You give callback the result to pass to the first callback in the deferred, why are you using a deferred for this? why not just reactor.callLater(3, checkForSanity) ? Sergio Trejo wrote:

I'm trying to be a good soldier by heeding the warning issued by the Twisted gods warning strongly *not* to use defer.Deferred's setTimeout() and instead using reactor.callLater

I've looked at the API for twisted.internet.defer.Deferred.callback and twisted.internet.default.SelectReactor.callLater (which refers one to see twisted.internet.interfaces.IReactorTime.callLater which I have also read). I don't understand why at least one args object must always be supplied to reactor.callLater, as in:

reactor.callLater(3, d.callback, "an unused arg")

even though the callback function:

d.addCallback(checkForSanity)

receives no args:

def checkForSanity(): print "this is a sanity test"

In order to get the reactor.callLater to perform the callback, I had to pass in at least one arg:

def checkForSanity(ignoreMe): print "this is a sanity test" d = defer.Deferred() d.addCallback(checkForSanity) reactor.callLater(3, d.callback, "ignore me")

There's sure to be a good reason why, perhaps something utterly obvious to most but as a newbie I'm still trying to grok as much as possible where needed. Thanks for any clarification.

Serg

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You give callback the result to pass to the first callback in the deferred, why are you using a deferred for this? why not just reactor.callLater(3, checkForSanity) ? Sergio Trejo wrote:

I'm trying to be a good soldier by heeding the warning issued by the Twisted gods warning strongly *not* to use defer.Deferred's setTimeout() and instead using reactor.callLater

I've looked at the API for twisted.internet.defer.Deferred.callback and twisted.internet.default.SelectReactor.callLater (which refers one to see twisted.internet.interfaces.IReactorTime.callLater which I have also read). I don't understand why at least one args object must always be supplied to reactor.callLater, as in:

reactor.callLater(3, d.callback, "an unused arg")

even though the callback function:

d.addCallback(checkForSanity)

receives no args:

def checkForSanity(): print "this is a sanity test"

In order to get the reactor.callLater to perform the callback, I had to pass in at least one arg:

def checkForSanity(ignoreMe): print "this is a sanity test" d = defer.Deferred() d.addCallback(checkForSanity) reactor.callLater(3, d.callback, "ignore me")

There's sure to be a good reason why, perhaps something utterly obvious to most but as a newbie I'm still trying to grok as much as possible where needed. Thanks for any clarification.

Serg

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