我想在不退出的情况下捕获和记录异常,例如,
try:
do_stuff()
except Exception as err:
print(Exception, err)
# I want to print the entire traceback here,
# not just the exception name and details
我想打印与抛出异常时打印的完全相同的输出,而不使用try/,只是拦截异常,并且我不希望它退出程序。
我想在不退出的情况下捕获和记录异常,例如,
try:
do_stuff()
except Exception as err:
print(Exception, err)
# I want to print the entire traceback here,
# not just the exception name and details
我想打印与抛出异常时打印的完全相同的输出,而不使用try/,只是拦截异常,并且我不希望它退出程序。
当前回答
在python3(适用于3.9)中,我们可以定义一个函数,并可以在任何需要打印详细信息的地方使用它。
import traceback
def get_traceback(e):
lines = traceback.format_exception(type(e), e, e.__traceback__)
return ''.join(lines)
try:
1/0
except Exception as e:
print('------Start--------')
print(get_traceback(e))
print('------End--------')
try:
spam(1,2)
except Exception as e:
print('------Start--------')
print(get_traceback(e))
print('------End--------')
输出如下所示:
bash-3.2$ python3 /Users/soumyabratakole/PycharmProjects/pythonProject/main.py
------Start--------
Traceback (most recent call last):
File "/Users/soumyabratakole/PycharmProjects/pythonProject/main.py", line 26, in <module>
1/0
ZeroDivisionError: division by zero
------End--------
------Start--------
Traceback (most recent call last):
File "/Users/soumyabratakole/PycharmProjects/pythonProject/main.py", line 33, in <module>
spam(1,2)
NameError: name 'spam' is not defined
------End--------
其他回答
要获得精确的堆栈跟踪(作为字符串),如果没有try/except进行跨步处理,则会引发该字符串,只需将其放置在捕获违规异常的except块中。
desired_trace = traceback.format_exc(sys.exc_info())
下面是如何使用它(假设定义了flaky_func,并且log调用您最喜欢的日志系统):
import traceback
import sys
try:
flaky_func()
except KeyboardInterrupt:
raise
except Exception:
desired_trace = traceback.format_exc(sys.exc_info())
log(desired_trace)
捕获并重新引发KeyboardInterrupts是个好主意,这样您仍然可以使用Ctrl-C终止程序。日志记录不在这个问题的范围之内,但是日志记录是一个很好的选择。sys和traceback模块的文档。
您需要traceback模块。它将允许您像Python通常那样打印堆栈转储。特别是,print_last函数将打印最后一个异常和堆栈跟踪。
其他一些答案已经指出了回溯模块。
请注意,使用print_exc,在某些极端情况下,您将无法获得您所期望的结果。在Python 2.x中:
import traceback
try:
raise TypeError("Oups!")
except Exception, err:
try:
raise TypeError("Again !?!")
except:
pass
traceback.print_exc()
...将显示上一个异常的回溯:
Traceback (most recent call last):
File "e.py", line 7, in <module>
raise TypeError("Again !?!")
TypeError: Again !?!
如果你真的需要访问原始的回溯,一个解决方案是将exc_info返回的异常信息缓存到一个局部变量中,并使用print_exception显示它:
import traceback
import sys
try:
raise TypeError("Oups!")
except Exception, err:
try:
exc_info = sys.exc_info()
# do you usefull stuff here
# (potentially raising an exception)
try:
raise TypeError("Again !?!")
except:
pass
# end of useful stuff
finally:
# Display the *original* exception
traceback.print_exception(*exc_info)
del exc_info
生产:
Traceback (most recent call last):
File "t.py", line 6, in <module>
raise TypeError("Oups!")
TypeError: Oups!
但这也有一些陷阱:
From the doc of sys_info: Assigning the traceback return value to a local variable in a function that is handling an exception will cause a circular reference. This will prevent anything referenced by a local variable in the same function or by the traceback from being garbage collected. [...] If you do need the traceback, make sure to delete it after use (best done with a try ... finally statement) but, from the same doc: Beginning with Python 2.2, such cycles are automatically reclaimed when garbage collection is enabled and they become unreachable, but it remains more efficient to avoid creating cycles.
另一方面,通过允许你访问与异常相关的回溯,Python 3产生了一个不那么令人惊讶的结果:
import traceback
try:
raise TypeError("Oups!")
except Exception as err:
try:
raise TypeError("Again !?!")
except:
pass
traceback.print_tb(err.__traceback__)
... 将显示:
File "e3.py", line 4, in <module>
raise TypeError("Oups!")
import io
import traceback
try:
call_code_that_fails()
except:
errors = io.StringIO()
traceback.print_exc(file=errors) # Instead of printing directly to stdout, the result can be further processed
contents = str(errors.getvalue())
print(contents)
errors.close()
关于这个答案的注释:print(traceback.format_exc())对我来说比traceback.print_exc()更好。对于后者,hello有时会奇怪地与回溯文本“混合”在一起,比如两者都想同时写入stdout或stderr,产生奇怪的输出(至少在从文本编辑器内部构建并在“构建结果”面板中查看输出时)。
回溯(最近一次调用): 文件“C:\Users\User\Desktop\test.py”,第7行,在 地狱do_stuff () 文件“C:\Users\User\Desktop\test.py”,第4行,do_stuff 1/0 ZeroDivisionError:整数除法或对0取模 o [0.1s完成]
所以我用:
import traceback, sys
def do_stuff():
1/0
try:
do_stuff()
except Exception:
print(traceback.format_exc())
print('hello')