package.py 文件源码

def lock(self):
        """
        Locks the package to avoid concurrent operations on its shared
        resources.
        Currently, the only resource shared among scripts executed from
        different directories is the repository.
        """
        if not self.locking_enabled:
            LOG.debug("This package has no shared resources to lock")
            return

        LOG.debug("Checking for lock on file {}.".format(self.lock_file_path))
        self.lock_file = open(self.lock_file_path, "w")
        try:
            fcntl.lockf(self.lock_file, fcntl.LOCK_EX | fcntl.LOCK_NB)
        except IOError as exc:
            RESOURCE_UNAVAILABLE_ERROR = 11
            if exc.errno == RESOURCE_UNAVAILABLE_ERROR:
                LOG.info("Waiting for other process to finish operations "
                         "on {}.".format(self.name))
            else:
                raise
        fcntl.lockf(self.lock_file, fcntl.LOCK_EX)