pit falls using deferred lists and lazy optimization

optimization pitfalls

from twisted.internet import defer


class DoStuff():

    def __init_(self):

        self.my_stuff = None

    @defer.inlineCallbacks
    def do_it(self):

        if self.my_stuff is None:
            self.my_stuff = yield expensive_get_my_stuff_method()

        defer.returnValue(do_more_stuff(self.my_stuff))


dostuff = DoStuff()

def_list = []

for i in range(1000):
    def_list.append(dostuff.do_it())

defer.DeferredList(def_list)