martdi wrote: > [EMAIL PROTECTED] wrote: > > I have inheirted some existing code, that i will explain in a moment, > > have needed to extend and ultimately should be able to run in threads. > > I've done a bunch of work with python but very little with threads and > > am looking for some pointers on how to implement, and if the lower > > level modules/objects need to be rewritten to use threading.local for > > all local variables. > > > > I have a module that communicates with a hardware device, which reads > > data off of sensors, that can only talk with one controller at a time. > > The controller (my module) needs to (in its simplest form) init, > > configure the device, request data, and write out xml, sleep, repeat. > > > > The new request is that the device needs to be queried until a > > condition is true, and then start requesting data. So an instance of a > > controller needs to be deadicated to a hardware device forever, or > > until the program ends....which ever comes first. > > > > This currently works in a non-threaded version, but only for one device > > at a time, there is a need to create a single windows(yeach) service > > that talks to many of these devices at once. I don't need worker > > threads that handle seperate portions of the entire job, i need a > > single application to spawn multiple processes to run through the > > entire communication from configure to report, sleep until the next > > interval time and run again. The communication could last from 1 > > minute to 10 minutes before it ends. > > > > > > Here is the code layout in pseudocode. > > > > module.Object - controller.Main - handles all socket communications > > > > class subcontroller(controller.Main): > > def __init__(self,id,configurationFile): > > controller.Main.__init__(self) > > // instantiate variables and local objects that handle > > configuration, logic and data output > > > > def configure(self,configurationFile): > > //read configurationFile and configure device > > > > def process(self): > > while 1: > > //based on configuration file, query the device until condition > > is true and then write xml, sleep until time to repeat and run again. > > > > within controller there are 5 objects and subcontroller is a sinlge > > object that loads other objects from the inherited controller.System > > > > I'm trying to figure out how difficult it is going to be to convert > > this to a threaded application. The original controller.Main is built > > to talk to devices in series, never in parallel. so no objects are > > considered to be thread safe, but no instance of any of the objects > > should need to share resources with any other instance of teh same > > object. they would all have unique configuration files and talk to > > devices on unique ip/ports. > > > > on a unix system, forking,while potentially not optimal, would be a > > fine solution, unfortunantely this needs to run on windows. > > > > I know i have left out many details, but hopefully this is enough to at > > least enable some kind soles to lend an opinnion or two. > > > > many thanks > > jd > > Taking a look at asyncore could be worthwhile, but if you want to > implement it with threads, you may be able to do it this way: > > In your main file, from where you start the program, let's call it > main: > > main(self) > Load Required configuration > spawn threads (1 for each controller) > define a queue object from module queue.queue used for communication > with threads > enter an infinite loop that checks for the conditions > once conditions are met, notify the proper thread > > > class ControllerThread(threading.Thread): > def __init__(self): > define a queue here, to process messages from the main > call threading.Thread.__init__(self) > > define method to load config for thread objects > (you might want to pass an argument to init to load your configs > from a file) > (you might also want to pass the queue of the main program to the > thread to send it messages) > define methods to post messages to the queue like read, send to the > machine, stop, ... > > define the run method that is what will be called when you start > your thread. > this method should enter an infinite loop that will check if > something has to be done (check in the queue). > > > > > > hope this might help you > good luck
thanks for the comments. the ControllerThread already extends a class. does this cause problems with classes that must extent threading.Thread. Normally it should not matter, but with threads i'm unsure. Should i just instantiate the object that i'm normally extending in the ControllerThread.__init__, and call it from the self.classthatusedtoextend.method(), or does it not matter. again, thanks. -- http://mail.python.org/mailman/listinfo/python-list
