401 lines
13 KiB
Python
401 lines
13 KiB
Python
# Copyright 2012-2014 Amazon.com, Inc. or its affiliates. All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License"). You
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# may not use this file except in compliance with the License. A copy of
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# the License is located at
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#
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# http://aws.amazon.com/apache2.0/
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#
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# or in the "license" file accompanying this file. This file is
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# distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF
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# ANY KIND, either express or implied. See the License for the specific
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# language governing permissions and limitations under the License.
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import logging
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import datetime
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from six import string_types, text_type
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import dateutil.parser
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from dateutil.tz import tzlocal
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from botocore.exceptions import InvalidExpressionError, ConfigNotFound
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from botocore.compat import json, quote
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from botocore.vendored import requests
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from botocore.compat import OrderedDict
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logger = logging.getLogger(__name__)
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DEFAULT_METADATA_SERVICE_TIMEOUT = 1
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METADATA_SECURITY_CREDENTIALS_URL = (
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'http://169.254.169.254/latest/meta-data/iam/security-credentials/'
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)
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# These are chars that do not need to be urlencoded.
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# Based on rfc2986, section 2.3
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SAFE_CHARS = '-._~'
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class _RetriesExceededError(Exception):
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"""Internal exception used when the number of retries are exceeded."""
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pass
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def normalize_url_path(path):
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if not path:
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return '/'
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return remove_dot_segments(path)
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def remove_dot_segments(url):
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# RFC 2986, section 5.2.4 "Remove Dot Segments"
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output = []
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while url:
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if url.startswith('../'):
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url = url[3:]
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elif url.startswith('./'):
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url = url[2:]
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elif url.startswith('/./'):
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url = '/' + url[3:]
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elif url.startswith('/../'):
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url = '/' + url[4:]
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if output:
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output.pop()
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elif url.startswith('/..'):
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url = '/' + url[3:]
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if output:
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output.pop()
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elif url.startswith('/.'):
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url = '/' + url[2:]
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elif url == '.' or url == '..':
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url = ''
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elif url.startswith('//'):
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# As far as I can tell, this is not in the RFC,
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# but AWS auth services require consecutive
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# slashes are removed.
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url = url[1:]
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else:
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if url[0] == '/':
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next_slash = url.find('/', 1)
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else:
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next_slash = url.find('/', 0)
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if next_slash == -1:
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output.append(url)
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url = ''
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else:
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output.append(url[:next_slash])
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url = url[next_slash:]
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return ''.join(output)
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def validate_jmespath_for_set(expression):
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# Validates a limited jmespath expression to determine if we can set a value
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# based on it. Only works with dotted paths.
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if not expression or expression == '.':
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raise InvalidExpressionError(expression=expression)
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for invalid in ['[', ']', '*']:
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if invalid in expression:
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raise InvalidExpressionError(expression=expression)
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def set_value_from_jmespath(source, expression, value, is_first=True):
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# This takes a (limited) jmespath-like expression & can set a value based
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# on it.
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# Limitations:
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# * Only handles dotted lookups
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# * No offsets/wildcards/slices/etc.
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if is_first:
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validate_jmespath_for_set(expression)
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bits = expression.split('.', 1)
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current_key, remainder = bits[0], bits[1] if len(bits) > 1 else ''
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if not current_key:
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raise InvalidExpressionError(expression=expression)
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if remainder:
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if not current_key in source:
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# We've got something in the expression that's not present in the
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# source (new key). If there's any more bits, we'll set the key with
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# an empty dictionary.
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source[current_key] = {}
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return set_value_from_jmespath(
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source[current_key],
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remainder,
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value,
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is_first=False
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)
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# If we're down to a single key, set it.
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source[current_key] = value
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class InstanceMetadataFetcher(object):
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def __init__(self, timeout=DEFAULT_METADATA_SERVICE_TIMEOUT,
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num_attempts=1, url=METADATA_SECURITY_CREDENTIALS_URL):
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self._timeout = timeout
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self._num_attempts = num_attempts
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self._url = url
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def _get_request(self, url, timeout, num_attempts=1):
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for i in range(num_attempts):
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try:
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response = requests.get(url, timeout=timeout)
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except (requests.Timeout, requests.ConnectionError) as e:
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logger.debug("Caught exception while trying to retrieve "
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"credentials: %s", e, exc_info=True)
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else:
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if response.status_code == 200:
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return response
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raise _RetriesExceededError()
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def retrieve_iam_role_credentials(self):
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data = {}
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url = self._url
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timeout = self._timeout
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num_attempts = self._num_attempts
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try:
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r = self._get_request(url, timeout, num_attempts)
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if r.content:
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fields = r.content.decode('utf-8').split('\n')
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for field in fields:
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if field.endswith('/'):
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data[field[0:-1]] = self.retrieve_iam_role_credentials(
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url + field, timeout, num_attempts)
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else:
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val = self._get_request(
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url + field,
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timeout=timeout,
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num_attempts=num_attempts).content.decode('utf-8')
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if val[0] == '{':
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val = json.loads(val)
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data[field] = val
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else:
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logger.debug("Metadata service returned non 200 status code "
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"of %s for url: %s, content body: %s",
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r.status_code, url, r.content)
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except _RetriesExceededError:
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logger.debug("Max number of attempts exceeded (%s) when "
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"attempting to retrieve data from metadata service.",
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num_attempts)
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# We sort for stable ordering. In practice, this should only consist
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# of one role, but may need revisiting if this expands in the future.
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final_data = {}
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for role_name in sorted(data):
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final_data = {
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'role_name': role_name,
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'access_key': data[role_name]['AccessKeyId'],
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'secret_key': data[role_name]['SecretAccessKey'],
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'token': data[role_name]['Token'],
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'expiry_time': data[role_name]['Expiration'],
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}
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return final_data
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def merge_dicts(dict1, dict2):
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"""Given two dict, merge the second dict into the first.
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The dicts can have arbitrary nesting.
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"""
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for key in dict2:
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if isinstance(dict2[key], dict):
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if key in dict1 and key in dict2:
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merge_dicts(dict1[key], dict2[key])
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else:
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dict1[key] = dict2[key]
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else:
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# At scalar types, we iterate and merge the
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# current dict that we're on.
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dict1[key] = dict2[key]
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def parse_key_val_file(filename, _open=open):
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try:
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with _open(filename) as f:
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contents = f.read()
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return parse_key_val_file_contents(contents)
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except OSError as e:
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raise ConfigNotFound(path=filename)
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def parse_key_val_file_contents(contents):
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# This was originally extracted from the EC2 credential provider, which was
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# fairly lenient in its parsing. We only try to parse key/val pairs if
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# there's a '=' in the line.
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final = {}
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for line in contents.splitlines():
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if '=' not in line:
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continue
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key, val = line.split('=', 1)
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key = key.strip()
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val = val.strip()
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final[key] = val
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return final
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def percent_encode_sequence(mapping, safe=SAFE_CHARS):
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"""Urlencode a dict or list into a string.
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This is similar to urllib.urlencode except that:
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* It uses quote, and not quote_plus
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* It has a default list of safe chars that don't need
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to be encoded, which matches what AWS services expect.
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This function should be preferred over the stdlib
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``urlencode()`` function.
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:param mapping: Either a dict to urlencode or a list of
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``(key, value)`` pairs.
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"""
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encoded_pairs = []
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if hasattr(mapping, 'items'):
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pairs = mapping.items()
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else:
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pairs = mapping
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for key, value in pairs:
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encoded_pairs.append('%s=%s' % (percent_encode(key),
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percent_encode(value)))
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return '&'.join(encoded_pairs)
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def percent_encode(input_str, safe=SAFE_CHARS):
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"""Urlencodes a string.
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Whereas percent_encode_sequence handles taking a dict/sequence and
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producing a percent encoded string, this function deals only with
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taking a string (not a dict/sequence) and percent encoding it.
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"""
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if not isinstance(input_str, string_types):
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input_str = text_type(input_str)
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return quote(text_type(input_str).encode('utf-8'), safe=safe)
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def parse_timestamp(value):
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"""Parse a timestamp into a datetime object.
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Supported formats:
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* iso8601
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* rfc822
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* epoch (value is an integer)
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This will return a ``datetime.datetime`` object.
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"""
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if isinstance(value, (int, float)):
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# Possibly an epoch time.
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return datetime.datetime.fromtimestamp(value, tzlocal())
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try:
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return dateutil.parser.parse(value)
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except (TypeError, ValueError) as e:
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raise ValueError('Invalid timestamp "%s": %s' % (value, e))
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class CachedProperty(object):
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"""A read only property that caches the initially computed value.
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This descriptor will only call the provided ``fget`` function once.
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Subsequent access to this property will return the cached value.
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"""
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def __init__(self, fget):
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self._fget = fget
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def __get__(self, obj, cls):
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if obj is None:
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return self
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else:
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computed_value = self._fget(obj)
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obj.__dict__[self._fget.__name__] = computed_value
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return computed_value
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class ArgumentGenerator(object):
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"""Generate sample input based on a shape model.
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This class contains a ``generate_skeleton`` method that will take
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an input shape (created from ``botocore.model``) and generate
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a sample dictionary corresponding to the input shape.
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The specific values used are place holder values. For strings an
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empty string is used, for numbers 0 or 0.0 is used. The intended
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usage of this class is to generate the *shape* of the input structure.
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This can be useful for operations that have complex input shapes.
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This allows a user to just fill in the necessary data instead of
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worrying about the specific structure of the input arguments.
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Example usage::
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s = botocore.session.get_session()
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ddb = s.get_service_model('dynamodb')
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arg_gen = ArgumentGenerator()
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sample_input = arg_gen.generate_skeleton(
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ddb.operation_model('CreateTable').input_shape)
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print("Sample input for dynamodb.CreateTable: %s" % sample_input)
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"""
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def __init__(self):
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pass
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def generate_skeleton(self, shape):
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"""Generate a sample input.
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:type shape: ``botocore.model.Shape``
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:param shape: The input shape.
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:return: The generated skeleton input corresponding to the
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provided input shape.
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"""
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stack = []
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return self._generate_skeleton(shape, stack)
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def _generate_skeleton(self, shape, stack):
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stack.append(shape.name)
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try:
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if shape.type_name == 'structure':
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return self._generate_type_structure(shape, stack)
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elif shape.type_name == 'list':
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return self._generate_type_list(shape, stack)
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elif shape.type_name == 'map':
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return self._generate_type_map(shape, stack)
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elif shape.type_name == 'string':
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return ''
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elif shape.type_name in ['integer', 'long']:
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return 0
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elif shape.type_name == 'float':
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return 0.0
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elif shape.type_name == 'boolean':
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return True
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finally:
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stack.pop()
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def _generate_type_structure(self, shape, stack):
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if stack.count(shape.name) > 1:
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return {}
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skeleton = OrderedDict()
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for member_name, member_shape in shape.members.items():
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skeleton[member_name] = self._generate_skeleton(member_shape,
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stack)
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return skeleton
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def _generate_type_list(self, shape, stack):
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# For list elements we've arbitrarily decided to
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# return two elements for the skeleton list.
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return [
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self._generate_skeleton(shape.member, stack),
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]
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def _generate_type_map(self, shape, stack):
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key_shape = shape.key
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value_shape = shape.value
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assert key_shape.type_name == 'string'
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return OrderedDict([
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('KeyName', self._generate_skeleton(value_shape, stack)),
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])
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