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# Copyright (C) 2012 Yahoo! Inc.
# Copyright (C) 2014 Amazon.com, Inc. or its affiliates.
#
# Author: Joshua Harlow <harlowja@yahoo-inc.com>
# Author: Andrew Jorgensen <ajorgens@amazon.com>
#
# This file is part of cloud-init. See LICENSE file for license information.
import functools
import json
import logging
from cloudinit import url_helper, util
LOG = logging.getLogger(__name__)
SKIP_USERDATA_CODES = frozenset([url_helper.NOT_FOUND])
class MetadataLeafDecoder:
"""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.warning(
"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:
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.warning("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 False if cause.code is in status_codes."""
return cause.code not in status_codes
def get_instance_userdata(
api_version="latest",
metadata_address="http://169.254.169.254",
ssl_details=None,
timeout=5,
retries=5,
headers_cb=None,
headers_redact=None,
exception_cb=None,
):
ud_url = url_helper.combine_url(metadata_address, api_version)
ud_url = url_helper.combine_url(ud_url, "user-data")
user_data = b""
try:
if not exception_cb:
# 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 = url_helper.read_file_or_url(
ud_url,
ssl_details=ssl_details,
timeout=timeout,
retries=retries,
exception_cb=exception_cb,
headers_cb=headers_cb,
headers_redact=headers_redact,
)
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(
tree,
api_version="latest",
metadata_address="http://169.254.169.254",
ssl_details=None,
timeout=5,
retries=5,
leaf_decoder=None,
headers_cb=None,
headers_redact=None,
exception_cb=None,
retrieval_exception_ignore_cb=None,
):
md_url = url_helper.combine_url(metadata_address, api_version, tree)
caller = functools.partial(
url_helper.read_file_or_url,
ssl_details=ssl_details,
timeout=timeout,
retries=retries,
headers_cb=headers_cb,
headers_redact=headers_redact,
exception_cb=exception_cb,
)
def mcaller(url):
try:
return caller(url).contents
except url_helper.UrlError as e:
if (
not retrieval_exception_ignore_cb
or not retrieval_exception_ignore_cb(e)
):
raise
else:
LOG.warning("Skipped retrieval of the content of %s", url)
return "(skipped)"
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 %s from url %s", tree, md_url)
return {}
def get_instance_metadata(
api_version="latest",
metadata_address="http://169.254.169.254",
ssl_details=None,
timeout=5,
retries=5,
leaf_decoder=None,
headers_cb=None,
headers_redact=None,
exception_cb=None,
retrieval_exception_ignore_cb=None,
):
# Note, 'meta-data' explicitly has trailing /.
# this is required for CloudStack (LP: #1356855)
return _get_instance_metadata(
tree="meta-data/",
api_version=api_version,
metadata_address=metadata_address,
ssl_details=ssl_details,
timeout=timeout,
retries=retries,
leaf_decoder=leaf_decoder,
headers_redact=headers_redact,
headers_cb=headers_cb,
exception_cb=exception_cb,
retrieval_exception_ignore_cb=retrieval_exception_ignore_cb,
)
def get_instance_identity(
api_version="latest",
metadata_address="http://169.254.169.254",
ssl_details=None,
timeout=5,
retries=5,
leaf_decoder=None,
headers_cb=None,
headers_redact=None,
exception_cb=None,
):
return _get_instance_metadata(
tree="dynamic/instance-identity",
api_version=api_version,
metadata_address=metadata_address,
ssl_details=ssl_details,
timeout=timeout,
retries=retries,
leaf_decoder=leaf_decoder,
headers_redact=headers_redact,
headers_cb=headers_cb,
exception_cb=exception_cb,
)
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