inspect_on_fail.py

# coding: utf-8
import sys
from inspect import getinnerframes
from functools import wraps
from pprint import pprint


def inspect_on_failure(msg_fmt):
    def decorator(func):
        @wraps(func)
        def wrapper(*args, **kwargs):
            try:
                return func(*args, **kwargs)
            except:
                ty, vl, tb = sys.exc_info()
                frames = (getinnerframes(tb))
                p, q, r, s, t, u = frames[-1]
                params = dict(p.f_globals)
                params.update(p.f_locals)
                if msg_fmt:
                    print(msg_fmt % params)
                raise
        return wrapper
    return decorator


@inspect_on_failure('Failure: %(bar)s and %(baz)s')
def foo(bar, baz):

    qux = 1, 2, 5
    quux = 'throw it now'
    raise ValueError('Holy!')

try:
    foo('cave', 'rabbit')
except:
    pass