PubSub-system

The main purpose for the project was to implement a simple Pub/Sub system, similar to Apache Kafka and RabbitMQ. The current implementation supports only 1 publisher and 1 subscriber and not multiple publishers and subscribers. The code is organized in 4 modules, broker.py, publisher.py, subscriber.py for the broker, the publisher and the subscriber respectively and the last one is my_sock.py. Of course, there are detailed comments on each module describing the whole procedure.

A Publisher/Subscriber system is a form of asynchronous service-to-service communication used in serverless and microservices architectures. In a pub/sub model, any message published to a topic is immediately received by all of the subscribers to the topic. Pub/sub messaging can be used to enable event-driven architectures, or to decouple applications in order to increase performance, reliability and scalability.

User instructions

1. Firstly create the respective files for the publisher and subscriber with the commands that will be executed.
2. Run firstly the broker.py file and then the other two files (publisher.py and subscriber.py) with the way that is diplayed below.

Broker

$ python3 broker.py -s s_port -p p_port

For example: $ python3 broker.py -s 9090 -p 9000
  
positional arguments:

    -s               Indicates the port of this specific broker where subscribers will connect.
    -p               Indicates the port of this specific broker where publishers will connect.

Publisher

$ python3 publisher.py -i ID -r sub_port -h broker_IP -p port [-f command_file]

For example: $ python3 publisher.py -i p1 -r 8200 -H localhost -p 9000 -f publisher1.cmd

positional arguments:

    -i               Indicates the id of this publisher.
    -r               Indicates the port of this specific publisher.
    -h               Indicates the IP address of the broker
    -p               Indicates the port of the broker.

optional arguments:

    -f               Indicates a file name where there are commands that the publisher will execute once started and connected 

Subscriber

$ python3 subscriber.py -i ID -r sub_port -h broker_IP -p port [-f command_file]

For example: $ python3 subscriber.py -i s1 -r 8000 -H localhost -p 9090 -f subscriber1.cmd

positional arguments:

    -i               Indicates the id of this subscriber.
    -r               Indicates the port of this specific subscriber.
    -h               Indicates the IP address of the broker
    -p               Indicates the port of the broker.

optional arguments:

    -f               Indicates a file name where there are commands that the subscriber will execute once started and connected to the broker