manila/manila/utils.py

1224 lines
39 KiB
Python

# vim: tabstop=4 shiftwidth=4 softtabstop=4
# Copyright 2010 United States Government as represented by the
# Administrator of the National Aeronautics and Space Administration.
# Copyright 2011 Justin Santa Barbara
# 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. You may obtain
# a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License 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.
"""Utilities and helper functions."""
import contextlib
import datetime
import errno
import functools
import hashlib
import inspect
import netaddr
import os
import paramiko
import pyclbr
import random
import re
import shlex
import shutil
import signal
import socket
import struct
import sys
import tempfile
import time
from xml.dom import minidom
from xml.parsers import expat
from xml import sax
from xml.sax import expatreader
from xml.sax import saxutils
from oslo.config import cfg
from eventlet import event
from eventlet.green import subprocess
from eventlet import greenthread
from eventlet import pools
from manila import exception
from manila.openstack.common import excutils
from manila.openstack.common import importutils
from manila.openstack.common import lockutils
from manila.openstack.common import log as logging
from manila.openstack.common import timeutils
CONF = cfg.CONF
LOG = logging.getLogger(__name__)
ISO_TIME_FORMAT = "%Y-%m-%dT%H:%M:%S"
PERFECT_TIME_FORMAT = "%Y-%m-%dT%H:%M:%S.%f"
synchronized = lockutils.synchronized_with_prefix('manila-')
def find_config(config_path):
"""Find a configuration file using the given hint.
:param config_path: Full or relative path to the config.
:returns: Full path of the config, if it exists.
:raises: `manila.exception.ConfigNotFound`
"""
possible_locations = [
config_path,
os.path.join(CONF.state_path, "etc", "manila", config_path),
os.path.join(CONF.state_path, "etc", config_path),
os.path.join(CONF.state_path, config_path),
"/etc/manila/%s" % config_path,
]
for path in possible_locations:
if os.path.exists(path):
return os.path.abspath(path)
raise exception.ConfigNotFound(path=os.path.abspath(config_path))
def fetchfile(url, target):
LOG.debug(_('Fetching %s') % url)
execute('curl', '--fail', url, '-o', target)
def _subprocess_setup():
# Python installs a SIGPIPE handler by default. This is usually not what
# non-Python subprocesses expect.
signal.signal(signal.SIGPIPE, signal.SIG_DFL)
def execute(*cmd, **kwargs):
"""Helper method to execute command with optional retry.
If you add a run_as_root=True command, don't forget to add the
corresponding filter to etc/manila/rootwrap.d !
:param cmd: Passed to subprocess.Popen.
:param process_input: Send to opened process.
:param check_exit_code: Single bool, int, or list of allowed exit
codes. Defaults to [0]. Raise
exception.ProcessExecutionError unless
program exits with one of these code.
:param delay_on_retry: True | False. Defaults to True. If set to
True, wait a short amount of time
before retrying.
:param attempts: How many times to retry cmd.
:param run_as_root: True | False. Defaults to False. If set to True,
the command is prefixed by the command specified
in the root_helper FLAG.
:raises exception.Error: on receiving unknown arguments
:raises exception.ProcessExecutionError:
:returns: a tuple, (stdout, stderr) from the spawned process, or None if
the command fails.
"""
process_input = kwargs.pop('process_input', None)
check_exit_code = kwargs.pop('check_exit_code', [0])
ignore_exit_code = False
if isinstance(check_exit_code, bool):
ignore_exit_code = not check_exit_code
check_exit_code = [0]
elif isinstance(check_exit_code, int):
check_exit_code = [check_exit_code]
delay_on_retry = kwargs.pop('delay_on_retry', True)
attempts = kwargs.pop('attempts', 1)
run_as_root = kwargs.pop('run_as_root', False)
shell = kwargs.pop('shell', False)
if len(kwargs):
raise exception.Error(_('Got unknown keyword args '
'to utils.execute: %r') % kwargs)
if run_as_root:
if CONF.rootwrap_config is None or CONF.root_helper != 'sudo':
LOG.deprecated(_('The root_helper option (which lets you specify '
'a root wrapper different from manila-rootwrap, '
'and defaults to using sudo) is now deprecated. '
'You should use the rootwrap_config option '
'instead.'))
if (CONF.rootwrap_config is not None):
cmd = ['sudo', 'manila-rootwrap',
CONF.rootwrap_config] + list(cmd)
else:
cmd = shlex.split(CONF.root_helper) + list(cmd)
cmd = map(str, cmd)
while attempts > 0:
attempts -= 1
try:
LOG.debug(_('Running cmd (subprocess): %s'), ' '.join(cmd))
_PIPE = subprocess.PIPE # pylint: disable=E1101
obj = subprocess.Popen(cmd,
stdin=_PIPE,
stdout=_PIPE,
stderr=_PIPE,
close_fds=True,
preexec_fn=_subprocess_setup,
shell=shell)
result = None
if process_input is not None:
result = obj.communicate(process_input)
else:
result = obj.communicate()
obj.stdin.close() # pylint: disable=E1101
_returncode = obj.returncode # pylint: disable=E1101
if _returncode:
LOG.debug(_('Result was %s') % _returncode)
if not ignore_exit_code and _returncode not in check_exit_code:
(stdout, stderr) = result
raise exception.ProcessExecutionError(
exit_code=_returncode,
stdout=stdout,
stderr=stderr,
cmd=' '.join(cmd))
return result
except exception.ProcessExecutionError:
if not attempts:
raise
else:
LOG.debug(_('%r failed. Retrying.'), cmd)
if delay_on_retry:
greenthread.sleep(random.randint(20, 200) / 100.0)
finally:
# NOTE(termie): this appears to be necessary to let the subprocess
# call clean something up in between calls, without
# it two execute calls in a row hangs the second one
greenthread.sleep(0)
def trycmd(*args, **kwargs):
"""
A wrapper around execute() to more easily handle warnings and errors.
Returns an (out, err) tuple of strings containing the output of
the command's stdout and stderr. If 'err' is not empty then the
command can be considered to have failed.
:discard_warnings True | False. Defaults to False. If set to True,
then for succeeding commands, stderr is cleared
"""
discard_warnings = kwargs.pop('discard_warnings', False)
try:
out, err = execute(*args, **kwargs)
failed = False
except exception.ProcessExecutionError, exn:
out, err = '', str(exn)
LOG.debug(err)
failed = True
if not failed and discard_warnings and err:
# Handle commands that output to stderr but otherwise succeed
LOG.debug(err)
err = ''
return out, err
def ssh_execute(ssh, cmd, process_input=None,
addl_env=None, check_exit_code=True):
LOG.debug(_('Running cmd (SSH): %s'), cmd)
if addl_env:
raise exception.Error(_('Environment not supported over SSH'))
if process_input:
# This is (probably) fixable if we need it...
raise exception.Error(_('process_input not supported over SSH'))
stdin_stream, stdout_stream, stderr_stream = ssh.exec_command(cmd)
channel = stdout_stream.channel
#stdin.write('process_input would go here')
#stdin.flush()
# NOTE(justinsb): This seems suspicious...
# ...other SSH clients have buffering issues with this approach
stdout = stdout_stream.read()
stderr = stderr_stream.read()
stdin_stream.close()
stdout_stream.close()
stderr_stream.close()
exit_status = channel.recv_exit_status()
# exit_status == -1 if no exit code was returned
if exit_status != -1:
LOG.debug(_('Result was %s') % exit_status)
if check_exit_code and exit_status != 0:
raise exception.ProcessExecutionError(exit_code=exit_status,
stdout=stdout,
stderr=stderr,
cmd=cmd)
channel.close()
return (stdout, stderr)
def create_channel(client, width, height):
"""Invoke an interactive shell session on server."""
channel = client.invoke_shell()
channel.resize_pty(width, height)
return channel
class SSHPool(pools.Pool):
"""A simple eventlet pool to hold ssh connections."""
def __init__(self, ip, port, conn_timeout, login, password=None,
privatekey=None, *args, **kwargs):
self.ip = ip
self.port = port
self.login = login
self.password = password
self.conn_timeout = conn_timeout if conn_timeout else None
self.privatekey = privatekey
super(SSHPool, self).__init__(*args, **kwargs)
def create(self):
try:
ssh = paramiko.SSHClient()
ssh.set_missing_host_key_policy(paramiko.AutoAddPolicy())
if self.password:
ssh.connect(self.ip,
port=self.port,
username=self.login,
password=self.password,
timeout=self.conn_timeout)
elif self.privatekey:
pkfile = os.path.expanduser(self.privatekey)
privatekey = paramiko.RSAKey.from_private_key_file(pkfile)
ssh.connect(self.ip,
port=self.port,
username=self.login,
pkey=privatekey,
timeout=self.conn_timeout)
else:
msg = _("Specify a password or private_key")
raise exception.ManilaException(msg)
# Paramiko by default sets the socket timeout to 0.1 seconds,
# ignoring what we set thru the sshclient. This doesn't help for
# keeping long lived connections. Hence we have to bypass it, by
# overriding it after the transport is initialized. We are setting
# the sockettimeout to None and setting a keepalive packet so that,
# the server will keep the connection open. All that does is send
# a keepalive packet every ssh_conn_timeout seconds.
if self.conn_timeout:
transport = ssh.get_transport()
transport.sock.settimeout(None)
transport.set_keepalive(self.conn_timeout)
return ssh
except Exception as e:
msg = _("Error connecting via ssh: %s") % e
LOG.error(msg)
raise paramiko.SSHException(msg)
def get(self):
"""
Return an item from the pool, when one is available. This may
cause the calling greenthread to block. Check if a connection is active
before returning it. For dead connections create and return a new
connection.
"""
if self.free_items:
conn = self.free_items.popleft()
if conn:
if conn.get_transport().is_active():
return conn
else:
conn.close()
return self.create()
if self.current_size < self.max_size:
created = self.create()
self.current_size += 1
return created
return self.channel.get()
def remove(self, ssh):
"""Close an ssh client and remove it from free_items."""
ssh.close()
ssh = None
if ssh in self.free_items:
self.free_items.pop(ssh)
if self.current_size > 0:
self.current_size -= 1
def maniladir():
import manila
return os.path.abspath(manila.__file__).split('manila/__init__.py')[0]
def debug(arg):
LOG.debug(_('debug in callback: %s'), arg)
return arg
def generate_uid(topic, size=8):
characters = '01234567890abcdefghijklmnopqrstuvwxyz'
choices = [random.choice(characters) for x in xrange(size)]
return '%s-%s' % (topic, ''.join(choices))
# Default symbols to use for passwords. Avoids visually confusing characters.
# ~6 bits per symbol
DEFAULT_PASSWORD_SYMBOLS = ('23456789', # Removed: 0,1
'ABCDEFGHJKLMNPQRSTUVWXYZ', # Removed: I, O
'abcdefghijkmnopqrstuvwxyz') # Removed: l
# ~5 bits per symbol
EASIER_PASSWORD_SYMBOLS = ('23456789', # Removed: 0, 1
'ABCDEFGHJKLMNPQRSTUVWXYZ') # Removed: I, O
def last_completed_audit_period(unit=None):
"""This method gives you the most recently *completed* audit period.
arguments:
units: string, one of 'hour', 'day', 'month', 'year'
Periods normally begin at the beginning (UTC) of the
period unit (So a 'day' period begins at midnight UTC,
a 'month' unit on the 1st, a 'year' on Jan, 1)
unit string may be appended with an optional offset
like so: 'day@18' This will begin the period at 18:00
UTC. 'month@15' starts a monthly period on the 15th,
and year@3 begins a yearly one on March 1st.
returns: 2 tuple of datetimes (begin, end)
The begin timestamp of this audit period is the same as the
end of the previous."""
if not unit:
unit = CONF.volume_usage_audit_period
offset = 0
if '@' in unit:
unit, offset = unit.split("@", 1)
offset = int(offset)
rightnow = timeutils.utcnow()
if unit not in ('month', 'day', 'year', 'hour'):
raise ValueError('Time period must be hour, day, month or year')
if unit == 'month':
if offset == 0:
offset = 1
end = datetime.datetime(day=offset,
month=rightnow.month,
year=rightnow.year)
if end >= rightnow:
year = rightnow.year
if 1 >= rightnow.month:
year -= 1
month = 12 + (rightnow.month - 1)
else:
month = rightnow.month - 1
end = datetime.datetime(day=offset,
month=month,
year=year)
year = end.year
if 1 >= end.month:
year -= 1
month = 12 + (end.month - 1)
else:
month = end.month - 1
begin = datetime.datetime(day=offset, month=month, year=year)
elif unit == 'year':
if offset == 0:
offset = 1
end = datetime.datetime(day=1, month=offset, year=rightnow.year)
if end >= rightnow:
end = datetime.datetime(day=1,
month=offset,
year=rightnow.year - 1)
begin = datetime.datetime(day=1,
month=offset,
year=rightnow.year - 2)
else:
begin = datetime.datetime(day=1,
month=offset,
year=rightnow.year - 1)
elif unit == 'day':
end = datetime.datetime(hour=offset,
day=rightnow.day,
month=rightnow.month,
year=rightnow.year)
if end >= rightnow:
end = end - datetime.timedelta(days=1)
begin = end - datetime.timedelta(days=1)
elif unit == 'hour':
end = rightnow.replace(minute=offset, second=0, microsecond=0)
if end >= rightnow:
end = end - datetime.timedelta(hours=1)
begin = end - datetime.timedelta(hours=1)
return (begin, end)
def generate_password(length=20, symbolgroups=DEFAULT_PASSWORD_SYMBOLS):
"""Generate a random password from the supplied symbol groups.
At least one symbol from each group will be included. Unpredictable
results if length is less than the number of symbol groups.
Believed to be reasonably secure (with a reasonable password length!)
"""
r = random.SystemRandom()
# NOTE(jerdfelt): Some password policies require at least one character
# from each group of symbols, so start off with one random character
# from each symbol group
password = [r.choice(s) for s in symbolgroups]
# If length < len(symbolgroups), the leading characters will only
# be from the first length groups. Try our best to not be predictable
# by shuffling and then truncating.
r.shuffle(password)
password = password[:length]
length -= len(password)
# then fill with random characters from all symbol groups
symbols = ''.join(symbolgroups)
password.extend([r.choice(symbols) for _i in xrange(length)])
# finally shuffle to ensure first x characters aren't from a
# predictable group
r.shuffle(password)
return ''.join(password)
def generate_username(length=20, symbolgroups=DEFAULT_PASSWORD_SYMBOLS):
# Use the same implementation as the password generation.
return generate_password(length, symbolgroups)
def last_octet(address):
return int(address.split('.')[-1])
def get_my_linklocal(interface):
try:
if_str = execute('ip', '-f', 'inet6', '-o', 'addr', 'show', interface)
condition = '\s+inet6\s+([0-9a-f:]+)/\d+\s+scope\s+link'
links = [re.search(condition, x) for x in if_str[0].split('\n')]
address = [w.group(1) for w in links if w is not None]
if address[0] is not None:
return address[0]
else:
raise exception.Error(_('Link Local address is not found.:%s')
% if_str)
except Exception as ex:
raise exception.Error(_("Couldn't get Link Local IP of %(interface)s"
" :%(ex)s") % locals())
def parse_mailmap(mailmap='.mailmap'):
mapping = {}
if os.path.exists(mailmap):
fp = open(mailmap, 'r')
for l in fp:
l = l.strip()
if not l.startswith('#') and ' ' in l:
canonical_email, alias = l.split(' ')
mapping[alias.lower()] = canonical_email.lower()
return mapping
def str_dict_replace(s, mapping):
for s1, s2 in mapping.iteritems():
s = s.replace(s1, s2)
return s
class LazyPluggable(object):
"""A pluggable backend loaded lazily based on some value."""
def __init__(self, pivot, **backends):
self.__backends = backends
self.__pivot = pivot
self.__backend = None
def __get_backend(self):
if not self.__backend:
backend_name = CONF[self.__pivot]
if backend_name not in self.__backends:
raise exception.Error(_('Invalid backend: %s') % backend_name)
backend = self.__backends[backend_name]
if isinstance(backend, tuple):
name = backend[0]
fromlist = backend[1]
else:
name = backend
fromlist = backend
self.__backend = __import__(name, None, None, fromlist)
LOG.debug(_('backend %s'), self.__backend)
return self.__backend
def __getattr__(self, key):
backend = self.__get_backend()
return getattr(backend, key)
class LoopingCallDone(Exception):
"""Exception to break out and stop a LoopingCall.
The poll-function passed to LoopingCall can raise this exception to
break out of the loop normally. This is somewhat analogous to
StopIteration.
An optional return-value can be included as the argument to the exception;
this return-value will be returned by LoopingCall.wait()
"""
def __init__(self, retvalue=True):
""":param retvalue: Value that LoopingCall.wait() should return."""
self.retvalue = retvalue
class LoopingCall(object):
def __init__(self, f=None, *args, **kw):
self.args = args
self.kw = kw
self.f = f
self._running = False
def start(self, interval, initial_delay=None):
self._running = True
done = event.Event()
def _inner():
if initial_delay:
greenthread.sleep(initial_delay)
try:
while self._running:
self.f(*self.args, **self.kw)
if not self._running:
break
greenthread.sleep(interval)
except LoopingCallDone, e:
self.stop()
done.send(e.retvalue)
except Exception:
LOG.exception(_('in looping call'))
done.send_exception(*sys.exc_info())
return
else:
done.send(True)
self.done = done
greenthread.spawn(_inner)
return self.done
def stop(self):
self._running = False
def wait(self):
return self.done.wait()
class ProtectedExpatParser(expatreader.ExpatParser):
"""An expat parser which disables DTD's and entities by default."""
def __init__(self, forbid_dtd=True, forbid_entities=True,
*args, **kwargs):
# Python 2.x old style class
expatreader.ExpatParser.__init__(self, *args, **kwargs)
self.forbid_dtd = forbid_dtd
self.forbid_entities = forbid_entities
def start_doctype_decl(self, name, sysid, pubid, has_internal_subset):
raise ValueError("Inline DTD forbidden")
def entity_decl(self, entityName, is_parameter_entity, value, base,
systemId, publicId, notationName):
raise ValueError("<!ENTITY> forbidden")
def unparsed_entity_decl(self, name, base, sysid, pubid, notation_name):
# expat 1.2
raise ValueError("<!ENTITY> forbidden")
def reset(self):
expatreader.ExpatParser.reset(self)
if self.forbid_dtd:
self._parser.StartDoctypeDeclHandler = self.start_doctype_decl
if self.forbid_entities:
self._parser.EntityDeclHandler = self.entity_decl
self._parser.UnparsedEntityDeclHandler = self.unparsed_entity_decl
def safe_minidom_parse_string(xml_string):
"""Parse an XML string using minidom safely.
"""
try:
return minidom.parseString(xml_string, parser=ProtectedExpatParser())
except sax.SAXParseException as se:
raise expat.ExpatError()
def xhtml_escape(value):
"""Escapes a string so it is valid within XML or XHTML.
"""
return saxutils.escape(value, {'"': '&quot;', "'": '&apos;'})
def utf8(value):
"""Try to turn a string into utf-8 if possible.
Code is directly from the utf8 function in
http://github.com/facebook/tornado/blob/master/tornado/escape.py
"""
if isinstance(value, unicode):
return value.encode('utf-8')
assert isinstance(value, str)
return value
def delete_if_exists(pathname):
"""delete a file, but ignore file not found error"""
try:
os.unlink(pathname)
except OSError as e:
if e.errno == errno.ENOENT:
return
else:
raise
def get_from_path(items, path):
"""Returns a list of items matching the specified path.
Takes an XPath-like expression e.g. prop1/prop2/prop3, and for each item
in items, looks up items[prop1][prop2][prop3]. Like XPath, if any of the
intermediate results are lists it will treat each list item individually.
A 'None' in items or any child expressions will be ignored, this function
will not throw because of None (anywhere) in items. The returned list
will contain no None values.
"""
if path is None:
raise exception.Error('Invalid mini_xpath')
(first_token, sep, remainder) = path.partition('/')
if first_token == '':
raise exception.Error('Invalid mini_xpath')
results = []
if items is None:
return results
if not isinstance(items, list):
# Wrap single objects in a list
items = [items]
for item in items:
if item is None:
continue
get_method = getattr(item, 'get', None)
if get_method is None:
continue
child = get_method(first_token)
if child is None:
continue
if isinstance(child, list):
# Flatten intermediate lists
for x in child:
results.append(x)
else:
results.append(child)
if not sep:
# No more tokens
return results
else:
return get_from_path(results, remainder)
def flatten_dict(dict_, flattened=None):
"""Recursively flatten a nested dictionary."""
flattened = flattened or {}
for key, value in dict_.iteritems():
if hasattr(value, 'iteritems'):
flatten_dict(value, flattened)
else:
flattened[key] = value
return flattened
def partition_dict(dict_, keys):
"""Return two dicts, one with `keys` the other with everything else."""
intersection = {}
difference = {}
for key, value in dict_.iteritems():
if key in keys:
intersection[key] = value
else:
difference[key] = value
return intersection, difference
def map_dict_keys(dict_, key_map):
"""Return a dict in which the dictionaries keys are mapped to new keys."""
mapped = {}
for key, value in dict_.iteritems():
mapped_key = key_map[key] if key in key_map else key
mapped[mapped_key] = value
return mapped
def subset_dict(dict_, keys):
"""Return a dict that only contains a subset of keys."""
subset = partition_dict(dict_, keys)[0]
return subset
def check_isinstance(obj, cls):
"""Checks that obj is of type cls, and lets PyLint infer types."""
if isinstance(obj, cls):
return obj
raise Exception(_('Expected object of type: %s') % (str(cls)))
# TODO(justinsb): Can we make this better??
return cls() # Ugly PyLint hack
def is_valid_boolstr(val):
"""Check if the provided string is a valid bool string or not. """
val = str(val).lower()
return (val == 'true' or val == 'false' or
val == 'yes' or val == 'no' or
val == 'y' or val == 'n' or
val == '1' or val == '0')
def is_valid_ipv4(address):
"""valid the address strictly as per format xxx.xxx.xxx.xxx.
where xxx is a value between 0 and 255.
"""
parts = address.split(".")
if len(parts) != 4:
return False
for item in parts:
try:
if not 0 <= int(item) <= 255:
return False
except ValueError:
return False
return True
def monkey_patch():
""" If the Flags.monkey_patch set as True,
this function patches a decorator
for all functions in specified modules.
You can set decorators for each modules
using CONF.monkey_patch_modules.
The format is "Module path:Decorator function".
Example: 'manila.api.ec2.cloud:' \
manila.openstack.common.notifier.api.notify_decorator'
Parameters of the decorator is as follows.
(See manila.openstack.common.notifier.api.notify_decorator)
name - name of the function
function - object of the function
"""
# If CONF.monkey_patch is not True, this function do nothing.
if not CONF.monkey_patch:
return
# Get list of modules and decorators
for module_and_decorator in CONF.monkey_patch_modules:
module, decorator_name = module_and_decorator.split(':')
# import decorator function
decorator = importutils.import_class(decorator_name)
__import__(module)
# Retrieve module information using pyclbr
module_data = pyclbr.readmodule_ex(module)
for key in module_data.keys():
# set the decorator for the class methods
if isinstance(module_data[key], pyclbr.Class):
clz = importutils.import_class("%s.%s" % (module, key))
for method, func in inspect.getmembers(clz, inspect.ismethod):
setattr(
clz, method,
decorator("%s.%s.%s" % (module, key, method), func))
# set the decorator for the function
if isinstance(module_data[key], pyclbr.Function):
func = importutils.import_class("%s.%s" % (module, key))
setattr(sys.modules[module], key,
decorator("%s.%s" % (module, key), func))
def convert_to_list_dict(lst, label):
"""Convert a value or list into a list of dicts"""
if not lst:
return None
if not isinstance(lst, list):
lst = [lst]
return [{label: x} for x in lst]
def timefunc(func):
"""Decorator that logs how long a particular function took to execute"""
@functools.wraps(func)
def inner(*args, **kwargs):
start_time = time.time()
try:
return func(*args, **kwargs)
finally:
total_time = time.time() - start_time
LOG.debug(_("timefunc: '%(name)s' took %(total_time).2f secs") %
dict(name=func.__name__, total_time=total_time))
return inner
def generate_glance_url():
"""Generate the URL to glance."""
# TODO(jk0): This will eventually need to take SSL into consideration
# when supported in glance.
return "http://%s:%d" % (CONF.glance_host, CONF.glance_port)
@contextlib.contextmanager
def logging_error(message):
"""Catches exception, write message to the log, re-raise.
This is a common refinement of save_and_reraise that writes a specific
message to the log.
"""
try:
yield
except Exception as error:
with excutils.save_and_reraise_exception():
LOG.exception(message)
@contextlib.contextmanager
def remove_path_on_error(path):
"""Protect code that wants to operate on PATH atomically.
Any exception will cause PATH to be removed.
"""
try:
yield
except Exception:
with excutils.save_and_reraise_exception():
delete_if_exists(path)
def make_dev_path(dev, partition=None, base='/dev'):
"""Return a path to a particular device.
>>> make_dev_path('xvdc')
/dev/xvdc
>>> make_dev_path('xvdc', 1)
/dev/xvdc1
"""
path = os.path.join(base, dev)
if partition:
path += str(partition)
return path
def total_seconds(td):
"""Local total_seconds implementation for compatibility with python 2.6"""
if hasattr(td, 'total_seconds'):
return td.total_seconds()
else:
return ((td.days * 86400 + td.seconds) * 10 ** 6 +
td.microseconds) / 10.0 ** 6
def sanitize_hostname(hostname):
"""Return a hostname which conforms to RFC-952 and RFC-1123 specs."""
if isinstance(hostname, unicode):
hostname = hostname.encode('latin-1', 'ignore')
hostname = re.sub('[ _]', '-', hostname)
hostname = re.sub('[^\w.-]+', '', hostname)
hostname = hostname.lower()
hostname = hostname.strip('.-')
return hostname
def read_cached_file(filename, cache_info, reload_func=None):
"""Read from a file if it has been modified.
:param cache_info: dictionary to hold opaque cache.
:param reload_func: optional function to be called with data when
file is reloaded due to a modification.
:returns: data from file
"""
mtime = os.path.getmtime(filename)
if not cache_info or mtime != cache_info.get('mtime'):
with open(filename) as fap:
cache_info['data'] = fap.read()
cache_info['mtime'] = mtime
if reload_func:
reload_func(cache_info['data'])
return cache_info['data']
def file_open(*args, **kwargs):
"""Open file
see built-in file() documentation for more details
Note: The reason this is kept in a separate module is to easily
be able to provide a stub module that doesn't alter system
state at all (for unit tests)
"""
return file(*args, **kwargs)
def hash_file(file_like_object):
"""Generate a hash for the contents of a file."""
checksum = hashlib.sha1()
any(map(checksum.update, iter(lambda: file_like_object.read(32768), '')))
return checksum.hexdigest()
@contextlib.contextmanager
def temporary_mutation(obj, **kwargs):
"""Temporarily set the attr on a particular object to a given value then
revert when finished.
One use of this is to temporarily set the read_deleted flag on a context
object:
with temporary_mutation(context, read_deleted="yes"):
do_something_that_needed_deleted_objects()
"""
NOT_PRESENT = object()
old_values = {}
for attr, new_value in kwargs.items():
old_values[attr] = getattr(obj, attr, NOT_PRESENT)
setattr(obj, attr, new_value)
try:
yield
finally:
for attr, old_value in old_values.items():
if old_value is NOT_PRESENT:
del obj[attr]
else:
setattr(obj, attr, old_value)
def service_is_up(service):
"""Check whether a service is up based on last heartbeat."""
last_heartbeat = service['updated_at'] or service['created_at']
# Timestamps in DB are UTC.
elapsed = total_seconds(timeutils.utcnow() - last_heartbeat)
return abs(elapsed) <= CONF.service_down_time
def generate_mac_address():
"""Generate an Ethernet MAC address."""
# NOTE(vish): We would prefer to use 0xfe here to ensure that linux
# bridge mac addresses don't change, but it appears to
# conflict with libvirt, so we use the next highest octet
# that has the unicast and locally administered bits set
# properly: 0xfa.
# Discussion: https://bugs.launchpad.net/manila/+bug/921838
mac = [0xfa, 0x16, 0x3e,
random.randint(0x00, 0x7f),
random.randint(0x00, 0xff),
random.randint(0x00, 0xff)]
return ':'.join(map(lambda x: "%02x" % x, mac))
def read_file_as_root(file_path):
"""Secure helper to read file as root."""
try:
out, _err = execute('cat', file_path, run_as_root=True)
return out
except exception.ProcessExecutionError:
raise exception.FileNotFound(file_path=file_path)
@contextlib.contextmanager
def temporary_chown(path, owner_uid=None):
"""Temporarily chown a path.
:params owner_uid: UID of temporary owner (defaults to current user)
"""
if owner_uid is None:
owner_uid = os.getuid()
orig_uid = os.stat(path).st_uid
if orig_uid != owner_uid:
execute('chown', owner_uid, path, run_as_root=True)
try:
yield
finally:
if orig_uid != owner_uid:
execute('chown', orig_uid, path, run_as_root=True)
@contextlib.contextmanager
def tempdir(**kwargs):
tmpdir = tempfile.mkdtemp(**kwargs)
try:
yield tmpdir
finally:
try:
shutil.rmtree(tmpdir)
except OSError, e:
LOG.debug(_('Could not remove tmpdir: %s'), str(e))
def strcmp_const_time(s1, s2):
"""Constant-time string comparison.
:params s1: the first string
:params s2: the second string
:return: True if the strings are equal.
This function takes two strings and compares them. It is intended to be
used when doing a comparison for authentication purposes to help guard
against timing attacks.
"""
if len(s1) != len(s2):
return False
result = 0
for (a, b) in zip(s1, s2):
result |= ord(a) ^ ord(b)
return result == 0
def walk_class_hierarchy(clazz, encountered=None):
"""Walk class hierarchy, yielding most derived classes first"""
if not encountered:
encountered = []
for subclass in clazz.__subclasses__():
if subclass not in encountered:
encountered.append(subclass)
# drill down to leaves first
for subsubclass in walk_class_hierarchy(subclass, encountered):
yield subsubclass
yield subclass
class UndoManager(object):
"""Provides a mechanism to facilitate rolling back a series of actions
when an exception is raised.
"""
def __init__(self):
self.undo_stack = []
def undo_with(self, undo_func):
self.undo_stack.append(undo_func)
def _rollback(self):
for undo_func in reversed(self.undo_stack):
undo_func()
def rollback_and_reraise(self, msg=None, **kwargs):
"""Rollback a series of actions then re-raise the exception.
.. note:: (sirp) This should only be called within an
exception handler.
"""
with excutils.save_and_reraise_exception():
if msg:
LOG.exception(msg, **kwargs)
self._rollback()
def ensure_tree(path):
"""Create a directory (and any ancestor directories required)
:param path: Directory to create
"""
try:
os.makedirs(path)
except OSError as exc:
if exc.errno == errno.EEXIST:
if not os.path.isdir(path):
raise
else:
raise
def to_bytes(text, default=0):
"""Try to turn a string into a number of bytes. Looks at the last
characters of the text to determine what conversion is needed to
turn the input text into a byte number.
Supports: B/b, K/k, M/m, G/g, T/t (or the same with b/B on the end)
"""
BYTE_MULTIPLIERS = {
'': 1,
't': 1024 ** 4,
'g': 1024 ** 3,
'm': 1024 ** 2,
'k': 1024,
}
# Take off everything not number 'like' (which should leave
# only the byte 'identifier' left)
mult_key_org = text.lstrip('-1234567890')
mult_key = mult_key_org.lower()
mult_key_len = len(mult_key)
if mult_key.endswith("b"):
mult_key = mult_key[0:-1]
try:
multiplier = BYTE_MULTIPLIERS[mult_key]
if mult_key_len:
# Empty cases shouldn't cause text[0:-0]
text = text[0:-mult_key_len]
return int(text) * multiplier
except KeyError:
msg = _('Unknown byte multiplier: %s') % mult_key_org
raise TypeError(msg)
except ValueError:
return default
def cidr_to_netmask(cidr):
"""Convert cidr to netmask."""
try:
network = netaddr.IPNetwork(cidr)
return str(network.netmask)
except netaddr.AddrFormatError:
raise exception.InvalidInput(_("Invalid cidr supplied %s") % cidr)