Source code for ansible.parsing.yaml.constructor

# (c) 2012-2014, Michael DeHaan <michael.dehaan@gmail.com>
#
# This file is part of Ansible
#
# Ansible is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# Ansible is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with Ansible.  If not, see <http://www.gnu.org/licenses/>.

# Make coding more python3-ish
from __future__ import (absolute_import, division, print_function)
__metaclass__ = type

from yaml.constructor import Constructor, ConstructorError
from yaml.nodes import MappingNode
from ansible.parsing.yaml.objects import AnsibleMapping, AnsibleSequence, AnsibleUnicode
from ansible.vars.unsafe_proxy import wrap_var

try:
    from __main__ import display
except ImportError:
    from ansible.utils.display import Display
    display = Display()


[docs]class AnsibleConstructor(Constructor):
    def __init__(self, file_name=None):
        self._ansible_file_name = file_name
        super(AnsibleConstructor, self).__init__()

[docs]    def construct_yaml_map(self, node):
        data = AnsibleMapping()
        yield data
        value = self.construct_mapping(node)
        data.update(value)
        data.ansible_pos = self._node_position_info(node)

[docs]    def construct_mapping(self, node, deep=False):
        # Most of this is from yaml.constructor.SafeConstructor.  We replicate
        # it here so that we can warn users when they have duplicate dict keys
        # (pyyaml silently allows overwriting keys)
        if not isinstance(node, MappingNode):
            raise ConstructorError(None, None,
                    "expected a mapping node, but found %s" % node.id,
                    node.start_mark)
        self.flatten_mapping(node)
        mapping = AnsibleMapping()

        # Add our extra information to the returned value
        mapping.ansible_pos = self._node_position_info(node)

        for key_node, value_node in node.value:
            key = self.construct_object(key_node, deep=deep)
            try:
                hash(key)
            except TypeError as exc:
                raise ConstructorError("while constructing a mapping", node.start_mark,
                        "found unacceptable key (%s)" % exc, key_node.start_mark)

            if key in mapping:
                display.warning(u'While constructing a mapping from {1}, line {2}, column {3}, found a duplicate dict key ({0}).  Using last defined value only.'.format(key, *mapping.ansible_pos))

            value = self.construct_object(value_node, deep=deep)
            mapping[key] = value

        return mapping

[docs]    def construct_yaml_str(self, node, unsafe=False):
        # Override the default string handling function
        # to always return unicode objects
        value = self.construct_scalar(node)
        ret = AnsibleUnicode(value)

        ret.ansible_pos = self._node_position_info(node)

        if unsafe:
            ret = wrap_var(ret)

        return ret

[docs]    def construct_yaml_seq(self, node):
        data = AnsibleSequence()
        yield data
        data.extend(self.construct_sequence(node))
        data.ansible_pos = self._node_position_info(node)

[docs]    def construct_yaml_unsafe(self, node):
        return self.construct_yaml_str(node, unsafe=True)

    def _node_position_info(self, node):
        # the line number where the previous token has ended (plus empty lines)
        # Add one so that the first line is line 1 rather than line 0
        column = node.start_mark.column + 1
        line = node.start_mark.line + 1

        # in some cases, we may have pre-read the data and then
        # passed it to the load() call for YAML, in which case we
        # want to override the default datasource (which would be
        # '<string>') to the actual filename we read in
        datasource = self._ansible_file_name or node.start_mark.name

        return (datasource, line, column)

AnsibleConstructor.add_constructor(
    u'tag:yaml.org,2002:map',
    AnsibleConstructor.construct_yaml_map)

AnsibleConstructor.add_constructor(
    u'tag:yaml.org,2002:python/dict',
    AnsibleConstructor.construct_yaml_map)

AnsibleConstructor.add_constructor(
    u'tag:yaml.org,2002:str',
    AnsibleConstructor.construct_yaml_str)

AnsibleConstructor.add_constructor(
    u'tag:yaml.org,2002:python/unicode',
    AnsibleConstructor.construct_yaml_str)

AnsibleConstructor.add_constructor(
    u'tag:yaml.org,2002:seq',
    AnsibleConstructor.construct_yaml_seq)

AnsibleConstructor.add_constructor(
    u'!unsafe',
    AnsibleConstructor.construct_yaml_unsafe)