🌐 LibP2P Showcase: A Decentralized Chat Application

A proof-of-concept application demonstrating core libp2p concepts through a decentralized chat interface. This project showcases peer discovery mechanisms, pubsub patterns, and real-time network monitoring in a practical P2P environment.

🎯 Project Overview

This application serves as a practical demonstration of key libp2p features:

• Hybrid peer discovery (mDNS + Kademlia DHT)
• PubSub messaging patterns
• Real-time network event monitoring
• P2P connection management
• Protocol negotiation

🔬 Technical Architecture

Peer Discovery Implementation

Local Network Discovery (mDNS)

• Uses multicast DNS for zero-configuration networking
• Automatic peer discovery within the same LAN
• Implementation of the mDNS discovery service interface
• Configurable retry mechanisms and connection handling

type MDNSDiscovery struct {
    host      host.Host
    peerChan  chan peer.AddrInfo
    // ... other fields
}

Global Network Discovery (Kademlia DHT)

• Distributed Hash Table based on Kademlia protocol
• Provides decentralized peer discovery across the internet
• Uses bootstrap nodes for initial network joining
• Implements key-based routing with XOR metric

type DHTDiscovery struct {
    dht       *dht.IpfsDHT
    discovery *routing.RoutingDiscovery
    // ... other fields
}

PubSub Messaging

• Built on libp2p's GossipSub protocol
• Topic-based message routing
• Automatic peer discovery and mesh formation
• Configurable message validation and scoring

Real-Time Network Monitoring

• Event-driven architecture tracking network state
• Monitored events include:
  • Peer connections/disconnections
  • Protocol negotiations
  • NAT traversal status
  • Local/remote address updates
  • Peer identification lifecycle

📊 Performance Metrics

The application provides real-time monitoring of:

// Metrics updated every 60 seconds
- Bandwidth usage (in/out rates)
- PubSub-specific bandwidth
- Connected peers count
- Active protocols
- Memory utilization

🚀 Getting Started

Installation

git clone https://github.com/alejoacosta74/p2p-chat
cd p2p-chat
go build

Command-Line Options

Usage: p2p-chat [flags]

Flags:
  -n, --nickname string   Nickname for chat (default "anonymous")
  -r, --room string      Chat room name (default "default")
  -l, --log string       Log level [debug|info|warn|error] (default "info")
  -f, --logfile string   Log file name (default "chat.log")

Debug Mode

Start with debug logging to see detailed libp2p events:

./p2p-chat --log debug

This enables the real-time event panel showing:

• Protocol negotiations
• Peer discovery events
• Connection state changes
• NAT traversal updates
• DHT operations

🖥️ User Interface

Multi-Panel Terminal UI

1. Message Area: Chat messages with colored nicknames
2. Peer List: Active participants in current room
3. Event Log Panel: Real-time libp2p events and metrics
4. Input Field: Message composition with commands

Debug Panel Features

• Real-time libp2p event streaming
• Network metrics updates
• Protocol negotiation logs
• Peer discovery events
• Connection state changes

🔜 Technical Roadmap

Network Improvements

• Custom peer scoring implementation
• Advanced DHT configuration options
• Alternative transport protocols (QUIC, WebRTC)
• Custom protocol handlers

Monitoring Enhancements

• Custom event subscribers
• Performance profiling tools

Security Features

• Noise protocol integration
• Custom PubSub message validation
• Peer authentication mechanisms
• Rate limiting implementation

🛠️ Development

This project serves as a learning tool for understanding:

• P2P network architecture
• Distributed systems concepts
• libp2p protocol stack
• Network event handling
• Decentralized discovery mechanisms

📚 References

• libp2p Documentation
• Kademlia DHT Paper
• GossipSub Specification
• mDNS RFC

📜 License

MIT License - see LICENSE

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