[Twisted-Python] Handling errors when using deferToThread

[Charlie Moad]

The deferred object from the deferToThread call is the same as any
other deferred.  Your example should work.  I have working code with
addCallback/addErrback.

On 10/28/05, Pedro Sanchez <psanchez at nortel.com> wrote:
> Hello,
>
> In the twisted documentation there is this example:
>
>
> from twisted.internet import threads
> def doLongCalculation():
>     # .... do long calculation here ...
>     return 3
>
> def printResult(x):
>     print x
>
> # run method in thread and get result as defer.Deferred
> d = threads.deferToThread(doLongCalculation)
> d.addCallback(printResult)
>
>
> This works well as long as doLongCalculation() doesn't fail for
> any reason. But if it does, how can it trigger an errBack?
> I want to do something like this:
>
> from twisted.internet import threads
> def doLongCalculation():
>     try:
>        # .... do long calculation here ...
>     except:
>        < what can I return here to tell that
>          the calculation failed? >
>     return 3
>
> def printResult(x):
>     print x
>
> def badResult(failure):
>     print "Calculation failed!"
>
> # run method in thread and get result as defer.Deferred
> d = threads.deferToThread(doLongCalculation)
> d.addCallbacks(printResult, badResult)
>
>
> Thanks in advance for your help,
>
> --
> Pedro
>
>
>
>
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