flowcontrol

type DroppedRequestsTracker interface {
	// RecordDroppedRequest records a request that was just
	// dropped from processing.
	RecordDroppedRequest(plName string)

	// GetRetryAfter returns the current suggested value of
	// RetryAfter value.
	GetRetryAfter(plName string) int64
}

type ForgetWatchFunc func()

type InitializationSignal interface {
	// Signal notifies the dispatcher about finished initialization.
	Signal()
	// Wait waits for the initialization signal.
	Wait()
}

type Interface interface {
	// Handle takes care of queuing and dispatching a request
	// characterized by the given digest.  The given `noteFn` will be
	// invoked with the results of request classification.
	// The given `workEstimator` is called, if at all, after noteFn.
	// `workEstimator` will be invoked only when the request
	//  is classified as non 'exempt'.
	// 'workEstimator', when invoked, must return the
	// work parameters for the request.
	// If the request is queued then `queueNoteFn` will be called twice,
	// first with `true` and then with `false`; otherwise
	// `queueNoteFn` will not be called at all.  If Handle decides
	// that the request should be executed then `execute()` will be
	// invoked once to execute the request; otherwise `execute()` will
	// not be invoked.
	// Handle() should never return while execute() is running, even if
	// ctx is cancelled or times out.
	Handle(ctx context.Context,
		requestDigest RequestDigest,
		noteFn func(fs *flowcontrol.FlowSchema, pl *flowcontrol.PriorityLevelConfiguration, flowDistinguisher string),
		workEstimator func() fcrequest.WorkEstimate,
		queueNoteFn fq.QueueNoteFn,
		execFn func(),
	)

	// Run monitors config objects from the main apiservers and causes
	// any needed changes to local behavior.  This method ceases
	// activity and returns after the given channel is closed.
	Run(stopCh <-chan struct{}) error

	// Install installs debugging endpoints to the web-server.
	Install(c *mux.PathRecorderMux)

	// WatchTracker provides the WatchTracker interface.
	WatchTracker

	// MaxSeatsTracker is invoked from the work estimator to track max seats
	// that can be occupied by a request for a priority level.
	MaxSeatsTracker
}

type MaxSeatsTracker interface {
	// GetMaxSeats returns the maximum seats a request should occupy for a given priority level.
	GetMaxSeats(priorityLevelName string) uint64

	// SetMaxSeats configures max seats for a priority level.
	SetMaxSeats(priorityLevelName string, maxSeats uint64)

	// ForgetPriorityLevel removes max seats tracking for a priority level.
	ForgetPriorityLevel(priorityLevelName string)
}

type RequestDigest struct {
	RequestInfo *request.RequestInfo
	User        user.Info
}

type StartFunction func(ctx context.Context, hashValue uint64) (execute bool, afterExecution func())

type TestableConfig struct {
	// Name of the controller
	Name string

	// Clock to use in timing deliberate delays
	Clock clock.PassiveClock

	// AsFieldManager is the string to use in the metadata for
	// server-side apply.  Normally this is
	// `ConfigConsumerAsFieldManager`.  This is exposed as a parameter
	// so that a test of competing controllers can supply different
	// values.
	AsFieldManager string

	// FoundToDangling maps the boolean indicating whether a
	// FlowSchema's referenced PLC exists to the boolean indicating
	// that FlowSchema's status should indicate a dangling reference.
	// This is a parameter so that we can write tests of what happens
	// when servers disagree on that bit of Status.
	FoundToDangling func(bool) bool

	// InformerFactory to use in building the controller
	InformerFactory kubeinformers.SharedInformerFactory

	// FlowcontrolClient to use for manipulating config objects
	FlowcontrolClient flowcontrolclient.FlowcontrolV1Interface

	// ServerConcurrencyLimit for the controller to enforce
	ServerConcurrencyLimit int

	// GaugeVec for metrics about requests, broken down by phase and priority_level
	ReqsGaugeVec metrics.RatioedGaugeVec

	// RatioedGaugePairVec for metrics about seats occupied by all phases of execution
	ExecSeatsGaugeVec metrics.RatioedGaugeVec

	// QueueSetFactory for the queuing implementation
	QueueSetFactory fq.QueueSetFactory
}

type WatchTracker interface {
	// RegisterWatch reqisters a watch based on the provided http.Request
	// in the tracker. It returns the function that should be called
	// to forget the watcher once it is finished.
	RegisterWatch(r *http.Request) ForgetWatchFunc

	// GetInterestedWatchCount returns the number of watches that are
	// potentially interested in a request with a given RequestInfo
	// for the purpose of estimating cost of that request.
	GetInterestedWatchCount(requestInfo *request.RequestInfo) int
}