Re: [Twisted-Python] Return only when value/handle is available
I would fiddle around with something like this. from twisted.internet.defer import inlineCallbacks, returnValue, Deferred from twisted.internet import reactor @inlineCallbacks def foo(self, retries=10, interval=10): while True: try: returnValue((yield self.get_handle())) except SystemDelayException as e: if retries 0: retries -= 1 d = Deferred() reactor.callLater(interval, d.callback, None) yield d else: raise e On Wed, Sep 3, 2014 at 1:32 PM, vikas kumar vikas.c.ku...@oracle.com wrote: Hi, I am little new to twisted. I've a function(get_handle) which returns a handle. But get_handle() may throw an exception(SystemDelayException) because of some delay in system. My requirement is : When I get SystemDelayException re-attempt get_handle() and return only when handle is available. How do I use deferred/reactor in this scenario? try: handle = yield self.get_handle() except SystemDelayException: // code to re-attempt get_handle and return only when handle is available Regards Vikas ___ Twisted-Python mailing list Twisted-Python@twistedmatrix.com http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python ___ Twisted-Python mailing list Twisted-Python@twistedmatrix.com http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python
Re: [Twisted-Python] Return only when value/handle is available
One option in which we have both reactor and deferred :) def do_low_level_stuff(deferred) try: deferred.callback(self.get_handle()) except SystemDelayException: reactor.callLater(1, do_low_level_stuff, deferred) def do_stuff(): deferred = Deferred() do_low_level_stuff(deferred) return deferred Cheers On 3 September 2014 12:32, vikas kumar vikas.c.ku...@oracle.com wrote: Hi, I am little new to twisted. I've a function(get_handle) which returns a handle. But get_handle() may throw an exception(SystemDelayException) because of some delay in system. My requirement is : When I get SystemDelayException re-attempt get_handle() and return only when handle is available. How do I use deferred/reactor in this scenario? try: handle = yield self.get_handle() except SystemDelayException: // code to re-attempt get_handle and return only when handle is available Regards Vikas ___ Twisted-Python mailing list Twisted-Python@twistedmatrix.com http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python -- Adi Roiban ___ Twisted-Python mailing list Twisted-Python@twistedmatrix.com http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python
Re: [Twisted-Python] Return only when value/handle is available
Hi Jonas, This is nice. But still we are retrying it repeatedly at regular interval(10). Can't we get the notified asynchronously as and when handle is available. Regards Vikas On 9/3/2014 6:10 PM, Jonas Brunsgaard wrote: I would fiddle around with something like this. from twisted.internet.defer import inlineCallbacks, returnValue, Deferred from twisted.internet import reactor @inlineCallbacks def foo(self, retries=10, interval=10): while True: try: returnValue((yield self.get_handle())) except SystemDelayException as e: if retries 0: retries -= 1 d = Deferred() reactor.callLater(interval, d.callback, None) yield d else: raise e On Wed, Sep 3, 2014 at 1:32 PM, vikas kumar vikas.c.ku...@oracle.com mailto:vikas.c.ku...@oracle.com wrote: Hi, I am little new to twisted. I've a function(get_handle) which returns a handle. But get_handle() may throw an exception(SystemDelayException) because of some delay in system. My requirement is : When I get SystemDelayException re-attempt get_handle() and return only when handle is available. How do I use deferred/reactor in this scenario? try: handle = yield self.get_handle() except SystemDelayException: // code to re-attempt get_handle and return only when handle is available Regards Vikas ___ Twisted-Python mailing list Twisted-Python@twistedmatrix.com mailto:Twisted-Python@twistedmatrix.com http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python ___ Twisted-Python mailing list Twisted-Python@twistedmatrix.com http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python ___ Twisted-Python mailing list Twisted-Python@twistedmatrix.com http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python
Re: [Twisted-Python] Return only when value/handle is available
On 05:52 pm, vikas.c.ku...@oracle.com wrote: Hi Jonas, This is nice. But still we are retrying it repeatedly at regular interval(10). Can't we get the notified asynchronously as and when handle is available. You tell us. What's a handle? Where do you get it from? Does that system produce an event when it is ready? Jean-Paul ___ Twisted-Python mailing list Twisted-Python@twistedmatrix.com http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python
