support different and user-suppliable merging algorithms for cloud-config

This adds a very useful mechanism for merging cloud-config, allowing
the user to append to lists (ie, just add more 'run_cmd') or other
things.

See doc/merging.txt for more information, it is intended to be backwards
compatible by default.

LP: #1023179

1 files changed, 34 insertions, 0 deletions

diff --git a/cloudinit/type_utils.py b/cloudinit/type_utils.py
new file mode 100644
index 00000000..2decbfc5
--- /dev/null
+++ b/cloudinit/type_utils.py
@@ -0,0 +1,34 @@
+# vi: ts=4 expandtab
+#
+#    Copyright (C) 2012 Canonical Ltd.
+#    Copyright (C) 2012 Hewlett-Packard Development Company, L.P.
+#    Copyright (C) 2012 Yahoo! Inc.
+#
+#    Author: Scott Moser <scott.moser@canonical.com>
+#    Author: Juerg Haefliger <juerg.haefliger@hp.com>
+#    Author: Joshua Harlow <harlowja@yahoo-inc.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/>.
+#
+# pylint: disable=C0302
+
+import types
+
+
+def obj_name(obj):
+    if isinstance(obj, (types.TypeType,
+                        types.ModuleType,
+                        types.FunctionType,
+                        types.LambdaType)):
+        return str(obj.__name__)
+    return obj_name(obj.__class__)