Print original exception in excepthook

Question

I am setting the sys.excepthook so that I can log every exception that occurs. Instead of writing to a log, let's use the following example:

def excepthook(self, type_, value, traceback): print "\n" print type_ print value print traceback print "\n" sys.excepthook = self.excepthook

Now let's say I create a type error, like so:

print 3 + str(2)

Without being caught, this goes into the excepthook and properly prints out the 3 variables:

<type 'exceptions.TypeError'> unsupported operand type(s) for + <traceback object at 0x02BAE800>

What I would like to do, is have it ALSO print out the full Exception that was sent to the excepthook (so, in this case, a TypeException). In other words, I'd like it to also display the following information).

Traceback (most recent call last): File "testcidnelite.py", line 13, in <module> print 3 + str(2) TypeError: unsupported operand type(s) for +: 'int' and 'str'

If I add the following line:

raise

it will display the exception properly; however, it will also display an error with the term raise:

Error in sys.excepthook: Traceback (most recent call last): File "C:\psi-test-automation\Selenium\TestMethods2.py", line 145, in excepthook raise TypeError: exceptions must be old-style classes or derived from BaseException, not NoneType

Altering it to:

raise type_

Will print out the following error:

Error in sys.excepthook: Traceback (most recent call last): File "C:\psi-test-automation\Selenium\TestMethods2.py", line 145, in excepthook raise type_ TypeError Original exception was: Traceback (most recent call last): File "testcidnelite.py", line 13, in <module> print 3 + str(2) TypeError: unsupported operand type(s) for +: 'int' and 'str'

I want it to print out only the 2nd chunk (the original exception). Is this possible?

Rob Cutmore · Accepted Answer · 2015-02-25 16:56:15Z

12

You can use Python's traceback module to format an exception.

from traceback import format_exception def excepthook(self, type_, value, traceback): print format_exception(type_, value, traceback) sys.excepthook = self.excepthook

Check out the official documentation for more information and examples.

answered Feb 25, 2015 at 16:56

Rob Cutmore

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1 Comment

Maximiliano Guerra Over a year ago

For printing the properly formatted exception I think the method print_exception works better, as per documentation of the format_exception: The return value is a list of strings, each ending in a newline and some containing internal newlines. When these lines are concatenated and printed, exactly the same text is printed as does print_exception().

BaiJiFeiLong · Accepted Answer · 2022-03-01 08:48:35Z

You can call the system sys.excepthook again.

Example code:

# Created by [email protected] at 2022/3/1 import logging import sys from sys import excepthook sys.excepthook = lambda *args: (logging.error("Exception occurred: %s", args[1]), excepthook(*args)) raise RuntimeError("IronChainException")

Example output:

ERROR:root:Exception occurred: IronChainException Traceback (most recent call last): File "/tmp/example.py", line 7, in <module> raise RuntimeError("IronChainException") RuntimeError: IronChainException

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