Python: Try/Except around whole module

Question

I have a python module containing functions and a few classes. This module is basically used as a tool-set by several of my co-workers.

I want to set-up a sort of bug reporting system where anytime someone generates an exception that I don't handle, an email will be sent with information on the exception. This way I can continually improve the robustness of my code and the help-fullness of my own error messages. Is the best way to do this to just put a try/except block around the entire module?

Answer 1

There are several reasons I think your approach might not be the best.

Sometimes exceptions should be thrown. For example, if I pass some stupid argument to a function, it should complain by throwing an exception. You don't want to get an email every time someone passes a string instead of an integer, etc. do you?

Besides, wrapping the entire thing in a try...except won't work, as that will only be catching exceptions that would occur during the definition of the classes/functions (when your module is loaded/imported). For example,

# Your python library
try:
   def foo():
       raise Exception('foo exception')
       return 42
except Exception as e:
   print 'Handled: ', e

# A consumer of your library
foo()

The exception is still uncaught.

Answer 2

I guess you can make your own SelfMailingException and subclass it. Not that I would recommend this approach.

another option:

def raises(*exception_list):
    def wrap(f):
        def wrapped_f(*x, **y):
            try:
                f(*x, **y)
            except Exception as e:
                if not isinstance(e, tuple(exception_list)):
                    print('send mail')
                    # send mail
                raise
        return wrapped_f
    return wrap

usage:

@raises(MyException)
def foo(): 
    ...