# 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 itertools
import json
import os
import pyclbr
import random
import re
import shlex
import shutil
import socket
import struct
import sys
import tempfile
import threading
import time
import types
import uuid
import warnings
from xml.sax import saxutils
from eventlet import corolocal
from eventlet import event
from eventlet import greenthread
from eventlet import semaphore
from eventlet.green import subprocess
import iso8601
import lockfile
import netaddr
from nova import exception
from nova import flags
from nova import log as logging
from nova.openstack.common import cfg
from nova.openstack.common import excutils
from nova.openstack.common import importutils
LOG = logging.getLogger(__name__)
ISO_TIME_FORMAT = "%Y-%m-%dT%H:%M:%S"
PERFECT_TIME_FORMAT = "%Y-%m-%dT%H:%M:%S.%f"
FLAGS = flags.FLAGS
FLAGS.register_opt(
cfg.BoolOpt('disable_process_locking', default=False,
help='Whether to disable inter-process locks'))
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: `nova.exception.ConfigNotFound`
"""
possible_locations = [
config_path,
os.path.join(FLAGS.state_path, "etc", "nova", config_path),
os.path.join(FLAGS.state_path, "etc", config_path),
os.path.join(FLAGS.state_path, config_path),
"/etc/nova/%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 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):
print struct.calcsize(fmt)
return False
(identifier, server_sess, client_sess) = struct.unpack(fmt, received)
if identifier == 0x40 and client_sess == session_id:
return server_sess
def fetchfile(url, target):
LOG.debug(_('Fetching %s') % url)
execute('curl', '--fail', url, '-o', target)
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 nova.rootwrap !
: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:
cmd = shlex.split(FLAGS.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,
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'), ' '.join(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()
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=' '.join(cmd))
return (stdout, stderr)
def novadir():
import nova
return os.path.abspath(nova.__file__).split('nova/__init__.py')[0]
def default_flagfile(filename='nova.conf', args=None):
if args is None:
args = sys.argv
for arg in args:
if arg.find('flagfile') != -1:
return arg[arg.index('flagfile') + len('flagfile') + 1:]
else:
if not os.path.isabs(filename):
# turn relative filename into an absolute path
script_dir = os.path.dirname(inspect.stack()[-1][1])
filename = os.path.abspath(os.path.join(script_dir, filename))
if not os.path.exists(filename):
filename = "./nova.conf"
if not os.path.exists(filename):
filename = '/etc/nova/nova.conf'
if os.path.exists(filename):
flagfile = '--flagfile=%s' % filename
args.insert(1, flagfile)
return filename
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 = FLAGS.instance_usage_audit_period
offset = 0
if '@' in unit:
unit, offset = unit.split("@", 1)
offset = int(offset)
rightnow = 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 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 utcnow():
"""Overridable version of utils.utcnow."""
if utcnow.override_time:
return utcnow.override_time
return datetime.datetime.utcnow()
utcnow.override_time = None
def is_older_than(before, seconds):
"""Return True if before is older than seconds."""
return utcnow() - before > datetime.timedelta(seconds=seconds)
def utcnow_ts():
"""Timestamp version of our utcnow function."""
return time.mktime(utcnow().timetuple())
def set_time_override(override_time=datetime.datetime.utcnow()):
"""Override utils.utcnow to return a constant time."""
utcnow.override_time = override_time
def advance_time_delta(timedelta):
"""Advance overriden time using a datetime.timedelta."""
assert(not utcnow.override_time is None)
utcnow.override_time += timedelta
def advance_time_seconds(seconds):
"""Advance overriden time by seconds."""
advance_time_delta(datetime.timedelta(0, seconds))
def clear_time_override():
"""Remove the overridden time."""
utcnow.override_time = None
def strtime(at=None, fmt=PERFECT_TIME_FORMAT):
"""Returns formatted utcnow."""
if not at:
at = utcnow()
return at.strftime(fmt)
def parse_strtime(timestr, fmt=PERFECT_TIME_FORMAT):
"""Turn a formatted time back into a datetime."""
return datetime.datetime.strptime(timestr, fmt)
def isotime(at=None):
"""Stringify time in ISO 8601 format"""
if not at:
at = datetime.datetime.utcnow()
str = at.strftime(ISO_TIME_FORMAT)
tz = at.tzinfo.tzname(None) if at.tzinfo else 'UTC'
str += ('Z' if tz == 'UTC' else tz)
return str
def parse_isotime(timestr):
"""Turn an iso formatted time back into a datetime."""
try:
return iso8601.parse_date(timestr)
except (iso8601.ParseError, TypeError) as e:
raise ValueError(e.message)
def normalize_time(timestamp):
"""Normalize time in arbitrary timezone to UTC"""
offset = timestamp.utcoffset()
return timestamp.replace(tzinfo=None) - offset if offset else timestamp
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 = FLAGS[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()
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 to_primitive(value, convert_instances=False, level=0):
"""Convert a complex object into primitives.
Handy for JSON serialization. We can optionally handle instances,
but since this is a recursive function, we could have cyclical
data structures.
To handle cyclical data structures we could track the actual objects
visited in a set, but not all objects are hashable. Instead we just
track the depth of the object inspections and don't go too deep.
Therefore, convert_instances=True is lossy ... be aware.
"""
nasty = [inspect.ismodule, inspect.isclass, inspect.ismethod,
inspect.isfunction, inspect.isgeneratorfunction,
inspect.isgenerator, inspect.istraceback, inspect.isframe,
inspect.iscode, inspect.isbuiltin, inspect.isroutine,
inspect.isabstract]
for test in nasty:
if test(value):
return unicode(value)
# value of itertools.count doesn't get caught by inspects
# above and results in infinite loop when list(value) is called.
if type(value) == itertools.count:
return unicode(value)
# FIXME(vish): Workaround for LP bug 852095. Without this workaround,
# tests that raise an exception in a mocked method that
# has a @wrap_exception with a notifier will fail. If
# we up the dependency to 0.5.4 (when it is released) we
# can remove this workaround.
if getattr(value, '__module__', None) == 'mox':
return 'mock'
if level > 3:
return '?'
# The try block may not be necessary after the class check above,
# but just in case ...
try:
if isinstance(value, (list, tuple)):
o = []
for v in value:
o.append(to_primitive(v, convert_instances=convert_instances,
level=level))
return o
elif isinstance(value, dict):
o = {}
for k, v in value.iteritems():
o[k] = to_primitive(v, convert_instances=convert_instances,
level=level)
return o
elif isinstance(value, datetime.datetime):
return str(value)
elif hasattr(value, 'iteritems'):
return to_primitive(dict(value.iteritems()),
convert_instances=convert_instances,
level=level)
elif hasattr(value, '__iter__'):
return to_primitive(list(value), level)
elif convert_instances and hasattr(value, '__dict__'):
# Likely an instance of something. Watch for cycles.
# Ignore class member vars.
return to_primitive(value.__dict__,
convert_instances=convert_instances,
level=level + 1)
else:
return value
except TypeError, e:
# Class objects are tricky since they may define something like
# __iter__ defined but it isn't callable as list().
return unicode(value)
def dumps(value):
try:
return json.dumps(value)
except TypeError:
pass
return json.dumps(to_primitive(value))
def loads(s):
return json.loads(s)
try:
import anyjson
except ImportError:
pass
else:
anyjson._modules.append(("nova.utils", "dumps", TypeError,
"loads", ValueError))
anyjson.force_implementation("nova.utils")
class GreenLockFile(lockfile.FileLock):
"""Implementation of lockfile that allows for a lock per greenthread.
Simply implements lockfile:LockBase init with an addiontall suffix
on the unique name of the greenthread identifier
"""
def __init__(self, path, threaded=True):
self.path = path
self.lock_file = os.path.abspath(path) + ".lock"
self.hostname = socket.gethostname()
self.pid = os.getpid()
if threaded:
t = threading.current_thread()
# Thread objects in Python 2.4 and earlier do not have ident
# attrs. Worm around that.
ident = getattr(t, "ident", hash(t)) or hash(t)
gident = corolocal.get_ident()
self.tname = "-%x-%x" % (ident & 0xffffffff, gident & 0xffffffff)
else:
self.tname = ""
dirname = os.path.dirname(self.lock_file)
self.unique_name = os.path.join(dirname,
"%s%s.%s" % (self.hostname,
self.tname,
self.pid))
_semaphores = {}
def synchronized(name, external=False):
"""Synchronization decorator.
Decorating a method like so::
@synchronized('mylock')
def foo(self, *args):
...
ensures that only one thread will execute the bar method at a time.
Different methods can share the same lock::
@synchronized('mylock')
def foo(self, *args):
...
@synchronized('mylock')
def bar(self, *args):
...
This way only one of either foo or bar can be executing at a time.
The external keyword argument denotes whether this lock should work across
multiple processes. This means that if two different workers both run a
a method decorated with @synchronized('mylock', external=True), only one
of them will execute at a time.
Important limitation: you can only have one external lock running per
thread at a time. For example the following will fail:
@utils.synchronized('testlock1', external=True)
def outer_lock():
@utils.synchronized('testlock2', external=True)
def inner_lock():
pass
inner_lock()
outer_lock()
"""
def wrap(f):
@functools.wraps(f)
def inner(*args, **kwargs):
# NOTE(soren): If we ever go natively threaded, this will be racy.
# See http://stackoverflow.com/questions/5390569/dyn
# amically-allocating-and-destroying-mutexes
if name not in _semaphores:
_semaphores[name] = semaphore.Semaphore()
sem = _semaphores[name]
LOG.debug(_('Attempting to grab semaphore "%(lock)s" for method '
'"%(method)s"...'), {'lock': name,
'method': f.__name__})
with sem:
LOG.debug(_('Got semaphore "%(lock)s" for method '
'"%(method)s"...'), {'lock': name,
'method': f.__name__})
if external and not FLAGS.disable_process_locking:
LOG.debug(_('Attempting to grab file lock "%(lock)s" for '
'method "%(method)s"...'),
{'lock': name, 'method': f.__name__})
lock_file_path = os.path.join(FLAGS.lock_path,
'nova-%s' % name)
lock = GreenLockFile(lock_file_path)
with lock:
LOG.debug(_('Got file lock "%(lock)s" for '
'method "%(method)s"...'),
{'lock': name, 'method': f.__name__})
retval = f(*args, **kwargs)
else:
retval = f(*args, **kwargs)
# If no-one else is waiting for it, delete it.
# See note about possible raciness above.
if not sem.balance < 1:
del _semaphores[name]
return retval
return inner
return wrap
def cleanup_file_locks():
"""clean up stale locks left behind by process failures
The lockfile module, used by @synchronized, can leave stale lockfiles
behind after process failure. These locks can cause process hangs
at startup, when a process deadlocks on a lock which will never
be unlocked.
Intended to be called at service startup.
"""
# NOTE(mikeyp) this routine incorporates some internal knowledge
# from the lockfile module, and this logic really
# should be part of that module.
#
# cleanup logic:
# 1) look for the lockfile modules's 'sentinel' files, of the form
# hostname.[thread-.*]-pid, extract the pid.
# if pid doesn't match a running process, delete the file since
# it's from a dead process.
# 2) check for the actual lockfiles. if lockfile exists with linkcount
# of 1, it's bogus, so delete it. A link count >= 2 indicates that
# there are probably sentinels still linked to it from active
# processes. This check isn't perfect, but there is no way to
# reliably tell which sentinels refer to which lock in the
# lockfile implementation.
if FLAGS.disable_process_locking:
return
hostname = socket.gethostname()
sentinel_re = hostname + r'\..*-(\d+$)'
lockfile_re = r'nova-.*\.lock'
files = os.listdir(FLAGS.lock_path)
# cleanup sentinels
for filename in files:
match = re.match(sentinel_re, filename)
if match is None:
continue
pid = match.group(1)
LOG.debug(_('Found sentinel %(filename)s for pid %(pid)s'),
{'filename': filename, 'pid': pid})
try:
os.kill(int(pid), 0)
except OSError, e:
# PID wasn't found
delete_if_exists(os.path.join(FLAGS.lock_path, filename))
LOG.debug(_('Cleaned sentinel %(filename)s for pid %(pid)s'),
{'filename': filename, 'pid': pid})
# cleanup lock files
for filename in files:
match = re.match(lockfile_re, filename)
if match is None:
continue
try:
stat_info = os.stat(os.path.join(FLAGS.lock_path, filename))
except OSError as e:
if e.errno == errno.ENOENT:
continue
else:
raise
LOG.debug(_('Found lockfile %(file)s with link count %(count)d'),
{'file': filename, 'count': stat_info.st_nlink})
if stat_info.st_nlink == 1:
delete_if_exists(os.path.join(FLAGS.lock_path, filename))
LOG.debug(_('Cleaned lockfile %(file)s with link count %(count)d'),
{'file': filename, 'count': stat_info.st_nlink})
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 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.debug(_('Invalid server_string: %s'), server_str)
return ('', '')
def gen_uuid():
return uuid.uuid4()
def is_uuid_like(val):
"""For our purposes, a UUID is a string in canonical form:
aaaaaaaa-aaaa-aaaa-aaaa-aaaaaaaaaaaa
"""
try:
uuid.UUID(val)
return True
except (TypeError, ValueError, AttributeError):
return False
def bool_from_str(val):
"""Convert a string representation of a bool into a bool value"""
if not val:
return False
try:
return True if int(val) else False
except ValueError:
return val.lower() == 'true'
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 is_valid_cidr(address):
"""Check if the provided ipv4 or ipv6 address is a valid
CIDR address or not"""
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 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 FLAGS.monkey_patch_modules.
The format is "Module path:Decorator function".
Example: 'nova.api.ec2.cloud:nova.notifier.api.notify_decorator'
Parameters of the decorator is as follows.
(See nova.notifier.api.notify_decorator)
name - name of the function
function - object of the function
"""
# If FLAGS.monkey_patch is not True, this function do nothing.
if not FLAGS.monkey_patch:
return
# Get list of modules and decorators
for module_and_decorator in FLAGS.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" % (FLAGS.glance_host, FLAGS.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 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 warn_deprecated_class(cls, msg):
"""
Issues a warning to indicate that the given class is deprecated.
If a message is given, it is appended to the deprecation warning.
"""
fullname = '%s.%s' % (cls.__module__, cls.__name__)
if msg:
fullmsg = _("Class %(fullname)s is deprecated: %(msg)s")
else:
fullmsg = _("Class %(fullname)s is deprecated")
# Issue the warning
warnings.warn(fullmsg % locals(), DeprecationWarning, stacklevel=3)
def warn_deprecated_function(func, msg):
"""
Issues a warning to indicate that the given function is
deprecated. If a message is given, it is appended to the
deprecation warning.
"""
name = func.__name__
# Find the function's definition
sourcefile = inspect.getsourcefile(func)
# Find the line number, if possible
if inspect.ismethod(func):
code = func.im_func.func_code
else:
code = func.func_code
lineno = getattr(code, 'co_firstlineno', None)
if lineno is None:
location = sourcefile
else:
location = "%s:%d" % (sourcefile, lineno)
# Build up the message
if msg:
fullmsg = _("Function %(name)s in %(location)s is deprecated: %(msg)s")
else:
fullmsg = _("Function %(name)s in %(location)s is deprecated")
# Issue the warning
warnings.warn(fullmsg % locals(), DeprecationWarning, stacklevel=3)
def _stubout(klass, message):
"""
Scans a class and generates wrapping stubs for __new__() and every
class and static method. Returns a dictionary which can be passed
to type() to generate a wrapping class.
"""
overrides = {}
def makestub_class(name, func):
"""
Create a stub for wrapping class methods.
"""
def stub(cls, *args, **kwargs):
warn_deprecated_class(klass, message)
return func(*args, **kwargs)
# Overwrite the stub's name
stub.__name__ = name
stub.func_name = name
return classmethod(stub)
def makestub_static(name, func):
"""
Create a stub for wrapping static methods.
"""
def stub(*args, **kwargs):
warn_deprecated_class(klass, message)
return func(*args, **kwargs)
# Overwrite the stub's name
stub.__name__ = name
stub.func_name = name
return staticmethod(stub)
for name, kind, _klass, _obj in inspect.classify_class_attrs(klass):
# We're only interested in __new__(), class methods, and
# static methods...
if (name != '__new__' and
kind not in ('class method', 'static method')):
continue
# Get the function...
func = getattr(klass, name)
# Override it in the class
if kind == 'class method':
stub = makestub_class(name, func)
elif kind == 'static method' or name == '__new__':
stub = makestub_static(name, func)
# Save it in the overrides dictionary...
overrides[name] = stub
# Apply the overrides
for name, stub in overrides.items():
setattr(klass, name, stub)
def deprecated(message=''):
"""
Marks a function, class, or method as being deprecated. For
functions and methods, emits a warning each time the function or
method is called. For classes, generates a new subclass which
will emit a warning each time the class is instantiated, or each
time any class or static method is called.
If a message is passed to the decorator, that message will be
appended to the emitted warning. This may be used to suggest an
alternate way of achieving the desired effect, or to explain why
the function, class, or method is deprecated.
"""
def decorator(f_or_c):
# Make sure we can deprecate it...
if not callable(f_or_c) or isinstance(f_or_c, types.ClassType):
warnings.warn("Cannot mark object %r as deprecated" % f_or_c,
DeprecationWarning, stacklevel=2)
return f_or_c
# If we're deprecating a class, create a subclass of it and
# stub out all the class and static methods
if inspect.isclass(f_or_c):
klass = f_or_c
_stubout(klass, message)
return klass
# OK, it's a function; use a traditional wrapper...
func = f_or_c
@functools.wraps(func)
def wrapper(*args, **kwargs):
warn_deprecated_function(func, message)
return func(*args, **kwargs)
return wrapper
return decorator
def _showwarning(message, category, filename, lineno, file=None, line=None):
"""
Redirect warnings into logging.
"""
fmtmsg = warnings.formatwarning(message, category, filename, lineno, line)
LOG.warning(fmtmsg)
# Install our warnings handler
warnings.showwarning = _showwarning
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(utcnow() - last_heartbeat)
return abs(elapsed) <= FLAGS.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/nova/+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
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()