Struct DeltaFIFO

tools/cache/delta_fifo.go:96–127

DeltaFIFO is like FIFO, but allows you to process deletes. DeltaFIFO is a producer-consumer queue, where a Reflector is intended to be the producer, and the consumer is whatever calls the Pop() method. DeltaFIFO solves this use case: * You want to process every object change (delta) at most once.

// object will be included in the DeleteFinalStateUnknown markers. These objects
// could be stale.
type DeltaFIFO struct {
	// lock/cond protects access to 'items' and 'queue'.
	lock sync.RWMutex
	cond sync.Cond

	// We depend on the property that items in the set are in
	// the queue and vice versa, and that all Deltas in this
	// map have at least one Delta.
	items map[string]Deltas
	queue []string

	// populated is true if the first batch of items inserted by Replace() has been populated
	// or Delete/Add/Update was called first.
	populated bool
	// initialPopulationCount is the number of items inserted by the first call of Replace()
	initialPopulationCount int

	// keyFunc is used to make the key used for queued item
	// insertion and retrieval, and should be deterministic.
	keyFunc KeyFunc

	// knownObjects list keys that are "known", for the
	// purpose of figuring out which items have been deleted
	// when Replace() or Delete() is called.
	knownObjects KeyListerGetter

	// Indication the queue is closed.
	// Used to indicate a queue is closed so a control loop can exit when a queue is empty.
	// Currently, not used to gate any of CRED operations.
	closed     bool
	closedLock sync.Mutex
}

var (
	_ = Queue(&DeltaFIFO{}) // DeltaFIFO is a Queue