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
这是我把错误写在日志文件和控制台的解决方案:
import logging, sys
import traceback
logging.basicConfig(filename='error.log', level=logging.DEBUG)
def handle_exception(exc_type, exc_value, exc_traceback):
if issubclass(exc_type, KeyboardInterrupt):
sys.__excepthook__(exc_type, exc_value, exc_traceback)
return
exc_info=(exc_type, exc_value, exc_traceback)
logging.critical("\nDate:" + str(datetime.datetime.now()), exc_info=(exc_type, exc_value, exc_traceback))
print("An error occured, check error.log to see the error details")
traceback.print_exception(*exc_info)
sys.excepthook = handle_exception
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。
你可以这样做:
try:
do_stuff()
except Exception, err:
print(Exception, err)
raise err
如何在不停止程序的情况下打印完整的回溯?
当你不想因为一个错误而停止你的程序时,你需要用try/except来处理这个错误:
try:
do_something_that_might_error()
except Exception as error:
handle_the_error(error)
要提取完整的回溯,我们将使用标准库中的traceback模块:
import traceback
并创建一个相当复杂的stacktrace来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()
印刷
要打印完整的回溯,请使用traceback。print_exc方法:
try:
do_something_that_might_error()
except Exception as error:
traceback.print_exc()
打印:
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!
优于打印、日志:
但是,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__)
在这种情况下,您将需要记录器。异常函数改为:
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!
或者,您可能只想要字符串,在这种情况下,您将需要回溯。Format_exc函数改为:
try:
do_something_that_might_error()
except Exception as error:
logger.debug(traceback.format_exc())
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!
结论
对于这三个选项,我们看到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!
使用哪种
性能问题在这里并不重要,因为IO通常占主导地位。我更喜欢,因为它精确地以向前兼容的方式执行请求:
logger.exception(error)
日志级别和输出可以调整,这样就可以很容易地关闭,而不需要修改代码。通常做直接需要的是最有效的方法。
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--------
您需要将try/except放在可能发生错误的最内层循环中,即。
for i in something:
for j in somethingelse:
for k in whatever:
try:
something_complex(i, j, k)
except Exception, e:
print e
try:
something_less_complex(i, j)
except Exception, e:
print e
... 等等
换句话说,您需要将可能在try/中失败的语句包装在尽可能具体的内部循环中。