Better hook to override

SpiffWorkflow/bpmn/PythonScriptEngine.py

@@ -270,21 +270,35 @@ def execute(self, task, script, data, external_methods=None):
             raise WorkflowTaskExecException(task, detail, err, line_number,
                                             error_line)
 
-    def service_task_external_methods(self):
+    def available_service_task_external_methods(self):
         """Allows consumers a hook to specify external methods that can be
         called from service tasks."""
         return None
 
-    def execute_service_task_script(self, task, script, data,
+    def external_methods_for_operation_name(self, operation_name):
+        """Returns a subset of available_service_task_external_methods
+        that can be called from a service task with the given
+        operation_name."""
+
+        external_methods = self.available_service_task_external_methods()
+        if external_methods is None or operation_name not in external_methods:
+            return {}
+
+        return { operation_name: external_methods[operation_name] }
+
+    def execute_service_task_script(self, task, operation_name, script, data,
             external_methods=None):
         """Execute the script, within the context of the specified task. Task
         is assumed to be a service task. service_task_external_methods are
-        merged with the supplied external_methods before execution."""
+        filtered by the given operation name and merged with the supplied
+        external_methods before execution."""
+
+        additions = self.external_methods_for_operation_name(operation_name)
 
         if external_methods is None:
-            external_methods = self.service_task_external_methods()
-        else:
-            external_methods.update(self.service_task_external_methods())
+            external_methods = {}
+
+        external_methods.update(additions)
 
         self.execute(task, script, data, external_methods=external_methods)
 

SpiffWorkflow/spiff/specs/service_task.py

@@ -16,5 +16,6 @@ def evaluate(expression):
         evaluated_params = {k: evaluate(v) for k, v in self.operation_params.items()}
         script = f'{self.operation_name}(**{operation_params_var_name}).execute()'
 
-        task.workflow.script_engine.execute_service_task_script(task, script, task.data,
+        task.workflow.script_engine.execute_service_task_script(task,
+                self.operation_name, script, task.data,
                 external_methods={ operation_params_var_name: evaluated_params })

tests/SpiffWorkflow/spiff/ServiceTaskTest.py

@@ -30,7 +30,7 @@ def execute(self):
         operatorExecuted = True
 
 class ExampleCustomScriptEngine(PythonScriptEngine):
-    def service_task_external_methods(self):
+    def available_service_task_external_methods(self):
         return { 'SlackWebhookOperator': SlackWebhookOperator }
 
 class ServiceTaskTest(BaseTestCase):