Merged trunk lp:cloud-init

1 files changed, 59 insertions, 0 deletions

diff --git a/cloudinit/ec2_utils.py b/cloudinit/ec2_utils.py
new file mode 100644
index 00000000..46b93f39
--- /dev/null
+++ b/cloudinit/ec2_utils.py
@@ -0,0 +1,59 @@
+# vi: ts=4 expandtab
+#
+#    Copyright (C) 2012 Yahoo! Inc.
+#
+#    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/>.
+
+import boto.utils as boto_utils
+
+# Versions of boto >= 2.6.0 (and possibly 2.5.2)
+# try to lazily load the metadata backing, which
+# doesn't work so well in cloud-init especially
+# since the metadata is serialized and actions are
+# performed where the metadata server may be blocked
+# (thus the datasource will start failing) resulting
+# in url exceptions when fields that do exist (or
+# would have existed) do not exist due to the blocking
+# that occurred.
+
+
+def _unlazy_dict(mp):
+    if not isinstance(mp, (dict)):
+        return mp
+    # Walk over the keys/values which
+    # forces boto to unlazy itself and
+    # has no effect on dictionaries that
+    # already have there items.
+    for (_k, v) in mp.items():
+        _unlazy_dict(v)
+    return mp
+
+
+def get_instance_userdata(api_version, metadata_address):
+    # Note: boto.utils.get_instance_metadata returns '' for empty string
+    # so the change from non-true to '' is not specifically necessary, but
+    # this way cloud-init will get consistent behavior even if boto changed
+    # in the future to return a None on "no user-data provided".
+    ud = boto_utils.get_instance_userdata(api_version, None, metadata_address)
+    if not ud:
+        ud = ''
+    return ud
+
+
+def get_instance_metadata(api_version, metadata_address):
+    metadata = boto_utils.get_instance_metadata(api_version, metadata_address)
+    if not isinstance(metadata, (dict)):
+        metadata = {}
+    return _unlazy_dict(metadata)