您也可以考虑使用内置的Python模块cgitb，以获得一些非常好的、格式化良好的异常信息，包括局部变量值、源代码上下文、函数参数等。

例如这段代码…

import cgitb
cgitb.enable(format='text')

def func2(a, divisor):
    return a / divisor

def func1(a, b):
    c = b - 5
    return func2(a, c)

func1(1, 5)

我们得到这个异常输出…

ZeroDivisionError
Python 3.4.2: C:\tools\python\python.exe
Tue Sep 22 15:29:33 2015

A problem occurred in a Python script.  Here is the sequence of
function calls leading up to the error, in the order they occurred.

 c:\TEMP\cgittest2.py in <module>()
    7 def func1(a, b):
    8   c = b - 5
    9   return func2(a, c)
   10
   11 func1(1, 5)
func1 = <function func1>

 c:\TEMP\cgittest2.py in func1(a=1, b=5)
    7 def func1(a, b):
    8   c = b - 5
    9   return func2(a, c)
   10
   11 func1(1, 5)
global func2 = <function func2>
a = 1
c = 0

 c:\TEMP\cgittest2.py in func2(a=1, divisor=0)
    3
    4 def func2(a, divisor):
    5   return a / divisor
    6
    7 def func1(a, b):
a = 1
divisor = 0
ZeroDivisionError: division by zero
    __cause__ = None
    __class__ = <class 'ZeroDivisionError'>
    __context__ = None
    __delattr__ = <method-wrapper '__delattr__' of ZeroDivisionError object>
    __dict__ = {}
    __dir__ = <built-in method __dir__ of ZeroDivisionError object>
    __doc__ = 'Second argument to a division or modulo operation was zero.'
    __eq__ = <method-wrapper '__eq__' of ZeroDivisionError object>
    __format__ = <built-in method __format__ of ZeroDivisionError object>
    __ge__ = <method-wrapper '__ge__' of ZeroDivisionError object>
    __getattribute__ = <method-wrapper '__getattribute__' of ZeroDivisionError object>
    __gt__ = <method-wrapper '__gt__' of ZeroDivisionError object>
    __hash__ = <method-wrapper '__hash__' of ZeroDivisionError object>
    __init__ = <method-wrapper '__init__' of ZeroDivisionError object>
    __le__ = <method-wrapper '__le__' of ZeroDivisionError object>
    __lt__ = <method-wrapper '__lt__' of ZeroDivisionError object>
    __ne__ = <method-wrapper '__ne__' of ZeroDivisionError object>
    __new__ = <built-in method __new__ of type object>
    __reduce__ = <built-in method __reduce__ of ZeroDivisionError object>
    __reduce_ex__ = <built-in method __reduce_ex__ of ZeroDivisionError object>
    __repr__ = <method-wrapper '__repr__' of ZeroDivisionError object>
    __setattr__ = <method-wrapper '__setattr__' of ZeroDivisionError object>
    __setstate__ = <built-in method __setstate__ of ZeroDivisionError object>
    __sizeof__ = <built-in method __sizeof__ of ZeroDivisionError object>
    __str__ = <method-wrapper '__str__' of ZeroDivisionError object>
    __subclasshook__ = <built-in method __subclasshook__ of type object>
    __suppress_context__ = False
    __traceback__ = <traceback object>
    args = ('division by zero',)
    with_traceback = <built-in method with_traceback of ZeroDivisionError object>

The above is a description of an error in a Python program.  Here is
the original traceback:

Traceback (most recent call last):
  File "cgittest2.py", line 11, in <module>
    func1(1, 5)
  File "cgittest2.py", line 9, in func1
    return func2(a, c)
  File "cgittest2.py", line 5, in func2
    return a / divisor
ZeroDivisionError: division by zero

让我们创建一个相当复杂的stacktrace，以演示我们得到完整的stacktrace:

def raise_error():
    raise RuntimeError('something bad happened!')

def do_something_that_might_error():
    raise_error()

记录完整的堆栈跟踪

最佳实践是为您的模块设置一个记录器。它将知道模块的名称，并且能够更改级别(在其他属性中，例如处理程序)

import logging
logging.basicConfig(level=logging.DEBUG)
logger = logging.getLogger(__name__)

我们可以使用这个日志来获取错误:

try:
    do_something_that_might_error()
except Exception as error:
    logger.exception(error)

日志:

ERROR:__main__:something bad happened!
Traceback (most recent call last):
  File "<stdin>", line 2, in <module>
  File "<stdin>", line 2, in do_something_that_might_error
  File "<stdin>", line 2, in raise_error
RuntimeError: something bad happened!

所以我们得到的输出和我们有错误时是一样的:

>>> do_something_that_might_error()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<stdin>", line 2, in do_something_that_might_error
  File "<stdin>", line 2, in raise_error
RuntimeError: something bad happened!

只获取字符串

如果你真的只想要字符串，使用回溯。取而代之的是Format_exc函数，在这里演示了记录字符串:

import traceback
try:
    do_something_that_might_error()
except Exception as error:
    just_the_string = traceback.format_exc()
    logger.debug(just_the_string)

日志:

DEBUG:__main__:Traceback (most recent call last):
  File "<stdin>", line 2, in <module>
  File "<stdin>", line 2, in do_something_that_might_error
  File "<stdin>", line 2, in raise_error
RuntimeError: something bad happened!

我定义了以下helper类:

import traceback
class TracedExeptions(object):
    def __init__(self):
        pass
    def __enter__(self):
        pass

    def __exit__(self, etype, value, tb):
      if value :
        if not hasattr(value, 'traceString'):
          value.traceString = "\n".join(traceback.format_exception(etype, value, tb))
        return False
      return True

我以后可以这样使用:

with TracedExeptions():
  #some-code-which-might-throw-any-exception

之后可以像这样消耗它:

def log_err(ex):
  if hasattr(ex, 'traceString'):
    print("ERROR:{}".format(ex.traceString));
  else:
    print("ERROR:{}".format(ex));

(背景:我很沮丧，因为使用承诺和异常一起，不幸的是将异常在一个地方引发到另一个地方的on_rejected处理程序，因此很难从原始位置获得回溯)

请参阅traceback模块，特别是format_exc()函数。在这里。

import traceback

try:
    raise ValueError
except ValueError:
    tb = traceback.format_exc()
else:
    tb = "No error"
finally:
    print tb

如果你想将你的回溯转换为dict的列表(适用于python > 3.5):

from traceback import TracebackException


def list_traceback(exc_value: BaseException):
    result = list()

    # get previous fails, so errors are appended by order of execution
    if exc_value.__context__:
        result += list_traceback(exc_value.__context__)

    # convert Exception into TracebackException
    tbe = TracebackException.from_exception(exc_value)

    # get stacktrace (cascade methods calls)
    error_lines = list()
    for frame_summary in tbe.stack:
        summary_details = {
            'filename': frame_summary.filename,
            'method'  : frame_summary.name,
            'lineno'  : frame_summary.lineno,
            'code'    : frame_summary.line
        }
        error_lines.append(summary_details)

    # append error, by order of execution
    result.append({"error_lines": error_lines,
                   "type"       : tbe.exc_type.__name__,
                   "message"    : str(tbe)})

    return result

这将是结果(一个例子):

[
   {
      "error_lines": [
         {
            "filename": "/home/demo/file2.py",
            "method": "do_error_2",
            "lineno": 18,
            "code": "a=1/0"
         }
      ],
      "type": "ZeroDivisionError",
      "message": "division by zero"
   },
   {
      "error_lines": [
         {
            "filename": "/home/demo/file_main.py",
            "method": "demo2",
            "lineno": 50,
            "code": "file2.DEMO().do_error_2()"
         },
         {
            "filename": "/home/demo/file2.py",
            "method": "do_error_2",
            "lineno": 20,
            "code": "raise AssertionError(\"Raised inside the except, after division by zero\")"
         }
      ],
      "type": "AssertionError",
      "message": "Raised inside the except, after division by zero"
   }
]

如果您希望在未处理异常时获得相同的信息，可以这样做。执行import trace，然后:

try:
    ...
except Exception as e:
    print(traceback.print_tb(e.__traceback__))

我使用的是Python 3.7。