openstack-ansible/rpc_deployment/library/memcached
James W Thorne 12bcb873b4 Typo fix
2014-10-17 11:16:43 -05:00

600 lines
18 KiB
Python

#!/usr/bin/python
# -*- coding: utf-8 -*-
# (c) 2014, Kevin Carter <kevin.carter@rackspace.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/>.
import os
import base64
import stat
import sys
import memcache
try:
from Crypto import Random
from Crypto.Cipher import AES
ENCRYPT_IMPORT = True
except ImportError:
ENCRYPT_IMPORT = False
DOCUMENTATION = """
---
module: memcached
version_added: "1.6.6"
short_description:
- Add, remove, and get items from memcached
description:
- Add, remove, and get items from memcached
options:
name:
description:
- Memcached key name
required: true
content:
description:
- Add content to memcached. Only used when state is 'present'.
required: false
file_path:
description:
- This can be used with state 'present' and 'retrieve'. When set
with state 'present' the contents of a file will be used, when
set with state 'retrieve' the contents of the memcached key will
be written to a file.
required: false
state:
description:
- ['absent', 'present', 'retrieve']
required: true
server:
description:
- server IP address and port. This can be a comma seperated list of
servers to connect to.
required: true
encrypt_string:
description:
- Encrypt/Decrypt a memcached object using a provided value.
required: false
dir_mode:
description:
- If a directory is created when using the ``file_path`` argument
the directory will be created with a set mode.
default: '0755'
required: false
file_mode:
description:
- If a file is created when using the ``file_path`` argument
the file will be created with a set mode.
default: '0644'
required: false
expires:
description:
- Seconds until an item is expired from memcached.
default: 300
required: false
notes:
- The "absent" state will remove an item from memcached.
- The "present" state will place an item from a string or a file into
memcached.
- The "retrieve" state will get an item from memcached and return it as a
string. If a ``file_path`` is set this module will also write the value
to a file.
- All items added into memcached are base64 encoded.
- All items retrieved will attempt base64 decode and return the string
value if not applicable.
- Items retrieve from memcached are returned within a "value" key unless
a ``file_path`` is specified which would then write the contents of the
memcached key to a file.
- The ``file_path`` and ``content`` fields are mutually exclusive.
- If you'd like to encrypt items in memcached PyCrypto is a required.
requirements:
- "python-memcached"
optional_requirements:
- "pycrypto"
author: Kevin Carter
"""
EXAMPLES = """
# Add an item into memcached.
- memcached:
name: "key_name"
content: "Super awesome value"
state: "present"
server: "localhost:11211"
# Read the contents of a memcached key, returned as "memcached_phrase.value".
- memcached:
name: "key_name"
state: "retrieve"
server: "localhost:11211"
register: memcached_key
# Add the contents of a file into memcached.
- memcached:
name: "key_name"
file_path: "/home/user_name/file.txt"
state: "present"
server: "localhost:11211"
# Write the contents of a memcached key to a file and is returned as
# "memcached_phrase.value".
- memcached:
name: "key_name"
file_path: "/home/user_name/file.txt"
state: "retrieve"
server: "localhost:11211"
register: memcached_key
# Delete an item from memcached.
- memcached:
name: "key_name"
state: "absent"
server: "localhost:11211"
"""
SERVER_MAX_VALUE_LENGTH = 1024 * 256
MAX_MEMCACHED_CHUNKS = 256
class AESCipher(object):
"""Encrypt an a string in using AES.
Solution derived from "http://stackoverflow.com/a/21928790"
"""
def __init__(self, key):
if ENCRYPT_IMPORT is False:
raise ImportError(
'PyCrypto failed to be imported. Encryption is not supported'
' on this system until PyCrypto is installed.'
)
self.bs = 32
if len(key) >= 32:
self.key = key[:32]
else:
self.key = self._pad(key)
def encrypt(self, raw):
"""Encrypt raw message.
:param raw: ``str``
:returns: ``str`` Base64 encoded string.
"""
raw = self._pad(raw)
iv = Random.new().read(AES.block_size)
cipher = AES.new(self.key, AES.MODE_CBC, iv)
return base64.b64encode(iv + cipher.encrypt(raw))
def decrypt(self, enc):
"""Decrypt an encrypted message.
:param enc: ``str``
:returns: ``str``
"""
enc = base64.b64decode(enc)
iv = enc[:AES.block_size]
cipher = AES.new(self.key, AES.MODE_CBC, iv)
return self._unpad(cipher.decrypt(enc[AES.block_size:]))
def _pad(self, string):
"""Pad an AES encryption key.
:param string: ``str``
"""
base = (self.bs - len(string) % self.bs)
back = chr(self.bs - len(string) % self.bs)
return string + base * back
@staticmethod
def _unpad(string):
"""Un-pad an AES encryption key.
:param string: ``str``
"""
ordinal_range = ord(string[len(string)-1:])
return string[:-ordinal_range]
class Memcached(object):
"""Manage objects within memcached."""
def __init__(self, module):
self.module = module
self.state_change = False
self.mc = None
def router(self):
"""Route all commands to their respected functions.
If an exception happens a failure will be raised.
"""
try:
action = getattr(self, self.module.params['state'])
self.mc = memcache.Client(
self.module.params['server'].split(','),
server_max_value_length=SERVER_MAX_VALUE_LENGTH,
debug=0
)
facts = action()
except Exception as exp:
self._failure(error=str(exp), rc=1, msg='general exception')
else:
self.mc.disconnect_all()
self.module.exit_json(
changed=self.state_change, **facts
)
def _failure(self, error, rc, msg):
"""Return a Failure when running an Ansible command.
:param error: ``str`` Error that occurred.
:param rc: ``int`` Return code while executing an Ansible command.
:param msg: ``str`` Message to report.
"""
self.module.fail_json(msg=msg, rc=rc, err=error)
def absent(self):
"""Remove a key from memcached.
If the value is not deleted when instructed to do so an exception will
be raised.
:return: ``dict``
"""
key_name = self.module.params['name']
get_keys = [
'%s.%s' % (key_name, i) for i in xrange(MAX_MEMCACHED_CHUNKS)
]
self.mc.delete_multi(get_keys)
value = self.mc.get_multi(get_keys)
if not value:
self.state_change = True
return {'absent': True, 'key': self.module.params['name']}
else:
self._failure(
error='Memcache key not deleted',
rc=1,
msg='Failed to remove an item from memcached please check your'
' memcached server for issues. If you are load balancing'
' memcached, attempt to connect to a single node.'
)
@staticmethod
def _decode_value(value):
"""Return a ``str`` from a base64 decoded value.
If the content is not a base64 ``str`` the raw value will be returned.
:param value: ``str``
:return:
"""
try:
b64_value = base64.decodestring(value)
except Exception:
return value
else:
return b64_value
def _encode_value(self, value):
"""Return a base64 encoded value.
If the value can't be base64 encoded an excption will be raised.
:param value: ``str``
:return: ``str``
"""
try:
b64_value = base64.encodestring(value)
except Exception as exp:
self._failure(
error=str(exp),
rc=1,
msg='The value provided can not be Base64 encoded.'
)
else:
return b64_value
def _file_read(self, full_path, pass_on_error=False):
"""Read the contents of a file.
This will read the contents of a file. If the ``full_path`` does not
exist an exception will be raised.
:param full_path: ``str``
:return: ``str``
"""
try:
with open(full_path, 'rb') as f:
o_value = f.read()
except IOError as exp:
if pass_on_error is False:
self._failure(
error=str(exp),
rc=1,
msg="The file you've specified does not exist. Please"
" check your full path @ [ %s ]." % full_path
)
else:
return None
else:
return o_value
def _chown(self, path, mode_type):
"""Chown a file or directory based on a given mode type.
If the file is modified the state will be changed.
:param path: ``str``
:param mode_type: ``str``
"""
mode = self.module.params.get(mode_type)
# Ensure that the mode type is a string.
mode = str(mode)
_mode = oct(stat.S_IMODE(os.stat(path).st_mode))
if _mode != mode or _mode[1:] != mode:
os.chmod(path, int(mode, 8))
self.state_change = True
def _file_write(self, full_path, value):
"""Write the contents of ``value`` to the ``full_path``.
This will return True upon success and will raise an exception upon
failure.
:param full_path: ``str``
:param value: ``str``
:return: ``bol``
"""
try:
# Ensure that the directory exists
dir_path = os.path.dirname(full_path)
try:
os.makedirs(dir_path)
except OSError as exp:
if exp.errno == errno.EEXIST and os.path.isdir(dir_path):
pass
else:
self._failure(
error=str(exp),
rc=1,
msg="The directory [ %s ] does not exist and couldn't"
" be created. Please check the path and that you"
" have permission to write the file."
)
# Ensure proper directory permissions
self._chown(path=dir_path, mode_type='dir_mode')
# Write contents of a cached key to a file.
with open(full_path, 'wb') as f:
if isinstance(value, list):
f.writelines(value)
else:
f.write(value)
# Ensure proper file permissions
self._chown(path=full_path, mode_type='file_mode')
except IOError as exp:
self._failure(
error=str(exp),
rc=1,
msg="There was an issue while attempting to write to the"
" file [ %s ]. Please check your full path and"
" permissions." % full_path
)
else:
return True
def retrieve(self):
"""Return a value from memcached.
If ``file_path`` is specified the value of the memcached key will be
written to a file at the ``file_path`` location. If the value of a key
is None, an exception will be raised.
:returns: ``dict``
"""
key_name = self.module.params['name']
get_keys = [
'%s.%s' % (key_name, i) for i in xrange(MAX_MEMCACHED_CHUNKS)
]
multi_value = self.mc.get_multi(get_keys)
if multi_value:
value = ''.join([i for i in multi_value.values() if i is not None])
# Get the file path if specified.
file_path = self.module.params.get('file_path')
if file_path is not None:
full_path = os.path.abspath(os.path.expanduser(file_path))
# Decode cached value
encrypt_string = self.module.params.get('encrypt_string')
if encrypt_string:
_d_value = AESCipher(key=encrypt_string)
d_value = _d_value.decrypt(enc=value)
if not d_value:
d_value = self._decode_value(value=value)
else:
d_value = self._decode_value(value=value)
o_value = self._file_read(
full_path=full_path, pass_on_error=True
)
# compare old value to new value and write if different
if o_value != d_value:
self.state_change = True
self._file_write(full_path=full_path, value=d_value)
return {
'present': True,
'key': self.module.params['name'],
'value': value,
'file_path': full_path
}
else:
return {
'present': True,
'key': self.module.params['name'],
'value': value
}
else:
self._failure(
error='Memcache key not found',
rc=1,
msg='The key you specified was not found within memcached. '
'If you are load balancing memcached, attempt to connect'
' to a single node.'
)
def present(self):
"""Create and or update a key within Memcached.
The state processed here is present. This state will ensure that
content is written to a memcached server. When ``file_path`` is
specified the content will be read in from a file.
"""
file_path = self.module.params.get('file_path')
if file_path is not None:
full_path = os.path.abspath(os.path.expanduser(file_path))
# Read the contents of a file into memcached.
o_value = self._file_read(full_path=full_path)
else:
o_value = self.module.params['content']
# Encode cached value
encrypt_string = self.module.params.get('encrypt_string')
if encrypt_string:
_d_value = AESCipher(key=encrypt_string)
d_value = _d_value.encrypt(raw=o_value)
else:
d_value = self._encode_value(value=o_value)
compare = 1024 * 128
chunks = sys.getsizeof(d_value) / compare
if chunks == 0:
chunks = 1
elif chunks > MAX_MEMCACHED_CHUNKS:
self._failure(
error='Memcache content too large',
rc=1,
msg='The content that you are attempting to cache is larger'
' than [ %s ] megabytes.'
% ((compare * MAX_MEMCACHED_CHUNKS / 1024 / 1024))
)
step = len(d_value) / chunks
if step == 0:
step = 1
key_name = self.module.params['name']
split_d_value = {}
count = 0
for i in range(0, len(d_value), step):
split_d_value['%s.%s' % (key_name, count)] = d_value[i:i+step]
count += 1
value = self.mc.set_multi(
mapping=split_d_value,
time=self.module.params['expires'],
min_compress_len=2048
)
if not value:
self.state_change = True
return {
'present': True,
'key': self.module.params['name']
}
else:
self._failure(
error='Memcache content not created',
rc=1,
msg='The content you attempted to place within memcached'
' was not created. If you are load balancing'
' memcached, attempt to connect to a single node.'
' Returned a value of unstored keys [ %s ].' % value
)
def main():
"""Main ansible run method."""
module = AnsibleModule(
argument_spec=dict(
name=dict(
type='str',
required=True
),
content=dict(
type='str',
required=False
),
file_path=dict(
type='str',
required=False
),
state=dict(
type='str',
required=True
),
server=dict(
type='str',
required=True
),
expires=dict(
type='int',
default=300,
required=False
),
file_mode=dict(
type='str',
default='0644',
required=False
),
dir_mode=dict(
type='str',
default='0755',
required=False
),
encrypt_string=dict(
type='str',
required=False
)
),
supports_check_mode=False,
mutually_exclusive=[
['content', 'file_path']
]
)
ms = Memcached(module=module)
ms.router()
# import module snippets
from ansible.module_utils.basic import *
if __name__ == '__main__':
main()