Source code for runway.cfngin.awscli_yamlhelper

"""Copy of ``awscli.customizations.cloudformation.yamlhelper.py``."""
# Copyright 2012-2015 Amazon.com, Inc. or its affiliates. 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. A copy of
# the License is located at
#
# http://aws.amazon.com/apache2.0/
#
# or in the "license" file accompanying this file. This file 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
from botocore.compat import six
from yaml.resolver import ScalarNode, SequenceNode


[docs]def intrinsics_multi_constructor( # pylint: disable=unused-argument loader, tag_prefix, node ): """YAML constructor to parse CloudFormation intrinsics. This will return a dictionary with key being the intrinsic name """ # Get the actual tag name excluding the first exclamation tag = node.tag[1:] # Some intrinsic functions doesn't support prefix "Fn::" prefix = "Fn::" if tag in ["Ref", "Condition"]: prefix = "" cfntag = prefix + tag if tag == "GetAtt" and isinstance(node.value, six.string_types): # ShortHand notation for !GetAtt accepts Resource.Attribute format # while the standard notation is to use an array # [Resource, Attribute]. Convert shorthand to standard format value = node.value.split(".", 1) elif isinstance(node, ScalarNode): # Value of this node is scalar value = loader.construct_scalar(node) elif isinstance(node, SequenceNode): # Value of this node is an array (Ex: [1,2]) value = loader.construct_sequence(node) else: # Value of this node is an mapping (ex: {foo: bar}) value = loader.construct_mapping(node) return {cfntag: value}
[docs]def yaml_dump(dict_to_dump): """Dump the dictionary as a YAML document.""" return yaml.safe_dump(dict_to_dump, default_flow_style=False)
[docs]def yaml_parse(yamlstr): """Parse a yaml string.""" try: # PyYAML doesn't support json as well as it should, so if the input # is actually just json it is better to parse it with the standard # json parser. return json.loads(yamlstr) except ValueError: yaml.SafeLoader.add_multi_constructor("!", intrinsics_multi_constructor) return yaml.safe_load(yamlstr)