UDP Gossip Node

A lightweight, fault-tolerant peer-to-peer node framework over UDP, implementing heartbeat-based peer discovery, gossip propagation, and HMAC-signed messaging. Designed as a foundation for distributed consensus experiments and minimal Raft-like systems.

Features

• UDP-based communication for low-latency, connectionless messaging
• Peer discovery and heartbeat gossip with automatic dead peer detection
• HMAC-signed JSON messages for message authenticity
• Simple node structure with follower/candidate/leader roles
• Concurrency-safe peer list management

Getting Started

Prerequisites

• Go 1.21+
• go.uber.org/zap for logging

Build

go build -o gossip-node cmd/main.go

Run

# Start first node
./gossip-node -addr 127.0.0.1:4100

# Start second node with first node as seed
./gossip-node -addr 127.0.0.1:4101 -seed 127.0.0.1:4100

Usage

• Nodes automatically exchange heartbeat messages and gossip peer lists.
• Dead peers are automatically detected using DeadPeerThreshold.
• Future updates may include leader election and log replication.

Code Overview

• Node — Represents a node with ID, role, and peer list
• Peer — Represents a peer node with last seen timestamp
• Message — HMAC-signed JSON messages for communication
• HBDetails — Heartbeat payload including peer information
• hearbeat() — Periodically sends heartbeats to all known peers
• recvloop() — Listens for incoming messages and updates peers