Decorators for actions executed in case of an exception
This package is intended to provide decorators which execute custom actions in case of exceptions. Let’s see an example:
First we need an object with some methods. These methods we decorate with the PrintOnFailure-decorator. This simple example decorator prints a given message in case of an exception.
>>> from failureaction import ConflictError >>> from failureaction import PrintOnFailure >>> class TestOb(object): ... ... @PrintOnFailure(msg='Some numeric calculation went wrong!') ... def divide(self, a, b): ... return a/b ... ... @PrintOnFailure() ... def doraise(self): ... raise ConflictError
We have two methods. One (divide) does numerical division of two numbers and another raises a custom defined ConflictError. Now let’s see the methods in action:
>>> ob = TestOb() >>> ob.divide(4, 2) 2>>> ob.divide(42, 0) Some numeric calculation went wrong!>>> ob.doraise() Traceback (most recent call last): ... ConflictError
The ActionOnFailure decorator provided by the module is intended to be overriden by a custom class. Like this:
>>> from failureaction import ActionOnFailure >>> class MailOnFailure(ActionOnFailure): ... ... def __init__(self, subject): ... self.subject = subject ... ... def _doaction(self, context, e): ... """ send a mail, if an exception was raised """ ... print "Subject:", self.subject ... print e>>> class TestOb2(object): ... ... @MailOnFailure(subject='An error occured') ... def critical(self): ... import _not_existent_hopefully_>>> ob2 = TestOb2() >>> ob2.critical() Subject: An error occured No module named _not_existent_hopefully_