provider

Documentation

Index

• type AbortContextMonitoring
  • func NewAbortableMonitoredContext(ctx context.Context) (context.Context, AbortContextMonitoring)
• type ETCDOption
  • func WithETCDConfig(config etcd.Config) ETCDOption
  • func WithLeaseTTL(t int) ETCDOption
  • func WithUsernamePassword(username, password string) ETCDOption
• type Election
• type ElectionMetaDataProvider
• type Lease
• type LeaseProvider
  • func NewETCDLeaseProvider(etcdEndPoints []string, options ...ETCDOption) LeaseProvider

Types

type AbortContextMonitoring

type AbortContextMonitoring func()

func NewAbortableMonitoredContext

func NewAbortableMonitoredContext(ctx context.Context) (context.Context, AbortContextMonitoring)

returns a context that monitors the given context for cancellations additionally returns an abort monitoring function that causes the monitoring to stop from that point onwards

type ETCDOption

type ETCDOption func(*etcdLeaseProvider)

func WithETCDConfig

func WithETCDConfig(config etcd.Config) ETCDOption

func WithLeaseTTL

func WithLeaseTTL(t int) ETCDOption

in seconds how long should ETCD wait until declaring me dead - in case I crash

func WithUsernamePassword

func WithUsernamePassword(username, password string) ETCDOption

type Election

type Election interface {
	Campaign(context.Context, string) error
	ReassureLeadership(context.Context, string) error
	Resign(context.Context) error
}

type ElectionMetaDataProvider

type ElectionMetaDataProvider interface {
	// identifying the locking key during election - the lowest denominator of lock
	Constituency(shard string) string
	// value that is used during campaigning for leadership
	CampaignPromise() string
	// value that is used as a part of a heartbeat during leadership
	LeadershipReassurance(electedAt time.Time) string
}

type Lease

type Lease interface {
	ID() string
	Expired() <-chan struct{}
	ElectionFor(constituency string) Election
	Close()
}

type LeaseProvider

type LeaseProvider interface {
	// if context is cancelled, return an error; otherwise block forever until lease is acquired
	// returning before a lease is acquired and the context still active will be considered a bugs
	AcquireLease(context.Context) (Lease, error)
}

A LeaseProvider implementation is backed by a remote endpoint used to implement a distributed lock. It facilitates the acquisition of a Lease that indicates liveness of the client as well as the server. The LeaseProvider should continuously renew it's lease before expiration via a heartbeat of some sort. From a client perspective if the remote endpoint is no longer available or for other reasons indicated by the server, an acquired lease should be expired. From a server perspective if a lease exprires, other lease holders can acquire locks previously held by the expiring lease holder.

func NewETCDLeaseProvider

func NewETCDLeaseProvider(etcdEndPoints []string, options ...ETCDOption) LeaseProvider

etcd backed LeaseProvider