Added support for default values to Lightweight python components (#890)

sdk/python/kfp/components/_python_op.py

@@ -96,6 +96,7 @@ def annotation_to_type_struct(annotation):
         input_spec = InputSpec(
             name=parameter.name,
             type=type_struct,
+            default=str(parameter.default) if parameter.default is not inspect.Parameter.empty else None,
         )
         inputs.append(input_spec)
 

sdk/python/tests/components/test_python_op.py

@@ -181,6 +181,18 @@ def add_two_numbers_decorated(a: float, b: float) -> float:
         self.assertEqual(component_spec.description.strip(), expected_description.strip())
         self.assertEqual(component_spec.implementation.container.image, expected_image)
 
+    def test_saving_default_values(self):
+        from typing import NamedTuple
+        def add_multiply_two_numbers(a: float = 3, b: float = 5) -> NamedTuple('DummyName', [('sum', float), ('product', float)]):
+            '''Returns sum and product of two arguments'''
+            return (a + b, a * b)
+
+        func = add_multiply_two_numbers
+        component_spec = comp._python_op._func_to_component_spec(func)
+
+        self.assertEqual(component_spec.inputs[0].default, '3')
+        self.assertEqual(component_spec.inputs[1].default, '5')
+
     def test_end_to_end_python_component_pipeline_compilation(self):
         import kfp.components as comp