# 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 functools
import hashlib
import inspect
import os
import pyclbr
import random
import re
import shutil
import socket
import struct
import sys
import tempfile
import time
from xml.sax import saxutils
import eventlet
import netaddr
from oslo.config import cfg
from nova import exception
from nova.openstack.common import excutils
from nova.openstack.common import importutils
from nova.openstack.common import lockutils
from nova.openstack.common import log as logging
from nova.openstack.common import processutils
from nova.openstack.common.rpc import common as rpc_common
from nova.openstack.common import timeutils
notify_decorator = 'nova.openstack.common.notifier.api.notify_decorator'
monkey_patch_opts = [
cfg.BoolOpt('monkey_patch',
default=False,
help='Whether to log monkey patching'),
cfg.ListOpt('monkey_patch_modules',
default=[
'nova.api.ec2.cloud:%s' % (notify_decorator),
'nova.compute.api:%s' % (notify_decorator)
],
help='List of modules/decorators to monkey patch'),
]
utils_opts = [
cfg.IntOpt('password_length',
default=12,
help='Length of generated instance admin passwords'),
cfg.StrOpt('instance_usage_audit_period',
default='month',
help='time period to generate instance usages for. '
'Time period must be hour, day, month or year'),
cfg.StrOpt('rootwrap_config',
default="/etc/nova/rootwrap.conf",
help='Path to the rootwrap configuration file to use for '
'running commands as root'),
cfg.StrOpt('tempdir',
default=None,
help='Explicitly specify the temporary working directory'),
]
CONF = cfg.CONF
CONF.register_opts(monkey_patch_opts)
CONF.register_opts(utils_opts)
LOG = logging.getLogger(__name__)
# Used for looking up extensions of text
# to their 'multiplied' byte amount
BYTE_MULTIPLIERS = {
'': 1,
't': 1024 ** 4,
'g': 1024 ** 3,
'm': 1024 ** 2,
'k': 1024,
}
synchronized = lockutils.synchronized_with_prefix('nova-')
def vpn_ping(address, port, timeout=0.05, session_id=None):
"""Sends a vpn negotiation packet and returns the server session.
Returns False on a failure. Basic packet structure is below.
Client packet (14 bytes)::
0 1 8 9 13
+-+--------+-----+
|x| cli_id |?????|
+-+--------+-----+
x = packet identifier 0x38
cli_id = 64 bit identifier
? = unknown, probably flags/padding
Server packet (26 bytes)::
0 1 8 9 13 14 21 2225
+-+--------+-----+--------+----+
|x| srv_id |?????| cli_id |????|
+-+--------+-----+--------+----+
x = packet identifier 0x40
cli_id = 64 bit identifier
? = unknown, probably flags/padding
bit 9 was 1 and the rest were 0 in testing
"""
if session_id is None:
session_id = random.randint(0, 0xffffffffffffffff)
sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
data = struct.pack('!BQxxxxx', 0x38, session_id)
sock.sendto(data, (address, port))
sock.settimeout(timeout)
try:
received = sock.recv(2048)
except socket.timeout:
return False
finally:
sock.close()
fmt = '!BQxxxxxQxxxx'
if len(received) != struct.calcsize(fmt):
LOG.warn(_('Expected to receive %(exp)s bytes, but actually %(act)s') %
dict(exp=struct.calcsize(fmt), act=len(received)))
return False
(identifier, server_sess, client_sess) = struct.unpack(fmt, received)
if identifier == 0x40 and client_sess == session_id:
return server_sess
def execute(*cmd, **kwargs):
"""Convenience wrapper around oslo's execute() method."""
if 'run_as_root' in kwargs and not 'root_helper' in kwargs:
kwargs['root_helper'] = 'sudo nova-rootwrap %s' % CONF.rootwrap_config
return processutils.execute(*cmd, **kwargs)
def trycmd(*args, **kwargs):
"""Convenience wrapper around oslo's trycmd() method."""
if 'run_as_root' in kwargs and not 'root_helper' in kwargs:
kwargs['root_helper'] = 'sudo nova-rootwrap %s' % CONF.rootwrap_config
return processutils.trycmd(*args, **kwargs)
def novadir():
import nova
return os.path.abspath(nova.__file__).split('nova/__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, before=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.
before: Give the audit period most recently completed before
<timestamp>. Defaults to now.
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.instance_usage_audit_period
offset = 0
if '@' in unit:
unit, offset = unit.split("@", 1)
offset = int(offset)
if before is not None:
rightnow = before
else:
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=None, 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!)
"""
if length is None:
length = CONF.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 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:
msg = _('Link Local address is not found.:%s') % if_str
raise exception.NovaException(msg)
except Exception as ex:
msg = _("Couldn't get Link Local IP of %(interface)s"
" :%(ex)s") % locals()
raise exception.NovaException(msg)
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, config_group=None, **backends):
self.__backends = backends
self.__pivot = pivot
self.__backend = None
self.__config_group = config_group
def __get_backend(self):
if not self.__backend:
if self.__config_group is None:
backend_name = CONF[self.__pivot]
else:
backend_name = CONF[self.__config_group][self.__pivot]
if backend_name not in self.__backends:
msg = _('Invalid backend: %s') % backend_name
raise exception.NovaException(msg)
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)
return self.__backend
def __getattr__(self, key):
backend = self.__get_backend()
return getattr(backend, key)
def xhtml_escape(value):
"""Escapes a string so it is valid within XML or XHTML.
"""
return saxutils.escape(value, {'"': '"', "'": '''})
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 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.NovaException('Invalid mini_xpath')
(first_token, sep, remainder) = path.partition('/')
if first_token == '':
raise exception.NovaException('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 diff_dict(orig, new):
"""
Return a dict describing how to change orig to new. The keys
correspond to values that have changed; the value will be a list
of one or two elements. The first element of the list will be
either '+' or '-', indicating whether the key was updated or
deleted; if the key was updated, the list will contain a second
element, giving the updated value.
"""
# Figure out what keys went away
result = dict((k, ['-']) for k in set(orig.keys()) - set(new.keys()))
# Compute the updates
for key, value in new.items():
if key not in orig or value != orig[key]:
result[key] = ['+', value]
return result
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)))
def parse_server_string(server_str):
"""
Parses the given server_string and returns a list of host and port.
If it's not a combination of host part and port, the port element
is a null string. If the input is invalid expression, return a null
list.
"""
try:
# First of all, exclude pure IPv6 address (w/o port).
if netaddr.valid_ipv6(server_str):
return (server_str, '')
# Next, check if this is IPv6 address with a port number combination.
if server_str.find("]:") != -1:
(address, port) = server_str.replace('[', '', 1).split(']:')
return (address, port)
# Third, check if this is a combination of an address and a port
if server_str.find(':') == -1:
return (server_str, '')
# This must be a combination of an address and a port
(address, port) = server_str.split(':')
return (address, port)
except Exception:
LOG.error(_('Invalid server_string: %s'), server_str)
return ('', '')
def is_int_like(val):
"""Check if a value looks like an int."""
try:
return str(int(val)) == str(val)
except Exception:
return False
def is_valid_ipv4(address):
"""Verify that address represents a valid IPv4 address."""
try:
return netaddr.valid_ipv4(address)
except Exception:
return False
def is_valid_ipv6(address):
try:
return netaddr.valid_ipv6(address)
except Exception:
return False
def is_valid_ipv6_cidr(address):
try:
str(netaddr.IPNetwork(address, version=6).cidr)
return True
except Exception:
return False
def get_shortened_ipv6(address):
addr = netaddr.IPAddress(address, version=6)
return str(addr.ipv6())
def get_shortened_ipv6_cidr(address):
net = netaddr.IPNetwork(address, version=6)
return str(net.cidr)
def is_valid_cidr(address):
"""Check if address is valid
The provided address can be a IPv6 or a IPv4
CIDR address.
"""
try:
# Validate the correct CIDR Address
netaddr.IPNetwork(address)
except netaddr.core.AddrFormatError:
return False
except UnboundLocalError:
# NOTE(MotoKen): work around bug in netaddr 0.7.5 (see detail in
# https://github.com/drkjam/netaddr/issues/2)
return False
# Prior validation partially verify /xx part
# Verify it here
ip_segment = address.split('/')
if (len(ip_segment) <= 1 or
ip_segment[1] == ''):
return False
return True
def get_ip_version(network):
"""Returns the IP version of a network (IPv4 or IPv6).
Raises AddrFormatError if invalid network.
"""
if netaddr.IPNetwork(network).version == 6:
return "IPv6"
elif netaddr.IPNetwork(network).version == 4:
return "IPv4"
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:
'nova.api.ec2.cloud:nova.openstack.common.notifier.api.notify_decorator'
Parameters of the decorator is as follows.
(See nova.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 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'):
LOG.debug(_("Reloading cached file %s") % filename)
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 hash_file(file_like_object):
"""Generate a hash for the contents of a file."""
checksum = hashlib.sha1()
for chunk in iter(lambda: file_like_object.read(32768), b''):
checksum.update(chunk)
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()
"""
def is_dict_like(thing):
return hasattr(thing, 'has_key')
def get(thing, attr, default):
if is_dict_like(thing):
return thing.get(attr, default)
else:
return getattr(thing, attr, default)
def set_value(thing, attr, val):
if is_dict_like(thing):
thing[attr] = val
else:
setattr(thing, attr, val)
def delete(thing, attr):
if is_dict_like(thing):
del thing[attr]
else:
delattr(thing, attr)
NOT_PRESENT = object()
old_values = {}
for attr, new_value in kwargs.items():
old_values[attr] = get(obj, attr, NOT_PRESENT)
set_value(obj, attr, new_value)
try:
yield
finally:
for attr, old_value in old_values.items():
if old_value is NOT_PRESENT:
delete(obj, attr)
else:
set_value(obj, attr, old_value)
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/nova/+bug/921838
mac = [0xfa, 0x16, 0x3e,
random.randint(0x00, 0xff),
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 processutils.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):
argdict = kwargs.copy()
if 'dir' not in argdict:
argdict['dir'] = CONF.tempdir
tmpdir = tempfile.mkdtemp(**argdict)
try:
yield tmpdir
finally:
try:
shutil.rmtree(tmpdir)
except OSError as e:
LOG.error(_('Could not remove tmpdir: %s'), str(e))
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 mkfs(fs, path, label=None):
"""Format a file or block device
:param fs: Filesystem type (examples include 'swap', 'ext3', 'ext4'
'btrfs', etc.)
:param path: Path to file or block device to format
:param label: Volume label to use
"""
if fs == 'swap':
args = ['mkswap']
else:
args = ['mkfs', '-t', fs]
#add -F to force no interactive execute on non-block device.
if fs in ('ext3', 'ext4'):
args.extend(['-F'])
if label:
if fs in ('msdos', 'vfat'):
label_opt = '-n'
else:
label_opt = '-L'
args.extend([label_opt, label])
args.append(path)
execute(*args)
def last_bytes(file_like_object, num):
"""Return num bytes from the end of the file, and remaining byte count.
:param file_like_object: The file to read
:param num: The number of bytes to return
:returns (data, remaining)
"""
try:
file_like_object.seek(-num, os.SEEK_END)
except IOError as e:
if e.errno == 22:
file_like_object.seek(0, os.SEEK_SET)
else:
raise
remaining = file_like_object.tell()
return (file_like_object.read(), remaining)
def metadata_to_dict(metadata):
result = {}
for item in metadata:
if not item.get('deleted'):
result[item['key']] = item['value']
return result
def dict_to_metadata(metadata):
result = []
for key, value in metadata.iteritems():
result.append(dict(key=key, value=value))
return result
def instance_sys_meta(instance):
if isinstance(instance['system_metadata'], dict):
return instance['system_metadata']
else:
return metadata_to_dict(instance['system_metadata'])
def get_wrapped_function(function):
"""Get the method at the bottom of a stack of decorators."""
if not hasattr(function, 'func_closure') or not function.func_closure:
return function
def _get_wrapped_function(function):
if not hasattr(function, 'func_closure') or not function.func_closure:
return None
for closure in function.func_closure:
func = closure.cell_contents
deeper_func = _get_wrapped_function(func)
if deeper_func:
return deeper_func
elif hasattr(closure.cell_contents, '__call__'):
return closure.cell_contents
return _get_wrapped_function(function)
class ExceptionHelper(object):
"""Class to wrap another and translate the ClientExceptions raised by its
function calls to the actual ones.
"""
def __init__(self, target):
self._target = target
def __getattr__(self, name):
func = getattr(self._target, name)
@functools.wraps(func)
def wrapper(*args, **kwargs):
try:
return func(*args, **kwargs)
except rpc_common.ClientException as e:
raise (e._exc_info[1], None, e._exc_info[2])
return wrapper
def check_string_length(value, name, min_length=0, max_length=None):
"""Check the length of specified string
:param value: the value of the string
:param name: the name of the string
:param min_length: the min_length of the string
:param max_length: the max_length of the string
"""
if not isinstance(value, basestring):
msg = _("%s is not a string or unicode") % name
raise exception.InvalidInput(message=msg)
if len(value) < min_length:
msg = _("%(name)s has less than %(min_length)s "
"characters.") % locals()
raise exception.InvalidInput(message=msg)
if max_length and len(value) > max_length:
msg = _("%(name)s has more than %(max_length)s "
"characters.") % locals()
raise exception.InvalidInput(message=msg)
def spawn_n(func, *args, **kwargs):
"""Passthrough method for eventlet.spawn_n.
This utility exists so that it can be stubbed for testing without
interfering with the service spawns.
"""
eventlet.spawn_n(func, *args, **kwargs)