[users at bb.net] Another anecdote from 0.9.2 scheduler modification.

[Neil Gilmore]

Hi all,

As always, thanks for the advice.

I think I've found an irregularity in ForceScheduler (naturally, this 
would be netter in trac...). If nothing else, it renders some of the 
documentation on Schedulers to be incorrect (I really can't say which 
way this should fall). I've run into it while adding back 
reconfiguration to the Force Scheduler.

It concerns the 'properties' argument. On the one hand, BaseScheduler 
expects this to be a dictionary, and will in fact force it to an empty 
dictionary if it isn't passed in. One the other, ForceScheduler expects 
it to be a list, and will force it to a list if it isn't passed in. 
Additionally, at least in 0.9.2, ForceScheduler.__init__() does not pass 
its properties argument to BaseScheduler.__init__(). Now, it certainly 
could be that ForceScheduler really doesn't implement the common 
'properties', preferring its own instead.

But this leads to problems when we attempt to eliminate the __init__() 
functions in favor of CheckConfig() and reconfigService(). We should 
preserve the ForceScheduler.__init__() properties (the list kind) in 
order to check them in checkConfig() and assign them in 
reconfigService(). But BaseScheduler already has 'properties' (the 
dictionary kind).

I think for now, I'll be introducing something like forceProperties in 
__init__() which will end up passed in kwargs. This won't affect the 
current interface to ForceScheduler, and will preserve the original 
properties (the list kind) to be used later. checkConfig and 
reconfigService will use it.

I'll also point out that ForceScheduler's check for name being a unicode 
string is incorrect. If passed a unicode string, it fails. The type 
checked against is 'str', which is not 'unicode'.

So far, I can start a buildbot with any of the variety of schedulers. I 
do need to test reconfiguration to make sure everything actually 
reconfigures.

Then I'll need to submit it and hope the devs like it.

Neil Gilmore
grammatech.com