I'm trying to write a Exception Handling class in Python so that I can re-use. If you have any ideas on how I can improve this to output more detailed information I would appreciate it:

class EHandle:
    def printit():
        exc_type, exc_obj, exc_tb = sys.exc_info()
        fname = os.path.split(exc_tb.tb_frame.f_code.co_filename)[1]
        print(exc_type, fname, exc_tb.tb_lineno)
        frm = inspect.trace()[-1]
        mod = inspect.getmodule(frm[0])
        modname = mod.__name__ if mod else frm[1]
        print 'Thrown from', modname

And I call the class and method like below:

  • 2
    \$\begingroup\$ The traceback itself holds a lot of information. You can print it with traceback.print_exc() \$\endgroup\$
    – zondo
    Commented Apr 26, 2016 at 0:01

1 Answer 1


Python's built-in exception traceback gives us:

Traceback (most recent call last):
  File "D:/code/python/error.py", line 43, in <module>
  File "D:/code/python/error.py", line 28, in error
  File "D:/code/python/error.py", line 31, in another_level
    return tuple()[0]
IndexError: tuple index out of range

Where your code gives us:

(<type 'exceptions.IndexError'>, 'error.py', 39)
Thrown from __main__

So yours is sparse from the go. But what makes it bad is line 39 is where I call error(). It's not where the error happens, that's line 31. It also doesn't give us the path to the file, if I have multiple files with the same name then your program is going to cause me some serious headaches. And finally the error doesn't throw in __main__ it throws in another_level.

If you are ok with printing the exact same as Python then, as zondo said, you can just change your code to:

def printit():

As you probably want to format it yourself, and be able to change the data. You should use sys.exc_info() and traceback.extract_tb(exc_traceback). And so if you wanted to implement print_exc yourself you can use:

def print_exc():
    exc_type, exc_value, exc_traceback = sys.exc_info()
    print 'Traceback (most recent call last):'
    print '\n'.join([
        '  File "{}", line {}, in {}\n    {}'.format(*level)
        for level in traceback.extract_tb(exc_traceback)])
    print '{}: {}\n'.format(exc_type.__name__, exc_value)

This allows you to format the error however you want.


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