Bring back the ec2 utils, non-boto userdata/metadata reading

This replacement uses our own userdata/metadata ec2 webservice
parser that we can easily modify, it also automatically allows
for reading the ec2 userdata/metdata from files and also brings
in the usage of requests instead of boto's usage of urllib which
did not support ssl properly.
This commit is contained in:
Joshua Harlow 2014-01-10 16:14:54 -08:00
parent 1a6ad1d61a
commit 1aa01899bb

View File

@ -16,48 +16,154 @@
# 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
from urlparse import (urlparse, urlunparse)
# 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.
import functools
import json
import urllib
# TODO(harlowja): https://github.com/boto/boto/issues/1401
# When boto finally moves to using requests, we should be able
# to provide it ssl details, it does not yet, so we can't provide them...
from cloudinit import log as logging
from cloudinit import util
LOG = logging.getLogger(__name__)
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 combine_url(base, add_on):
base_parsed = list(urlparse(base))
path = base_parsed[2]
if path and not path.endswith("/"):
path += "/"
path += urllib.quote(str(add_on), safe="/:")
base_parsed[2] = path
return urlunparse(base_parsed)
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
# See: http://bit.ly/TyoUQs
#
# Since boto metadata reader uses the old urllib which does not
# support ssl, we need to ahead and create our own reader which
# works the same as the boto one (for now).
class MetadataMaterializer(object):
def __init__(self, blob, base_url, caller):
self._blob = blob
self._md = None
self._base_url = base_url
self._caller = caller
def _parse(self, blob):
leaves = {}
children = []
if not blob:
return (leaves, children)
def has_children(item):
if item.endswith("/"):
return True
else:
return False
def get_name(item):
if item.endswith("/"):
return item.rstrip("/")
return item
for field in blob.splitlines():
field = field.strip()
field_name = get_name(field)
if not field or not field_name:
continue
if has_children(field):
if field_name not in children:
children.append(field_name)
else:
contents = field.split("=", 1)
resource = field_name
if len(contents) > 1:
# What a PITA...
(ident, sub_contents) = contents
checked_ident = util.safe_int(ident)
if checked_ident is not None:
resource = "%s/openssh-key" % (checked_ident)
field_name = sub_contents
leaves[field_name] = resource
return (leaves, children)
def materialize(self):
if self._md is not None:
return self._md
self._md = self._materialize(self._blob, self._base_url)
return self._md
def _decode_leaf_blob(self, blob):
if not blob:
return blob
stripped_blob = blob.strip()
if stripped_blob.startswith("{") and stripped_blob.endswith("}"):
# Assume and try with json
try:
return json.loads(blob)
except (ValueError, TypeError):
pass
if blob.find("\n") != -1:
return blob.splitlines()
return blob
def _materialize(self, blob, base_url):
(leaves, children) = self._parse(blob)
child_contents = {}
for c in children:
child_url = combine_url(base_url, c)
if not child_url.endswith("/"):
child_url += "/"
child_blob = str(self._caller(child_url))
child_contents[c] = self._materialize(child_blob, child_url)
leaf_contents = {}
for (field, resource) in leaves.items():
leaf_url = combine_url(base_url, resource)
leaf_blob = str(self._caller(leaf_url))
leaf_contents[field] = self._decode_leaf_blob(leaf_blob)
joined = {}
joined.update(child_contents)
for field in leaf_contents.keys():
if field in joined:
LOG.warn("Duplicate key found in results from %s", base_url)
else:
joined[field] = leaf_contents[field]
return joined
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)
def get_instance_userdata(api_version='latest',
metadata_address='http://169.254.169.254',
ssl_details=None, timeout=5, retries=5):
ud_url = combine_url(metadata_address, api_version)
ud_url = combine_url(ud_url, 'user-data')
try:
response = util.read_file_or_url(ud_url,
ssl_details=ssl_details,
timeout=timeout,
retries=retries)
return str(response)
except Exception:
util.logexc(LOG, "Failed fetching userdata from url %s", ud_url)
return None
def get_instance_metadata(api_version='latest',
metadata_address='http://169.254.169.254',
ssl_details=None, timeout=5, retries=5):
md_url = combine_url(metadata_address, api_version)
md_url = combine_url(md_url, 'meta-data')
caller = functools.partial(util.read_file_or_url,
ssl_details=ssl_details, timeout=timeout,
retries=retries)
try:
response = caller(md_url)
materializer = MetadataMaterializer(str(response), md_url, caller)
md = materializer.materialize()
if not isinstance(md, (dict)):
md = {}
return md
except Exception:
util.logexc(LOG, "Failed fetching metadata from url %s", md_url)
return {}