python-gyanclient/gyanclient/common/template_format.py

65 lines
2.0 KiB
Python

# 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 json
import yaml
if hasattr(yaml, 'CSafeDumper'):
yaml_dumper_base = yaml.CSafeDumper
else:
yaml_dumper_base = yaml.SafeDumper
# We create custom class to not overriden the default yaml behavior
class yaml_loader(yaml.SafeLoader):
pass
class yaml_dumper(yaml_dumper_base):
pass
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)
# 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)
def parse(tmpl_str):
"""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.
"""
# strip any whitespace before the check
tmpl_str = tmpl_str.strip()
if tmpl_str.startswith('{'):
tpl = json.loads(tmpl_str)
else:
try:
tpl = yaml.safe_load(tmpl_str)
except yaml.YAMLError as yea:
raise ValueError(yea)
else:
if tpl is None:
tpl = {}
return tpl