hashring-go

This is a library that provides consistent hashing with bounded loads.

Overview

The package makes sure that all the keys are distributed uniformly and we operate consistently. We offer all the standard functionality such as Add, Remove and Get operations. The user can configure what the ReplicationFactor and PartitionCount should be -- bear in mind, that these values can not be chaned after initializing the hashring object with them. Before rushing in, try to find a combination of values that suits your needs -- also make sure, that your hashing function is uniformly distributing the values around the ring for best performance.

Contributing

Before creating a pull request, create an issue first.

Install

go get github.com/odvarkadaniel/hashring-go

You can find some usage examples in the examples folder.

Documentation

To see a list of all functions, please visit pkg.go.dev.

Examples

As mentioned before, more examples can be seen in the examples folder.

package main

import (
	"fmt"
	"hash/fnv"

	"github.com/odvarkadaniel/hashring-go"
)

type Server string

func (s *Server) String() string {
	return string(*s)
}

func Sum64(data []byte) uint64 {
	h := fnv.New64()
	h.Write(data)
	return h.Sum64()
}

func main() {
	cfg := hashring.Config{
		PartitionCount:    23,
		ReplicationFactor: 20,
		Hasher:            Sum64,
	}

	buckets := []hashring.Bucket{}

    // Create our fake servers
	for i := 0; i < 8; i++ {
		b := Server(fmt.Sprintf("node%d", i))
		buckets = append(buckets, &b)
	}

    // Create a new HashRing object
	ring := hashring.New(cfg, buckets)

	key := "test-key"
    // Get a bucket that holds the key
	bucket := ring.Get(key)

	// This should print node7.
	fmt.Println(bucket.String())
}

License

This project uses MIT LICENSE, for more details, please see the LICENSE file.