leaderless

Package leaderless implements leader election without the need for coordination. It does this using a highly stable set of peers and a hash ring. Since we know that each node shares the same view of the world, then we know that the computed hash ring will be the same between instances. However, if peer knowledge is not stable (for example, members come and go freely) then leaderless can result in a split brain state where some nodes share a different view of the world until the other nodes "catch up".

This package is loosely inspired by Uber's ringpop system which seems like it's used quite extensively.

import go.pitz.tech/lib/leaderless

Usage

type Director

type Director struct {
}

Director contains logic for routing requests to a leader or set of replicas.

func New

func New() *Director

New returns a Director that can aid in the coordination of work within a cluster.

func (*Director) GetLeader

func (d *Director) GetLeader(key string) (string, bool)

GetLeader returns the current "leader" for a given key.

func (*Director) GetReplicas

func (d *Director) GetReplicas(key string, replicas int) ([]string, bool)

GetReplicas returns a list of peers to replicate information to given a key.

func (*Director) Start

func (d *Director) Start(ctx context.Context, membership *cluster.Membership) error

Start begins the director by observing membership changes in the cluster.