2011-3-14 上午11:43 於 "Robert Kluin" <[email protected]> 寫道： > Task retry is very useful and desirable feature; however, if you > blindly insert continuation or fan-out tasks without somehow making > sure you've not already inserted those tasks you'll get a fork bomb > (http://en.wikipedia.org/wiki/Fork_bomb). Naming tasks is an easy way > to prevent inserting the same task over and over, should there be an > error in one your tasks. > > > As an example, just think about what would happen if you had the following: > > class ForkBomber(webapp.RequestHandler): > def post(self): > taskqueue.add(url='/fork') > raise Exception('boom') > > application = webapp.WSGIApplication([('/fork', ForkBomber),])) > > > If you name the tasks, they will still fail and keep retrying, but you > won't get the same forking behavior. (You'll want to catch > TaskAlreadyExistsError and TombstonedTaskError errors if you name the > tasks.) > > > Robert > > > > On Sun, Mar 13, 2011 at 09:46, Matija <[email protected]> wrote: >> Wait !!! Can somebody explain me that 'fork bomb'. We are designing out >> tasks so that if any exception is thrown it's retried execution is desired >> and safe. Why is this approach wrong ? Did we miss something ? >> >> -- >> You received this message because you are subscribed to the Google Groups >> "Google App Engine" group. >> To post to this group, send email to [email protected]. >> To unsubscribe from this group, send email to >> [email protected]. >> For more options, visit this group at >> http://groups.google.com/group/google-appengine?hl=en. >> > > -- > You received this message because you are subscribed to the Google Groups "Google App Engine" group. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to [email protected]. > For more options, visit this group at http://groups.google.com/group/google-appengine?hl=en. >
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