python_log_1.py

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
#
# Karl.Lv@outlook.com, KarlLv@126.com
# 24 March, 2017
#

from time import time

def logged(when):
    def log(f,*args,**kargs):
        print("called: function:%s,args:%r,kargs:%r"%(f,args,kargs))
    def pre_logged(f):
        def wrapper(*args,**kargs):
            log(f,*args,**kargs)
            return f(*args,**kargs)
    def post_logged(f):
        def wrapped(*args,**kargs):
            now=time()
            try:
                return f(*args,**kargs)
            finally:
                log(f,*args,**kargs)
                print("time delta:%s"%(time()-now))
        return wrapped
    try:
        # I don't understand this line code
        return{"pre":pre_logged,"post":post_logged}[when]
    except Exception as e:
        print(e)

@logged("post")
def hello(name):
    print("hello",name)

@logged("post")
def test(a,b=1):
    print(a+b)

hello("world")
test(1,2)