How do I catch an exception in a decorator but allow the caller to catch it as well?
I just wrote a class similar to what you are doing, but with a little more options available. Here it is:
class ErrorIgnore(object):
def __init__(self, errors, errorreturn = None, errorcall = None):
self.errors = errors
self.errorreturn = errorreturn
self.errorcall = errorcall
def __call__(self, function):
def returnfunction(*args, **kwargs):
try:
return function(*args, **kwargs)
except Exception as E:
if type(E) not in self.errors:
raise E
if self.errorcall is not None:
self.errorcall(E, *args, **kwargs)
return self.errorreturn
return returnfunction
Common usage would be something like:
def errorcall(E, *args):
print 'exception skipped', E
@ErrorIgnore(errors = [ZeroDivisionError, ValueError], errorreturn = None, errorcall = errorcall)
def myfunction(stuff):
# do stuff
# return stuff
# the errors shown are skipped
Graeme Perrow
I am a software developer working for SAP in Waterloo, Ontario. I am a member of the SAP HANA Cockpit engineering team. For twenty years, I was a member of the SAP SQL Anywhere engineering team. I write primarily in Javascript, C, C++, python, and perl. In my spare time, I enjoy sports, primarily lacrosse, baseball, and hockey.
Updated on June 03, 2022Comments
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Graeme Perrow about 2 years
I have a python function that may raise an exception. The caller catches the exception and deals with it. Now I would like to add a decorator to that function that also catches the exception, does some handling, but then re-raises the exception to allow the original caller to handle it. This works, except that when the original caller displays the call stack from the exception, it shows the line in the decorator where it was re-raised, not where it originally occurred. Example code:
import sys,traceback def mydec(func): def dec(): try: func() except Exception,e: print 'Decorator handled exception %s' % e raise e return dec @mydec def myfunc(): x = 1/0 try: myfunc() except Exception,e: print 'Exception: %s' % e type,value,tb = sys.exc_info() traceback.print_tb(tb)
The output is:
Decorator handled exception integer division or modulo by zero Exception: integer division or modulo by zero File "allbug.py", line 20, in <module> myfunc() File "allbug.py", line 9, in dec raise e
I would like the decorator to be able to handle the exception but the traceback should indicate the
x = 1/0
line rather than theraise
line. How can I do this?