# Copyright 2014 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 re
import jmespath
from botocore import xform_name
from ..exceptions import ResourceLoadException
INDEX_RE = re.compile('\[(.*)\]$')
[docs]def get_data_member(parent, path):
"""
Get a data member from a parent using a JMESPath search query,
loading the parent if required. If the parent cannot be loaded
and no data is present then an exception is raised.
:type parent: ServiceResource
:param parent: The resource instance to which contains data we
are interested in.
:type path: string
:param path: The JMESPath expression to query
:raises ResourceLoadException: When no data is present and the
resource cannot be loaded.
:returns: The queried data or ``None``.
"""
# Ensure the parent has its data loaded, if possible.
if parent.meta.data is None:
if hasattr(parent, 'load'):
parent.load()
else:
raise ResourceLoadException(
'{0} has no load method!'.format(parent.__class__.__name__))
return jmespath.search(path, parent.meta.data)
[docs]def create_request_parameters(parent, request_model, params=None, index=None):
"""
Handle request parameters that can be filled in from identifiers,
resource data members or constants.
By passing ``params``, you can invoke this method multiple times and
build up a parameter dict over time, which is particularly useful
for reverse JMESPath expressions that append to lists.
:type parent: ServiceResource
:param parent: The resource instance to which this action is attached.
:type request_model: :py:class:`~boto3.resources.model.Request`
:param request_model: The action request model.
:type params: dict
:param params: If set, then add to this existing dict. It is both
edited in-place and returned.
:type index: int
:param index: The position of an item within a list
:rtype: dict
:return: Pre-filled parameters to be sent to the request operation.
"""
if params is None:
params = {}
for param in request_model.params:
source = param.source
target = param.target
if source == 'identifier':
# Resource identifier, e.g. queue.url
value = getattr(parent, xform_name(param.name))
elif source == 'data':
# If this is a data member then it may incur a load
# action before returning the value.
value = get_data_member(parent, param.path)
elif source in ['string', 'integer', 'boolean']:
# These are hard-coded values in the definition
value = param.value
elif source == 'input':
# This is provided by the user, so ignore it here
continue
else:
raise NotImplementedError(
'Unsupported source type: {0}'.format(source))
build_param_structure(params, target, value, index)
return params
[docs]def build_param_structure(params, target, value, index=None):
"""
This method provides a basic reverse JMESPath implementation that
lets you go from a JMESPath-like string to a possibly deeply nested
object. The ``params`` are mutated in-place, so subsequent calls
can modify the same element by its index.
>>> build_param_structure(params, 'test[0]', 1)
>>> print(params)
{'test': [1]}
>>> build_param_structure(params, 'foo.bar[0].baz', 'hello world')
>>> print(params)
{'test': [1], 'foo': {'bar': [{'baz': 'hello, world'}]}}
"""
pos = params
parts = target.split('.')
# First, split into parts like 'foo', 'bar[0]', 'baz' and process
# each piece. It can either be a list or a dict, depending on if
# an index like `[0]` is present. We detect this via a regular
# expression, and keep track of where we are in params via the
# pos variable, walking down to the last item. Once there, we
# set the value.
for i, part in enumerate(parts):
# Is it indexing an array?
result = INDEX_RE.search(part)
if result:
if result.group(1):
if result.group(1) == '*':
part = part[:-3]
else:
# We have an explicit index
index = int(result.group(1))
part = part[:-len(str(index) + '[]')]
else:
# Index will be set after we know the proper part
# name and that it's a list instance.
index = None
part = part[:-2]
if part not in pos or not isinstance(pos[part], list):
pos[part] = []
# This means we should append, e.g. 'foo[]'
if index is None:
index = len(pos[part])
while len(pos[part]) <= index:
# Assume it's a dict until we set the final value below
pos[part].append({})
# Last item? Set the value, otherwise set the new position
if i == len(parts) - 1:
pos[part][index] = value
else:
# The new pos is the *item* in the array, not the array!
pos = pos[part][index]
else:
if part not in pos:
pos[part] = {}
# Last item? Set the value, otherwise set the new position
if i == len(parts) - 1:
pos[part] = value
else:
pos = pos[part]