How can I get the traceback object ( sys.exc_info()[2] , same as sys.exc_traceback ) as a string?

Question

I have a function which catches all exceptions, and I want to be able to get the traceback as a string within this function.

So far this is not working:

def handle_errors(error_type, error_message, error_traceback):
    """catch errors"""
    import traceback
    error = {}
    error['type'] = error_type.__name__
    error['message'] = str(error_message)
    error['file'] = os.path.split(error_traceback.tb_frame.f_code.co_filename)[1]
    error['line'] = error_traceback.tb_lineno
    error['traceback'] = repr(traceback.print_tb(error_traceback))
    ### finalise error handling and exit ###

sys.excepthook = handle_errors

It's the error['traceback'] line which is wrong. Do i even need to use the traceback module?

As per this other vaguely similar question, I have tried:

error['traceback'] = repr(error_traceback.print_exc())

...but this gives an error:

Error in sys.excepthook:
Traceback (most recent call last):
  File "xxxxxxxxxxx", line 54, in handle_errors
    error['traceback'] = repr(error_traceback.print_exc())
AttributeError: 'traceback' object has no attribute 'print_exc'

possible duplicate of [Get full traceback](http://stackoverflow.com/questions/13210436/get-full-traceback) — Paolo Casciello, Nov 27 '13 at 11:43
that question is not applicable. i will update my question explaining why — mulllhausen, Nov 27 '13 at 11:47
Hello. See my answer please. Why did you wrote that your question isn't applicable ? — eyquem, Dec 12 '13 at 15:08
@eyquem because [that other question](http://stackoverflow.com/questions/13210436/get-full-traceback) is not about capturing a traceback within an excepthook function. the excepthook function provides a traceback frame to query (`error_traceback`) but that other question does not address how to use this frame. — mulllhausen, Dec 13 '13 at 13:07
I don't understand what you say because of _"that other question"_ ? Which **other** question ?? — eyquem, Dec 13 '13 at 14:19
Besides, I remark something I didn't until now: in the definition of ``handle_errors``, the reference _error['traceback']_ is assigned to repr() of ``traceback.print_tb(error_traceback))`` while the account of the exception says it is repr() of ``error_traceback.print_exc())`` — eyquem, Dec 13 '13 at 14:23
to see the other question i am talking about, please click on the link-words 'that other question' in my previous comment. its the one which you have put `This question may already have an answer here:` at the top of my original post — mulllhausen, Dec 14 '13 at 00:01

score 19 · Accepted Answer · answered Nov 27 '13 at 11:50

19

Use traceback.format_tb() instead of print_tb() to get the formatted stack trace (as a list of lines):

error['traceback'] = ''.join(traceback.format_tb(error_traceback))

print_tb() directly prints the traceback, that's why you get None as a result (that's the default for any Python function that doesn't return anything explicitely).

answered Nov 27 '13 at 11:50

Lukas Graf

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Your answer led me to the precise solution. – eyquem Dec 12 '13 at 15:09

score 0 · Answer 2 · answered Dec 12 '13 at 14:33

0

traceback.format_exc([limit])
This is like print_exc(limit) but returns a string instead of printing to a file.

New in version 2.4.

error['traceback'] = traceback.format_exc(error_traceback)

answered Dec 12 '13 at 14:33

eyquem

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This does not work due to reasons pointed out by Lukas G. in the accepted answer that was posted earlier than yours. – andyn Oct 27 '16 at 08:56

How can I get the traceback object ( sys.exc_info()[2] , same as sys.exc_traceback ) as a string?

2 Answers2