sml

Documentation

Overview

Simple Memberlist is a wrapper around hashicorp memberlist, that leverages the gossip protocol and exposes a simpler interface. Main features include: automatic rejoining a list of cluster anchors, providing a channel of node changes, encoding and decoding of node metadata, plus caching of decoded metadata.

Index

• func NewTransport(config *memberlist.NetTransportConfig, logger logr.Logger) (*instrumentedTransport, error)
• type ClusterData
• type ClusterState
• type Instrumentation
• type Memberlist
  • func New[M any, S any, MP MetaPointer[M], SP StatePointer[S]](nodeName string, nodeIP net.IP, port int, anchors []string, key []byte, ...) *Memberlist[M, S, MP, SP]
  • func (m *Memberlist[M, S, MP, SP]) Events() <-chan struct{}
  • func (m *Memberlist[M, S, MP, SP]) GetBroadcasts(overhead, limit int) [][]byte
  • func (m *Memberlist[M, S, MP, SP]) Instr() Instrumentation
  • func (m *Memberlist[M, S, MP, SP]) LocalState(join bool) []byte
  • func (m *Memberlist[M, S, MP, SP]) MergeRemoteState(buf []byte, join bool)
  • func (m *Memberlist[M, S, MP, SP]) NodeMeta(limit int) []byte
  • func (m *Memberlist[M, S, MP, SP]) Nodes() []MP
  • func (m *Memberlist[M, S, MP, SP]) NotifyConflict(node, other *memberlist.Node)
  • func (m *Memberlist[M, S, MP, SP]) NotifyJoin(n *memberlist.Node)
  • func (m *Memberlist[M, S, MP, SP]) NotifyLeave(n *memberlist.Node)
  • func (m *Memberlist[M, S, MP, SP]) NotifyMsg([]byte)
  • func (m *Memberlist[M, S, MP, SP]) NotifyUpdate(n *memberlist.Node)
  • func (m *Memberlist[M, S, MP, SP]) Run() error
  • func (m *Memberlist[M, S, MP, SP]) Start() error
  • func (m *Memberlist[M, S, MP, SP]) Update()
• type MetaPointer
• type NodeMeta
• type StatePointer

Functions

func NewTransport

func NewTransport(config *memberlist.NetTransportConfig, logger logr.Logger) (*instrumentedTransport, error)

Create a new instrumented transport

Types

type ClusterData

type ClusterData interface {
	Encode() ([]byte, error)
	Decode([]byte) error
	String() string
}

Cluster data can be encoded and decoded to bytes, required by Memberlist wire protocol

type ClusterState

type ClusterState interface {
	ClusterData
	Merge([]byte) (bool, error)
}

Cluster state is node data that can be merged, crdt-style

type Instrumentation

type Instrumentation interface {
	// Instrumentation data was updated
	Updates() <-chan struct{}
	// Get the current minimum observed path MTU with any other node in the
	// cluster, useful for setting cluster-wide MTU
	MinMTU() int
}

type Memberlist

type Memberlist[M any, S any, MP MetaPointer[M], SP StatePointer[S]] struct {
	Meta  MP
	State SP
	// contains filtered or unexported fields
}

func New

func New[M any, S any, MP MetaPointer[M], SP StatePointer[S]](nodeName string, nodeIP net.IP, port int, anchors []string, key []byte, logger logr.Logger) *Memberlist[M, S, MP, SP]

func (*Memberlist[M, S, MP, SP]) Events

func (m *Memberlist[M, S, MP, SP]) Events() <-chan struct{}

Get a channel for notifications of network changes

func (*Memberlist[M, S, MP, SP]) GetBroadcasts

func (m *Memberlist[M, S, MP, SP]) GetBroadcasts(overhead, limit int) [][]byte

Cluster implements the memberlist.Delegate interface

func (*Memberlist[M, S, MP, SP]) Instr

func (m *Memberlist[M, S, MP, SP]) Instr() Instrumentation

Get the instrumentation interface

func (*Memberlist[M, S, MP, SP]) LocalState

func (m *Memberlist[M, S, MP, SP]) LocalState(join bool) []byte

Cluster implements the memberlist.Delegate interface

func (*Memberlist[M, S, MP, SP]) MergeRemoteState

func (m *Memberlist[M, S, MP, SP]) MergeRemoteState(buf []byte, join bool)

Clutser implements the memberlist.Delegate interface

func (*Memberlist[M, S, MP, SP]) NodeMeta

func (m *Memberlist[M, S, MP, SP]) NodeMeta(limit int) []byte

Cluter implements the memberlist.Delegate interface

func (*Memberlist[M, S, MP, SP]) Nodes

func (m *Memberlist[M, S, MP, SP]) Nodes() []MP

Get the list of current cluster nodes

func (*Memberlist[M, S, MP, SP]) NotifyConflict

func (m *Memberlist[M, S, MP, SP]) NotifyConflict(node, other *memberlist.Node)

Cluster implements the memberlist.Delegate interface

func (*Memberlist[M, S, MP, SP]) NotifyJoin

func (m *Memberlist[M, S, MP, SP]) NotifyJoin(n *memberlist.Node)

Cluster implements the EventDelegate interface

func (*Memberlist[M, S, MP, SP]) NotifyLeave

func (m *Memberlist[M, S, MP, SP]) NotifyLeave(n *memberlist.Node)

Node implements the EventDelegate interface

func (*Memberlist[M, S, MP, SP]) NotifyMsg

func (m *Memberlist[M, S, MP, SP]) NotifyMsg([]byte)

Clutser implements the memberlist.Delegate interface

func (*Memberlist[M, S, MP, SP]) NotifyUpdate

func (m *Memberlist[M, S, MP, SP]) NotifyUpdate(n *memberlist.Node)

Node implements the EventDelegate interface

func (*Memberlist[M, S, MP, SP]) Run

func (m *Memberlist[M, S, MP, SP]) Run() error

Run the memberlist cluster main loop, that awaits cluster changes, maintains the cluster state and propagates information to channels

func (*Memberlist[M, S, MP, SP]) Start

func (m *Memberlist[M, S, MP, SP]) Start() error

Start the memberlist cluster by listening on main sockets

func (*Memberlist[M, S, MP, SP]) Update

func (m *Memberlist[M, S, MP, SP]) Update()

Update the current node

type MetaPointer

type MetaPointer[M any] interface {
	NodeMeta
	*M
}

Pointer type to node meta, for generics trickery This is required because we create meta instances while the interface specification requires pointer receivers for decoding

type NodeMeta

type NodeMeta interface {
	ClusterData
}

type StatePointer

type StatePointer[S any] interface {
	ClusterState
	*S
}

Pointer type to cluster state, for generics trickery This is required because we create state instances while the interface specification requires pointer receivers for decoding and merging