Exception passing

[Alex Martelli]

Thomas Dybdahl Ahle <lobais at gmail.com> wrote:

> Hi, I have a function, which looks like the following:
> 
> connecting = False
> def func ():
>     global connecting
>     connecting = True
>     try:
>        # Do lot of network stuff
>     except Exception, e:
>         connecting = False
>         raise e
> 
> This works quite good, but it is a hell to debug. Instead of getting a
> log message to the line which originally raised the exception.
> 
> Is there anyway to reraise an exception, but preserve the log?

Just use
  raise
without any argument.

E.g.:

>>> def raiser():  
...   print 1/0
... 
>>> def reraise1():
...   print 'before'
...   try: raiser()
...   except Exception, e:
...     print 'after'
...     raise e
... 
>>> def reraise2():
...   print 'before'
...   try: raiser()
...   except Exception, e:
...     print 'after'
...     raise  
... 
>>> reraise1()
before
after
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<stdin>", line 6, in reraise1
ZeroDivisionError: integer division or modulo by zero
>>> reraise2()
before
after
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<stdin>", line 3, in reraise2
  File "<stdin>", line 2, in raiser
ZeroDivisionError: integer division or modulo by zero
>>> 

As you see, the traceback is "maintained" when you just "raise", though
it's altered when you "raise e".


Alex