leaderelection

Documentation

Index

• Constants
• type LeaderCallbacks
• type LeaderElectionConfig
• type LeaderElector
  • func NewLeaderElector(lec LeaderElectionConfig) (*LeaderElector, error)
  • func (le *LeaderElector) GetLeader() string
  • func (le *LeaderElector) IsLeader() bool
  • func (le *LeaderElector) Run(task <-chan bool)

Constants

const (
	JitterFactor         = 1.2
	DefaultLeaseDuration = 15 * time.Second
	DefaultRenewDeadline = 10 * time.Second
	DefaultRetryPeriod   = 2 * time.Second
	DefaultTermLimit     = 30 * time.Second
)

Types

type LeaderCallbacks

type LeaderCallbacks struct {
	// OnStartedLeading is called when a LeaderElector client starts leading
	OnStartedLeading func(stop <-chan struct{})
	// OnStoppedLeading is called when a LeaderElector client stops leading
	OnStoppedLeading func()
	// OnNewLeader is called when the client observes a leader that is
	// not the previously observed leader. This includes the first observed
	// leader when the client starts.
	OnNewLeader func(identity string)
}

LeaderCallbacks are callbacks that are triggered during certain lifecycle events of the LeaderElector. These are invoked asynchronously.

possible future callbacks:

• OnChallenge()

type LeaderElectionConfig

type LeaderElectionConfig struct {
	// Lock is the resource that will be used for locking
	Lock rl.Interface

	// LeaseDuration is the duration that non-leader candidates will
	// wait to force acquire leadership. This is measured against time of
	// last observed ack.
	LeaseDuration time.Duration
	// RenewDeadline is the duration that the acting master will retry
	// refreshing leadership before giving up.
	RenewDeadline time.Duration
	// RetryPeriod is the duration the LeaderElector clients should wait
	// between tries of actions.
	RetryPeriod time.Duration
	// TermLimit is the maximum duration that a leader may remain the leader
	// to complete the task before it must give up its leadership. 0 for forever
	// or indefinite.
	TermLimit time.Duration

	// Callbacks are callbacks that are triggered during certain lifecycle
	// events of the LeaderElector
	Callbacks LeaderCallbacks
}

type LeaderElector

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

LeaderElector is a leader election client.

possible future methods:

• (le *LeaderElector) IsLeader()
• (le *LeaderElector) GetLeader()

func NewLeaderElector

func NewLeaderElector(lec LeaderElectionConfig) (*LeaderElector, error)

NewLeaderElector creates a LeaderElector from a LeaderElecitionConfig

func (*LeaderElector) GetLeader

func (le *LeaderElector) GetLeader() string

GetLeader returns the identity of the last observed leader or returns the empty string if no leader has yet been observed.

func (*LeaderElector) IsLeader

func (le *LeaderElector) IsLeader() bool

IsLeader returns true if the last observed leader was this client else returns false.

func (*LeaderElector) Run

func (le *LeaderElector) Run(task <-chan bool)

Run starts the leader election loop