在 Python 中配置日志记录

Question

我有一个关于如何配置我的 python 记录器的问题。您可以在下面看到我当前的记录器设置。 (http://docs.python.org/2/howto/logging-cookbook.html)

logger = logging.getLogger("someName")
logger.setLevel(logging.DEBUG)
fh = logging.FileHandler("./log/log.out", "w")
fh.setLevel(logging.DEBUG)
ch = logging.StreamHandler(sys.stderr)
ch.setLevel(logging.ERROR)

frm = logging.Formatter('%(asctime)s,%(msecs)d %(name)s %(levelname)s %(message)s','H:%M:%S')
fh.setFormatter(frm)
ch.setFormatter(frm)
logger.addHandler(fh)
logger.addHandler(ch)

有没有办法配置记录器，使其也写入如下错误消息：

print a
>>> NameError: global name 'a' is not defined

非常感谢您的帮助。

Answer 1

将您的代码包装在try:、except Exception: 块中并调用logger.exception()：

try:
    print a
except Exception:
    logger.exception('Oops, something went wrong')

您可以在其中添加 raise 语句以重新引发捕获的异常。

演示：

>>> import logging
>>> logging.basicConfig()
>>> logger = logging.getLogger()
>>> def foo():
...     print a
... 
>>> def bar(i=0):
...     if i < 3:
...         bar(i + 1)
...     else:
...         foo()
... 
>>> def baz():
...     try:
...         bar()
...     except Exception:
...        logger.exception('Oops, something went wrong')
... 
>>> def spam(): baz()
... 
>>> spam()
ERROR:root:Oops, something went wrong
Traceback (most recent call last):
  File "<stdin>", line 3, in baz
  File "<stdin>", line 3, in bar
  File "<stdin>", line 3, in bar
  File "<stdin>", line 3, in bar
  File "<stdin>", line 5, in bar
  File "<stdin>", line 2, in foo
NameError: global name 'a' is not defined

回溯是由 logging 模块记录的，而不是由我的交互式 Python 会话记录的。

从try 块的回溯导致异常； spam()函数是上面的例子不包括在内。