logic

Documentation

Index

• Variables
• func AccountedDiscoverInstance(instanceKey inst.InstanceKey, pendingTokens chan bool, ...)
• func AttemptElection() (bool, error)
• func AttemptFailureDetectionRegistration(analysisEntry *inst.ReplicationAnalysis) (bool, error)
• func AttemptRecoveryRegistration(analysisEntry *inst.ReplicationAnalysis) (bool, error)
• func CheckAndRecover(specificInstance *inst.InstanceKey, candidateInstanceKey *inst.InstanceKey, ...) (actionTaken bool, instance *inst.Instance, err error)
• func ClearActiveFailureDetections() error
• func ClearActiveRecoveries() error
• func ContinuousAgentsPoll()
• func ContinuousDiscovery()
• func CreateElectionAnchor(force bool) error
• func DiscoverInstance(instanceKey inst.InstanceKey)
• func ElectedNode() (string, string, bool, error)
• func GetCandidateSiblingOfIntermediateMaster(intermediateMasterKey *inst.InstanceKey) (*inst.Instance, error)
• func GetHash(input []byte) string
• func GetRandomData() []byte
• func GrabElection() (bool, error)
• func IsElected() (bool, error)
• func RecoverDeadIntermediateMaster(analysisEntry inst.ReplicationAnalysis) (actionTaken bool, successorInstance *inst.Instance, err error)
• func RecoverDeadMaster(analysisEntry inst.ReplicationAnalysis) (bool, *inst.Instance, error)
• func Reelect() error
• func ResolveRecovery(failedKey *inst.InstanceKey, successorKey *inst.InstanceKey) error
• func StartDiscovery(instanceKey inst.InstanceKey)
• type HealthStatus
  • func HealthTest() (*HealthStatus, error)
• type InstancesByCountSlaves
  • func (this InstancesByCountSlaves) Len() int
  • func (this InstancesByCountSlaves) Less(i, j int) bool
  • func (this InstancesByCountSlaves) Swap(i, j int)
• type Token
  • func NewToken() *Token
• type TopologyRecovery
  • func ReadActiveClusterRecovery(clusterName string) ([]TopologyRecovery, error)
  • func ReadActiveRecoveries() ([]TopologyRecovery, error)
  • func ReadCompletedRecoveries(page int) ([]TopologyRecovery, error)
  • func ReadRecentFailureDetections(page int) ([]TopologyRecovery, error)
  • func ReadRecentRecoveries(page int) ([]TopologyRecovery, error)
  • func ReadRecentlyActiveClusterRecovery(clusterName string) ([]TopologyRecovery, error)
  • func ReadRecentlyActiveInstanceRecovery(instanceKey *inst.InstanceKey) ([]TopologyRecovery, error)

Variables

var ThisHostname string

Functions

func AccountedDiscoverInstance

func AccountedDiscoverInstance(instanceKey inst.InstanceKey, pendingTokens chan bool, completedTokens chan bool)

AccountedDiscoverInstance will call upon DiscoverInstance and will keep track of discovery tokens such that management of multiple discoveries can figure out whether all instances in a topology are accounted for.

func AttemptElection

func AttemptElection() (bool, error)

AttemptElection tries to grab leadership (become active node)

func AttemptFailureDetectionRegistration

func AttemptFailureDetectionRegistration(analysisEntry *inst.ReplicationAnalysis) (bool, error)

AttemptFailureDetectionRegistration tries to add a failure-detection entry; if this fails that means the problem has already been detected

func AttemptRecoveryRegistration

func AttemptRecoveryRegistration(analysisEntry *inst.ReplicationAnalysis) (bool, error)

AttemptRecoveryRegistration tries to add a recovery entry; if this fails that means recovery is already in place.

func CheckAndRecover

func CheckAndRecover(specificInstance *inst.InstanceKey, candidateInstanceKey *inst.InstanceKey, skipFilters bool) (actionTaken bool, instance *inst.Instance, err error)

CheckAndRecover is the main entry point for the recovery mechanism

func ClearActiveFailureDetections

func ClearActiveFailureDetections() error

ClearActiveFailureDetections clears the "in_active_period" flag for old-enough detections, thereby allowing for further detections on cleared instances.

func ClearActiveRecoveries

func ClearActiveRecoveries() error

ClearActiveRecoveries clears the "in_active_period" flag for old-enough recoveries, thereby allowing for further recoveries on cleared instances.

func ContinuousAgentsPoll

func ContinuousAgentsPoll()

ContinuousAgentsPoll starts an asynchronuous infinite process where agents are periodically investigated and their status captured, and long since unseen agents are purged and forgotten.

func ContinuousDiscovery

func ContinuousDiscovery()

ContinuousDiscovery starts an asynchronuous infinite discovery process where instances are periodically investigated and their status captured, and long since unseen instances are purged and forgotten.

func CreateElectionAnchor

func CreateElectionAnchor(force bool) error

func DiscoverInstance

func DiscoverInstance(instanceKey inst.InstanceKey)

DiscoverInstance will attempt discovering an instance (unless it is already up to date) and will list down its master and slaves (if any) for further discovery.

func ElectedNode

func ElectedNode() (string, string, bool, error)

ElectedNode returns the hostname of the elected node

func GetCandidateSiblingOfIntermediateMaster

func GetCandidateSiblingOfIntermediateMaster(intermediateMasterKey *inst.InstanceKey) (*inst.Instance, error)

GetCandidateSiblingOfIntermediateMaster chooses the best sibling of a dead intermediate master to whom the IM's slaves can be moved.

func GetHash

func GetHash(input []byte) string

func GetRandomData

func GetRandomData() []byte

func GrabElection

func GrabElection() (bool, error)

GrabElection forcibly grabs leadership. Use with care!!

func IsElected

func IsElected() (bool, error)

IsElected checks whether this node is the elected active node

func RecoverDeadIntermediateMaster

func RecoverDeadIntermediateMaster(analysisEntry inst.ReplicationAnalysis) (actionTaken bool, successorInstance *inst.Instance, err error)

func RecoverDeadMaster

func RecoverDeadMaster(analysisEntry inst.ReplicationAnalysis) (bool, *inst.Instance, error)

func Reelect

func Reelect() error

Reelect clears the way for re-elections. Active node is immediately demoted.

func ResolveRecovery

func ResolveRecovery(failedKey *inst.InstanceKey, successorKey *inst.InstanceKey) error

ResolveRecovery is called on completion of a recovery process and updates the recovery status. It does not clear the "active period" as this still takes place in order to avoid flapping.

func StartDiscovery

func StartDiscovery(instanceKey inst.InstanceKey)

Start discovery begins a one time asynchronuous discovery process for the given instance and all of its topology connected instances. That is, the instance will be investigated for master and slaves, and the routines will follow on each and every such found master/slave. In essense, assuming all slaves in a replication topology are running, and given a single instance in such topology, this function will detect the entire topology.

Types

type HealthStatus

type HealthStatus struct {
	Healthy        bool
	Hostname       string
	Token          string
	IsActiveNode   bool
	ActiveNode     string
	Error          error
	AvailableNodes []string
}

func HealthTest

func HealthTest() (*HealthStatus, error)

HealthTest attempts to write to the backend database and get a result

type InstancesByCountSlaves

type InstancesByCountSlaves [](*inst.Instance)

InstancesByCountSlaves sorts instances by umber of slaves, descending

func (InstancesByCountSlaves) Len

func (this InstancesByCountSlaves) Len() int

func (InstancesByCountSlaves) Less

func (this InstancesByCountSlaves) Less(i, j int) bool

func (InstancesByCountSlaves) Swap

func (this InstancesByCountSlaves) Swap(i, j int)

type Token

type Token struct {
	Hash string
}

Token is used to identify and validate requests to this service

var ProcessToken *Token = NewToken()

func NewToken

func NewToken() *Token

type TopologyRecovery

type TopologyRecovery struct {
	Id                     int64
	AnalysisEntry          inst.ReplicationAnalysis
	SuccessorKey           inst.InstanceKey
	IsActive               bool
	RecoveryStartTimestamp string
	RecoveryEndTimestamp   string
	ProcessingNodeHostname string
	ProcessingNodeToken    string
}

TopologyRecovery represents an entry in the topology_recovery table

func ReadActiveClusterRecovery

func ReadActiveClusterRecovery(clusterName string) ([]TopologyRecovery, error)

ReadActiveRecoveries reads active recovery entry/audit entires from topology_recovery

func ReadActiveRecoveries

func ReadActiveRecoveries() ([]TopologyRecovery, error)

ReadActiveRecoveries reads active recovery entry/audit entires from topology_recovery

func ReadCompletedRecoveries

func ReadCompletedRecoveries(page int) ([]TopologyRecovery, error)

ReadCompletedRecoveries reads completed recovery entry/audit entires from topology_recovery

func ReadRecentFailureDetections

func ReadRecentFailureDetections(page int) ([]TopologyRecovery, error)

ReadCRecoveries reads latest recovery entreis from topology_recovery

func ReadRecentRecoveries

func ReadRecentRecoveries(page int) ([]TopologyRecovery, error)

ReadCRecoveries reads latest recovery entreis from topology_recovery

func ReadRecentlyActiveClusterRecovery

func ReadRecentlyActiveClusterRecovery(clusterName string) ([]TopologyRecovery, error)

ReadRecentlyActiveInstanceRecovery reads recently completed entries for a given cluster

func ReadRecentlyActiveInstanceRecovery

func ReadRecentlyActiveInstanceRecovery(instanceKey *inst.InstanceKey) ([]TopologyRecovery, error)

ReadRecentlyActiveInstanceRecovery reads recently completed entries for a given instance