simple pub/sub

[Steve Howell]

On Jan 21, 9:03 am, Adam Tauno Williams <awill... at opengroupware.us>
wrote:
> On Thu, 2010-01-21 at 08:54 -0800, Steve Howell wrote:
> > Hi, I'm looking for ideas on building a simple architecture that
> > allows a bunch of independent Python processes to exchange data using
> > files and perform calculations.
> > One Python program would be collecting data from boat instruments on a
> > serial port, then writing that info out to a file, and also
> > transmitting data to instruments as needed (again through the serial
> > port).  It would be the most complex program in terms of having to
> > poll file descriptors, or something similar, but I want to limit its
> > job to pure communication handling.
>
> This should be pretty easy using multiprocessing.  In OpenGroupware
> Coils we have a master process
> <http://coils.hg.sourceforge.net/hgweb/coils/coils/file/2c7847ef0527/s...> that spins up children (workers, that each provide a distinct service) it opens a Pipe to each child to send messages to the child and a Queue from which it reads [all children (clients) write to the Queue and listen on their Pipe].  Then the master just listens on its pipe and forwards messages from children to other children.
>
> All children are Service objects
> <http://coils.hg.sourceforge.net/hgweb/coils/coils/file/2c7847ef0527/s...>.  Then implementing a new service [type of worker] is as easy as (our brutally simple pubsub service) <http://coils.hg.sourceforge.net/hgweb/coils/coils/file/2c7847ef0527/s...>
>
> Hope that helps.
>

It does indeed!  I'm gonna try this approach for now.