openstack/placement
Code Issues Proposed changes

Merge "External locking for image caching."

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Jenkins
2012-08-30 19:34:18 +00:00
committed by Gerrit Code Review
parent 9ceb5103eb cbb9668ad5
commit d6726ec779
1 changed files with 26 additions and 8 deletions
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34
nova/utils.py
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@@ -661,7 +661,7 @@ else:
_semaphores = weakref.WeakValueDictionary()
def synchronized(name, external=False):
def synchronized(name, external=False, lock_path=None):
"""Synchronization decorator.
Decorating a method like so::
@@ -688,6 +688,10 @@ def synchronized(name, external=False):
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.
The lock_path keyword argument is used to specify a special location for
external lock files to live. If nothing is set, then FLAGS.lock_path is
used as a default.
"""
def wrap(f):
@@ -703,9 +707,6 @@ def synchronized(name, external=False):
# (only valid in greenthreads)
_semaphores[name] = sem
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,
@@ -714,8 +715,25 @@ def synchronized(name, external=False):
LOG.debug(_('Attempting to grab file lock "%(lock)s" for '
'method "%(method)s"...'),
{'lock': name, 'method': f.__name__})
lock_path = FLAGS.lock_path or tempfile.mkdtemp()
lock_file_path = os.path.join(lock_path, 'nova-%s' % name)
cleanup_dir = False
def wrap_mkdtemp():
cleanup_dir = True
return tempfile.mkdtemp()
# We need a copy of lock_path because it is non-local
local_lock_path = lock_path
if not local_lock_path:
local_lock_path = FLAGS.lock_path or wrap_mkdtemp()
if not os.path.exists(local_lock_path):
ensure_tree(local_lock_path)
# NOTE(mikal): the lock name cannot contain directory
# separators
safe_name = name.replace(os.sep, '_')
lock_file_path = os.path.join(local_lock_path,
'nova-%s' % safe_name)
lock = InterProcessLock(lock_file_path)
try:
with lock:
@@ -727,8 +745,8 @@ def synchronized(name, external=False):
# NOTE(vish): This removes the tempdir if we needed
# to create one. This is used to cleanup
# the locks left behind by unit tests.
if not FLAGS.lock_path:
shutil.rmtree(lock_path)
if cleanup_dir:
shutil.rmtree(local_lock_path)
else:
retval = f(*args, **kwargs)