Python: Exception decorator. How to preserve stacktrace

Question

I am writing a decorator to apply to a function. It should catch any exception, and then raise a custom exception based on the original exception message. (This is because

Answer 1

I've faced this problem with tests that were decorated with my custom decorators.

I used following construct in decorator body to preserve original trace printed in unittests output:

try:
    result = func(self, *args, **kwargs)
except Exception:
    exc_type, exc_instance, exc_traceback = sys.exc_info()
    formatted_traceback = ''.join(traceback.format_tb(
        exc_traceback))
    message = '\n{0}\n{1}:\n{2}'.format(
        formatted_traceback,
        exc_type.__name__,
        exc_instance.message
    )
    raise exc_type(message)