On Fri, May 28, 2010 at 12:10 PM, <vitaly@synapticvision.com> wrote:
Of course its up to me to determine if it's a data collision or not, but I was thinking may be Twisted can provide me with some already existing mechanism of its own. After all its already a pretty massive and complicated framework with tons of capabilities ...
But I'd like to get back to the point of the question: if at some point EventA callbacks and EventB callbacks need to work on the same global variable, than what would be a Twisted way (if exist) to prevent data collision ?
In the way that you have described it, that's a question for your code. In the general case, you don't know what order callbacks on two chains will be called in. The advantage of async is that you can use a standard Python type as a mutex, and relinquish control if it's not ready. Set a variable when one chain is working, and if another chain encounters that, have it try later by creating and retuning a new Deferred with its work on that callback, or with reactor.callLater().