The document discusses the history and development of various workflow engines in the Zope/Plone ecosystem, including state-based and activity-based workflows. It highlights the enhancements made to the zope.wfmc project and related tools, along with challenges faced in workflow management such as irreversibility and simulation requirements. Future plans include supporting users in workflow creation and improving the user experience through simulations and debugging features.

2. Since 2006
Anton (9) Konrad (6)

3. Jun 2001
Zope/Plone Workflow Relationship
Feb 2001
Products.CMFCore.WorkflowCore
Dec 2004 May 2006
Infrastructure for workflow development
Core engine capability for Plone created
Products.DCWorkflow
Implementation of a CMF workflow
Filled Out Functionality
zope.wfmc
Workflow Engine based on WfMC XPDL
Attempt to standardize with
development communities
hurry.workflow
Simple Zope 3 workflow engine
Modelled after CMFWorkflow
2013 zope.wfmc is
resurrected!
20132011

4. State-Based
Workflows
Examples: Products.DCWorkflow and
hurry.workflow
State is stored on a target
Transitions between states are defined
Transitions between states are defined
(including permissions, etc.)
State Machine ("Workflow Engine")
- Manages states and transitions
- Manages progression of states

5. Simple State-Based Publication Workflow

6. State-Based
Workflows:
One process manages single target
Only one state can be maintained at a time
The Reality
Problems
.NET and Java world have adopted this design pattern
Are we
to blame?

7. Activity-Based
Workflows
Examples: zope.wfmc
Business Process Model and Notation
(BPMN) is a graphical representation
XPDL is an XML-based serialization
format for BPMN
Editor: Java Workflow Editor (JaWE)
- Developed by the Workflow Management
Coalition (WfMC)
- BPMN 1.0 did not specify a serialization
format.
- XPDL is obsolete with BPMN 2.0 which
defines an XML serialization format

8. Simple Activity-Based Publication Workflow

9. Challenges
Workflow is too high-level to be
machine processable
Engine provides little (trivial) value
Only benefit is graphical presentation
and easy modification
- But publication workflow is too simple for
that to matter.

10. Realistic Publication Workflow
Demo

11. Workflow Engine
Requirements
Security
Machine executable
Full User Interface generation
(and other IO)
- But publication workflow is too simple
for that to matter.
Back and Forth
Discarding with clean up
Exception Handling
Migrations
- Input Data Retention

12. zope.wfmc enhancements
Parameter InitialValue Support
OTHERWISE Condition
Script Tag Support
Arguments are dictionaries, not lists! (Jim!!!)
Deadlines Support
XPDL 2.1 Support
Extended Attributes Support
Participant Types / Candidates Support
Subflow (sync & async) & TaskScript Support
DataField Support

13. Small activity label position
(Start, Finish, Gates)
Lots of small bug fixes
JaWE Enhancements
Script Support
External Editor
Support

14. Discarding
● Requires reversable applications/workitems (operations)
● Process must keep track of finished activities
● Deal with irreversible actions
﹣ Make workflow non-discardable
﹣ May not be reverted on discard

15. Back & Forth
● Requires Revert of activities in correct order
● Restore workflow state properly
● Remember inputs (not fully solved yet)
● It's a very hard problem! (6mm effort)

16. Wizard
● Wizard entries specified via Extended Attribute
● Needs to be generated from workflow definition itself
● No state available
﹣ Relies on default transitions and lane assignments
● Also, a very hard problem. (3mm effort)

17. Simulations
● Automatic Testing of Workflows
﹣ Coverage Included
● Strategy: Provide activity completion
instructions
﹣ Implemented on API and UI level!
● Savepoints
● Debugging
● Screenshots
● Parameterized Simulations allow for complex
sampledata setups (onions)

18. Quality Assurance
● Executes each simulation on multiple
browsers
﹣ Provides PDFs with screenshots for each
browser
● Visualizes workflow paths and coverage
● Shows all output artifacts (documents,
changed data, etc.)
● Linter: External links, spell check, data
integrity, etc.

19. Future
● Shoobx Chronicles (Support/Help)
﹣ Convert onion instructions to readable documents
● Simulation video recordings (Support/Help)
● Support Power Users to create Workflows (Process Editor
UX)
● Personal: Bike across the US :-)

20. Questions?
Comments?

21. Links
● Shoobx zope.wfmc: https://github.com/Shoobx/zope.wfmc
● Java Workflow Editor: https://sourceforge.net/projects/jawe/
● BPMN: http://www.bpmn.org/
● WfMC/XPDL: http://www.wfmc.org/

22. Help us Improve
Please use the survey app to send us feedback.
http://ploneconf.sixfeetup.com