Question

当前行为：

DEBUG:package:123 > message with
multiple lines
foo bar

想要的行为：

DEBUG:package:123 > message with
                    multiple lines
                    foo bar

DEBUG:package:123的宽度可以不同，因此无法在将消息发送到记录器之前对其进行调整。

Answer 1

最后使用自定义格式化程序，在fmt字符串中没有消息：

import textwrap

class Formatter(logging.Formatter):
    def __init__(self):
        super(Formatter, self).__init__(fmt="%(levelname)-8s %(name)20s:%(lineno)-3d > ")

    def format(self, record):
        header = super(Formatter, self).format(record)
        msg = textwrap.indent(record.message, ' ' * len(header)).strip()
        return header + msg

Answer 2

这是更加现代化和灵活的 aiven 版本。

class MultiLineFormatter(logging.Formatter):
    def format(self, record):
        message = record.msg
        record.msg = ''
        header = super().format(record)
        msg = textwrap.indent(message, ' ' * len(header)).lstrip()
        record.msg = message
        return header + msg

为了使用这个：

formatter = MultiLineFormatter(
    fmt='%(asctime)s %(levelname)-8s %(message)s',
    datefmt='%Y-%m-%d %H:%M:%S',
)
log_handler = logging.StreamHandler()
log_handler.setFormatter(formatter)

Answer 3

修改了aiven的版本以使其正常工作。

class Formatter(logging.Formatter):
    def __init__(self, format_str):
        super(Formatter, self).__init__(fmt=format_str)

    def format(self, record):
        message = record.msg
        record.msg = ''
        header = super(Formatter, self).format(record)
        msg = textwrap.indent(message, ' ' * len(header)).strip()
        record.msg = message
        return header + msg

Answer 4

现有答案很好地回答了缩进部分。但是与原始 format 相比，新的 exec_info 实现没有正确处理其他字段（例如 stack_info、logging.Formatter）。

以下实现基于 simonzack's answer 并重用原始格式化程序以尽量减少副作用。

class MultiLineFormatter(logging.Formatter):
    """Multi-line formatter."""

    def get_header_length(self, record):
        """Get the header length of a given record."""
        record = copy.copy(record)
        record.msg = ''
        record.exc_info = None
        record.exc_text = None
        record.stack_info = None
        header = super().format(record)
        return len(header)

    def format(self, record):
        """Format a record with added indentation."""
        message = record.msg
        # For now we only indent string typed messages
        # Other message types like list or bytes won't be touched
        if isinstance(message, str):
            msgs = message.splitlines(True)
            if len(msgs) > 1:
                header_len = self.get_header_length(record)
                # Indent lines (except the first line)
                indented_message = msgs[0] + ''.join(map(
                    lambda m: ' ' * header_len + m if m != '\n' else m, msgs[1:]))
                # Use the original formatter since it handles exceptions well
                record.msg = indented_message
                formatted_text = super().format(record)
                # Revert to keep the msg field untouched
                # As other modules may capture the log for further processing
                record.msg = message
                return formatted_text

        return super().format(record)

如何缩进由python记录器打印的多行消息？

4 个答案: