In this PDC session, Nicholas Allen, Program Manager at Microsoft Corporation, reviewed various extensibility points in Windows Serer AppFabric workflow hosting .
AppFabric ships with three out-of-the-box extensible workflow hosts:
- Workflow Driven Application – A host for workflows which are used as an execution engine and which do not require WCF interaction to drive them.
- Workflow Service – A host for workflows which require WCF message interactions with the outside world.
- Scaled-Out-Service – A host which includes built-in tools for scaling out a workflow application across servers.
In addition, one can also write a custom host for his own specific purposes and requirements.
Host Extension Points Reviewed
- Persistence Participation – It is now possible to write persistence participants in order to customize the persistence process to the Instance Store.
- Application Identity Correlation – AppFabric supports storing multiple keys or names for each application instance, so that different systems can identify the same application instance by different aspects. For example, your application will identify the instance via a client ID of some sort, and an application of a shipping partner will identify the same instance with a Shipment ID, and the correlation is done by the host.
- Collecting Workflow Events – You can customize the ETW events which are published and collected and published to the DB, and also write custom visualizations on top of this DB in order to support advanced monitoring scenarios custom-fit for your needs.
The Bottom Line
I have shown my enthusiasm from the AppFabric application server before, however I’m not sure I correctly understood all of the extension points reviewed and their internal implementation. In addition, the speaker mentioned that there are additional extension points which were not mentioned during this session. I’ll deep-dive into AppFabric sometime after the PDC and update accordingly.
Want to Know More?
Take a look at the Sela Developer Practice (SDP) homepage, and come join Sasha’s and mine session on “Building Workflow Services with WF 4.0 and WCF 4.0”, hear all the details in person and watch the demos live.