Monday, May 26, 2008

Metastorm BPM 7.6 and Windows Workflow part 1 - The basics

The new version of Metastorm BPM, 7.6, has several new features (and I may do a full review at some point), but the one that interests me the most is the integration with Windows Workflow. This has been a fairly long time in development, a screenshot appeared on the web about 18 months ago. The first WF integration appeared in 7.5, which allowed BPM functionality to be called from WF workflows. This was not of great interest to me as it always seemed more useful to be able to call WF workflows from Metastorm. This is what has been added in 7.6.

Installation is easy, although a complete re-install is required, rather than an in-place upgrade. An upgrade will update the 7.5 pieces, but will not install the new 7.6 pieces.

The main thing of interest is the new WF designer (called WF Composer) that is used to develop and publish WF workflows to the Metastorm database. It's quite a nice tool, but my main gripe is that it's not Visual Studio. If it's aimed at developers then integration with Visual Studio would be a more preferable solution. Metastorm don't have the resources to produce an alternative to VS and hence any WF designer they produce will always look poor in comparison. Perhaps developers aren't the target audience, but if not then why does it include a C# editor? This is also much less useable than the Visual Studio code editor.

Another problem is that it isn't possible to add your own activities into the Designer. I'd always imagined WF could be used by a non-technical person, but to achieve this would require developers to go off and write activities specific to their organisation, that could then be plugged together by the non-technical people. So to my mind, the Composer isn't suitable for a non-technical person either.

To be fair, the Composer does add some functionality to make life simpler. When creating a workflow, it adds the Process Context activity, which provides access to the data in the BPM folder. It also simplifies adding properties to the workflow, since you can add a property just by selecting a name and a type (much like adding custom variables in Metastorm BPM). This then adds the relevant code to the generated workflow. It also includes some activities that implement familiar Metastorm BPM functions such as Email, Manager, SelectSQL etc. Not all functions are wrapped as activities but the rest can be accessed via the generic EvaluateFunction activity.

Executing workflows from BPM is pretty straightforward. Add the Workflow Support Library to a procedure and then use the Integration Wizard to execute the workflow synchronously or asynchronously. One thing to consider when executing a long-running workflow is how you're going to track its life time. It will have to be executed asynchronously since a synchronous execution will lock up your BPM folder and will also likely time out. You can get hold of the ID of the WF instance when you execute it and the tracking data is stored in the Metastorm database so it should be possible to get hold of the tracking data to display in a Metastorm grid. If your WF workflow must complete before your BPM workflow can continue, you'll probably need to add a timed loopback action to keep checking until your workflow is complete. Alternatively you could send a message back from the WF workflow to inform the Metastorm folder it has finished. There is unfortunately no user interface to view WF instances which could make debugging more difficult.

That all said, I am still interested in getting WF workflows executing in Metastorm BPM. This could be very useful so we can re-use functionality in different workflow environments and even help us to migrate away from Metastorm BPM when we are looking for a cheaper solution. But given that I would like to use Visual Studio to author my workflows how do we get them into Metastorm? I'm going to investigate this and will report back in part 2.

Part 2 - The database tables

Part 3 - Using Visual Studio

Part 4 - Using your own activities

Part 5 - Long running workflows

Part 6 - State machines

2 comments:

Anonymous said...

In fact it is possible to reference assemblies with custom activities. It is available through options in file menu.

All activities from referenced assemblies will appear in toolbox.

Cheers

Doogal Bell said...

Thanks for the info, I've posted a follow-up at http://doogalbellend.blogspot.com/2008/09/metastorm-bpm-76-and-windows-workflow.html which you can correct some more!