publish-subscribe pattern window publisher python publisher py with each of the windows running its processlet' enter message into the publisher window and see what happens we see the dispatcher received the message and sent it to the subscriber listening on port subscribing [ /aug/ : : "post /rpc http/ sending messagetopicmessagetopic payloadthis is an awesome payload [ /aug/ : : "post /rpc http/ the subscriber receives the message and prints the message listening on port messagethis is an awesome payload [ /aug/ : : "post /rpc http/ arting shots the pubsub pattern has many usesespecially as systems expand and grow into the cloud this process of growingexpandingand evolving is one of the reasons chose to start with the simple implementation of the observer pattern we saw in and then move through the steps of improved design to the final full pubsub implementation this is the same pattern of growth that you will repeat in your own projects simple project grows little bitand with every bit of functionality that you addyou should be asking yourself what ideas from this bookor elsewherewill make this project easier to maintain in the future once you hit upon such an ideado not hesitate--improve the code you will quickly come to realize that bit of time spent at the tail end of project will make your development time significantly shorter in future phases of the project