(WF4) WF4 Sessions from //build/

As I mentioned earlier this week there were two WF focused sessions at //build/ this week. Now they’re done, but the videos are available online.

Of course, also this week, at //build/ the developer previews of Windows 8, .Net Framework 4.5, and Visual Studio 11 were announced. For VS and .net you can even go download them now and start playing with it straight away. Please read the general info, limitations, etc. first.

Building event-driven, long-running apps with Windows workflow 

This talk is similar to some of Ron’s previous talks such as PDC last year. The .Net 4.5 stuff starts about 16 minutes into the talk, and there isn’t too much new versus previous talks. Some of what there is:

New in the Visual Studio side are C# Expressions, support for Contract-first WCF development in WF, State Machine (which was already available in platform update, but finally becomes part of a standard framework install) and a bunch of other usability improvements.

New in the runtime side are support for workflow dynamic updates, an expression extensibility story, and running workflows under partial trust.

Building apps with Windows Workflow Foundation and Windows Azure

This talk is actually highly focused on WF4, not WF4.5, but I thought it is a very nice talk.

-it explains options for hosting WF on Azure, and does a good Worker vs Web role walkthrough
-it compares WF hosts (WorkflowApplication, WorkflowServiceHost)
-the realistic end-to-end demo of development of how to get an actual WF service application running in the cloud [emulator]
-Josh even hits a common gotcha with persistence timeouts in his talk, and is saved by the audience, so you get to see what not to do if you’re building the similar app

Finally, about 45 minutes in, comes the highlight of Josh's talk - he announces support for Workflows running as a service in Azure with high density!

It's a work in progress, not released yet, but I think there's a lot to be excited about here, or at least two really good things - low cost, and ease-of-use. Unlike the rest of his talk, there's no need to worry about choosing a host, allocating Azure worker roles, waiting 15 minutes to deploy the roles on the cloud, etc. Also, you're not paying for unused CPU time. Good stuff. It comes with a REST based programming model for managing the workflows.