Brick fix BrickException message formatting

This patch fixes an issue when passing in a
formatting key and value for formatted
text messages for all Brick exceptions.

Added unit tests for brick's exception

Change-Id: I76dcfc6872ca20305d1844162dd0ae28c4bb565c
Related-Bug: 1238085

cinder/brick/exception.py

@@ -14,8 +14,6 @@
 
 """Exceptions for the Brick library."""
 
-import sys
-
 from cinder.openstack.common.gettextutils import _
 from cinder.openstack.common import log as logging
 
@@ -30,7 +28,7 @@ class BrickException(Exception):
     a 'msg_fmt' property. That msg_fmt will get printf'd
     with the keyword arguments provided to the constructor.
     """
-    msg_fmt = _("An unknown exception occurred.")
+    message = _("An unknown exception occurred.")
     code = 500
     headers = {}
     safe = False
@@ -46,23 +44,28 @@ class BrickException(Exception):
 
         if not message:
             try:
-                message = self.msg_fmt % kwargs
+                message = self.message % kwargs
 
             except Exception:
-                exc_info = sys.exc_info()
                 # kwargs doesn't match a variable in the message
                 # log the issue and the kwargs
                 msg = (_("Exception in string format operation.  msg='%s'")
-                       % self.msg_fmt)
+                       % self.message)
                 LOG.exception(msg)
                 for name, value in kwargs.iteritems():
                     LOG.error("%s: %s" % (name, value))
 
                 # at least get the core message out if something happened
-                message = self.msg_fmt
+                message = self.message
 
+        # Put the message in 'msg' so that we can access it.  If we have it in
+        # message it will be overshadowed by the class' message attribute
+        self.msg = message
         super(BrickException, self).__init__(message)
 
+    def __unicode__(self):
+        return unicode(self.msg)
+
 
 class NotFound(BrickException):
     message = _("Resource could not be found.")

cinder/tests/brick/test_brick_exception.py

@@ -0,0 +1,62 @@
+
+# Copyright 2010 United States Government as represented by the
+# Administrator of the National Aeronautics and Space Administration.
+# All Rights Reserved.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+from cinder.brick import exception
+from cinder import test
+
+
+class BrickExceptionTestCase(test.TestCase):
+    def test_default_error_msg(self):
+        class FakeBrickException(exception.BrickException):
+            message = "default message"
+
+        exc = FakeBrickException()
+        self.assertEqual(unicode(exc), 'default message')
+
+    def test_error_msg(self):
+        self.assertEqual(unicode(exception.BrickException('test')), 'test')
+
+    def test_default_error_msg_with_kwargs(self):
+        class FakeBrickException(exception.BrickException):
+            message = "default message: %(code)s"
+
+        exc = FakeBrickException(code=500)
+        self.assertEqual(unicode(exc), 'default message: 500')
+
+    def test_error_msg_exception_with_kwargs(self):
+        # NOTE(dprince): disable format errors for this test
+        self.flags(fatal_exception_format_errors=False)
+
+        class FakeBrickException(exception.BrickException):
+            message = "default message: %(mispelled_code)s"
+
+        exc = FakeBrickException(code=500)
+        self.assertEqual(unicode(exc), 'default message: %(mispelled_code)s')
+
+    def test_default_error_code(self):
+        class FakeBrickException(exception.BrickException):
+            code = 404
+
+        exc = FakeBrickException()
+        self.assertEqual(exc.kwargs['code'], 404)
+
+    def test_error_code_from_kwarg(self):
+        class FakeBrickException(exception.BrickException):
+            code = 500
+
+        exc = FakeBrickException(code=404)
+        self.assertEqual(exc.kwargs['code'], 404)