Get the full exception type/message and stack trace

Question

I've written an API which returns Json in the following format...

{"Success": true, Result: {...}}

{"Success": false, ExceptionId: "(some uuid)"}

The exceptions are logged. This is fine in principle for allowing someone to discuss an error without us ever telling them what it is (as a security measure). During debugging I also want to output the error message to stop me having to refer to a database all the time.

As things stand, the problem is getting useful information from the exception (either to return or log in the db)

I'm doing something like this...

try:
    Ret['Result'] = <Blah>
    Ret['Success'] = True
except Exception as e:
    # ... Logging/ExceptionId
    if Settings.DebugMode: 
        Ret['Exception'] = str(e)

If I put a breakpoint on the last line and inspect e in eclipse's watch window, I get KeyError: 'Something', but str(e) results in 'Something' which is very unhelpful.

I've googled and I can't find any way to get a proper message from an exception. Apparently there used to be a .message in v<2.4 but that's no help to me in 3.3

As an alternative, I tried doing:

Ret['Exception'] = str(type(e)) + ": " + str(e)

Which resulted in <class 'KeyError'>: 'job' which is a little closer but it's starting to feel more and more hackish.

I also want to include a Stack Trace but have had even less luck there - I can get the __traceback__ but of course it's not serializable and calling str() on it just results in a description of the object eg <traceback object at 0x0000000004024E48>

How can I get a decent/comprehensive error message?

Answer 1

You probably want repr:

Ret['Exception'] = repr(e)

For the traceback, use the traceback module:

from traceback import format_exc
Ret['Traceback'] = format_exc()