Question

I’m adding logging to some python code that deals with exceptions, in the example below what’s the correct syntax for wanting to log exception details (e.g. via logger.exception()) when a TypeError or AttributeError occurs?

    try:
        ...
    except (TypeError, AttributeError):
        # want to do a logger.exception(x) here but not sure what to use for x
        ...
        raise CustomError("Unable to parse column status)

Answer 1

If you want the exception details, you need to bind the exception itself to a local variable, like this:

except (TypeError, AttributeError), e:
    # e is the Exception object
    logger.exception(e)

If you need to do different things based on the type of the exception, then you can catch them separately:

except TypeError, e:
    logger.exception('There was a Type Error; details are %s' % e)
    # Do something, or raise another exception
except AttributeError, e:
    logger.exception('There was an Attribute Error; details are %s' % e)
    # Do something, or raise another exception

And if you need more information about the context of the exception itself, look into the sys.exc_info() function; it can get you the traceback, and the details about exactly where the exception occurred.