gms

type ApplicationState ¶

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

ApplicationState is the state associated with a particular node which an application wants to make available to the rest of the nodes in the cluster. Whenever a piece of state needs to be disseminated to the rest of cluster, wrap the state in an instance of ApplicationState and add it to the Gossiper. e.g. if we want to disseminate load information for node A, do the following:

loadState := ApplicationState{<load string>}
gms.GetGossiper().AddAppState("LOAD STATE", loadState)

func NewApplicationState(state string, version int) *ApplicationState

func NewApplicationStateS(state string) *ApplicationState

func (p *ApplicationState) GetState() string

func (p *ApplicationState) GetStateVersion() int

type ArrivalWindow ¶

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

ArrivalWindow ...

func NewArrivalWindow(size int) *ArrivalWindow

func (p *ArrivalWindow) Add(value float64)

func (p *ArrivalWindow) Clear()

func (p *ArrivalWindow) Mean() float64

func (p *ArrivalWindow) P(t float64) float64

func (p *ArrivalWindow) Phi(tnow int64) float64

func (p *ArrivalWindow) Stdev() float64

func (p *ArrivalWindow) Sum() float64

func (p *ArrivalWindow) SumOfDeviations() float64

func (p *ArrivalWindow) Variance() float64

type ByDigest ¶

type ByDigest []*GossipDigest

ByDigest ...

func (p ByDigest) Len() int

func (p ByDigest) Less(i, j int) bool

func (p ByDigest) Swap(i, j int)

type EndPointState ¶

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

EndPointState contains the HeartBeatState and ApplicationState.

func NewEndPointState(hbState *HeartBeatState) *EndPointState

func (e *EndPointState) AddApplicationState(key string, appState *ApplicationState)

func (e *EndPointState) GetApplicationState(key string) *ApplicationState

func (e *EndPointState) GetHeartBeatState() *HeartBeatState

func (e *EndPointState) IsAlive() bool

func (e *EndPointState) SetAlive(live bool)

func (e *EndPointState) SetGossiper(g bool)

func (e *EndPointState) SetHeartBeatState(hbState *HeartBeatState)

func (e *EndPointState) UpdateTimestamp()

type FailureDetector ¶

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

FailureDetector implements IFailureDetector

func (f *FailureDetector) IsAlive(ep network.EndPoint) bool

func (f *FailureDetector) RegisterEventListener(listener IFailureDetectionEventListener)

func (f *FailureDetector) UnregisterEventListener(listener IFailureDetectionEventListener)

type GossipDigest ¶

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

GossipDigest contains information about a specified list of EndPoints and the largest version of the state they have generated as known by the local endpoint.

func NewGossipDigest(endPoint network.EndPoint, generation, maxVersion int) *GossipDigest

type GossipDigestAck2Args ¶

type GossipDigestAck2Args struct {
	From      network.EndPoint
	ClusterID string
	// contains filtered or unexported fields
}

GossipDigestAck2Args ...

type GossipDigestAck2Reply ¶

type GossipDigestAck2Reply struct{}

GossipDigestAck2Reply ...

type GossipDigestAckArgs ¶

type GossipDigestAckArgs struct {
	From      network.EndPoint
	ClusterID string
	GDigest   []*GossipDigest
	// contains filtered or unexported fields
}

GossipDigestAckArgs ...

type GossipDigestAckReply ¶

type GossipDigestAckReply struct{}

GossipDigestAckReply ...

type GossipDigestSynArgs ¶

type GossipDigestSynArgs struct {
	From      network.EndPoint
	ClusterID string
	GDigest   []*GossipDigest
}

GossipDigestSynArgs ...

type GossipDigestSynReply ¶

type GossipDigestSynReply struct{}

GossipDigestSynReply ...

type Gossiper ¶

type Gossiper struct {
	MaxGossipPacketSize  int
	GossipStage          string
	JoinVerbHandler      string
	GossipDigestSynVerb  string
	GossipDigestAckVerb  string
	GossipDigestAck2Verb string
	// contains filtered or unexported fields
}

Gossiper is responsible for Gossiping information for the local endpoint. It maintains the list of live and dead endpoints. It will periodically (every 1 sec.) chooses a random node and initiates a round of Gossip with it. A round of Gossip involves 3 rounds of messaging: If A wants to initiate a round of Gossip with B:

1. A -> B using GossipDigestSynMessage.
2. B -> A using GossipDigestAckMessage.
3. A -> B using GossipDigestAck2Message.

When this module heads from one of the above messages, it will update the FailureDetector with the liveness information.

func GetGossiper() *Gossiper

func NewGossiper() *Gossiper

func (g *Gossiper) AddApplicationState(key string, appState *ApplicationState)

func (g *Gossiper) Convict(endpoint network.EndPoint)

func (g *Gossiper) GetEndPointStateForEndPoint(ep network.EndPoint) *EndPointState

func (g *Gossiper) OnGossipDigestAck(args *GossipDigestAckArgs, reply *GossipDigestAckReply) error

func (g *Gossiper) OnGossipDigestAck2(args *GossipDigestAck2Args, reply *GossipDigestAck2Reply) error

func (g *Gossiper) OnGossipDigestSyn(args *GossipDigestSynArgs, reply *GossipDigestSynReply) error

func (g *Gossiper) Register(subscriber IEndPointStateChangeSubscriber)

func (g *Gossiper) RunTimerTask()

func (g *Gossiper) Start(generation int)

func (g *Gossiper) Suspect(endpoint network.EndPoint)

type HeartBeatState ¶

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

HeartBeatState associated with any given endpoint.

func NewHeartBeatState(generation, heartBeat int) *HeartBeatState

func (h *HeartBeatState) GetHeartBeat() int32

func (h *HeartBeatState) GetVersion() int32

func (h *HeartBeatState) UpdateHeartBeat()

type IEndPointStateChangeSubscriber ¶

type IEndPointStateChangeSubscriber interface {
	OnChange(endpoint network.EndPoint, epState *EndPointState)
}

IEndPointStateChangeSubscriber provides an interface for endpoint state change subscribers

type IFailureDetectionEventListener ¶

type IFailureDetectionEventListener interface {
	// convict the specified endpoint
	Convict(ep network.EndPoint)
	// suspect the specified endpoint
	Suspect(ep network.EndPoint)
}

IFailureDetectionEventListener provides an interface for fd event listener

type IFailureDetector ¶

type IFailureDetector interface {
	IsAlive(ep network.EndPoint) bool

	RegisterEventListener(listener IFailureDetectionEventListener)
	UnregisterEventListener(listener IFailureDetectionEventListener)
	// contains filtered or unexported methods
}

IFailureDetector provides an interface that can query liveness information of a node in the cluster.

func GetFailureDetector() IFailureDetector