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 an 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})