On Fri, Nov 3, 2017 at 11:00 AM, Dennis Lee Bieber <wlfr...@ix.netcom.com> wrote: > On Thu, 2 Nov 2017 12:32:35 -0800, Israel Brewster <isr...@ravnalaska.net> > declaimed the following: > > >> >>I *must* be thinking about this wrong. Take even a basic chat app that uses >>websockets. Client a, which connected to process 1, sends a message to the >>server. There are three other clients connected, each of which needs to >>receive said message. Given that the way UWSGI works said clients could have >>connected to any one of the worker processes, how can the server push the >>message out to *all* clients? What am I missing here? >> > > This is beginning to sound like a form of publisher/subscriber system. > > http://learning-0mq-with-pyzmq.readthedocs.io/en/latest/pyzmq/patterns/pubsub.html > > Though I have to admit I don't quite see how to set up bidirectional > communication. Having the workers subscribe to receive data from a single > publisher is the easier part -- but how a worker can send data to the > publisher for distribution is not clear; the distribution process can't > subscribe to every worker automatically... Perhaps something using > > http://learning-0mq-with-pyzmq.readthedocs.io/en/latest/pyzmq/devices/forwarder.html > > with each worker making both publisher and subscriber connections. That > could let a worker publish to the forwarder, which then distributes to all > subscribed workers. Might need some way to identify one's own message > (perhaps each worker has a topic, and filters its own topic out of the > return stream).
Websockets are perfect for this sort of thing. It's not difficult.... but you need to have all the clients managed by a single central hub, which is the exact problem the OP faced. Here's a simple websocket app that does this sort of thing: https://github.com/Rosuav/monopoly-open-bid/blob/master/server.py It depends on running a single process to handle every client, and then simply maintains an in-memory list of concurrent clients. (This uses asyncio, but equivalent models using threads are also possible.) ChrisA -- https://mail.python.org/mailman/listinfo/python-list
