00mjk / easyraft

Easy to use Raft library to make your app distributed, highly available and fault-tolerant

An easy to use customizable library to make your Go application Distributed, Highly available, Fault Tolerant etc... using Hashicorp's Raft library which implements the Raft Consensus Algorithm.

Features

• Configure and start a fully functional Raft node by writing ~10 lines of code
• Automatic Node discovery (nodes are discovering each other using Discovery method)
  1. Built-in discovery methods:
     1. Static Discovery (having a fixed list of nodes addresses)
     2. mDNS Discovery for local network node discovery
     3. Kubernetes discovery
• Cloud Native because of kubernetes discovery and easy to load balance features
• Automatic forward to leader - you can contact any node to perform operations, everything will be forwarded to the actual leader node
• Node monitoring/removal - the nodes are monitoring each other and if there are some failures then the offline nodes get removed automatically from cluster
• Simplified state machine - there is an already implemented generic state machine which handles the basic operations and routes requests to State Machine Services (see Examples)
• All layers are customizable - you can select or implement your own State Machine Service, Message Serializer and Discovery Method
• gRPC transport layer - the internal communications are done through gRPC based communication, if needed you can add your own services

Note: snapshots are not supported at the moment, will be handled at later point Note: at the moment the communication between nodes are insecure, I recommend to not expose that port

Get Started

You can create a simple EasyRaft Node with local mDNS discovery, an in-memory Map service and MsgPack as serializer(this is the only one built-in at the moment)

import (
"github.com/ksrichard/easyraft"
"github.com/ksrichard/easyraft/discovery"
"github.com/ksrichard/easyraft/fsm"
"github.com/ksrichard/easyraft/serializer"
)

func main() {
    raftPort := 5000
    discoveryPort := 5001
    dataDir := "s1"
    node, err := easyraft.NewNode(
        raftPort,
        discoveryPort,
        dataDir,
        []fsm.FSMService{fsm.NewInMemoryMapService()},
        serializer.NewMsgPackSerializer(),
        discovery.NewMDNSDiscovery(),
        false,
    )
    
    if err != nil {
        panic(err)
    }
    stoppedCh, err := node.Start()
    if err != nil {
        panic(err)
    }
    defer node.Stop()
}

Examples

Examples can be found in the examples directory

Build

To regenerate gRPC code and install dependencies simply run make install

TODO

• Add more examples
• Test coverage
• Secure communication between nodes (SSL/TLS)
• Backup/Restore backup handling
• Allow configuration option to pass any custom raft.FSM