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1f51db962 Merge pull request #283 from sartography/feature/better_errors 69fb4967e Patching up some bugs and logical disconnects as I test out the errors. cf5be0096 * Making a few more things consistent in the error messages -- so there isn't filename for validation errors, and file_name for WorkflowExceptions. Same for line_number vs sourceline. * Assure than an error_type is consistently set on exceptions. * ValidationExceptions should not bild up a detailed error message that replicates information available within it. 440ee16c8 Responding to some excellent suggestions from Elizabeth: 655e415e1 Merge pull request #282 from subhakarks/fix-workfowspec-dump 1f6d3cf4e Explain that the error happened in a pre-script or post script. 8119abd14 Added a top level SpiffWorklowException that all exceptions inherit from. Aside from a message string you can append information to these exceptions with "add_note", which is a new method that all exceptions have starting in python 3.11 Switched arguments to the WorkflowException, WorkflowTaskException - which now always takes a string message as the first argument, and named arguments thereafter to be consistent with all other error messages in Python. Consistently raise ValidationExceptions whenever we encounter an error anywhere during parsing of xml. The BPMN/WorkflowTaskExecException is removed, in favor of just calling a WorkflowTaskException. There is nothing BPMN Specific in the logic, so no need for this. Consolidated error message logic so that things like "Did you mean" just get added by default if possible. So we don't have to separately deal with that logic each time. Better Error messages for DMN (include row number as a part of the error information) 13463b5c5 fix for workflowspec dump be26100bc Merge pull request #280 from sartography/feature/remove-unused-bpmn-attributes-and-methods 23a5c1d70 remove 'entering_* methods 4e5875ec8 remove sequence flow 5eed83ab1 Merge pull request #278 from sartography/feature/remove-old-serializer 614f1c68a remove compact serializer and references e7e410d4a remove old serializer and references git-subtree-dir: SpiffWorkflow git-subtree-split: 1f51db962ccaed5810f5d0f7d76a932f056430ab |
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README.md
SpiffWorkflow
Spiff Workflow is a workflow engine implemented in pure Python. It is based on the excellent work of the Workflow Patterns initiative. In 2020 and 2021, extensive support was added for BPMN / DMN processing.
Motivation
We created SpiffWorkflow to support the development of low-code business applications in Python. Using BPMN will allow non-developers to describe complex workflow processes in a visual diagram, coupled with a powerful python script engine that works seamlessly within the diagrams. SpiffWorkflow can parse these diagrams and execute them. The ability for businesses to create clear, coherent diagrams that drive an application has far reaching potential. While multiple tools exist for doing this in Java, we believe that wide adoption of the Python Language, and it's ease of use, create a winning strategy for building Low-Code applications.
Build status
Code style
Dependencies
We've worked to minimize external dependencies. We rely on lxml for parsing XML Documents, and there is some legacy support for Celery, but it is not core to the implementation, it is just a way to interconnect these systems. Built with
Features
- BPMN - support for parsing BPMN diagrams, including the more complex components, like pools and lanes, multi-instance tasks, sub-workflows, timer events, signals, messages, boudary events and looping.
- DMN - We have a baseline implementation of DMN that is well integrated with our Python Execution Engine.
- Forms - forms, including text fields, selection lists, and most every other thing you can be extracted from the Camunda xml extension, and returned as json data that can be used to generate forms on the command line, or in web applications (we've used Formly to good success)
- Python Workflows - We've retained support for building workflows directly in code, or running workflows based on a internal json data structure.
A complete list of the latest features is available with our release notes for version 1.0.
Code Examples and Documentation
Detailed documentation is available on ReadTheDocs Also, checkout our example application, which we reference extensively from the Documentation.
Installation
pip install spiffworkflow
Tests
cd tests/SpiffWorkflow
coverage run --source=SpiffWorkflow -m unittest discover -v . "*Test.py"
Support
You can find us on Discord at https://discord.gg/BYHcc7PpUC
Commercial support for SpiffWorkflow is available from Sartography
Contribute
Pull Requests are and always will be welcome!
Please check your formatting, assure that all tests are passing, and include any additional tests that can demonstrate the new code you created is working as expected. If applicable, please reference the issue number in your pull request.
Credits and Thanks
Samuel Abels (@knipknap) for creating SpiffWorkflow and maintaining it for over a decade.
Matthew Hampton (@matthewhampton) for his initial contributions around BPMN parsing and execution.
The University of Virginia for allowing us to take on the mammoth task of building a general-purpose workflow system for BPMN, and allowing us to contribute that back to the open source community. In particular, we would like to thank Ron Hutchins, for his trust and support. Without him our efforts would not be possible.
Bruce Silver, the author of BPMN Quick and Easy Using Method and Style, whose work we referenced extensively as we made implementation decisions and educated ourselves on the BPMN and DMN standards.
The BPMN.js library, without which we would not have the tools to effectively build out our models, embed an editor in our application, and pull this mad mess together.
Kelly McDonald (@w4kpm) who dove deeper into the core of SpiffWorkflow than anyone else, and was instrumental in helping us get some of these major enhancements working correctly.
Thanks also to the many contributions from our community. Large and small. From Ziad (@ziadsawalha) in the early days to Elizabeth (@essweine) more recently. It is good to be a part of this long lived and strong community.
License
GNU LESSER GENERAL PUBLIC LICENSE