python - Python 日志记录是否默认写入 stdout 或 stderr？

Question

logging docs不要提及默认记录器从 basicConfig 获得的内容写入:stdout 或 stderr。

默认行为是什么？

Answer 1

如果没有 filename 参数传递给 logging.basicconfig它将配置一个StreamHandler。如果将 stream 参数传递给 logging.basicconfig，它将把它传递给 StreamHandler，否则 StreamHandler 默认使用sys.stderr 从StreamHandler docs可以看出

class logging.StreamHandler(stream=None)

Returns a new instance of the StreamHandler class. If stream is specified, the instance will use it for logging output; otherwise, sys.stderr will be used.

和 source code :

class StreamHandler(Handler):
    """
    A handler class which writes logging records, appropriately formatted,
    to a stream. Note that this class does not close the stream, as
    sys.stdout or sys.stderr may be used.
    """

    def __init__(self, stream=None):
        """
        Initialize the handler.
        If stream is not specified, sys.stderr is used.
        """
        Handler.__init__(self)
        if stream is None:
            stream = sys.stderr
        self.stream = stream