Merge "Modified message of exception and log"

glance/common/exception.py

@@ -397,7 +397,9 @@ class MetadefDuplicateResourceTypeAssociation(Duplicate):
 
 class MetadefDuplicateTag(Duplicate):
     message = _("A metadata tag with name=%(name)s"
-                " already exists in namespace=%(namespace_name)s.")
+                " already exists in namespace=%(namespace_name)s."
+                " (Please note that metadata tag names are"
+                " case insensitive).")
 
 
 class MetadefForbidden(Forbidden):

glance/db/sqlalchemy/metadef_api/tag.py

@@ -100,7 +100,9 @@ def create(context, namespace_name, values, session):
         metadef_tag.save(session=session)
     except db_exc.DBDuplicateEntry:
         LOG.debug("A metadata tag name=%(name)s"
-                  " in namespace=%(namespace_name)s already exists.",
+                  " already exists in namespace=%(namespace_name)s."
+                  " (Please note that metadata tag names are"
+                  " case insensitive).",
                   {'name': metadef_tag.name,
                    'namespace_name': namespace_name})
         raise exc.MetadefDuplicateTag(