Don't include traceback when wrapping exceptions

The fix in fa52cb0 strips tracebacks
from exceptions when returning them to the user, but it still spams
the log with a long traceback. We shouldn't be including the traceback
when we wrap the exception in the first place. Instead we just
include the message.

It also updates the error code to 409 for device in use since this
is actually a conflict.

Fix for:

  bug 1155315
  bug 1103324
  bug 1092610

Change-Id: I95019a3022eb52e0335c455009c13fe229475d03
(cherry picked from commit d63bd8d)

nova/api/openstack/wsgi.py

@@ -654,11 +654,12 @@ def __exit__(self, ex_type, ex_value, ex_traceback):
             return True
 
         if isinstance(ex_value, exception.NotAuthorized):
-            msg = unicode(ex_value)
+            msg = unicode(ex_value.message % ex_value.kwargs)
             raise Fault(webob.exc.HTTPForbidden(explanation=msg))
         elif isinstance(ex_value, exception.Invalid):
+            msg = unicode(ex_value.message % ex_value.kwargs)
             raise Fault(exception.ConvertedException(
-                code=ex_value.code, explanation=unicode(ex_value)))
+                    code=ex_value.code, explanation=msg))
 
         # Under python 2.6, TypeError's exception value is actually a string,
         # so test # here via ex_type instead:
@@ -1167,6 +1168,10 @@ def __call__(self, req):
         # Replace the body with fault details.
         code = self.wrapped_exc.status_int
         fault_name = self._fault_names.get(code, "computeFault")
+        explanation = self.wrapped_exc.explanation
+        LOG.debug(_("Returning %(code)s to user: %(explanation)s"),
+                  {'code': code, 'explanation': explanation})
+
         fault_data = {
             fault_name: {
                 'code': code,

nova/exception.py

@@ -387,6 +387,7 @@ class InvalidDevicePath(Invalid):
 
 class DevicePathInUse(Invalid):
     message = _("The supplied device path (%(path)s) is in use.")
+    code = 409
 
 
 class DeviceIsBusy(Invalid):