too_many_decorators.py

from functools import wraps
import logging

user_id = "user"

people_db = [
    {'id': '001', 'name': 'Andrew M. Tatum'},
    {'id': '002', 'name': 'Frances G. Marzano'},
    {'id': '003', 'name': 'Tammy R. Green'},]

def add_tag(tag_name):
    def add_tag_decorator(func):
        @wraps(func)
        def wrapper(*args, **kwargs):
            return "<{0}>{1}</{0}>".format(tag_name, func(*args, **kwargs))
        return wrapper
    return add_tag_decorator

def audit(func):
    @wraps(func)
    def wrapper(*args, **kwargs):
        logging.critical("[{0}] Accessing: {1}".format(user_id, func.__name__))
        return func(*args, **kwargs)
    return wrapper

def secured(func):
    @wraps(func)
    def wrapper(*args, **kwargs):
        if user_id == 'user':
            return func(*args, **kwargs)
        else:
            raise Exception('Not Authorized.')
    return wrapper

@add_tag("p")
@audit
@secured
def find_person_by_id(id):
    try:
        return (person for person in people_db if person["id"] == id).next()
    except StopIteration:
        return None

print ""

print "Locates a user:  {0}\n".format(find_person_by_id('001'))
print "Does not locate a user:  {0}\n".format(find_person_by_id('004'))

try:
    user_id = 'not_a_user'
    print find_person_by_id('001')
except Exception:
    print "Access denied :("