From 0dc7e293b79c524b1691ea08fa0b91277256b9ad Mon Sep 17 00:00:00 2001 From: Steven Hardy Date: Tue, 14 Oct 2014 21:18:02 +0100 Subject: [PATCH] Remove unused oslo lockutils module This isn't specified in openstack-common.conf and is unused, so remove it. Change-Id: Iff88b6b68b9c9c739e96f4bf6a9de83e4c4de812 Partial-Bug: #1380629 --- etc/heat/heat.conf.sample | 11 - heat/openstack/common/lockutils.py | 378 ----------------------------- 2 files changed, 389 deletions(-) delete mode 100644 heat/openstack/common/lockutils.py diff --git a/etc/heat/heat.conf.sample b/etc/heat/heat.conf.sample index 9d723b2177..cec3f01c48 100644 --- a/etc/heat/heat.conf.sample +++ b/etc/heat/heat.conf.sample @@ -418,17 +418,6 @@ #backdoor_port= -# -# Options defined in heat.openstack.common.lockutils -# - -# Enables or disables inter-process locks. (boolean value) -#disable_process_locking=false - -# Directory to use for lock files. (string value) -#lock_path= - - # # Options defined in heat.openstack.common.log # diff --git a/heat/openstack/common/lockutils.py b/heat/openstack/common/lockutils.py deleted file mode 100644 index aa035ac19d..0000000000 --- a/heat/openstack/common/lockutils.py +++ /dev/null @@ -1,378 +0,0 @@ -# Copyright 2011 OpenStack Foundation. -# 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. - -import contextlib -import errno -import fcntl -import functools -import os -import shutil -import subprocess -import sys -import tempfile -import threading -import time -import weakref - -from oslo.config import cfg - -from heat.openstack.common import fileutils -from heat.openstack.common.gettextutils import _, _LE, _LI -from heat.openstack.common import log as logging - - -LOG = logging.getLogger(__name__) - - -util_opts = [ - cfg.BoolOpt('disable_process_locking', default=False, - help='Enables or disables inter-process locks.'), - cfg.StrOpt('lock_path', - default=os.environ.get("HEAT_LOCK_PATH"), - help='Directory to use for lock files.') -] - - -CONF = cfg.CONF -CONF.register_opts(util_opts) - - -def set_defaults(lock_path): - cfg.set_defaults(util_opts, lock_path=lock_path) - - -class _FileLock(object): - """Lock implementation which allows multiple locks, working around - issues like bugs.debian.org/cgi-bin/bugreport.cgi?bug=632857 and does - not require any cleanup. Since the lock is always held on a file - descriptor rather than outside of the process, the lock gets dropped - automatically if the process crashes, even if __exit__ is not executed. - - There are no guarantees regarding usage by multiple green threads in a - single process here. This lock works only between processes. Exclusive - access between local threads should be achieved using the semaphores - in the @synchronized decorator. - - Note these locks are released when the descriptor is closed, so it's not - safe to close the file descriptor while another green thread holds the - lock. Just opening and closing the lock file can break synchronisation, - so lock files must be accessed only using this abstraction. - """ - - def __init__(self, name): - self.lockfile = None - self.fname = name - - def acquire(self): - basedir = os.path.dirname(self.fname) - - if not os.path.exists(basedir): - fileutils.ensure_tree(basedir) - LOG.info(_LI('Created lock path: %s'), basedir) - - self.lockfile = open(self.fname, 'w') - - while True: - try: - # Using non-blocking locks since green threads are not - # patched to deal with blocking locking calls. - # Also upon reading the MSDN docs for locking(), it seems - # to have a laughable 10 attempts "blocking" mechanism. - self.trylock() - LOG.debug('Got file lock "%s"', self.fname) - return True - except IOError as e: - if e.errno in (errno.EACCES, errno.EAGAIN): - # external locks synchronise things like iptables - # updates - give it some time to prevent busy spinning - time.sleep(0.01) - else: - raise threading.ThreadError(_("Unable to acquire lock on" - " `%(filename)s` due to" - " %(exception)s") % - { - 'filename': self.fname, - 'exception': e, - }) - - def __enter__(self): - self.acquire() - return self - - def release(self): - try: - self.unlock() - self.lockfile.close() - LOG.debug('Released file lock "%s"', self.fname) - except IOError: - LOG.exception(_LE("Could not release the acquired lock `%s`"), - self.fname) - - def __exit__(self, exc_type, exc_val, exc_tb): - self.release() - - def exists(self): - return os.path.exists(self.fname) - - def trylock(self): - raise NotImplementedError() - - def unlock(self): - raise NotImplementedError() - - -class _WindowsLock(_FileLock): - def trylock(self): - msvcrt.locking(self.lockfile.fileno(), msvcrt.LK_NBLCK, 1) - - def unlock(self): - msvcrt.locking(self.lockfile.fileno(), msvcrt.LK_UNLCK, 1) - - -class _FcntlLock(_FileLock): - def trylock(self): - fcntl.lockf(self.lockfile, fcntl.LOCK_EX | fcntl.LOCK_NB) - - def unlock(self): - fcntl.lockf(self.lockfile, fcntl.LOCK_UN) - - -class _PosixLock(object): - def __init__(self, name): - # Hash the name because it's not valid to have POSIX semaphore - # names with things like / in them. Then use base64 to encode - # the digest() instead taking the hexdigest() because the - # result is shorter and most systems can't have shm sempahore - # names longer than 31 characters. - h = hashlib.sha1() - h.update(name.encode('ascii')) - self.name = str((b'/' + base64.urlsafe_b64encode( - h.digest())).decode('ascii')) - - def acquire(self, timeout=None): - self.semaphore = posix_ipc.Semaphore(self.name, - flags=posix_ipc.O_CREAT, - initial_value=1) - self.semaphore.acquire(timeout) - return self - - def __enter__(self): - self.acquire() - return self - - def release(self): - self.semaphore.release() - self.semaphore.close() - - def __exit__(self, exc_type, exc_val, exc_tb): - self.release() - - def exists(self): - try: - semaphore = posix_ipc.Semaphore(self.name) - except posix_ipc.ExistentialError: - return False - else: - semaphore.close() - return True - - -if os.name == 'nt': - import msvcrt - InterProcessLock = _WindowsLock - FileLock = _WindowsLock -else: - import base64 - import hashlib - import posix_ipc - InterProcessLock = _PosixLock - FileLock = _FcntlLock - -_semaphores = weakref.WeakValueDictionary() -_semaphores_lock = threading.Lock() - - -def _get_lock_path(name, lock_file_prefix, lock_path=None): - # NOTE(mikal): the lock name cannot contain directory - # separators - name = name.replace(os.sep, '_') - if lock_file_prefix: - sep = '' if lock_file_prefix.endswith('-') else '-' - name = '%s%s%s' % (lock_file_prefix, sep, name) - - local_lock_path = lock_path or CONF.lock_path - - if not local_lock_path: - # NOTE(bnemec): Create a fake lock path for posix locks so we don't - # unnecessarily raise the RequiredOptError below. - if InterProcessLock is not _PosixLock: - raise cfg.RequiredOptError('lock_path') - local_lock_path = 'posixlock:/' - - return os.path.join(local_lock_path, name) - - -def external_lock(name, lock_file_prefix=None, lock_path=None): - LOG.debug('Attempting to grab external lock "%(lock)s"', - {'lock': name}) - - lock_file_path = _get_lock_path(name, lock_file_prefix, lock_path) - - # NOTE(bnemec): If an explicit lock_path was passed to us then it - # means the caller is relying on file-based locking behavior, so - # we can't use posix locks for those calls. - if lock_path: - return FileLock(lock_file_path) - return InterProcessLock(lock_file_path) - - -def remove_external_lock_file(name, lock_file_prefix=None): - """Remove a external lock file when it's not used anymore - This will be helpful when we have a lot of lock files - """ - with internal_lock(name): - lock_file_path = _get_lock_path(name, lock_file_prefix) - try: - os.remove(lock_file_path) - except OSError: - LOG.info(_LI('Failed to remove file %(file)s'), - {'file': lock_file_path}) - - -def internal_lock(name): - with _semaphores_lock: - try: - sem = _semaphores[name] - except KeyError: - sem = threading.Semaphore() - _semaphores[name] = sem - - LOG.debug('Got semaphore "%(lock)s"', {'lock': name}) - return sem - - -@contextlib.contextmanager -def lock(name, lock_file_prefix=None, external=False, lock_path=None): - """Context based lock - - This function yields a `threading.Semaphore` instance (if we don't use - eventlet.monkey_patch(), else `semaphore.Semaphore`) unless external is - True, in which case, it'll yield an InterProcessLock instance. - - :param lock_file_prefix: The lock_file_prefix argument is used to provide - lock files on disk with a meaningful prefix. - - :param external: The external keyword argument denotes whether this lock - should work across multiple processes. This means that if two different - workers both run a method decorated with @synchronized('mylock', - external=True), only one of them will execute at a time. - """ - int_lock = internal_lock(name) - with int_lock: - if external and not CONF.disable_process_locking: - ext_lock = external_lock(name, lock_file_prefix, lock_path) - with ext_lock: - yield ext_lock - else: - yield int_lock - LOG.debug('Released semaphore "%(lock)s"', {'lock': name}) - - -def synchronized(name, lock_file_prefix=None, external=False, lock_path=None): - """Synchronization decorator. - - Decorating a method like so:: - - @synchronized('mylock') - def foo(self, *args): - ... - - ensures that only one thread will execute the foo 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. - """ - - def wrap(f): - @functools.wraps(f) - def inner(*args, **kwargs): - try: - with lock(name, lock_file_prefix, external, lock_path): - LOG.debug('Got semaphore / lock "%(function)s"', - {'function': f.__name__}) - return f(*args, **kwargs) - finally: - LOG.debug('Semaphore / lock released "%(function)s"', - {'function': f.__name__}) - return inner - return wrap - - -def synchronized_with_prefix(lock_file_prefix): - """Partial object generator for the synchronization decorator. - - Redefine @synchronized in each project like so:: - - (in nova/utils.py) - from nova.openstack.common import lockutils - - synchronized = lockutils.synchronized_with_prefix('nova-') - - - (in nova/foo.py) - from nova import utils - - @utils.synchronized('mylock') - def bar(self, *args): - ... - - The lock_file_prefix argument is used to provide lock files on disk with a - meaningful prefix. - """ - - return functools.partial(synchronized, lock_file_prefix=lock_file_prefix) - - -def main(argv): - """Create a dir for locks and pass it to command from arguments - - If you run this: - python -m openstack.common.lockutils python setup.py testr - - a temporary directory will be created for all your locks and passed to all - your tests in an environment variable. The temporary dir will be deleted - afterwards and the return value will be preserved. - """ - - lock_dir = tempfile.mkdtemp() - os.environ["HEAT_LOCK_PATH"] = lock_dir - try: - ret_val = subprocess.call(argv[1:]) - finally: - shutil.rmtree(lock_dir, ignore_errors=True) - return ret_val - - -if __name__ == '__main__': - sys.exit(main(sys.argv))