Add more robust gettext interpolation handling

While integrating the new delayed messaging gettextutils
functionality into Nova, there were issues with handling
the string interpolation operations. This change adds some
paths for dealing with these cases, such as non-deep-copyable
parameters, and python code-like objects. Also, adds some
much needed test coverage.

Change-Id: I65879875adf7a12fa0d1873167c2efadfc23a54b

1 files changed, 32 insertions, 1 deletions

diff --git a/openstack/common/gettextutils.py b/openstack/common/gettextutils.py
index 0e27425..011ddb6 100644
--- a/openstack/common/gettextutils.py
+++ b/openstack/common/gettextutils.py
@@ -28,6 +28,7 @@ import copy
 import gettext
 import logging.handlers
 import os
+import re
 import UserString
 
 _localedir = os.environ.get('oslo'.upper() + '_LOCALEDIR')
@@ -122,14 +123,44 @@ class Message(UserString.UserString, object):
 
         return unicode(full_msg)
 
+    def _save_dictionary_parameter(self, dict_param):
+        full_msg = self.data
+        # look for %(blah) fields in string;
+        # ignore %% and deal with the
+        # case where % is first character on the line
+        keys = re.findall('(?:[^%]|^)%\((\w*)\)[a-z]', full_msg)
+
+        # if we don't find any %(blah) blocks but have a %s
+        if not keys and re.findall('(?:[^%]|^)%[a-z]', full_msg):
+            # apparently the full dictionary is the parameter
+            params = copy.deepcopy(dict_param)
+        else:
+            params = {}
+            for key in keys:
+                try:
+                    params[key] = copy.deepcopy(dict_param[key])
+                except TypeError:
+                    # cast uncopyable thing to unicode string
+                    params[key] = unicode(dict_param[key])
+
+        return params
+
     def _save_parameters(self, other):
         # we check for None later to see if
         # we actually have parameters to inject,
         # so encapsulate if our parameter is actually None
         if other is None:
             self.params = (other, )
+        elif isinstance(other, dict):
+            self.params = self._save_dictionary_parameter(other)
         else:
-            self.params = copy.deepcopy(other)
+            # fallback to casting to unicode,
+            # this will handle the problematic python code-like
+            # objects that cannot be deep-copied
+            try:
+                self.params = copy.deepcopy(other)
+            except TypeError:
+                self.params = unicode(other)
 
         return self