Back at the beginning of the year I wrote a blog post about the awkward conflict that BizTalk faced now that WF was on the scene.  Although at the time of writing there was an obvious cross over between the products, BizTalk still offered a number of key advantages over bog standard workflow. Due to some emails I received I decided to look around Microsoft's code projects and see what I could find. It was way back in Feb that I came across OSLO.

9 Months later and with PDC out of the way, OSLO and Microsofts strategy for WF is far more clear. OSLO seemed to evolve over the last few months into the codename primarily used for the modelling language and toolset announced. Microsoft also showed off a whole new version of WF for .NET 4.0. This new version of WF comes with some major improvements.

• WF has been rewritten from the ground up.
• Performance has been dramatically increased
• Services and Workflow can be written purely with XAML
• A new customisable designer surface
• Large number of new activities for developing workflows
• Seamless integration with WCF

So with WF being upgraded to a spanky new version which offers a wealth of new features please bare in mind that BizTalk'ers are still waiting for their orchestration engine to be updated to use the new WF engine. Given the new version of WF being announced I would be wondering how long its going to take before I see that in BizTalk?

Back to the original OSLO article I found way back in Februrary, the article talked of a new WF hosting engine. This part of the puzzle we now know has been codenamed "Dublin". If you haven't heard of Dublin yet and your into BizTalk then hold your breath as the diagram below (taken from MSDN) may look familiar.

 Dublin is the application server that has long been missing from the Microsoft product set. Announced to be a part of Windows Server , Dublin provides a runtime which hosts WF workflows and provides services for persistence, tracking, management, message forwarding and much more. The Dublin runtime is implemented on SQL Server server which allows WF developers to create long running workflows. Prior to Dublin this was only possible by either rolling your own or implementing BizTalk.

Is this sounding familiar to you? Well it doesn't stop there I'm afraid. Dublin can also run as part of farm of servers whereby each instance  can use a single shared persistence store. Dublin also provides automatic workflow activation as part of its message routing architecture.

As you can see Dublin is the future. Even Microsoft recognise the awkward overlap of features as evidenced by this MSDN article.

For anybody familiar with BizTalk Server, looking at “Dublin” might cause a slight sense of déjà vu. Supporting workflow-based logic, providing a monitoring and management infrastructure: These are things that BizTalk Server does today. What’s the future of BizTalk Server in a “Dublin” world?

The key thing to understand is that “Dublin” doesn’t directly target traditional BizTalk scenarios. For example, enterprise application integration and business-to-business connections via EDI will still use BizTalk Server. Similarly, bringing existing applications into the service-oriented world by exposing their functions and/or data through BizTalk Server will continue to make sense. While the reach of “Dublin” may grow over time, BizTalk Server remains important for connecting the Microsoft application platform to the diverse systems common in most enterprises.

If an organization needs an application container for WCF services, however, especially those implemented using WF, “Dublin” is a better choice—this is what it’s designed for. And expect BizTalk Server’s connection with “Dublin” to get stronger: Look for a future release after BizTalk Server 2009 to build on the “Dublin” infrastructure. Even though the functions of BizTalk Server and “Dublin” appear to overlap in some ways, each technology has a clear role to play. 

So where do we stand? In my opinion I think BizTalks days are numbered, apart from some BAM, Adaptors and some tools there is very little separating the two technologies. Key to remember is that Dublin is where the innovation is happening and I dont expect to see that change.  If your a BizTalk dev today I recommend getting yourself orientated with WF and Dublin asap.