This is an example of a simple peer-to-peer network of servers that communicate with each other using a gossip protocol. Where a message submitted to a single node is eventually received by all nodes in the network, thereby reaching eventual consistency.
To run this on your own computer, all you need are Python 3.9+ and basic Unix
tooling (specifically kill & xargs).
The project's Python dependencies are managed using Poetry, which you may install yourself manually; or as I prefer, using an environment manager such as Conda.
After cloning this repo, setting up your Python environment (with poetry), you
can use install the Python dependencies with $ poetry install.
All interactions with the network take place through a simple CLI; to see its
full usage details, just run $ poetry run gossip -h. The following are some
select examples.
The start-network command spins up a network of 16 nodes (by default) using
Python's multiprocessing module. Each node runs as a separate Python process
and is exposed at a unique port number ranging from 7001-7016. The default
random network starts with 3 neighbors assinged to each node.
Example usages:
# start the default random network, and plot its topology
poetry run gossip start-network --plot
# start a random network where all nodes have 5 neighboring connections
poetry run gossip start-network random 5
# start a circularly connected network with 32 nodes
poetry run gossip start-network circular --num-nodes=32The stop-network command stops all nodes running in the network.
Usage:
poetry run gossip stop-network
The send-message command sends a message to a node in the network after it
has been started with start-network.
Example usages:
# Send the message "apple" to node 4
poetry run gossip send-message 4 apple
# Send the message "banana" to node 8, where each node broadcasts the message
# 3× to its neighbors
poetry run gossip send-message 8 banana --relays=3The get-messages command returns messages that have been received by a
single node.
Example usages:
# Get all messages received by node 8
poetry run gossip get-messages 8
# Get only unread messages received by node 3
poetry run gossip get-messages 3 unread
# Get only read messages received by node 3, along with their received times,
# showing the shortest path taken
poetry run gossip get-messages 3 read -p --timeThe remove-node command stops a single node in the network.
Example usage:
# Stop node 9
poetry run gossip remove-node 9The list-peers command displays all peers for a single node in the network.
Example usage:
# List the peers for node 5
poetry run gossip list-peers 5This project was created strictly for self-education, with no practical utilities, nor commitments to further development.
See my blog post for a walkthrough.