????????????????????????????????????????coding?????????????????????????????ù???????????????????????????????????????????????棬???????????
from functools import wraps
from time import sleep
def retry(attempts=3?? wait=2):
if attempts < 0 or attempts > 5:
retry_times = 3
else:
retry_times = attempts
if wait < 0 or wait > 5:
retry_wait = 2
else:
retry_wait = after
def retry_decorator(func):
@wraps(func)
def wrapped_function(*args?? **kwargs):
while retry_times > 0:
try:
return func(*args?? **kwargs)
except :
sleep(retry_wait)
retry_times -= 1
return wrapped_function
return retry_decorator
??????????retry??????????????????????????????????????????????????????????????????????????retry_times???????unresolved reference)???????????????????????????????????????????Python???????(????д???е???е??????￡????Ь??ú??????????????????????￡?????????????????????????????retry_times??retry_wait??????????retry??????????????????wrapped_function?????????????????????????????????????????μ??????????????????????????retry_times????????????ü??????????????????????????retry_wait??????ú????????
????python??duck-typing?????????????warning???????д???????????????????????????????wrapped_function??????????????????????????????????????????????????????:UnboundLocalError: local variable 'retry_attempts' referenced before assignment?? ?????warning msg???????
????@retry(7?? 8)
????def test():
????print 23333
????raise Exception('Call me exception 2333.')
????if __name__ == '__main__':
????test()
????output: UnboundLocalError: local variable 'retry_times' referenced before assignment
??????????????????e??????????????????????????????????????????(????t??дC#????????????????????ε???????????C#.net???棬????????????????????????????????????????????????????????????????????????????????????get????????????????????Lazy Evaluation??????漰???????????
def retry(attempts=3?? wait=2):
temp_dict = {
'retry_times': 3 if attempts < 0 or attempts > 5 else attempts??
'retry_wait': 2 if wait < 0 or wait > 5 else wait
}
def retry_decorate(fn):
@wraps(fn)
def wrapped_function(*args?? **kwargs):
print id(temp_dict)?? temp_dict
while temp_dict.get('retry_times') > 0:
try:
return fn(*args?? **kwargs)
except :
sleep(temp_dict.get('retry_wait'))
temp_dict['retry_times'] = temp_dict.get('retry_times') - 1
print id(temp_dict)?? temp_dict
print id(temp_dict)?? temp_dict
return wrapped_function
return retry_decorate
@retry(7?? 8)
def test():
print 23333
raise Exception('Call me exception 2333.')
if __name__ == '__main__':
test()
#output??
4405472064 {'retry_wait': 2?? 'retry_times': 3}
4405472064 {'retry_wait': 2?? 'retry_times': 3}
23333
4405472064 {'retry_wait': 2?? 'retry_times': 2}
23333
4405472064 {'retry_wait': 2?? 'retry_times': 1}
23333
4405472064 {'retry_wait': 2?? 'retry_times': 0}
??????output?п??????????dict???????????????????????????????￡???????????????????????????????
????>>> test.func_closure[1].cell_contents
????{'retry_wait': 2?? 'retry_times': 2}
?????????β??PEACE!