107 lines
4.0 KiB
Python
107 lines
4.0 KiB
Python
import xml.etree.ElementTree as ElementTree
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from SpiffWorkflow.bpmn.BpmnScriptEngine import BpmnScriptEngine
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from SpiffWorkflow.bpmn.serializer.BpmnSerializer import BpmnSerializer
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from SpiffWorkflow.bpmn.workflow import BpmnWorkflow
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from SpiffWorkflow.camunda.parser.CamundaParser import CamundaParser
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from crc import session
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from crc.models.file import FileDataModel, FileModel
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from crc.models.workflow import WorkflowStatus
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class CustomBpmnScriptEngine(BpmnScriptEngine):
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"""This is a custom script processor that can be easily injected into Spiff Workflow.
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Rather than execute arbitrary code, this assumes the script references a fully qualified python class
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such as myapp.RandomFact. """
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def execute(self, task, script, **kwargs):
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"""
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Assume that the script read in from the BPMN file is a fully qualified python class. Instantiate
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that class, pass in any data available to the current task so that it might act on it.
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Assume that the class implements the "do_task" method.
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This allows us to reference custom code from the BPMN diagram.
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"""
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module_name = "crc." + script
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class_name = module_name.split(".")[-1]
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mod = __import__(module_name, fromlist=[class_name])
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klass = getattr(mod, class_name)
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klass().do_task(task.data)
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class WorkflowProcessor:
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_script_engine = CustomBpmnScriptEngine()
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_serializer = BpmnSerializer()
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def __init__(self, workflow_spec_id, bpmn_json):
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wf_spec = self.get_spec(workflow_spec_id)
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self.bpmn_workflow = self._serializer.deserialize_workflow(bpmn_json, workflow_spec=wf_spec)
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self.bpmn_workflow.script_engine = self._script_engine
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@staticmethod
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def get_spec(workflow_spec_id):
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file_data_models = session.query(FileDataModel) \
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.join(FileModel) \
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.filter(FileModel.workflow_spec_id == workflow_spec_id).all()
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parser = CamundaParser()
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for file_data in file_data_models:
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bpmn: ElementTree.Element = ElementTree.fromstring(file_data.data)
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process_id = WorkflowProcessor.__get_process_id(bpmn)
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parser.add_bpmn_xml(bpmn, filename=file_data.file_model.name)
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return parser.get_spec(process_id)
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@classmethod
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def create(cls, workflow_spec_id):
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parser = CamundaParser()
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spec = WorkflowProcessor.get_spec(workflow_spec_id)
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bpmn_workflow = BpmnWorkflow(spec, script_engine=cls._script_engine)
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bpmn_workflow.do_engine_steps()
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json = cls._serializer.serialize_workflow(bpmn_workflow)
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processor = cls(workflow_spec_id, json)
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return processor
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def get_status(self):
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if self.bpmn_workflow.is_completed():
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return WorkflowStatus.complete
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user_tasks = self.bpmn_workflow.get_ready_user_tasks()
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if len(user_tasks) > 0:
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return WorkflowStatus.user_input_required
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else:
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return WorkflowStatus.waiting
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def do_engine_steps(self):
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self.bpmn_workflow.do_engine_steps()
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def serialize(self):
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return self._serializer.serialize_workflow(self.bpmn_workflow)
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def next_user_tasks(self):
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return self.bpmn_workflow.get_ready_user_tasks()
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def complete_task(self, task):
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self.bpmn_workflow.complete_task_from_id(task.id)
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def get_data(self):
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return self.bpmn_workflow.data
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def get_ready_user_tasks(self):
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return self.bpmn_workflow.get_ready_user_tasks()
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@staticmethod
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def __get_process_id(et_root: ElementTree.Element):
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process_elements = []
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for child in et_root:
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if child.tag.endswith('process') and child.attrib.get('isExecutable', False):
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process_elements.append(child)
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if len(process_elements) == 0:
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raise Exception('No executable process tag found')
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if len(process_elements) > 1:
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raise Exception('Multiple executable processes tags found')
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return process_elements[0].attrib['id']
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