leadership

Documentation

Index

• Variables
• func Manifold(config ManifoldConfig) dependency.Manifold
• type ManifoldConfig
• type Tracker
  • func NewTracker(tag names.UnitTag, claimer leadership.Claimer, duration time.Duration) *Tracker
  • func (t *Tracker) ClaimDuration() time.Duration
  • func (t *Tracker) ClaimLeader() leadership.Ticket
  • func (t *Tracker) Kill()
  • func (t *Tracker) ServiceName() string
  • func (t *Tracker) Wait() error
  • func (t *Tracker) WaitLeader() leadership.Ticket
  • func (t *Tracker) WaitMinion() leadership.Ticket

Variables

var NewManifoldWorker = func(agent agent.Agent, apiCaller base.APICaller, guarantee time.Duration) (worker.Worker, error) {
	tag := agent.CurrentConfig().Tag()
	unitTag, ok := tag.(names.UnitTag)
	if !ok {
		return nil, fmt.Errorf("expected a unit tag; got %q", tag)
	}
	claimer := leadership.NewClient(apiCaller)
	return NewTracker(unitTag, claimer, guarantee), nil
}

NewManifoldWorker wraps NewTracker for the convenience of startFunc. It exists primarily to be patched out via NewManifoldWorker for ease of testing, and is not itself directly tested. It would almost certainly be better to pass the constructor dependencies in as explicit manifold config.

Functions

func Manifold

func Manifold(config ManifoldConfig) dependency.Manifold

Manifold returns a manifold whose worker wraps a Tracker working on behalf of the dependency identified by AgentName.

Types

type ManifoldConfig

type ManifoldConfig struct {
	AgentName           string
	APICallerName       string
	LeadershipGuarantee time.Duration
}

ManifoldConfig defines the names of the manifolds on which a Manifold will depend.

type Tracker

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

func NewTracker

func NewTracker(tag names.UnitTag, claimer leadership.Claimer, duration time.Duration) *Tracker

NewTracker returns a *Tracker that attempts to claim and retain service leadership for the supplied unit. It will claim leadership for twice the supplied duration, and once it's leader it will renew leadership every time the duration elapses. Thus, successful leadership claims on the resulting Tracker will guarantee leadership for the duration supplied here without generating additional calls to the supplied manager (which may very well be on the other side of a network connection).

func (*Tracker) ClaimDuration

func (t *Tracker) ClaimDuration() time.Duration

ClaimDuration is part of the leadership.Tracker interface.

func (*Tracker) ClaimLeader

func (t *Tracker) ClaimLeader() leadership.Ticket

ClaimLeader is part of the leadership.Tracker interface.

func (*Tracker) Kill

func (t *Tracker) Kill()

Kill is part of the worker.Worker interface.

func (*Tracker) ServiceName

func (t *Tracker) ServiceName() string

ServiceName is part of the leadership.Tracker interface.

func (*Tracker) Wait

func (t *Tracker) Wait() error

Wait is part of the worker.Worker interface.

func (*Tracker) WaitLeader

func (t *Tracker) WaitLeader() leadership.Ticket

WaitLeader is part of the leadership.Tracker interface.

func (*Tracker) WaitMinion

func (t *Tracker) WaitMinion() leadership.Ticket

WaitMinion is part of the leadership.Tracker interface.