consistenthash

Documentation

Overview

Package consistenthash provides a ring hash implementation.

Index

• Variables
• type Ring
  • func NewRing(replicas int, nodes ...string) (*Ring, error)
  • func (m *Ring) Get(key string) string

Variables

var (
	// ErrNoNodes is returned when a hash is requested containing no nodes.
	ErrNoNodes = errors.New(
		"there must be at least one node, otherwise keys cannot be mapped")
)

Types

type Ring

type Ring struct {
	// contains filtered or unexported fields
}

Ring is an immutable ring hash.

func NewRing

func NewRing(replicas int, nodes ...string) (*Ring, error)

NewRing creates a new consistent hash ring, initialised with the provided nodes (order does not matter). When the node list changes, a new hash should be created; updating a hash in place is not supported, as it would drastically increase the time complexity of lookups, which are expected to be the vastly more common operation. Replicas must be at least one, and should be greater when there are few nodes in order to reduce the variance in load amongst them. 50 is usually a reasonable choice.

func (*Ring) Get

func (m *Ring) Get(key string) string

Get returns the node in the hash that owns the provided key.