A powerful workflow engine implemented in pure Python

Samuel

Last update: Jan 8, 2023

Related tags

Job Scheduler python workflow bpmn bpmn-engine spiff-workflow workflow-specification workflowpatterns

Overview

Spiff Workflow

Summary

Spiff Workflow is a workflow engine implemented in pure Python. It is based on the excellent work of the Workflow Patterns initiative.

Do you need commercial support?

Spiff Workflow is supported by Procedure 8. Get in touch if you need anything!

Main design goals

Spiff Workflow aims to directly support as many of the patterns of workflowpatterns.com as possible.
Spiff Workflow uses unit testing as much as possible.
Spiff Workflow provides a clean Python API.
Spiff Workflow allows for mapping patterns into workflow elements that are easy to understand for non-technical users in a workflow GUI editor.
Spiff Workflow implements the best possible path prediction for workflows.

Spiff Workflow also provides a parser and workflow emulation layer that can be used to create executable Spiff Workflow specifications from Business Process Model and Notation (BPMN) documents.

Quick Intro

The process of using Spiff Workflow involves the following steps:

Write a workflow specification. A specification may be written using XML (example), JSON, or Python (example).
Run the workflow using the Python API. Example code for running the workflow:

from SpiffWorkflow.specs import WorkflowSpec
from SpiffWorkflow.serializer.prettyxml import XmlSerializer
from SpiffWorkflow import Workflow

# Load the workflow specification:
with open('my_workflow.xml') as fp:
    serializer = XmlSerializer()
    spec = WorkflowSpec.deserialize(serializer, fp.read())

# Create an instance of the workflow, according to the specification.
wf = Workflow(spec)

# Complete tasks as desired. It is the job of the workflow engine to
# guarantee a consistent state of the workflow.
wf.complete_task_from_id(...)

# Of course, you can also persist the workflow instance:
xml = wf.serialize(XmlSerializer, 'workflow_state.xml')

Documentation

Full documentation is here:

http://spiffworkflow.readthedocs.io/en/latest/

Comments

BPMN engine documentation
I recently added a ton of documentation for most parts of SpiffWorkflow (and ported the module to Py3). The only missing part is documentation for the BPMN layer, which I am now trying to add.

@matthewhampton can you help out with the following questions?:

What is the purpose of the BpmnWorkflow.accept_message() method?

Do you have a minimal example of how to run a BPMN workflow?

Why did you add BpmnWorkflow.do_engine_steps() in addition to the already inherited BpmnWorkflow.complete_all()? Is this actually needed?
opened by knipknap 14
Memory Usage

Hi. Thanks very much for maintaining this amazing library! I'm currently using SpiffWorkflow to generate logs for a somewhat big BPMN (~1.5 MB). Unfortunately, creating a Workflow from the spec uses way too much memory (exceeding 100 GB easily).

I figured that the problem lies within the gateways, since every node with multiple children creates several distinct paths throughout the workflow (whilst also creating mulitple task instances of the same task-spec) creating a total of >10 bil. instances of tasks in just one Workflow.

Now that I haven't understood the deepest of functionings in SpiffWorkflow: Is it necessary to create those distinct paths from a Gateway up until the end or is there a way to prevent this while maintaining the main functioning?

Thanks you very much!

opened by IAsmodai 12
Multi Instance Call Activities stopped working since 1.1.1
Problem:

Multi Instance Call Activities stopped working since Version 1.1.1.

Reason:

Class determination in method _handle_special_cases() works different than isinstance() so CallActivity can't be identified as subclass of SubWorkflowTask.

Fix:

In bpmn/specs/MultiInstanceTask.py:

425c425 < classes = [BusinessRuleTask,ScriptTask,SubWorkflowTask,SubWorkflow] --- > classes = [BusinessRuleTask,ScriptTask,SubWorkflowTask,SubWorkflow,CallActivity]
opened by kaihasse 10
Make a release on PyPi

The latest release on PyPi was 0.3.0 in 2009. The code has changed a fair amount since then. It's time for a new version number - 1.0 maybe? - and a new release.

opened by dee42 9
Initial support for BPMN escalation boundary event on CallActivity tasks

Escalation boundary events attached to CallActivity tasks will be activated if subworkflow embedded in CallActivity reaches any escalation end event node.

Boundary events with and without escalation code filter are supported in both interrupting and non-interrupting variants.

opened by demostenes 8
Task.is_descendant_of? can't deal with multiple parents

I've stumbled into this recently, where we rely on Task.is_descendant_of?, however we also support parallel tasks with a Merge. Tasks in Spiff only have one parent, which means that some of our use-cases fail to traverse back in the tree, because the multiple previous paths of a merge can't be traversed (only one).

I'm working around it with a separate implementation that starts at the "possible parent", and traverses the task tree downwards.

opened by HoneyryderChuck 7

Get Error "Duplicate task spec name" when flow to Multi-Instance twice

Steps

Start Process
Complete UserTask A (Multi-Instance) 3 times (set data approved = False)
exclusive gateway flow to UserTask B
Get Error Message KeyError: 'Duplicate task spec name: Gateway_for_task-A_start'

Test BPMN File

<?xml version="1.0" encoding="UTF-8"?>
<bpmn:definitions xmlns:bpmn="http://www.omg.org/spec/BPMN/20100524/MODEL" xmlns:bpmndi="http://www.omg.org/spec/BPMN/20100524/DI" xmlns:dc="http://www.omg.org/spec/DD/20100524/DC" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:di="http://www.omg.org/spec/DD/20100524/DI" xmlns:modeler="http://camunda.org/schema/modeler/1.0" id="Definitions_0y9pl5m" targetNamespace="http://bpmn.io/schema/bpmn" exporter="Camunda Modeler" exporterVersion="5.0.0" modeler:executionPlatform="Camunda Platform" modeler:executionPlatformVersion="7.17.0">
  <bpmn:process id="Process_1" isExecutable="true">
    <bpmn:startEvent id="start-event" name="Start">
      <bpmn:outgoing>start-to-A</bpmn:outgoing>
    </bpmn:startEvent>
    <bpmn:sequenceFlow id="start-to-A" sourceRef="start-event" targetRef="task-A" />
    <bpmn:exclusiveGateway id="check" name="check">
      <bpmn:incoming>go-to-check</bpmn:incoming>
      <bpmn:outgoing>approved-ng</bpmn:outgoing>
      <bpmn:outgoing>approved-ok</bpmn:outgoing>
    </bpmn:exclusiveGateway>
    <bpmn:sequenceFlow id="go-to-check" sourceRef="task-A" targetRef="check" />
    <bpmn:sequenceFlow id="approved-ng" name="ng" sourceRef="check" targetRef="task-B">
      <bpmn:conditionExpression xsi:type="bpmn:tFormalExpression">approved == False</bpmn:conditionExpression>
    </bpmn:sequenceFlow>
    <bpmn:sequenceFlow id="approved-ok" name="ok" sourceRef="check" targetRef="task-C">
      <bpmn:conditionExpression xsi:type="bpmn:tFormalExpression">approved == True</bpmn:conditionExpression>
    </bpmn:sequenceFlow>
    <bpmn:endEvent id="end-event" name="End">
      <bpmn:incoming>go-to-end</bpmn:incoming>
    </bpmn:endEvent>
    <bpmn:sequenceFlow id="go-to-end" sourceRef="task-C" targetRef="end-event" />
    <bpmn:sequenceFlow id="return-A" sourceRef="task-B" targetRef="task-A" />
    <bpmn:userTask id="task-A" name="A">
      <bpmn:incoming>start-to-A</bpmn:incoming>
      <bpmn:incoming>return-A</bpmn:incoming>
      <bpmn:outgoing>go-to-check</bpmn:outgoing>
      <bpmn:multiInstanceLoopCharacteristics>
        <bpmn:loopCardinality xsi:type="bpmn:tFormalExpression">3</bpmn:loopCardinality>
      </bpmn:multiInstanceLoopCharacteristics>
    </bpmn:userTask>
    <bpmn:userTask id="task-C" name="C">
      <bpmn:incoming>approved-ok</bpmn:incoming>
      <bpmn:outgoing>go-to-end</bpmn:outgoing>
    </bpmn:userTask>
    <bpmn:userTask id="task-B" name="B">
      <bpmn:incoming>approved-ng</bpmn:incoming>
      <bpmn:outgoing>return-A</bpmn:outgoing>
    </bpmn:userTask>
  </bpmn:process>
  <bpmndi:BPMNDiagram id="BPMNDiagram_1">
    <bpmndi:BPMNPlane id="BPMNPlane_1" bpmnElement="Process_1">
      <bpmndi:BPMNEdge id="Flow_1iikmgj_di" bpmnElement="start-to-A">
        <di:waypoint x="215" y="177" />
        <di:waypoint x="270" y="177" />
      </bpmndi:BPMNEdge>
      <bpmndi:BPMNEdge id="Flow_1a8y7jv_di" bpmnElement="go-to-check">
        <di:waypoint x="370" y="177" />
        <di:waypoint x="425" y="177" />
      </bpmndi:BPMNEdge>
      <bpmndi:BPMNEdge id="Flow_1bjb5x4_di" bpmnElement="approved-ng">
        <di:waypoint x="450" y="202" />
        <di:waypoint x="450" y="300" />
        <bpmndi:BPMNLabel>
          <dc:Bounds x="459" y="248" width="13" height="14" />
        </bpmndi:BPMNLabel>
      </bpmndi:BPMNEdge>
      <bpmndi:BPMNEdge id="Flow_0lgyq5h_di" bpmnElement="approved-ok">
        <di:waypoint x="475" y="177" />
        <di:waypoint x="590" y="177" />
        <bpmndi:BPMNLabel>
          <dc:Bounds x="527" y="159" width="12" height="14" />
        </bpmndi:BPMNLabel>
      </bpmndi:BPMNEdge>
      <bpmndi:BPMNEdge id="Flow_0x702io_di" bpmnElement="go-to-end">
        <di:waypoint x="690" y="177" />
        <di:waypoint x="782" y="177" />
      </bpmndi:BPMNEdge>
      <bpmndi:BPMNEdge id="Flow_0b9ygw9_di" bpmnElement="return-A">
        <di:waypoint x="400" y="340" />
        <di:waypoint x="320" y="340" />
        <di:waypoint x="320" y="217" />
      </bpmndi:BPMNEdge>
      <bpmndi:BPMNShape id="_BPMNShape_StartEvent_2" bpmnElement="start-event">
        <dc:Bounds x="179" y="159" width="36" height="36" />
        <bpmndi:BPMNLabel>
          <dc:Bounds x="185" y="202" width="24" height="14" />
        </bpmndi:BPMNLabel>
      </bpmndi:BPMNShape>
      <bpmndi:BPMNShape id="Gateway_1qk7uju_di" bpmnElement="check" isMarkerVisible="true">
        <dc:Bounds x="425" y="152" width="50" height="50" />
        <bpmndi:BPMNLabel>
          <dc:Bounds x="436" y="122" width="29" height="14" />
        </bpmndi:BPMNLabel>
      </bpmndi:BPMNShape>
      <bpmndi:BPMNShape id="Activity_0lo4mlm_di" bpmnElement="task-A">
        <dc:Bounds x="270" y="137" width="100" height="80" />
      </bpmndi:BPMNShape>
      <bpmndi:BPMNShape id="Activity_08cbyyr_di" bpmnElement="task-B">
        <dc:Bounds x="400" y="300" width="100" height="80" />
      </bpmndi:BPMNShape>
      <bpmndi:BPMNShape id="Activity_1lr38ba_di" bpmnElement="task-C">
        <dc:Bounds x="590" y="137" width="100" height="80" />
      </bpmndi:BPMNShape>
      <bpmndi:BPMNShape id="Event_1qba375_di" bpmnElement="end-event">
        <dc:Bounds x="782" y="159" width="36" height="36" />
        <bpmndi:BPMNLabel>
          <dc:Bounds x="790" y="202" width="20" height="14" />
        </bpmndi:BPMNLabel>
      </bpmndi:BPMNShape>
    </bpmndi:BPMNPlane>
  </bpmndi:BPMNDiagram>
</bpmn:definitions>

opened by kadyang 6

1.1.7 contains breaking changes

Hi 👋 I've tested the upgrade to teh latest version, and it seems that some variables were moved around, specifically TaskStates. The code in question breaks because it relies on available of constants when having tasks, so there's a lot of task.WAITING and the like.

Would you reconsider reverting this? Even if we would redo the code, It seems a bit of overhead for no real gain, i.e. now I have to import TaskStates in order to access the state static variables.

opened by HoneyryderChuck 6
A year of BPMN / DMN Enhancements

I'm working on a project that hopes to use SpiffWorkflow to build out a multi-purpose tool for managing some complex workflow tasks for a university. We'd like to support the open source Camunda modeler for creating BPMN diagrams as well. I think this is general purpose enough to be of benefit to a wider community. I wanted to get this in front of you to see if these are additions you believe would be good for SpiffWorkflow, or if I should attempt to create a separate companion project.

This initial effort is just adding in a basic form processor. But in the future I'd like to support the BMN notation for handing basic business rule definitions. Rather than author detailed documentation for the main project, I'd also like to build out that documentation here, and write tutorials on creating BPMN diagrams and using them to execute a workflow. Delve into serialization for storage and communication over an API, etc ....

opened by danfunk 6
Any real world usage example I can use to inspire myself?

Hi,

I've been taking a look at Spiffworkflow for a project I'm working on and it seems it could perfectly fit the bill, since I need to develop a workflow system where a process may have several steps, several people are involved in this process and have different permissions to execute certain steps, etc.

However I'm having trouble finding real usages of this library, and how to bind each task to python code or functions (e.g. notify by email a user once a step has been completed), how to decide which person is allowed to execute a certain step on a workflow, etc. Is there any complex implementation I could see as a source of inspiration?

Thank you and kind regards.

opened by Rydra 6

Documentation issue

Here http://spiffworkflow.readthedocs.io/en/latest/tutorial/index.html, in the json, the president task

"president": {
            "class": "SpiffWorkflow.specs.ExclusiveChoice.ExclusiveChoice",
            "name": "president",
            "manual": true,
            "inputs": [
                "general"
            ],
            "outputs": [
                "workflow_aborted",
                "nuclear_strike"
            ],
            "choice": null,
            "default_task_spec": "workflow_aborted",
            "cond_task_specs": [
                [
                    [
                        "SpiffWorkflow.operators.Equal",
                        [
                            [
                                "Attrib",
                                "confirmation"
                            ],
                            [
                                "value",
                                "yes"
                            ]
                        ]
                    ],
                    "president"
                ]
            ]
        }

Here in the output task if the condition is true, president is given. I think it should be nuclear_strike.

opened by junaidiiith 6

getting error while restoring state from file which contains subprocess

Hi, I am getting the below error when I am restoring the state from a file containing a subprocess. Normally it is working fine without a subprocess.

I was using/referring spiff-cli example. and this doc

$ ./run.py -p order_product -d bpmn/product_prices.dmn bpmn/shipping_costs.dmn -b bpmn/events.bpmn bpmn/call_activity.bpmn -r test6.json
Traceback (most recent call last):
  File "D:\spiff-example-cli\run.py", line 82, in <module>
    wf = serializer.deserialize_json(state.read())
  File "D:\spiff-example-cli\venv\lib\site-packages\SpiffWorkflow\bpmn\serializer\workflow.py", line 143, in deserialize_json
    return self.workflow_from_dict(dct, read_only)
_1
    subprocesses[sp]['tasks'][task_id]['parent'] = None
KeyError: 'data

opened by imrushi 1

[Question] Support for groups?

Hi, I was looking at the NodeParser code (1.2.1) and it looks like for Tasks, Groups are not yet supported. But Positions and Lanes are. I'd like to try to add it but maybe better to ask before :)

I guess the trick would be to get the goups postions from the XML then check the Task positions and find out which one is around ?

Thanks !

opened by shazz 9

Data Object and Data Object Reference name vs ID

Hello,

I am facing multiple issues regarding the data object and its reference. I am using either Camunda or Modelio to model my BPMN, which is a simple user task that output a decision DataObject and an exclusive gate that either go to the end or redo the user task based on the Decision DataObject.

I checked both examples (cli and ducks) and tests, but everything is based on Camunda Forms, which isn't a route I want to go. Keeping with BPMN only, I was thinking of using DataObject as a trigger to my python app that something must be provided to the process.

I currently use a standalone script based on your CLI example (hardcoded the BPMN files, forced the debug and changed the user task to set the value of the data output) to figure out how to work with BPMN and your library. You'll find below relevant part of codes. To summarize, here my issues.

The parser and specs uses BPMN ID as the name, which is a value auto-generated and not exposed in either Modelio or Camunda. This is not very friendly as it require the end-user that will make the process to open the raw XML and find out the BPMN ID of the DataObject and either change it everywhere in the XML to some meaningful value; or go back to the conditional expression and use the non-meaningful BPMN ID as the condition checker.
Even after changing the conditional expression to match the name (BPMN ID), I still get that this name is not defined (maybe the PythonScriptEngine is not considering those DataObject?).

Thanks for reading me, and hopefully you'll have some idea how to sort this out!

BTW, I am using a editable from source installation of the package, since the latest released version does not have support for those data object.

Here is where you use the ID as the name. https://github.com/sartography/SpiffWorkflow/blob/0fa2048ef2d9dd5fe856f2e476df77966bdab892/SpiffWorkflow/bpmn/specs/BpmnProcessSpec.py#L73-L82

Here is where you use the same ID to check if it exist as a data object. https://github.com/sartography/SpiffWorkflow/blob/0fa2048ef2d9dd5fe856f2e476df77966bdab892/SpiffWorkflow/bpmn/parser/node_parser.py#L30-L48

Here is how I changed the complete_user_task(task). It is hardcoded for now, assuming only one output requested.

def complete_user_task(task):

    display_task(task)
    if task.data is None:
        task.data = {}

    if len(task.task_spec.data_output_associations) > 0:
        task.data[task.task_spec.data_output_associations[0].name] = "redo"

Here is the error I got that the name is not defined.

Set the value of `DataObject_17prm6c` to `redo`
{'DataObject_17prm6c': 'redo'}
Traceback (most recent call last):
  File "C:\Users\sa830268\Documents\dev\projects\be_tracker.backend\.venv\src\spiffworkflow\SpiffWorkflow\bpmn\PythonScriptEngine.py", line 196, in evaluate
    return self._evaluate(expression, task.data, task=task)
  File "C:\Users\sa830268\Documents\dev\projects\be_tracker.backend\.venv\src\spiffworkflow\SpiffWorkflow\bpmn\PythonScriptEngine.py", line 223, in _evaluate
    return eval(expression, globals, lcls)
  File "<string>", line 1, in <module>
NameError: name 'DataObject_17prm6c' is not defined

During handling of the above exception, another exception occurred:

  File "C:\Users\sa830268\Documents\dev\bin\pyenv\pyenv-win\versions\3.10.5\lib\runpy.py", line 196, in _run_module_as_main
    return _run_code(code, main_globals, None,
  File "C:\Users\sa830268\Documents\dev\bin\pyenv\pyenv-win\versions\3.10.5\lib\runpy.py", line 86, in _run_code
    exec(code, run_globals)
  File "C:\Users\sa830268\Documents\dev\projects\be_tracker.backend\app\workflow\workflow.py", line 188, in <module>
    run(myWorkflow, True)
  File "C:\Users\sa830268\Documents\dev\projects\be_tracker.backend\app\workflow\workflow.py", line 167, in run
    workflow.do_engine_steps()
  File "C:\Users\sa830268\Documents\dev\projects\be_tracker.backend\.venv\src\spiffworkflow\SpiffWorkflow\bpmn\workflow.py", line 187, in do_engine_steps
    task.complete()
  File "C:\Users\sa830268\Documents\dev\projects\be_tracker.backend\.venv\src\spiffworkflow\SpiffWorkflow\task.py", line 783, in complete
    return self.task_spec._on_complete(self)
  File "C:\Users\sa830268\Documents\dev\projects\be_tracker.backend\.venv\src\spiffworkflow\SpiffWorkflow\specs\base.py", line 405, in _on_complete
    self._on_complete_hook(my_task)
  File "C:\Users\sa830268\Documents\dev\projects\be_tracker.backend\.venv\src\spiffworkflow\SpiffWorkflow\specs\ExclusiveChoice.py", line 82, in _on_complete_hook
    if condition is None or condition._matches(my_task):
  File "C:\Users\sa830268\Documents\dev\projects\be_tracker.backend\.venv\src\spiffworkflow\SpiffWorkflow\bpmn\specs\BpmnSpecMixin.py", line 33, in _matches
    return task.workflow.script_engine.evaluate(task, self.args[0])
  File "C:\Users\sa830268\Documents\dev\projects\be_tracker.backend\.venv\src\spiffworkflow\SpiffWorkflow\bpmn\PythonScriptEngine.py", line 198, in evaluate
    raise WorkflowTaskExecException(task,
SpiffWorkflow.bpmn.exceptions.WorkflowTaskExecException: Gateway_1i6bkpl: Error evaluating expression 'DataObject_17prm6c=='redo'', name 'DataObject_17prm6c' is not defined

Here my BPMN process from Camunda. It will fail to evaluate decision="redo" because it is stored as DataObject_17prm6c.

  <bpmn:process id="process" name="process" isExecutable="true">
    <bpmn:startEvent id="StartEvent_1">
      <bpmn:extensionElements />
      <bpmn:outgoing>Flow_0xkz2ar</bpmn:outgoing>
    </bpmn:startEvent>
    <bpmn:sequenceFlow id="Flow_0xkz2ar" sourceRef="StartEvent_1" targetRef="Activity_1repqrz" />
    <bpmn:userTask id="Activity_1repqrz" name="Init">
      <bpmn:extensionElements />
      <bpmn:incoming>Flow_0xkz2ar</bpmn:incoming>
      <bpmn:incoming>Flow_0zwwzf9</bpmn:incoming>
      <bpmn:outgoing>Flow_08d7vel</bpmn:outgoing>
      <bpmn:dataOutputAssociation id="DataOutputAssociation_1s559c4">
        <bpmn:targetRef>DataObjectReference_05w9q7s</bpmn:targetRef>
      </bpmn:dataOutputAssociation>
    </bpmn:userTask>
    <bpmn:exclusiveGateway id="Gateway_1i6bkpl" name="Check Decision?" default="Flow_0tgoifw">
      <bpmn:incoming>Flow_08d7vel</bpmn:incoming>
      <bpmn:outgoing>Flow_0tgoifw</bpmn:outgoing>
      <bpmn:outgoing>Flow_0zwwzf9</bpmn:outgoing>
    </bpmn:exclusiveGateway>
    <bpmn:sequenceFlow id="Flow_08d7vel" sourceRef="Activity_1repqrz" targetRef="Gateway_1i6bkpl" />
    <bpmn:endEvent id="Event_0v8tu84">
      <bpmn:incoming>Flow_0tgoifw</bpmn:incoming>
    </bpmn:endEvent>
    <bpmn:sequenceFlow id="Flow_0tgoifw" name="Go" sourceRef="Gateway_1i6bkpl" targetRef="Event_0v8tu84" />
    <bpmn:sequenceFlow id="Flow_0zwwzf9" name="Redo" sourceRef="Gateway_1i6bkpl" targetRef="Activity_1repqrz">
      <bpmn:conditionExpression xsi:type="bpmn:tFormalExpression">decision=='redo'</bpmn:conditionExpression>
    </bpmn:sequenceFlow>
    <bpmn:dataObjectReference id="DataObjectReference_05w9q7s" name="Decision" dataObjectRef="DataObject_17prm6c" />
    <bpmn:dataObject id="DataObject_17prm6c" />
  </bpmn:process>

Here the same process as generated by Modelio

    <process isClosed="false" isExecutable="true" processType="Public" name="CR_Process" id="bbc9568e-4664-4a24-929e-bd3854857707">
        <dataObject name="decision" id="REF-af032a66-519a-4e2f-93db-b85804d3dd47"/>
        <startEvent isInterrupting="false" parallelMultiple="false" name="" id="modelio-80b31935-5e9b-4607-b08d-34fca404aa05">
            <ns5:outgoing xmlns:ns5="http://www.omg.org/spec/BPMN/20100524/MODEL" xmlns="">modelio-6af02fe6-8c7c-4ce6-b581-ef5b0217d60f</ns5:outgoing>
        </startEvent>
        <sequenceFlow sourceRef="modelio-80b31935-5e9b-4607-b08d-34fca404aa05" targetRef="modelio-6331c10a-3991-4fe9-9153-8b705ca1484e" name="" id="modelio-6af02fe6-8c7c-4ce6-b581-ef5b0217d60f"/>
        <userTask implementation="##WebService" isForCompensation="false" startQuantity="1" completionQuantity="1" name="Init" id="modelio-6331c10a-3991-4fe9-9153-8b705ca1484e">
            <ns5:incoming xmlns:ns5="http://www.omg.org/spec/BPMN/20100524/MODEL" xmlns="">modelio-6af02fe6-8c7c-4ce6-b581-ef5b0217d60f</ns5:incoming>
            <ns5:incoming xmlns:ns5="http://www.omg.org/spec/BPMN/20100524/MODEL" xmlns="">modelio-15cba2c4-c161-4612-b70a-0d30521ecd5e</ns5:incoming>
            <ns5:outgoing xmlns:ns5="http://www.omg.org/spec/BPMN/20100524/MODEL" xmlns="">modelio-1641545c-6422-4639-9ad9-8b4fbff74f28</ns5:outgoing>
            <ioSpecification>
                <dataOutput id="modelio-6331c10a-3991-4fe9-9153-8b705ca1484e-af032a66-519a-4e2f-93db-b85804d3dd47"/>
                <inputSet id="InputSet_modelio-6331c10a-3991-4fe9-9153-8b705ca1484e"/>
                <outputSet id="OutputSet_modelio-6331c10a-3991-4fe9-9153-8b705ca1484e">
                    <dataOutputRefs>modelio-6331c10a-3991-4fe9-9153-8b705ca1484e-af032a66-519a-4e2f-93db-b85804d3dd47</dataOutputRefs>
                </outputSet>
            </ioSpecification>
            <dataOutputAssociation id="modelio-64e43a05-949f-44f0-9912-7f0cb6712af3">
                <sourceRef>modelio-6331c10a-3991-4fe9-9153-8b705ca1484e-af032a66-519a-4e2f-93db-b85804d3dd47</sourceRef>
                <targetRef>af032a66-519a-4e2f-93db-b85804d3dd47</targetRef>
            </dataOutputAssociation>
        </userTask>
        <sequenceFlow sourceRef="modelio-6331c10a-3991-4fe9-9153-8b705ca1484e" targetRef="f5552950-c5a9-43c8-b203-b81ab0ddb8ec" name="Sequence Flow" id="modelio-1641545c-6422-4639-9ad9-8b4fbff74f28"/>
        <exclusiveGateway default="e38cee12-2744-48a0-85f6-81280c4b4aa6" gatewayDirection="Unspecified" name="Check Decision?" id="f5552950-c5a9-43c8-b203-b81ab0ddb8ec">
            <ns5:incoming xmlns:ns5="http://www.omg.org/spec/BPMN/20100524/MODEL" xmlns="">modelio-1641545c-6422-4639-9ad9-8b4fbff74f28</ns5:incoming>
            <ns5:outgoing xmlns:ns5="http://www.omg.org/spec/BPMN/20100524/MODEL" xmlns="">e38cee12-2744-48a0-85f6-81280c4b4aa6</ns5:outgoing>
            <ns5:outgoing xmlns:ns5="http://www.omg.org/spec/BPMN/20100524/MODEL" xmlns="">modelio-15cba2c4-c161-4612-b70a-0d30521ecd5e</ns5:outgoing>
        </exclusiveGateway>
        <endEvent name="" id="e3f80147-cf6f-47f4-92f0-9f94e83e1455">
            <ns5:incoming xmlns:ns5="http://www.omg.org/spec/BPMN/20100524/MODEL" xmlns="">e38cee12-2744-48a0-85f6-81280c4b4aa6</ns5:incoming>
        </endEvent>
        <dataObjectReference dataObjectRef="REF-af032a66-519a-4e2f-93db-b85804d3dd47" name="decision" id="af032a66-519a-4e2f-93db-b85804d3dd47"/>
        <sequenceFlow sourceRef="f5552950-c5a9-43c8-b203-b81ab0ddb8ec" targetRef="e3f80147-cf6f-47f4-92f0-9f94e83e1455" name="Sequence Flow1" id="e38cee12-2744-48a0-85f6-81280c4b4aa6"/>
        <sequenceFlow sourceRef="f5552950-c5a9-43c8-b203-b81ab0ddb8ec" targetRef="modelio-6331c10a-3991-4fe9-9153-8b705ca1484e" name="Sequence Flow2" id="modelio-15cba2c4-c161-4612-b70a-0d30521ecd5e">
            <conditionExpression>decision=="redo"</conditionExpression>
        </sequenceFlow>
    </process>

opened by sharky98 8

DMN "-" character is misinterpreted

Blank fields are displayed with a "-" character in DMN tables. But if the user actually types a "-" into the field, our BPMN editor attempts to interpret it, and fails.

opened by danfunk 0
Drop camunda attributes on Events

Our core BPMN code currently references camunda attributes for some aspects of events. Specifically Expression and ResultVariable. We should not have direct dependencies on these attributes. We could add support for them through the CamundaParser, but no reference to the Camunda namespace should exist in the core BPMN classes and methods.

We want to create and maintain the oppertunity to evolve our own definition of variable scopes and data handling that will strive to be more in line with the BPMN 2.0 standard, and when not defined there, as pythonic as possible, and in keeping with the scoping of variables that is inherent in python programming.

opened by danfunk 0

Releases(v1.2.1)

v1.2.1(Oct 19, 2022)
What's Changed

do not install importlib-metadata if greater than python 3.7 w/ burnettk by @jasquat in https://github.com/sartography/SpiffWorkflow/pull/253

New Contributors

@jasquat made their first contribution in https://github.com/sartography/SpiffWorkflow/pull/253

Full Changelog: https://github.com/sartography/SpiffWorkflow/compare/v1.2.0...v1.2.1
Source code(tar.gz)
Source code(zip)
v1.2.0(Oct 14, 2022)
Data Objects, Messages and Services

Note: there are some minor breaking changes in this release, please see "Minor Breaking Changes and their Fixes" below for how to fix them.

This Version of SpiffWorkflow adds support for Data Objects, Messages, and Service Tasks. These are powerful new tools for managing workflows as they grow in complexity. Details below.

This is also our first step towards a larger ecosystem. One that includes a customized Diagram Editor that is still under development, but available on GitHub and perfectly serviceable. You will need the editor to take full advantage of the new features mentioned above. A new project, code named SpiffArena is also under heavy development. SpiffArena will connect this SpiffWorkflow library to the new BPMN Editor and provide a complete Workflow Engine with a backend and frontend that can be configured to manage and execute a collection of your own BPMN diagrams. Keep an eye out for an initial release before the end of the year.

In addition to major new features, we've improved some existing core features. The Python Expression Engine is now easier to extend and modify for custom deployments, and SubProcesses have a far stronger and more consistent internal representation and are easier to control. We've also added the ability to unit test your script tasks - to make it much easier to write small python scripts to re-structure your data.

Finally, we undertook hours of effort to clean up the code base, so that imports are consistent, circular dependencies are removed, and code smells are eliminated. It is by no means perfect, but we are arcing in the right direction.

Major Changes

Data Objects, Inputs and Outputs

We now support Data Objects, providing powerful tools for controlling the scope and access of variables within a workflow. For an overview of how Data Objects work, please check out our article "Understanding BPMN Data Objects". Detailed information is also available in our ReadTheDocs page.

explicitly add data associations on serializing MI tasks by @danfunk in PR

add messages to data object exceptions by @essweine in PR

Messages

Communication between running workflow instances is a powerful tool as workflows become more complex. For a detailed overview of this topic, please check out our article "Understanding BPMN Messages"

messages and business rules by @burnettk in PR

messages no longer send all keys by @essweine in PR

Service Tasks

Service Tasks are now supported, and offer an easy way for BPMN Developers to make calls to external APIs. Examples for working with this critical new tool will be documented in our ReadTheDocs page.

First pass of ServiceTask handling by @jbirddog in PR

Service task connector delegate by @jbirddog in PR

Store service task response in task data by @jbirddog in PR

get description aka name when parsing service tasks by @burnettk in PR

Follow up on service task bug fix, quote string literals by @jbirddog in PR

Pass task data to service task delegate by @jbirddog in PR

Custom BPMN Editor Support

Still in heavy development is a custom BPMN Editor, which you can find on GitHub This new editor provides the tools that will make creating valid Service Tasks, Data Objects, and Messages possible. Many thanks to the BPMN.js community for this highly extensible diagramming library!

Support for Spiff pre/postscript extensions by @essweine in PR z* parses out spiffworklow:property tags in bpmn extensions and makes th… by @danfunk in PR

Improved Script Engine

A Script Engine that is overall easier to understand and extend.

Feature/improved script engine by @essweine in PR

make globals an argument in the script engine by @essweine in PR

Script Task Unit Testing

Added the ability to create, store, and execute assertions against Script Tasks. Allows you to define a Json data structure as input, and an expected Json data structure as output. So you can assert your script is producing exactly the right data.

Script Task Unit Test Extensions (Attempt #2) by @danfunk in PR

New spec_type attribute

Given the ability to overload classes, and mix-in properties, it could be difficult to look at a Task Spec's class to determine if it was a User Task or Script Task, etc... All Task Specs now have a spec_type attribute, containing a descriptive string of the type, expect to see "User Task", "Script Task", "Start Event" etc...

add spec type property to task specs with BPMN names by @essweine in PR

Improved Subprocess Handling

Allows recursive calls to subprocesses, and improves serialization and execution by @essweine in PR

add bpmn spec mixin functionality to subworkflow tasks by @essweine in PR

handle all data copying in bpmn subworkflow task by @essweine in PR

Vastly Faster Tests!

Profile and improve run time of the test suite by @jbirddog in PR

Improve test suite run time, part 2 by @jbirddog in PR

ParallelTest.py split by @jbirddog in PR

Up some sleep times in tests for CI stability by @jbirddog in PR

Bug Fixes

fix loop reset task to handle multiple subprocess properly by @essweine in PR

Bugfix/separate subprocess dict for serializer by @danfunk in PR

Update make tests to run tests per the README, remove unused test runners by @jbirddog in PR

Bug/service task variable by @jbirddog in PR

Fix for failures with Python 3.7 by @jbirddog in PR

Code Cleanup and Documentation Changes

Support custom JSON encoder/decoder in BpmnWorkflowSerializer by @soby in PR

Add Python 3.10 to CI by @jbirddog in PR

list dependencies by @danfunk in PR

Feature/centralized logging by @essweine in PR

[FIX] Use self.spec_class instead of direct use of base object by @Giulios74 in PR

add more documentation about serializer migration by @essweine in PR

docs: Fix a few typos by @timgates42 in PR

Fix a few docstring typos in the tests by @jbirddog in PR

Remove unused imports by @jbirddog in PR

Reorganized parser PR

fix for a serialization bug by @danfunk in PR

fix serialization bug by @essweine in PR

Don't use bpmn exception from core spec by @jbirddog in PR

added task name to the spiff logs by @burnettk in PR

Remove navigation.py, tests and related bpmn files by @jbirddog in PR

Remove bpmn imports from task.py by @jbirddog in PR

Remove bpmn references from dict.py and json.py by @jbirddog in PR

Remove some lingering bpmn imports by @jbirddog in PR

Empty SpiffWorkflow/init.py by @jbirddog in PR

Various fixes as I attempted to get our CR-Connect application working against the lastest SpiffWorkflow build by @danfunk in PR

Minor Breaking Changes and their Fixes

This Minor Release includes a few minor breaking changes that should be easy to correct. Please apply these fixes as appropriate

Top Level Imports moved to appropriate modules

REPLACE 'from SpiffWorkflow import WorkflowException' WITH 'from SpiffWorkflow.exceptions import WorkflowException'

REPLACE 'from SpiffWorkflow import TaskState' WITH: 'from SpiffWorkflow.task import TaskState'

REPLACE: 'from SpiffWorkflow import Task' WITH 'from SpiffWorkflow.task import Task'

Navigation code was removed

Proved to be of little use to folks, was super complex and difficult to maintain.

If you depended on this code, you can take the original code and embed it in your project.

remove all references of timeit (no longer in SpiffWorkflow)

timing is now available for all tasks in the spiff.metrics log without having to edit the code

Same as above, this standalone code can be added to your code if needed.

pythonScriptEngine._evaluate no longer accepts a task argument. If you were overriding this method for some reason, please change your method signature

If you were previously using the workflow.signal() or workflow.message() functions, these should be replaced with workflow.catch().

Task States are JUST integers and TaskSpecNames is now a public dictionary, and can be used to covert a state to human readable string

REPLACE: user_task.state.name WITH: TaskStateNames[user_task.state]

Other Notes

When inserting custom functions into the PythonExecutionEngine - be aware that the task data will act as the full context for execution, and will contain global functions and methods during the exec call.

New Contributors

@Giulios74 made their first contribution in PR

@jbirddog made their first contribution in PR

@burnettk made their first contribution in PR

Full Changelog: PR
Source code(tar.gz)
Source code(zip)
v1.1.7(May 20, 2022)
What's Changed

This push covers a major overhaul of our JSON serializer, which previously depended on using pickle making the json difficult to read and parse outside of Spiff and creating some potential security concerns.

IMPORTANT: If you have existing workflows stored as JSON you will need to migrate them to the new version, you can do this on the fly by following the Migration Instructions

fix broken links by @essweine in https://github.com/sartography/SpiffWorkflow/pull/173

Enhancement/167 drop the pickles by @essweine in https://github.com/sartography/SpiffWorkflow/pull/174

Bug/serializer call activity issue by @danfunk in https://github.com/sartography/SpiffWorkflow/pull/179

refactor: move TaskState object out of Task object by @a358003542 in https://github.com/sartography/SpiffWorkflow/pull/178

Enhancement/improve subprocess serialization by @danfunk in https://github.com/sartography/SpiffWorkflow/pull/181

New Contributors

@a358003542 made their first contribution in https://github.com/sartography/SpiffWorkflow/pull/178

Full Changelog: https://github.com/sartography/SpiffWorkflow/compare/v1.1.6...v1.1.7
Source code(tar.gz)
Source code(zip)
v1.1.6(Mar 24, 2022)
This is just a very quick release to fix an issue with 1.1.5 that could prevent people from deserializing their existing workflows.

What's Changed

Error deserializing with v1.1.5 by @danfunk in https://github.com/sartography/SpiffWorkflow/pull/172 Full Changelog: https://github.com/sartography/SpiffWorkflow/compare/v1.1.5...v1.1.6

Source code(tar.gz)
Source code(zip)
v1.1.5(Mar 18, 2022)
Overview

We've made some significant improvements to our documentation and heavily refactored our code around events. We made some minor performance improvements by reducing the size of our serialization (but we are in the midst of a much larger refactor of serialization with even larger payoffs). More details follow.

What's Changed

DMN - pay attention to quotes when you see the '?' symbol. by @danfunk in https://github.com/sartography/SpiffWorkflow/pull/154

More improvements to SubWorkflow / MultiInstance by @danfunk in https://github.com/sartography/SpiffWorkflow/pull/155

Enhancement/improve bpmn event handling by @essweine in https://github.com/sartography/SpiffWorkflow/pull/156

Fix bug where deserialization failed when a sub-workflow had tasks with the same id as the parent workflow by @danfunk in https://github.com/sartography/SpiffWorkflow/pull/160

Chore/performance by @danfunk in https://github.com/sartography/SpiffWorkflow/pull/162

miscellaneous updates to events by @essweine in https://github.com/sartography/SpiffWorkflow/pull/163

Fix updateDotDict to not truncate last segment by @soby in https://github.com/sartography/SpiffWorkflow/pull/165

Refactoring the PythonScriptEngine signature methods for DMN: by @danfunk in https://github.com/sartography/SpiffWorkflow/pull/166

If a sub-process occurs within a lane, the tasks within that sub-process should be aware that they occur within that lane. by @danfunk in https://github.com/sartography/SpiffWorkflow/pull/168

Better Errors for Call Activities by @danfunk in https://github.com/sartography/SpiffWorkflow/pull/169

Enhancement/documentation updates by @danfunk in https://github.com/sartography/SpiffWorkflow/pull/170

New Contributors

@soby made their first contribution in https://github.com/sartography/SpiffWorkflow/pull/165

Full Changelog: https://github.com/sartography/SpiffWorkflow/compare/v1.1.3...v1.1.5
Source code(tar.gz)
Source code(zip)
v1.1.3(Jan 14, 2022)

Correcting an issue with data creation in a multi-instance sub-workflow / call-activity.
Source code(tar.gz)
Source code(zip)
v1.1.2(Jan 5, 2022)

This release just updates the documentation, and gets PiPy and GitHub in sync. Please see Release 1.1.1 for additional release notes as these will occur on top of each other.
Source code(tar.gz)
Source code(zip)
1.1.1(Jan 5, 2022)
What's Changed

connect gateway start to matching conditions in transitions from exclusive gateways to multiinstance by @essweine in https://github.com/sartography/SpiffWorkflow/pull/141

improve error messages on missing processes by @essweine in https://github.com/sartography/SpiffWorkflow/pull/144

Replace absolute import self-references with relative imports by @jarradh in https://github.com/sartography/SpiffWorkflow/pull/147

looping back to an earlier point in the workflow is grossly inefficient by @danfunk in https://github.com/sartography/SpiffWorkflow/pull/148

Enhancement/add transaction subprocesses by @danfunk in https://github.com/sartography/SpiffWorkflow/pull/149

New Contributors

@jarradh made their first contribution in https://github.com/sartography/SpiffWorkflow/pull/147

Full Changelog: https://github.com/sartography/SpiffWorkflow/compare/1.1...1.1.1
Source code(tar.gz)
Source code(zip)
1.1(Nov 3, 2021)
Features and Improvements

Support for DMN v1.3

Better handling of timezone for timer events: dateparser.parse('in 10 minutes') now works

Script tasks now capture and make available the the script_format attribute if provided.

Bug Fixes:

We should not fail to serialize if a function is included in a script task.

Script Engines were not consistent after deserialization. We now require you to pass the correct script engine into when deserializing, and guarantee this engine will be used throughout.

Improved the escalation for boundary events

User tasks were ordered by their position in the diagram, now script tasks are as well.

Some performance improvements for large workflows.

We no longer set an arbitrary default for exclusive gateways, and raise an exception if no default is defined, and not condition is met at runtime.

What's Changed (auto generated)

Updated readme. by @danfunk in https://github.com/sartography/SpiffWorkflow/pull/116

Add support for date instead of only datetime by @rgcalsaverini in https://github.com/sartography/SpiffWorkflow/pull/81

Fix of return type hint in workflow.py by @robocad in https://github.com/sartography/SpiffWorkflow/pull/100

Pull request 79 - fixes to Escalation Boundary Events by @danfunk in https://github.com/sartography/SpiffWorkflow/pull/118

Initial support for BPMN escalation boundary event on CallActivity tasks by @demostenes in https://github.com/sartography/SpiffWorkflow/pull/79

Chore/sonarcloud by @ajlouie in https://github.com/sartography/SpiffWorkflow/pull/119

Removes coveralls. Replaces coveralls coverage badge with sonarcloud … by @ajlouie in https://github.com/sartography/SpiffWorkflow/pull/120

Replaces mutable default arguments by @ajlouie in https://github.com/sartography/SpiffWorkflow/pull/122

Tweaks the xpath so it can handle the DMN v1.3 XML that Camunda's edi… by @ajlouie in https://github.com/sartography/SpiffWorkflow/pull/123

Fix #425 by @w4kpm in https://github.com/sartography/SpiffWorkflow/pull/124

Small typo in documentation by @afjlambert in https://github.com/sartography/SpiffWorkflow/pull/126

One Script Engine to rule them all by @danfunk in https://github.com/sartography/SpiffWorkflow/pull/130

Calculate script task position in its parser by @Leashys in https://github.com/sartography/SpiffWorkflow/pull/133

Add task-mapping attribute to workflow to make sure workflow will not… by @JsZero in https://github.com/sartography/SpiffWorkflow/pull/135

Bug/137 no default exclusive gateway by @essweine in https://github.com/sartography/SpiffWorkflow/pull/139

New Contributors

@rgcalsaverini made their first contribution in https://github.com/sartography/SpiffWorkflow/pull/81

@robocad made their first contribution in https://github.com/sartography/SpiffWorkflow/pull/100

@ajlouie made their first contribution in https://github.com/sartography/SpiffWorkflow/pull/119

@w4kpm made their first contribution in https://github.com/sartography/SpiffWorkflow/pull/124

@afjlambert made their first contribution in https://github.com/sartography/SpiffWorkflow/pull/126

@Leashys made their first contribution in https://github.com/sartography/SpiffWorkflow/pull/133

@JsZero made their first contribution in https://github.com/sartography/SpiffWorkflow/pull/135

@essweine made their first contribution in https://github.com/sartography/SpiffWorkflow/pull/139

Full Changelog: https://github.com/sartography/SpiffWorkflow/compare/1.0...1.1
Source code(tar.gz)
Source code(zip)
1.0(Jul 15, 2021)
Spiff Workflow - Release Notes for Version 1.0

After a year of extensive development to get SpiffWorkflow to support our effort at building a BPMN based workflow application, Sartography (our software development company) is pleased to announce an official release of Version 1.0 of SpiffWorkflow.

That's an auspicious jump from the previous 0.6, but we think it merits the version. We have used Spiff Workflow in roughly the present state for several months in a production environment supporting real users. We believe it is ready for this 1.0 moniker. We look forward to the rapid release of many subsequent versions over the coming years.

Here is a list of major enhancements:

Preserved Features - Most of the previously-existing tests were maintained, so these changes will hopefully still support any existing users. We’ve kept dependencies on external dependencies very low. And where we added things like Box and Levenshtein along the way, we pulled them back out, replacing them with internal implementations.

DMN Support - While it is not eye-watering perfect, we have a baseline of support for DMN processing that is fully integrated into the existing Execution Engine, so your DMN rules can be applied in the same language as your preferred execution language for BPMN expressions.

Forms - We’ve added support for Camunda-specific web forms, which are currently parsed and returned as JSON data structures. We’ve used this to generate Formly (an NPM package for Angular) forms for web pages and it works great, but we hope to extract it in the future and pass this through directly, to make SpiffWorkflow more general-purpose and allow just about any additional complex data to accompany a user task.

BPMN Additional Support - We made nearly innumerable enhancements to BPMN support. These, at a glance, include:

Full Serialization - A running BPMN/DMN-based workflow can now be fully serialized into JSON and restored to its original state from that JSON representation.

Multi-Instance Tasks - We can now handle multi-instance tasks of nearly any variety, including both Parallel and Sequential variants, as they occur in User Tasks, Script Tasks, or even Sub-Processes.

Pools & Lanes - We added support for BPMN pools and lanes which we used to successfully implement some complex approval processes in a production system.

Pluggable Script Engine - While our focus was on building a Python Script Engine, we added support for a broad set of FEEL expressions in the BPMN specification. We didn’t end up using them in production, as crossing languages proved to be an enormous headache for everyone, and the ability to write in Python for quick DMN expressions, and also complex scripts tasks proved too useful to deny. We assured that the same script engine is used throughout, and that it can be replaced by an alternate implementation by the calling application.

Visual Ordering of Tasks - When you have a series of parallel tasks that are aligned vertically in the diagram, that order is preserved in execution and in navigation data.

Sub-Workflows and Call Activities - We spent a lot of time improving the use of sub-workflows and call activities to assure it is easy to compose complex multi-file workflows that behave consistently and as expected.

Timer Events - Added ISO duration parsing for fine grained control over timed events.

Signals and Messages - Support for BPMN signals and listeners and adding the ability for the calling application to issue events - such as the “Cancel” event, so that workflows that are forced to stop can react before being terminated.

Boundary Events - For timed events, and messages, added support for BPMN events that alter the flow based on external events, with support for both interrupting and non-interrupting variants.

Looping Back - As BPMN diagrams can easily loop back to previous tasks, we put effort into testing this in SpiffWorkflow and resolving a number of performance and serialization issues related to the natural looping nature of BPMN.

Improved Logging and Better Errors - We spent a lot of time improving and standardizing error messages in Spiff so it is easier to tell what is going on where, when and why, particularly as you attempt to debug issues that occur in Script Tasks. We can even tell you the line in the script that failed, and offer “did you mean…” suggestions through a simple implementation of the Levenshtein distance algorithm. We also added the ability to halt a workflow at a specific engine_step, which can be useful if you want to run tests of your workflow, but have it stop at a specific moment.

Dot Notation - Our one major departure from Python syntax, we added the ability to use dot notation when referencing values deep within the Task Data, we found that using MyData.key was easier than MyData[“key”] for many areas in BPMN and DMN. Resets - We added the ability to reset the workflow to any previously completed task, and resume work from that point.

Navigation - We created a rich and complex navigation generator that is capable of describing any point in the tree of tasks. We found we desperately needed a way to tell where we were when parsing complex diagrams. While it didn’t prove terribly useful in the user interface so far, it’s a ludicrously-robust tool for debugging. At any moment, you can now print out the full data structure in a meaningful, visual way directly from the command line.

Tests - We added hundreds of tests, many of which load up example BPMN diagrams and clearly show expectations of how Spiff should behave in a large array of situations and edge cases.

Performance Improvements - As we used this in production we found numerous performance issues, which we have tried to address - mostly related to serializing and deserializing the workflows which happens a lot in a stateless web-based architecture. We added and iteratively refined some tools for gathering and reporting performance metrics, opening these up to the larger application, so you can debug and get a consistent log and tell if it is your app that is slow, or if things are slow within Spiff.

My God, It’s Full of Edge Cases - Some 40% of our commits are related to edge cases we encountered as we developed dozens of real-world BPMN/DMN-based workflows and fixing issues as we attempted to use complex BPMN elements together.

Dropping Support for Python 2:

We did need to remove a few items from Spiff along the way, the most notable is a drop in support for Python 2. Python 3.6, 3.7 and 3.8 are all supported and a part of our automated test suite.

Special Thanks:

Sartography (Sartography.com) undertook these efforts to support the development of a custom web application for the University of Virginia. We would like to thank UVA for their support and trust in allowing us to take on the mammoth task of building a general-purpose workflows system, and contributing something back to the open source community.

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.

Samuel Abels (@knipknap) for keeping SpiffWorkflow alive for the past few years, and offering us commit access to make these contributions, and Matthew Hampton for kicking this project off and giving us sound footing on which to build.

Camunda, for whom, without their open source Modeler and the BPMN.js library, 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.

We would like to thank Denny Weinberg for his early contributions to DMN support, which we used as a baseline and then extended.

What is coming:

Clean-up: Moving forward, we want to drop direct support and parsing of Camunda-specific elements. We would like to pass non-BPMN parsing on to the calling application, allowing users to build plugin-based architectures that can address domain-specific objectives.

Cleaner Serialization: While our serialization and deserialization is rigorously tested, the JSON it produces is not easy to understand on its own. We would love to take time to clean this up, and make it easier to parse and extract data from a running workflow’s JSON representation.

Other Projects:

We are also working on a layered system architecture that will make the development of web-based applications for authoring and running BPMN-based workflows easier to accomplish. We’ve built a full REST based API on top of SpiffWorkflow for our pilot application, but it isn’t general enough to release. We’ve also created Javascript applications for both editing and running workflows specifications in a browser, but these still need to be generalized.

Our Dream:

A full stack of interconnected open source tools is the direction we are headed, along with a plug-in based architecture that will work seamlessly across that stack. We believe such grand ambitions are possible. Our ultimate ambition is the development of a Platform as a Service Business that facilitates the use of an increasingly standards compliant suite of powerful open source libraries and components.
Source code(tar.gz)
Source code(zip)