Merge pull request #55 from demostenes/bpmn_fixes

One bug fix in EndEvent and one improvement in ScriptTask

SpiffWorkflow/bpmn/specs/EndEvent.py

@@ -18,10 +18,11 @@
 # 02110-1301  USA
 
 from .BpmnSpecMixin import BpmnSpecMixin
+from ...specs.Simple import Simple
 from ...task import Task
 
 
-class EndEvent(BpmnSpecMixin):
+class EndEvent(Simple, BpmnSpecMixin):
 
     """
     Task Spec for a bpmn:endEvent node.

SpiffWorkflow/bpmn/specs/ScriptTask.py

@@ -16,9 +16,14 @@
 # License along with this library; if not, write to the Free Software
 # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 # 02110-1301  USA
+import logging
 
 from .BpmnSpecMixin import BpmnSpecMixin
+from ...task import Task
 from ...specs.Simple import Simple
+from ...exceptions import WorkflowTaskExecException
+
+LOG = logging.getLogger(__name__)
 
 
 class ScriptTask(Simple, BpmnSpecMixin):
@@ -40,5 +45,13 @@ def _on_complete_hook(self, task):
         if task.workflow._is_busy_with_restore():
             return
         assert not task.workflow.read_only
-        task.workflow.script_engine.execute(task, self.script)
+        try:
+            task.workflow.script_engine.execute(task, self.script)
+        except Exception:
+            LOG.error('Error executing ScriptTask; task=%r', task, exc_info=True)
+            # set state to WAITING (because it is definitely not COMPLETED)
+            # and raise WorkflowException pointing to this task because
+            # maybe upstream someone will be able to handle this situation
+            task._setstate(Task.WAITING, force=True)
+            raise WorkflowTaskExecException(task, 'Error during script execution')
         super(ScriptTask, self)._on_complete_hook(task)

SpiffWorkflow/exceptions.py

@@ -28,13 +28,34 @@ def __init__(self, sender, error):
         """
         Standard exception class.
 
-        :param sender: the task that threw the exception.
-        :type sender: Task
+        :param sender: the task spec that threw the exception
+        :type sender: TaskSpec
         :param error: a human readable error message
         :type error: string
         """
         Exception.__init__(self, '%s: %s' % (sender.name, error))
-        self.sender = sender  # Points to the Task that generated the exception.
+        self.sender = sender  # Points to the TaskSpec that generated the exception.
+
+
+class WorkflowTaskExecException(WorkflowException):
+    """
+    Exception during execution of task "payload". For example:
+
+    * ScriptTask during execution of embedded script,
+    * ServiceTask during external service call.
+    """
+
+    def __init__(self, task, error):
+        """
+        Exception initialization.
+
+        :param sender: the task that threw the exception
+        :type sender: Task
+        :param error: a human readable error message
+        :type error: string
+        """
+        WorkflowException.__init__(self, task.task_spec, error)
+        self.task = task
 
 
 class StorageException(Exception):