此defer非golang中的defer https://tour.golang.org/flowcontrol/12 

 

from twitter.common.concurrent import Timeout, deadline, deferfrom twitter.common.quantity import Amount, Timeimport timedef _stop():    print 'stop begin'    time.sleep(7)    print 'stop done'def stop():    defer(_stop)deadline(stop, timeout= Amount(3, Time.SECONDS), daemon=True, propagate=True)

这个代码是不会抛出exception的，twitter中defer主要用途是并发启动一些命令，不会相互block。

 

refer to: https://github.com/twitter/commons/tree/master/src/python/twitter/common/concurrent