consistent

README

Package consistent

A Golang implementation of Consistent Hashing and Consistent Hashing With Bounded Loads.

https://en.wikipedia.org/wiki/Consistent_hashing

https://research.googleblog.com/2017/04/consistent-hashing-with-bounded-loads.html

Initially forked from github.com/lafikl/consistent

Docs

https://godoc.org/github.com/akram/go-consistent-hashing-with-bounded-loads

License

MIT License

Copyright (c) 2017 Khalid Lafi

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

Documentation

Overview

An implementation of Consistent Hashing and Consistent Hashing With Bounded Loads.

https://en.wikipedia.org/wiki/Consistent_hashing

https://research.googleblog.com/2017/04/consistent-hashing-with-bounded-loads.html

Index

• Variables
• type Consistent
  • func New() *Consistent
  • func NewWithReplicationFactor(replicationFactor int) *Consistent
  • func (c *Consistent) Add(server string)
  • func (c *Consistent) Done(server string)
  • func (c *Consistent) Get(client string) (string, error)
  • func (c *Consistent) GetLeast(client string) (string, error)
  • func (c *Consistent) GetLoads() map[string]int64
  • func (c *Consistent) Inc(server string)
  • func (c *Consistent) MaxLoad() int64
  • func (c *Consistent) Remove(server string) bool
  • func (c *Consistent) Servers() (servers []string)
  • func (c *Consistent) UpdateLoad(server string, load int64)
• type Host

Variables

var ErrNoHosts = errors.New("no hosts added")

Types

type Consistent

type Consistent struct {
	sync.RWMutex
	// contains filtered or unexported fields
}

func New

func New() *Consistent

func NewWithReplicationFactor

func NewWithReplicationFactor(replicationFactor int) *Consistent

func (*Consistent) Add

func (c *Consistent) Add(server string)

func (*Consistent) Done

func (c *Consistent) Done(server string)

Decrements the load of host by 1

should only be used with if you obtained a host with GetLeast

func (*Consistent) Get

func (c *Consistent) Get(client string) (string, error)

Get returns the server that owns the given client. As described in https://en.wikipedia.org/wiki/Consistent_hashing It returns ErrNoHosts if the ring has no servers in it.

func (*Consistent) GetLeast

func (c *Consistent) GetLeast(client string) (string, error)

GetLeast returns the least loaded host that can serve the key. It uses Consistent Hashing With Bounded loads. https://research.googleblog.com/2017/04/consistent-hashing-with-bounded-loads.html It returns ErrNoHosts if the ring has no hosts in it.

func (*Consistent) GetLoads

func (c *Consistent) GetLoads() map[string]int64

Returns the loads of all the hosts

func (*Consistent) Inc

func (c *Consistent) Inc(server string)

Increments the load of host by 1

should only be used with if you obtained a host with GetLeast

func (*Consistent) MaxLoad

func (c *Consistent) MaxLoad() int64

Returns the maximum load of the single host which is: (total_load/number_of_hosts)*1.25 total_load = is the total number of active requests served by hosts for more info: https://research.googleblog.com/2017/04/consistent-hashing-with-bounded-loads.html

func (*Consistent) Remove

func (c *Consistent) Remove(server string) bool

Deletes host from the ring

func (*Consistent) Servers

func (c *Consistent) Servers() (servers []string)

Return the list of servers in the ring

func (*Consistent) UpdateLoad

func (c *Consistent) UpdateLoad(server string, load int64)

Sets the load of `server` to the given `load`

type Host

type Host struct {
	Name string
	Load int64
}