Alternatives to Windows Workflow Foundation?

Question

I've been using WWF for a while as part of an internal call center application (ASP.NET), and while learning it was a good practice in understanding how a state machine based workflow system should work, I am definitely not in love with WWF itself. In my opinion it is:

1. Overly complex, especially for use within web apps (all that threaded runtime stuff)
2. Immature (ever worked with that horrible designer?)
3. Anemic in its current feature set

Does anyone have a suggestion for a better .NET based workflow framework? Specifically, I am looking for the following features:

1. State machine based (mapping states to available actions)
2. A focus on user permissions (controlling who has access to what actions)
3. The ability to run workflows as timed background tasks (for example, to send out reminders for items that have been sitting in a certain state for x days)

That's really all I need. I don't need to be able to "drag and drop" any activities or visually design the flow. I am perfectly comfortable writing actual code once a particular action is triggered.

Answer 1

You could try Simple State Machine. You would have to implement access control and background timers yourself, but that shouldn't be a big deal. SSM was also built out of frustration with WF. There are some other state machine implementations on Codeplex as well. If one of them doesn't fit he bill out of the box, they are open source and should get you close enough.

I wholeheartedly agree with you about state machines in WF - they aren't testable, are too complicated, the threading model is peculiar and hard to follow, and I'm not sure a visual designer could have been more poorly conceived for designing state machines graphically. I think this may be because the state machine concept feels tacked onto the WF runtime, which was designed for sequential state machines, something WF does a much better job with, in my opinion. The problem is that state machines are really not the same animal as a sequential work flow, and should have been given a first class implementation of their own, because the warping of WF to make it seem to support them turned out to be more or less unsupportable, if not actually unusable.

Answer 2

I would stay away from Drools.Net since it's last SVN commit was in September 2007. Looks nice but it seems a bit too risky to make such a big library part of your project when you know it doesn't get any attention anymore.

Answer 3

Try Drools.NET

Answer 4

Have a look at Workflow Engine. It is a lightweight workflow framework for .NET and Java solutions. It has an HTML5 visual designer, version control, a decent UI and supports a wide range of databases.

Answer 5

Do you have the option to consider BizTalk Server?

Answer 6

I quite enjoyed working with Oracle BPEL Process Manager. It's part of JDeveloper.

http://www.oracle.com/technology/bpel/index.html http://gemsres.com/story/dec06/313602/jellema-fig1.jpg

Answer 7

You may want to take a look at Jazz - http://jazz.codeplex.com/

Answer 8

Try WF4.5. It was completely redesigned since .NET4.0.

Answer 9

First of all you should look for a engine supporting BPMN. BPMN is a standard in Workflow and Process management and well supported from a lot of projects. Second you should think about the requirements to thus an engine. When you look for a BPMN Engine, there are two different approaches:

Task-Orientated

These engines (e.g. JBoss BPM - jbpm) are designed to process an input data by a well defined process model. Each task in the model gives the control to a piece of code - either a standard or an individual implementation. The process ends when the process-token reaches the end of the process model (End-Event). This kind of processing takes milliseconds. The engine can be used for batch jobs or processing data with a complex process orientated flow.

Event-Driven

Human-Centric workflow engines are event driven (e.g. Imixs-Workflow). This is a kind of state machine but offers typically much more functionality. You can start a new processinstance by assigning your business object with the initial task (defined by the start event). Than the workflow engine allows you to trigger events assigned to each task, defined in your model. Each event (Intermediate CatchEvent) triggers the workflow engine to transfer the running processinstance to the next task (state). Until no new event is triggered, the processinstance 'waits' in the current task (state). An approval process is an typical example for this kind of human-centric workflow.

You can find a list of engines here.