Add _FATAL_EXCEPTION_FORMAT_ERRORS global.

Add a new global variable to control when exception format errors
are fatal.

Also, updates the Oslo test base class to enable fatal exception
format errors.

The motivation for this change is to give projects that use
openstack common a hook to enable exception format checking when
testing.

Change-Id: Id8f4a0946b1614c8e987976b79069532a2e8608f

1 files changed, 8 insertions, 3 deletions

diff --git a/openstack/common/exception.py b/openstack/common/exception.py
index fa06d6a..4a7c72b 100644
--- a/openstack/common/exception.py
+++ b/openstack/common/exception.py
@@ -23,6 +23,8 @@ import logging
 
 from openstack.common.gettextutils import _
 
+_FATAL_EXCEPTION_FORMAT_ERRORS = False
+
 
 class Error(Exception):
     def __init__(self, message=None):
@@ -121,9 +123,12 @@ class OpenstackException(Exception):
         try:
             self._error_string = self.message % kwargs
 
-        except Exception:
-            # at least get the core message out if something happened
-            self._error_string = self.message
+        except Exception as e:
+            if _FATAL_EXCEPTION_FORMAT_ERRORS:
+                raise e
+            else:
+                # at least get the core message out if something happened
+                self._error_string = self.message
 
     def __str__(self):
         return self._error_string