Separate message and traceback even if not a remote error

Faultwrap exposes tracebacks in error messages when Oslo.messaging
cannot add a _remote suffix to the exception generated by the Heat
engine.

Change-Id: Iaf91dafacce1abe94fb10aa2ba380cafb6fc4a84
closes-bug: #1432726

heat/api/middleware/fault.py

@@ -104,6 +104,7 @@ class FaultWrapper(wsgi.Middleware):
     def _error(self, ex):
 
         trace = None
+        traceback_marker = 'Traceback (most recent call last)'
         webob_exc = None
         if isinstance(ex, exception.HTTPExceptionDisguise):
             # An HTTP exception was disguised so it could make it here
@@ -120,8 +121,12 @@ class FaultWrapper(wsgi.Middleware):
             ex_type = ex_type[:-len('_Remote')]
 
         full_message = six.text_type(ex)
-        if full_message.find('\n') > -1 and is_remote:
+        if '\n' in full_message and is_remote:
             message, msg_trace = full_message.split('\n', 1)
+        elif traceback_marker in full_message:
+            message, msg_trace = full_message.split(traceback_marker, 1)
+            message = message.rstrip('\n')
+            msg_trace = traceback_marker + msg_trace
         else:
             msg_trace = traceback.format_exc()
             message = full_message

heat/tests/test_fault_middleware.py

@@ -53,6 +53,21 @@ class FaultMiddlewareTest(common.HeatTestCase):
                     'title': 'Bad Request'}
         self.assertEqual(expected, msg)
 
+    def test_http_exception_with_traceback(self):
+        wrapper = fault.FaultWrapper(None)
+        newline_error = ErrorWithNewline(
+            'Error with \n newline\nTraceback (most recent call last):\nFoo')
+        msg = wrapper._error(heat_exc.HTTPExceptionDisguise(newline_error))
+        expected = {'code': 400,
+                    'error': {'message': 'Error with \n newline',
+                              'traceback': None,
+                              'type': 'ErrorWithNewline'},
+                    'explanation': ('The server could not comply with the '
+                                    'request since it is either malformed '
+                                    'or otherwise incorrect.'),
+                    'title': 'Bad Request'}
+        self.assertEqual(expected, msg)
+
     def test_openstack_exception_with_kwargs(self):
         wrapper = fault.FaultWrapper(None)
         msg = wrapper._error(heat_exc.StackNotFound(stack_name='a'))