Python日志配置：控制台屏蔽Traceback，文件保留异常信息

现有配置 #

config.conf #

version: 1
formatters:
  simple:
    format: '%(asctime)s - %(name)s - %(levelname)s - %(message)s'
filters:
  warnings_and_below:
    "()": log.filter_maker
    level: WARNING
    sense: below
  errors_and_above:
    "()": log.filter_maker
    level: ERROR
    sense: above
handlers:
  outconsole:
    class: logging.StreamHandler
    level: INFO
    formatter: simple
    filters: [warnings_and_below] 
    stream: ext://sys.stdout
  errconsole:
    class: logging.StreamHandler
    level: WARNING
    formatter: simple
    filters: [errors_and_above]
    stream: ext://sys.stderr
  file_handler:
    class: logging.FileHandler
    level: DEBUG
    formatter: simple
    filename: info.log
    encoding: utf8
    mode: w

root:
  level: DEBUG
  handlers: [file_handler, outconsole, errconsole]
  propagate: no

log.py #

import logging.config
import logging
import yaml

def filter_maker(level, sense):
    level = getattr(logging, level) # 获取日志级别对应的数值
    if sense == 'below':  # 只允许级别小于等于阈值的日志通过
        def filter(record):
            return record.levelno <= level
    else:  # 只允许级别大于等于阈值的日志通过
        def filter(record):
            return record.levelno >= level
    return filter

with open("config.conf", "r") as f:
        config = yaml.safe_load(f.read())
        logging.config.dictConfig(config)

Logger = logging.getLogger(__name__)

Logger.error("Some error")
Logger.error("Some error", exc_info=True)

需求 #

执行最后两行Logger.error语句时：

• errconsole处理器始终以exc_info=False输出（不显示Traceback）
• file_handler处理器始终以exc_info=True输出（保留异常信息）

解答：完全可以用单个Logger实现，无需配置第二个 #

核心就是通过自定义过滤器或者处理器，让不同的Handler对日志记录里的exc_info属性做不同处理，不用搞两个Logger这么麻烦。

方式一：给errconsole加专属过滤器，直接关掉exc_info #

1. 在log.py里新增一个过滤器函数：

def suppress_exc_info_filter(record):
    # 把exc_info设为False，让这个Handler不输出Traceback
    record.exc_info = False
    record.exc_text = None
    return True

2. 修改config.conf的过滤器和errconsole配置：

filters:
  # 保留原有两个过滤器
  warnings_and_below:
    "()": log.filter_maker
    level: WARNING
    sense: below
  errors_and_above:
    "()": log.filter_maker
    level: ERROR
    sense: above
  # 新增屏蔽exc_info的过滤器
  suppress_exc:
    "()": log.suppress_exc_info_filter

handlers:
  errconsole:
    class: logging.StreamHandler
    level: WARNING
    formatter: simple
    filters: [errors_and_above, suppress_exc]  # 添加新过滤器
    stream: ext://sys.stderr

方式二：自定义Handler类，输出时临时屏蔽Traceback #

1. 在log.py里定义自定义Handler：

class NoTracebackStreamHandler(logging.StreamHandler):
    def emit(self, record):
        # 先保存原有的exc_info属性，输出后恢复，不影响其他Handler
        original_exc_info = record.exc_info
        original_exc_text = record.exc_text
        # 临时关掉exc_info
        record.exc_info = False
        record.exc_text = None
        # 调用父类方法输出日志
        super().emit(record)
        # 恢复原属性
        record.exc_info = original_exc_info
        record.exc_text = original_exc_text

2. 修改config.conf中errconsole的class配置：

handlers:
  errconsole:
    class: log.NoTracebackStreamHandler  # 替换为自定义Handler
    level: WARNING
    formatter: simple
    filters: [errors_and_above]
    stream: ext://sys.stderr

两种方法都能实现单个Logger下，不同Handler分别控制是否显示Traceback的需求，没必要额外创建第二个Logger。

内容的提问来源于stack exchange，提问作者MattyOstrowsky