releases/openstack_releases/yamlutils.py
Joshua Harlow 9c1ac3dace Add a yamlutils file and a reformatting command
Do note this will lose comments, if pyyaml ever supports
not losing those then this can avoid losing those.

Change-Id: I4b26362f7cab42eb40804751c86d9145490c78d9
2016-05-16 21:45:40 -07:00

99 lines
3.6 KiB
Python

# All Rights Reserved.
#
# 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 collections
import textwrap
import six
import yaml
import yamlordereddictloader
class PrettySafeDumper(yaml.dumper.SafeDumper):
"""Yaml dumper that tries to not alter original formats (to much)."""
BINARY_ENCODING = 'utf8'
MAX_LINE_LENGTH = 60
def represent_ordereddict(self, data):
values = []
node = yaml.nodes.MappingNode(
'tag:yaml.org,2002:map', values, flow_style=None)
if self.alias_key is not None:
self.represented_objects[self.alias_key] = node
for key, value in six.iteritems(data):
key_item = self.represent_data(key)
value_item = self.represent_data(value)
values.append((key_item, value_item))
return node
def choose_scalar_style(self):
# Avoid messing up dict keys...
if self.states[-1] == self.expect_block_mapping_simple_value:
self.event.style = 'plain'
return super(PrettySafeDumper, self).choose_scalar_style()\
if self.event.style != 'plain' else ("'" if ' ' in
self.event.value else None)
def represent_string(self, data):
if isinstance(data, six.binary_type):
data = data.decode(self.BINARY_ENCODING)
if len(data) > self.MAX_LINE_LENGTH:
data = textwrap.fill(data)
style = "plain"
if "\n" in data:
style = "|"
return yaml.representer.ScalarNode('tag:yaml.org,2002:str',
data, style=style)
def represent_undefined(self, data):
if isinstance(data, collections.OrderedDict):
return self.represent_odict(data)
else:
return super(PrettySafeDumper, self).represent_undefined(data)
# NOTE(harlowja): at some point this may not be needed...
# See: http://pyyaml.org/ticket/29
PrettySafeDumper.add_representer(collections.OrderedDict,
PrettySafeDumper.represent_ordereddict)
PrettySafeDumper.add_representer(None,
PrettySafeDumper.represent_undefined)
# Ensure we use our own routine here, because the style that comes by
# default is sort of wonky and messes up the values....
for str_type in [six.binary_type, six.text_type]:
PrettySafeDumper.add_representer(str_type,
PrettySafeDumper.represent_string)
def dumps(obj):
"""Dump a python object -> blob and apply our pretty styling."""
buff = six.BytesIO()
yaml.dump_all([obj], buff,
explicit_start=True, indent=2,
default_flow_style=False,
line_break="\n", Dumper=PrettySafeDumper,
allow_unicode=True)
return buff.getvalue()
def loads(blob):
"""Load a yaml blob and retain key ordering."""
# This does use load, which is unsafe, but should be ok
# for what we are loading here in this program; we should
# be able to fix that in the future (if it matters).
return yaml.load(blob, Loader=yamlordereddictloader.Loader)