deb-heat/heat/common/template_format.py

111 lines
3.8 KiB
Python

# vim: tabstop=4 shiftwidth=4 softtabstop=4
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
import re
import yaml
import json
HEAT_VERSIONS = (u'2012-12-12',)
CFN_VERSIONS = (u'2010-09-09',)
def _construct_yaml_str(self, node):
# Override the default string handling function
# to always return unicode objects
return self.construct_scalar(node)
yaml.Loader.add_constructor(u'tag:yaml.org,2002:str', _construct_yaml_str)
yaml.SafeLoader.add_constructor(u'tag:yaml.org,2002:str', _construct_yaml_str)
# Unquoted dates like 2013-05-23 in yaml files get loaded as objects of type
# datetime.data which causes problems in API layer when being processed by
# openstack.common.jsonutils. Therefore, make unicode string out of timestamps
# until jsonutils can handle dates.
yaml.Loader.add_constructor(u'tag:yaml.org,2002:timestamp',
_construct_yaml_str)
yaml.SafeLoader.add_constructor(u'tag:yaml.org,2002:timestamp',
_construct_yaml_str)
def parse(tmpl_str, add_template_sections=True):
'''
Takes a string and returns a dict containing the parsed structure.
This includes determination of whether the string is using the
JSON or YAML format.
'''
if tmpl_str.startswith('{'):
tpl = json.loads(tmpl_str)
else:
try:
tpl = yaml.safe_load(tmpl_str)
except (yaml.scanner.ScannerError, yaml.parser.ParserError) as e:
raise ValueError(e)
else:
if tpl is None:
tpl = {}
if add_template_sections and u'heat_template_version' not in tpl:
default_for_missing(tpl, u'HeatTemplateFormatVersion',
HEAT_VERSIONS)
return tpl
def default_for_missing(tpl, version_param, versions):
'''
Checks a parsed template for missing version and sections.
This is currently only applied to YAML templates.
'''
# if version is missing, implicitly use the lastest one
if version_param not in tpl:
tpl[version_param] = versions[-1]
# create empty placeholders for any of the main dict sections
for param in (u'Parameters', u'Mappings', u'Resources', u'Outputs'):
if param not in tpl:
tpl[param] = {}
def convert_json_to_yaml(json_str):
'''Convert a string containing the AWS JSON template format
to an equivalent string containing the Heat YAML format.
'''
global key_order
# Replace AWS format version with Heat format version
json_str = re.sub('"AWSTemplateFormatVersion"\s*:\s*"[^"]+"\s*,',
'', json_str)
# insert a sortable order into the key to preserve file ordering
key_order = 0
def order_key(matchobj):
global key_order
key = '%s"__%05d__order__%s" :' % (
matchobj.group(1),
key_order,
matchobj.group(2))
key_order = key_order + 1
return key
key_re = re.compile('^(\s*)"([^"]+)"\s*:', re.M)
json_str = key_re.sub(order_key, json_str)
# parse the string as json to a python structure
tpl = yaml.safe_load(json_str)
# dump python structure to yaml
yml = "HeatTemplateFormatVersion: '2012-12-12'\n" + yaml.safe_dump(tpl)
# remove ordering from key names
yml = re.sub('__\d*__order__', '', yml)
return yml