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 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})