[Twisted-Python] how to cancel a long running job on a server ?
Hello, another newbie question: I have a server, where I can remotely call a function like remote_calc(), using the perspective broker, which returns giving a result. Sometimes, I want to cancel that computation, calling e.g. remote_cancel() (which remains to be implemented.....) How can I have remote_calc() not to return before the result is done, and still be able to call remote_cancel while its running ? I tried this: ============================================================= from twisted.spread import pb from twisted.internet import reactor,defer,threads @defer.deferredGenerator def calc(adeferred): print "this is calc..." d=defer.waitForDeferred(adeferred) yield d result=d.getResult() print "calc: result=",result return def do_calc(): print "do_calc starting..." for i in range(10000): for j in range(10000): pass print "do_calc done..." return 456 class ServerObject(pb.Root): def remote_cancel(self): print "this is server::cancel..." def remote_calc(self,result): print "server::calc: ..." # thought this would wait until done, but doesnt.... calc(threads.deferToThread(do_calc)) print "server::calc: returning" return 123 if __name__ == '__main__': factory = pb.PBServerFactory(ServerObject()) reactor.listenTCP(8800, factory) reactor.run() =============================================================================== My expectation was that the call to "calc" in remote_calc would block, but it does not. And if I dont defer the calculation to a thread, remote_cancel is not done until calculation finishes ... Maybe there is some completely different way to do this in twisted ? Thanks for any hint ! -- Dr. Thomas Jung Fraunhofer-Institut IISB 91058 Erlangen, Schottkystr. 10 +49 9131 761264
On Wed, 2005-05-11 at 11:38 +0200, Thomas Jung wrote:
I could not believe that you can even return a deferred from a remote server ... thats really great !
It's not that the PB protocol knows about Deferreds, it doesn't, but rather the PB implementation in Twisted does the right thing when you return a Deferred.
On Wed, 2005-05-11 at 11:38 +0200, Thomas Jung wrote:
I could not believe that you can even return a deferred from a remote server ... thats really great !
It's not that the PB protocol knows about Deferreds, it doesn't, but rather the PB implementation in Twisted does the right thing when you return a Deferred.
participants (2)
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Itamar Shtull-Trauring -
Thomas Jung