introduce recipe_exception in result.proto

recipe_engine/run.py

Index: recipe_engine/run.py
diff --git a/recipe_engine/run.py b/recipe_engine/run.py
index 77c9b4e5f187a4f3c0961db17c651402ee110e31..b6fee45accb9ce8cf64a26f6de4a67e7030303e7 100644
--- a/recipe_engine/run.py
+++ b/recipe_engine/run.py
@@ -335,6 +335,17 @@ class RecipeEngine(object):
         result.failure.human_reason = "Step time out: %r" % ex
         result.failure.timeout.timeout_s = ex.timeout
 
+      except loader.RecipeException as ex:
+        result.failure.human_reason = "Uncaught Exception: %r" % ex
+        result.failure.recipe_exception.traceback[:] = [
+          line.rstrip('\n')
+          for line in traceback.format_exception(
+              type(ex.inner_exception), ex.inner_exception, ex.traceback)
+        ]
+
+        # Let the step runner run_context decide what to do.
+        raise type(ex.inner_exception), ex.inner_exception, ex.traceback
+
       except Exception as ex:
         result.failure.human_reason = "Uncaught Exception: %r" % ex
         result.failure.exception.traceback[:] = (
@@ -377,13 +388,24 @@ class RecipeEngine(object):
           "traceback": traceback.format_exc().splitlines(),
           "status_code": -1
         }
+      except loader.RecipeException as ex:
+        result = {
+          "reason": "Uncaught Exception: %r" % ex.inner_exception,
+          "traceback": [
+            line.rstrip('\n')
+            for line in traceback.format_exception(
+                type(ex.inner_exception), ex.inner_exception, ex.traceback)
+          ],
+          "status_code": -1
+        }
+        assert all('\n' not in line for line in result["traceback"])
+        raise type(ex.inner_exception), ex.inner_exception, ex.traceback
       except Exception as ex:
         result = {
           "reason": "Uncaught Exception: %r" % ex,
           "traceback": traceback.format_exc().splitlines(),
           "status_code": -1
         }
-
         raise
 
     result['name'] = '$result'