[Twisted-Python] run queries in deffered, but not in transaction

[Pet]

On Tue, Sep 15, 2009 at 5:19 PM, Mark Visser <markv at lumierevfx.com> wrote:
> exarkun at twistedmatrix.com wrote:
>> On 10:37 am, petshmidt at googlemail.com wrote:
>>>
>>> I'd like to run several queries in background, some of them may fail.
>>>
>>
>> If you have a function along the lines of this one:
>>
>>     def someInteractions(db):
>>         interactions = [
>>             db.runInteraction(one),
>>             db.runInteraction(two),
>>             db.runInteraction(three)]
>>
>> Then a failure in one shouldn't affect two or three; likewise for any
>> other failure or combination of failures.  They are naturally (ugh, not
>> a good word, but I can't think of a better one) independent.  You have
>> to go out of your way to associate them somehow.
>>
> I think he might mean he wants them to run sequentially, even if one fails.
>
> You can do that explicitly via @inlineCallbacks like this:
>
> @inlineCallbacks
> def someInteractions(db):
>    try:
>        yield db.runInteraction(one)
>    except:
>       pass
>
>    try:
>        yield db.runInteraction(two)
>    except:
>       pass
>
>    try:
>        yield db.runInteraction(three)
>    except:
>       pass
>
> Or with callback/errbacks, like this:
>
> def someInteractions(db)
>        d = db.runInteraction(one).addBoth(db.runInteraction,
> two).addBoth(db.runInteraction, three)

Hi Mark!

Yes, I'd like run them sequentially, it was not clear for me, how to
do it in one deferred.

I will try your suggestions out.

Thanks for help!

Pet

>
> addBoth is a convenience method that adds the same function as a
> callback and an errback:
>
> http://twistedmatrix.com/documents/8.2.0/api/twisted.internet.defer.Deferred.html#addBoth
>
> --
> Mark Visser, Software Director
> Lumière VFX
> Email: markv at lumierevfx.com
> Phone: +1-514-316-1080 x3030
>
>
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