasis on "getting the words right", and why he is so passionate about behaviour-driven development, communication and how people learn. He has been working in the IT industry since he graduated in 1991, and he occasionally blogs at dannorth.net.

At NNUG Dan is going to talk about The relationship between Domain-Driven Design and Behaviour-Driven Development.

 

Christian is co-founder of ThinkTecture, a European software development support company. He has been modeling and implementing distributed applications with Java, COM, DCOM, COM+, Web Services and other technologies for many many years. Recently his focus has been on the ideas and concepts of service-orientation and their practical translation in customer projects with Windows Communication Foundation (WCF) and Windows Workflow Foundation (WF) being the two main technologies applied. Especially the more than natural marriage of WF and WCF currently has gotten his attention.

Christian's talk will be about WCF, but other than that he's quite open to suggestions. I'm thinking it would be interesting to hear about why we should move from Asmx to WCF and the benefits (and any drawbacks) we get from that move. What do you want to know about WCF? Drop me a comment and we'll see what we can do... Be quick though, we need a decision soon.

Christian Weyer has an article on MSDN Mag together with Steve Maine and Dominick Baier about using Windows Process Activation Service (WAS) for non http protocols. Actually it's about much more than that, but that is what I found interesting. Hosting WCF services in WAS gives you the possibility to use NetTcp, Named Pipes and MSMQ protocols. For more info about WAS you should read the article. Anyway, using WAS as a host for WCF services sounds like a good idea. You don't have to create and maintain your own NT Service and you get stuff like "on-demand activation, process health monitoring, enterprise-class manageability and rapid failure protection" for free. But then you also get some lifetime management "features":

"...WAS does demand activation (as you know, the "A" in "WAS" stands for activation). This means that the application domain hosting a service only gets created when a request message comes in. Application domains shut down again after a configurable idle period. There are also several reasons why WAS or the ASP.NET runtime may decide to recycle the application domain or even the whole worker process."

So I suspect there would be some overhead of creating and shutting down the app domain, unless you can set the idle period to infinite of course. And then you have the recycle bit... Hmmm.... Do I want that?

If I were asked: "WAS or NT Service?", I think I'll go for the NT Service, unless there's something I totally missed out on here... which definitely could be the case <smile>.

If you want to try this out you might find these code samples interesting in addition to the article mentioned.

Just a reminder for MSDN Live in Bergen the 23rd of April. This time Microsoft have joined forces with Norwegian .Net User Group and me and John St. Clair are speaking at the last session of the day. I will talk about migration to WCF and John will do Debugging, Tracing, and Administration: Tips & Tricks. Here you'll find details about the "NNUG Agenda".

Just found this whitepaper from Saurabh Gupta at Microsoft comparing different messaging technologies to WCF. Very nice! I have been doing some perf testing myself to justify (don’t ask!) migration to WCF. I will add my results to my blog when I’m finished. First I need to convince management to agree to the migration.

Great news! We have invited Christian Weyer from ThinkTecture to speak at NNUG in Oslo, Bergen and Kristiansand. I’m really looking forward to this. Christian is a well known speaker and especially known for his excelent expertise in SOA.

I had the opportunity to see him talk at TechEd in Barcelona last year, and this guy really knows his stuff. Come to our meeting in Bergen at May 30th and please tell all your friends and co workers!  For those of you not living in Bergen, he will also talk in Oslo the 29th and Kristiansand the 31st. More info will be available at NNUG later.

At work at the moment I’m trying to calculate the migration complexity of our software from .net framework 1.1 to 3.0, with main focus on WCF. Specifically I’ve been doing some test migration of web services to WCF and regenerating our DTO’s to support data contracts. During this test migration an interesting issue came up. With our “old” web services we did our own serialization of DTO’s. Several reasons for that, which I’m not going into now, but this was a bit problematic in WCF at first. I’ll show you a quick example of a typical web service at my company:

[WebMethod]
public XmlNode GetSomeData() {
    return StaticBusiness.GetSomeData().Serialize2XmlNode();
}

In the example I just do a call to a static business method called GetSomeData. The return value from this method (which is one of our DTO’s) is then serialized to an XmlNode by calling Serialize2XmlNode().

In WCF we do not want to handle serialization by our self, so we want WCF to take care of this for us and choose the best serialization mechanism available. So our service in WCF would look something like this:

[ServiceContract()]
public interface IMyService {
    [OperationContract]
    SomeDataObject GetSomeData();
}

public SomeDataObject GetSomeData() {
    return StaticBusiness.GetSomeData();
}

One of the reasons why we did our own serialization in 1.1 was lack of xml serialization support for circular references, but in WCF this is no longer an issue.

So as long as my SomeDataObject  has a data contract it will be serialized and returned to the caller. As you probably have guessed we also de-serialized our DTO’s on the client side (since we returned an XmlNode), but that is now of course handled by WCF. Since we did our own serialization we were not dependent on proxy generation of our DTO’s and we could just reuse the dll on the client side. In our case we had .net on both sides so this was ok. In 1.1 we did it like this:

return SomeDataObject.DeSerialize(MyWebService.GetSomeData());

So I was trying to find a simple way of doing this in WCF. The solution was much simpler than I’d ever expected. By manually generating the proxy and using the /r parameter I was able to bypass proxy serialization of DTO’s. Fantastic!

So a typical call to svcutil would look like this:

svcutil /nologo /out:Proxy.cs /r:C:\Test\DTOs.dll /config:App.config /namespace:*,MyProxies net.tcp://localhost:9000/MyService/tcpmex

This gives me a proxy called Proxy.cs and with my method looking like this:

public DTOs.SomeDataObject GetSomeData
{
    return base.Channel.GetSomeData();
}

This solved a great challenge for us. My next task at hand is to do some performance testing and see if we get the desired performance improvements by using NetTcp as appose to POWS (Plain Old Web Service).

Thanks to Rick Strahl for his great blogpost on this subject.