pitraft

Overview

pitraft is an implementation of the game Pit using the distributed consensus protocol Raft.

Code Architecture

This repository contains code for the following:

1. Running a server for pitraft that implements the Raft distributed consensus protocol for playing Pit.
2. Running a client to play Pit by communicating to this server.
3. An implementation of Paxos separate from pitraft.

Pit Server

Note: Much of the code (especially in main.go and server.go is borrowed from raftd), which implements a key-value store in distributed fashion. Our main change here is to adapt this to playing Pit.

The main file here is main.go in the top-level of the directory. Upon running, it starts a RaftServer (see Raft's source code) and starts an HTTP Server that accepts certain requests, such as proposing trades. The code to start this server is mainly in server/server.go.

Requests are mainly read or write requests. If the server receives a read request (e.g. to see the outstanding trades), it simply returns an HTTP Response with that information. If the server receives a write request (e.g. to propose a trade), it runs a Command that each server machine applies to itself through Raft's distributed consensus protocol. See consensus/ for examples. The server data pertaining to each player's cards and to existing trades; the models for those objects can be found in db/ and tradedb/.

Pit Client

The main file here is server/server.go. Upon running, it starts a command line client through which the player can issue commands to read (e.g. to see the state of outstanding trades) and to write (e.g. to propose a new trade). Clients may join and leave the game at any time; they each start with a fixed number of resources.

Paxos Implementation

Running

To start a game and play, do the following:

1. Install Go.

2. Get the source code via go get https://github.com/abliu/pitraft.

3. To start running a leader machine for the distributed consensus algorithm, first make a directory in which you want to store log files. Then, from command line, execute:

      go run main.go -p 4001 <your_log_file_folder>```
   

4. To start running a follower machine for the distributed consensus algorithm, first make a directory in which you want to store log files. Then, from command line, execute:

      go run main.go -p <desired_port> -join <host_address:port>
      <your_log_file_folder>```
   where `host_address:port` denotes the leader's address and port number,
   specified in -p in #3.
   

5. To start running a client machine that plays Pit, execute:

      go run client.go -u <host_address:port>```
   where `host_address:port` again denotes the leader's address and port number,
   specified in -p in #3.
   

6. When you are playing on the client machine, you will be playing through a command line shell. You can enter

   propose [resource] [amount]: propose a trade of [amount] of [resource]; returns tradeID and stats on trade proposed;

   cancel [tradeID]: cancel a trade with ID [tradeID];

   getState: get (my own) state;

   view: view all live trades