Raft Chat

A peer-to-peer Raft chat application that provides a more durable and private platform during disaster scenarios. By utilizing the Raft concensus protocol, we have a decentralized way for having consistent chat messages across devices/users that can handle crash faults. NuRaft, a lightweight C++ Raft library written by Gene Zhang and Jung-Sang Ahn of eBay, was used as a foundation. (The authors based their work on prior work by Andy Chen)

Code Structure

.
├── NuRaft 
|   ├── examples 
|   │   ├── central_server.hxx           # Central Server API Header
|   │   ├── central_server.cxx           # Central Server API Implementation
|   │   ├── central_server_common.hxx    # Contains shared CS functions & variables
|   │   ├── example_common.hxx           # Helper functions and main user interface loop
|   │   ├── echo
|   |   │   ├── echo_server.cxx          # Entry point for app
|   |   │   ├── echo_state_machine.hxx   # Modified for evaluations
|   |   |   └── ... 
|   │   └── ...
|   ├── include 
|   │   ├── libnuraft                    # Controls forwarding from follower to leaders
|   │   └── ...
|   ├── blocking_tcp_echo_server.cpp     # Central Server program
|   └── ...
└── ...

The Raft Chat project is comprised of the chat app and the central server. All related files currently reside in the NuRaft folder. (those related to the app are under examples and include, while the central server file is at the base)

Getting Started

These instructions will get you a copy of the project up and running on your local machine and/or remote servers for development and testing purposes.

Prerequisites

The following dependencies are required:

  build-essential \
  zlib1g          \
  zlib1g-dev      \
  cmake           \
  openssl         \
  libssl-dev 

Installation

You must first install NuRaft

Then you must build the central server code:

  cd NuRaft
  make asio_server

Deployment

To run a lobby of clients, you must run this on seperate machines:

  cd NuRaft/build/examples
  ./echo_server [server number] [IP Address]:[port number]

Then you want to run the central server:

  cd NuRaft
  ./asio_server [port number]

This allows for auto joining between clients and lobbies

For testing on localhost, can type in separate terminal windows:

./echo_server 1 localhost:10001  
./echo_server 2 localhost:10002

You will then be greeted by a prompt. As this is run locally, the central server will not be active. To add other clients to the lobby, type:

add [server number] [IP Address]

Server that adds others is initial leader (only leader can add).

To send message type:

msg [message text]

To leave chat, type:

leave