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# 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 file is part of cloud-init. See LICENSE file for license information.
import jsonpatch
from cloudinit import handlers
from cloudinit import log as logging
from cloudinit import mergers, safeyaml, util
from cloudinit.settings import PER_ALWAYS
LOG = logging.getLogger(__name__)
MERGE_HEADER = "Merge-Type"
# Due to the way the loading of yaml configuration was done previously,
# where previously each cloud config part was appended to a larger yaml
# file and then finally that file was loaded as one big yaml file we need
# to mimic that behavior by altering the default strategy to be replacing
# keys of prior merges.
#
#
# For example
# #file 1
# a: 3
# #file 2
# a: 22
# #combined file (comments not included)
# a: 3
# a: 22
#
# This gets loaded into yaml with final result {'a': 22}
DEF_MERGERS = mergers.string_extract_mergers("dict(replace)+list()+str()")
CLOUD_PREFIX = "#cloud-config"
JSONP_PREFIX = "#cloud-config-jsonp"
class CloudConfigPartHandler(handlers.Handler):
# The content prefixes this handler understands.
prefixes = [CLOUD_PREFIX, JSONP_PREFIX]
def __init__(self, paths, **_kwargs):
handlers.Handler.__init__(self, PER_ALWAYS, version=3)
self.cloud_buf = None
self.cloud_fn = paths.get_ipath("cloud_config")
if "cloud_config_path" in _kwargs:
self.cloud_fn = paths.get_ipath(_kwargs["cloud_config_path"])
self.file_names = []
def _write_cloud_config(self):
if not self.cloud_fn:
return
# Capture which files we merged from...
file_lines = []
if self.file_names:
file_lines.append("# from %s files" % (len(self.file_names)))
for fn in self.file_names:
if not fn:
fn = "?"
file_lines.append("# %s" % (fn))
file_lines.append("")
if self.cloud_buf is not None:
# Something was actually gathered....
lines = [
CLOUD_PREFIX,
"",
]
lines.extend(file_lines)
lines.append(safeyaml.dumps(self.cloud_buf))
else:
lines = []
util.write_file(self.cloud_fn, "\n".join(lines), 0o600)
def _extract_mergers(self, payload, headers):
merge_header_headers = ""
for h in [MERGE_HEADER, "X-%s" % (MERGE_HEADER)]:
tmp_h = headers.get(h, "")
if tmp_h:
merge_header_headers = tmp_h
break
# Select either the merge-type from the content
# or the merge type from the headers or default to our own set
# if neither exists (or is empty) from the later.
payload_yaml = util.load_yaml(payload)
if payload_yaml is None:
raise ValueError("empty cloud config")
mergers_yaml = mergers.dict_extract_mergers(payload_yaml)
mergers_header = mergers.string_extract_mergers(merge_header_headers)
all_mergers = []
all_mergers.extend(mergers_yaml)
all_mergers.extend(mergers_header)
if not all_mergers:
all_mergers = DEF_MERGERS
return (payload_yaml, all_mergers)
def _merge_patch(self, payload):
# JSON doesn't handle comments in this manner, so ensure that
# if we started with this 'type' that we remove it before
# attempting to load it as json (which the jsonpatch library will
# attempt to do).
payload = payload.lstrip()
payload = util.strip_prefix_suffix(payload, prefix=JSONP_PREFIX)
patch = jsonpatch.JsonPatch.from_string(payload)
LOG.debug("Merging by applying json patch %s", patch)
self.cloud_buf = patch.apply(self.cloud_buf, in_place=False)
def _merge_part(self, payload, headers):
(payload_yaml, my_mergers) = self._extract_mergers(payload, headers)
LOG.debug("Merging by applying %s", my_mergers)
merger = mergers.construct(my_mergers)
self.cloud_buf = merger.merge(self.cloud_buf, payload_yaml)
def _reset(self):
self.file_names = []
self.cloud_buf = None
def handle_part(self, data, ctype, filename, payload, frequency, headers):
if ctype == handlers.CONTENT_START:
self._reset()
return
if ctype == handlers.CONTENT_END:
self._write_cloud_config()
self._reset()
return
try:
# First time through, merge with an empty dict...
if self.cloud_buf is None or not self.file_names:
self.cloud_buf = {}
if ctype == handlers.INCLUSION_TYPES_MAP[JSONP_PREFIX]:
self._merge_patch(payload)
else:
self._merge_part(payload, headers)
# Ensure filename is ok to store
for i in ("\n", "\r", "\t"):
filename = filename.replace(i, " ")
self.file_names.append(filename.strip())
except ValueError as err:
LOG.warning(
"Failed at merging in cloud config part from %s: %s",
filename,
err,
)
except Exception:
util.logexc(
LOG, "Failed at merging in cloud config part from %s", filename
)
# vi: ts=4 expandtab
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