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# Copyright (C) 2012 Yahoo! Inc.
#
# Author: Joshua Harlow <harlowja@yahoo-inc.com>
#
# This file is part of cloud-init. See LICENSE file for license information.
import functools
import json
from cloudinit import log as logging
from cloudinit import url_helper
from cloudinit import util
LOG = logging.getLogger(__name__)
SKIP_USERDATA_CODES = frozenset([url_helper.NOT_FOUND])
class MetadataLeafDecoder(object):
"""Decodes a leaf blob into something meaningful."""
def _maybe_json_object(self, text):
if not text:
return False
text = text.strip()
if text.startswith("{") and text.endswith("}"):
return True
return False
def __call__(self, field, blob):
if not blob:
return ''
try:
blob = util.decode_binary(blob)
except UnicodeDecodeError:
return blob
if self._maybe_json_object(blob):
try:
# Assume it's json, unless it fails parsing...
return json.loads(blob)
except (ValueError, TypeError) as e:
LOG.warn("Field %s looked like a json object, but it was"
" not: %s", field, e)
if blob.find("\n") != -1:
return blob.splitlines()
return blob
# See: http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/
# ec2-instance-metadata.html
class MetadataMaterializer(object):
def __init__(self, blob, base_url, caller, leaf_decoder=None):
self._blob = blob
self._md = None
self._base_url = base_url
self._caller = caller
if leaf_decoder is None:
self._leaf_decoder = MetadataLeafDecoder()
else:
self._leaf_decoder = leaf_decoder
def _parse(self, blob):
leaves = {}
children = []
blob = util.decode_binary(blob)
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
# Don't materialize credentials
if field_name == 'security-credentials':
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
ident = util.safe_int(ident)
if ident is not None:
resource = "%s/openssh-key" % (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 _materialize(self, blob, base_url):
(leaves, children) = self._parse(blob)
child_contents = {}
for c in children:
child_url = url_helper.combine_url(base_url, c)
if not child_url.endswith("/"):
child_url += "/"
child_blob = self._caller(child_url)
child_contents[c] = self._materialize(child_blob, child_url)
leaf_contents = {}
for (field, resource) in leaves.items():
leaf_url = url_helper.combine_url(base_url, resource)
leaf_blob = self._caller(leaf_url)
leaf_contents[field] = self._leaf_decoder(field, 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 _skip_retry_on_codes(status_codes, _request_args, cause):
"""Returns if a request should retry based on a given set of codes that
case retrying to be stopped/skipped.
"""
return cause.code in status_codes
def get_instance_userdata(api_version='latest',
metadata_address='http://169.254.169.254',
ssl_details=None, timeout=5, retries=5):
ud_url = url_helper.combine_url(metadata_address, api_version)
ud_url = url_helper.combine_url(ud_url, 'user-data')
user_data = ''
try:
# It is ok for userdata to not exist (thats why we are stopping if
# NOT_FOUND occurs) and just in that case returning an empty string.
exception_cb = functools.partial(_skip_retry_on_codes,
SKIP_USERDATA_CODES)
response = util.read_file_or_url(ud_url,
ssl_details=ssl_details,
timeout=timeout,
retries=retries,
exception_cb=exception_cb)
user_data = response.contents
except url_helper.UrlError as e:
if e.code not in SKIP_USERDATA_CODES:
util.logexc(LOG, "Failed fetching userdata from url %s", ud_url)
except Exception:
util.logexc(LOG, "Failed fetching userdata from url %s", ud_url)
return user_data
def get_instance_metadata(api_version='latest',
metadata_address='http://169.254.169.254',
ssl_details=None, timeout=5, retries=5,
leaf_decoder=None):
md_url = url_helper.combine_url(metadata_address, api_version)
# Note, 'meta-data' explicitly has trailing /.
# this is required for CloudStack (LP: #1356855)
md_url = url_helper.combine_url(md_url, 'meta-data/')
caller = functools.partial(util.read_file_or_url,
ssl_details=ssl_details, timeout=timeout,
retries=retries)
def mcaller(url):
return caller(url).contents
try:
response = caller(md_url)
materializer = MetadataMaterializer(response.contents,
md_url, mcaller,
leaf_decoder=leaf_decoder)
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 {}
# vi: ts=4 expandtab
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