orchestrator

Documentation

Index

• Variables
• func AccountedDiscoverInstance(instanceKey inst.InstanceKey, pendingTokens chan bool, ...)
• func AttemptElection() (bool, error)
• func AttemptRecoveryRegistration(failedKey *inst.InstanceKey) (bool, error)
• func CheckAndRecover(specificInstance *inst.InstanceKey, candidateInstanceKey *inst.InstanceKey, ...) (actionTaken bool, instance *inst.Instance, err error)
• func ClearActiveRecoveries() error
• func ContinuousAgentsPoll()
• func ContinuousDiscovery()
• 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(failedInstanceKey *inst.InstanceKey) (bool, *inst.Instance, error)
• func RecoverDeadMaster(failedInstanceKey *inst.InstanceKey) (bool, *inst.Instance, 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

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 AttemptRecoveryRegistration

func AttemptRecoveryRegistration(failedKey *inst.InstanceKey) (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 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 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)

GetCandidateSlave chooses the best slave to promote given a (possibly dead) master

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(failedInstanceKey *inst.InstanceKey) (bool, *inst.Instance, error)

func RecoverDeadMaster

func RecoverDeadMaster(failedInstanceKey *inst.InstanceKey) (bool, *inst.Instance, error)

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
}

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