plenum

README

plenum

A package for membership and consensus that uses Serf and Raft.

Configuration

• PLENUM_DEBUG: Exposes Serf and Raft logging to stdout

Usage

Package

bindAddress := "10.0.0.10"
bindPort := 6789
members := []string{"10.0.0.20:6789", "10.0.0.30:6789"}

p, err := plenum.Convene(nil, bindAddress, bindPort, members)
if err != nil {
  log.Fatal(err)
}
go p.Procede()

// Wait for, and act on leader designation
go func(*plenum.Plenum) {
  for <-p.IsLeader {
    fmt.Println("Members: ", p.Members())
    fmt.Println("Leader: ", p.Consensus())
    fmt.Println("Elected leader!")
  }
}(p)

Example CLI

1. Start three members, in three terminals, with different ports:

# Terminal A
go run cmd/plenum/main.go -port 1111

# Terminal B
go run cmd/plenum/main.go -port 2222 -members=127.0.0.1:1111

# Terminal C
go run cmd/plenum/main.go -port 3333 -members=127.0.0.1:2222

1. Kill the member (CTRL+C) in terminal A, and watch consensus adjust.

2. Rejoin terminal A with:

go run cmd/plenum/main.go -port 1111 -members=127.0.0.1:2222

Each member also starts an HTTP listener with the followings routes for discovery:

• /members: Returns list of active membership
• /leader: Returns active leader

Documentation

Index

• type Plenum
  • func Convene(logger *log.Logger, address string, port int, members []string) (*Plenum, error)
  • func (p *Plenum) Consensus() string
  • func (p *Plenum) Membership() []string
  • func (p *Plenum) Procede()

Types

type Plenum

type Plenum struct {
	Procedures chan serf.Event // Exposed channel for handling Serf events

	IsLeader chan bool      // Exposed channel for determining leadership
	IsClosed chan os.Signal // Exposed channel for graceful shutdown
	// contains filtered or unexported fields
}

func Convene

func Convene(
	logger *log.Logger,
	address string,
	port int,
	members []string,
) (*Plenum, error)

Convene creates a new membership and consensus group

func (*Plenum) Consensus

func (p *Plenum) Consensus() string

Consensus returns the current leader of the plenum

func (*Plenum) Membership

func (p *Plenum) Membership() []string

Membership returns the current membership list

func (*Plenum) Procede

func (p *Plenum) Procede()

Procede starts the core consensus loop