external_search_command.py 文件源码

def _execute(path, argv=None, environ=None):
            """ Executes an external search command.

            :param path: Path to the external search command.
            :type path: unicode

            :param argv: Argument list.
            :type argv: list or tuple
            The arguments to the child process should start with the name of the command being run, but this is not
            enforced. A value of :const:`None` specifies that the base name of path name :param:`path` should be used.

            :param environ: A mapping which is used to define the environment variables for the new process.
            :type environ: dict or None.
            This mapping is used instead of the current process’s environment. A value of :const:`None` specifies that
            the :data:`os.environ` mapping should be used.

            :return: None

            """
            search_path = os.getenv('PATH') if environ is None else environ.get('PATH')
            found = ExternalSearchCommand._search_path(path, search_path)

            if found is None:
                raise ValueError('Cannot find command on path: {}'.format(path))

            path = found
            logger.debug('starting command="%s", arguments=%s', path, argv)

            def terminate(signal_number, frame):
                sys.exit('External search command is terminating on receipt of signal={}.'.format(signal_number))

            def terminate_child():
                if p.pid is not None and p.returncode is None:
                    logger.debug('terminating command="%s", arguments=%d, pid=%d', path, argv, p.pid)
                    os.kill(p.pid, CTRL_BREAK_EVENT)

            p = Popen(argv, executable=path, env=environ, stdin=sys.stdin, stdout=sys.stdout, stderr=sys.stderr)
            atexit.register(terminate_child)
            signal(SIGBREAK, terminate)
            signal(SIGINT, terminate)
            signal(SIGTERM, terminate)

            logger.debug('started command="%s", arguments=%s, pid=%d', path, argv, p.pid)
            p.wait()

            logger.debug('finished command="%s", arguments=%s, pid=%d, returncode=%d', path, argv, p.pid, p.returncode)

            if p.returncode != 0:
                sys.exit(p.returncode)