smplchat

This project demonstrates that a fully distributed, fault-tolerant chat system can be built with a simple Gossip-style messaging algorithm and UDP networking.

graph TB
    N1((Node 1))
    N2((Node 2))
    N3((Node 3))
    N4((New Node))
    
    N4 -->|"/join IP"| N2
    N2 -->|"IPs + History"| N4
    N2 -.-> N1
    N2 -.-> N3
    N1 -.-> N2
    N3 -.-> N2
    N3 -.-> N1
    N1 -.-> N3

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Operation

Just run the app

Application can be run directly from src directory like:

python3 -m smplchat

Installation

Installation can be done with pip (or pipx):

pip install <project folder>

And then run app normally:

smplchat

Development Environment

Installation

Development environment with dependencies can be installed with poetry:

poetry install

Running

Run the app inside development environment via:

poetry run smplchat

Testing

Pytest and other tools can be run like:

poetry run pytest

Development related commands like pytest, coverage, pylint can also be run through dev.sh which is also used in the GitHub workflow.

Operating multiple clients locally

You can test multiple clients on your own locally with Docker running.

In root, run this to build a Docker image of the app:

docker build -t smplchat .

This will build an image but not start any containers yet.

Then in however many terminals with this command we start a container and also start the app in it:

docker run -it --rm smplchat

All the containers get their own IP that you can use for the /join command. Use flag " -e SMPLCHAT_DEBUG=1" before smplchat for debug mode.

You can run the build command again for any code changes, but if you want to remove the image, run:

docker rmi smplchat

Tweaking settings

Settings can be modified in two places. Directly from settings.py file or by environment variables.

Environment variables have SMPLCHAT_ prefix.

For example adjust settings so that gossipping relays message to 5 others and stops after it:

SMPLCHAT_GOSSIP_FANOUT=5 SMPLCHAT_RELAY_SEEN_LIMIT=1 smplchat