COMP90020-Raft-API

Team

Written by team Handshake

Project Description

This is the backend for team Handshake of comp90020 Distributed Algorithm, implementing raft algorithm

QUICK START FOR WINDOWS

run start.cmd

please make sure you add java 15 and maven into your System Environment Variables

Raft Structure

├───main
│   ├───java
│   │   └───com
│   │       └───handshake
│   │           └───raft
│   │               ├───common
│   │               │   ├───constants
│   │               │   ├───exceptions
│   │               │   ├───response
│   │               │   └───utils
│   │               ├───config
│   │               ├───controller
│   │               ├───dao
│   │               ├───raftServer
│   │               │   ├───log
│   │               │   │   └───Impl
│   │               │   ├───proto
│   │               │   │   └───Impl
│   │               │   ├───rpc
│   │               │   ├───service
│   │               │   │   └───Impl
│   │               │   └───ThreadPool
│   │               ├───service
│   │               │   └───Impl
│   │               └───test
│   └───resources
│       ├───static
│       └───templates
└───test
└───java
└───com
└───handshake
└───raft

It is a Springboot application with built-in raft server.

Controller package handles the request from web.

Service package handles the actions on database.

All things about raft are included in raftServer package exclude the configuration.

Configurations are in config package.

raft

raftServer
│   AddSelf.java
│   Election.java
│   ElectionTimer.java
│   Heartbeat.java
│   LifeCycle.java
│   Node.java
│   Role.java
│   Status.java
│
├───log
│   │   LogDatabase.java
│   │   LogInfo.java
│   │   LogSystem.java
│   │
│   └───Impl
│           LogDatabaseImpl.java
│           LogSystemImpl.java
│
├───proto
│   │   AddPeerParam.java
│   │   AddPeerResult.java
│   │   AppendEntriesParam.java
│   │   AppendEntriesResult.java
│   │   Command.java
│   │   GetClusterInfoParam.java
│   │   GetClusterInfoResult.java
│   │   LogEntry.java
│   │   RemovePeerParam.java
│   │   RemovePeerResult.java
│   │   RequestVoteParam.java
│   │   RequestVoteResult.java
│   │   ServerInfo.java
│   │
│   └───Impl
│           ChangeConfigurationCommand.java
│           CreateBookCommand.java
│           UploadChapterCommand.java
│
├───rpc
│       RpcClient.java
│       RpcServiceProvider.java
│
├───service
│   │   RaftConsensusService.java
│   │
│   └───Impl
│           RaftConsensusServiceImpl.java
│
└───ThreadPool
        RaftThreadPool.java

Basic functions

ThreadPool package provides manages the threads;

service package provides the services for rpc server and clients.

rpc package is used for rpc communication between nodes.

proto package defines the variable transmitted between nodes,

log package manages the log for raft.

node

Node first start as follower and start ElectionTimer.

When election timeout elapses, the node change to candidate and run Election.

When node receive majority votes, it becomes leader. It will stop the ElectionTimer and start Heartbeat.

When node is started as new server, it will try to add itself to cluster using AddSelf

Environment

download OpenJDK 15

download Maven 3.8.5

Configuration

if you want to set the configuration, create a file name application-1.yml

Then add--spring.config.location=classpath:/application-1.yaml to Environment Variables

basic node application-1.yml

server:
  port: 5000

# common log level
logging:
  level:
    root: INFO
  # where to save system log
  file:
    name: "log1.log"


raft:
  # raft servers
  servers:
    - "localhost:5001"
  # the spring ip and port for this raft servers
  serversSpringAddress:
    - "localhost:5000"
  # self address for raft server
  self: "localhost:5001"
  electionTimeout: 7000
  heartBeatFrequent: 5000
  clientTimeout: 10000
  # where to save raft log
  log: "logs/log1.json"
  # where try to add itself to cluster when start
  newServer: false

# where to save books
library:
  address: "libraries/library1"

spring:
  mvc:
    pathmatch:
      matching-strategy: ANT_PATH_MATCHER

Other nodes' property file

need to include at least one node in cluster

Here we include "localhost:5001"

new nodeapplication-2.yml

server:
  port: 9000

# common log level
logging:
  level:
    root: INFO
  file:
    name: "log2.log"

raft:
  servers:
    # node already in cluster
    - "localhost:5001"
    #self
    - "localhost:9001"
  serversSpringAddress:
    # Spring address of node already in cluster
    - "localhost:5000"
    #self Spring address
    - "localhost:9000"
  self: "localhost:9001"
  electionTimeout: 15000
  heartBeatFrequent: 5000
  clientTimeout: 10000
  log: "logs/log2.json"
  # try to add itself to cluster
  newServer: true

library:
  address: "libraries/library2"

spring:
  mvc:
    pathmatch:
      matching-strategy: ANT_PATH_MATCHER

We already provided some pre-configured property file under src/main/resource.

Basic multi-server

We also include a basic implementation for basic multi-servers which removed all functionality in raft.

It is in bacis modules