add 'safeyaml' to cloudinit

In 0.7.0 we started using yaml.safe_load to load data rather than
yaml.load.  Some producers (namely, ubuntu MAAS created) have produced
cloud-config data in the past that included python unicode types.

This creates a specialized safe_loader that is basically safe_load +
support for python unicode.

1 files changed, 31 insertions, 0 deletions

diff --git a/cloudinit/safeyaml.py b/cloudinit/safeyaml.py
new file mode 100644
index 00000000..8b4da1fa
--- /dev/null
+++ b/cloudinit/safeyaml.py
@@ -0,0 +1,31 @@
+# vi: ts=4 expandtab
+#
+#    Copyright (C) 2012 Canonical Ltd.
+#
+#    Author: Scott Moser <scott.moser@canonical.com>
+#
+#    This program is free software: you can redistribute it and/or modify
+#    it under the terms of the GNU General Public License version 3, as
+#    published by the Free Software Foundation.
+#
+#    This program is distributed in the hope that it will be useful,
+#    but WITHOUT ANY WARRANTY; without even the implied warranty of
+#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#    GNU General Public License for more details.
+#
+#    You should have received a copy of the GNU General Public License
+#    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+import yaml
+
+
+class _CustomSafeLoader(yaml.SafeLoader):
+    def construct_python_unicode(self, node):
+        return self.construct_scalar(node)
+
+_CustomSafeLoader.add_constructor(
+    u'tag:yaml.org,2002:python/unicode',
+    _CustomSafeLoader.construct_python_unicode)
+
+def load(blob):
+    return(yaml.load(blob, Loader=_CustomSafeLoader))