[Twisted-Python] Return only when value/handle is available

[vikas kumar]

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.kumar at oracle.com 
> <mailto:vikas.c.kumar at 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
>
>
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>
>
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