input_data_registry

type FakeInputDataRegistry struct {
	HasNoCACertificate               bool
	Watcher                          *KapiWatcher
	ShouldWatcherNotifyOfPreexisting bool

	MinSampleGap time.Duration
	// contains filtered or unexported fields
}

type InputDataRegistry interface {
	// DataSource returns an InputDataSource interface to the registry, which is focused on metrics consumption, and
	// abstracts other details away.
	DataSource() InputDataSource
	// GetKapiData returns a KapiData object which contains the registry's information, specific to the Kapi pod identified
	// by shootNamespace and podName.
	// The output is a deep copy, and fully detached from the registry. If the registry has no information about the
	// specified pod, nil is returned.
	GetKapiData(shootNamespace string, podName string) *KapiData
	// SetKapiData stores registry data specific to the k8s Kapi pod object identified by shootNamespace and podName.
	SetKapiData(
		shootNamespace string, podName string, podUID types.UID, podLabels map[string]string, metricsUrl string)
	// RemoveKapiData deletes all registry data specific to the Kapi pod identified by shootNamespace and podName.
	// The output value is false if the registry did not contain data for the identified pod.
	RemoveKapiData(shootNamespace string, podName string) bool
	// SetKapiMetrics records the current metrics value for the Kapi pod identified by shootNamespace and podName.
	// If the registry does not contain a record for the specified pod, the operation has no effect.
	SetKapiMetrics(shootNamespace string, podName string, currentTotalRequestCount int64)
	// SetKapiLastScrapeTime records the start time of the last scrape for the Kapi pod identified by shootNamespace and podName.
	// If the registry does not contain a record for the specified pod, the operation has no effect.
	SetKapiLastScrapeTime(shootNamespace string, podName string, value time.Time)
	// NotifyKapiMetricsFault is the counterpart of SetKapiMetrics which is used when a metrics scrape fails. Instead of
	// recording the newly obtained metrics values, it records the fact that values could not be obtained.
	// If the registry does not contain a record for the specified pod, the operation has no effect.
	//
	// The function returns the number of consecutive faults on record, including the one reflected by this call.
	// Returns -1 if the registry currently does not maintain a record for the specified pod.
	NotifyKapiMetricsFault(shootNamespace string, podName string) int
	// GetShootAuthSecret retrieves the authentication secret used to access Kapi metrics on the shoot identified by shootNamespace.
	// Returns empty string if there is no auth secret on record for that shoot.
	GetShootAuthSecret(shootNamespace string) string
	// SetShootAuthSecret records the specified authentication secret for the shoot identified by ShootNamespace, so it can
	// later be retrieved via GetShootAuthSecret(). Passing authSecret="" deletes the record, if one exists.
	SetShootAuthSecret(shootNamespace string, authSecret string)
	// GetShootCACertificate retrieves the Kapi CA certificate registered for the shoot identified by shootNamespace.
	// Returns nil if a CA cert is not registered for the shoot. The result is in the form of a CertPool, containing
	// only the shoot's CA certificate. Callers should not modify the returned object.
	GetShootCACertificate(shootNamespace string) *x509.CertPool
	// SetShootCACertificate records the specified certificate as the CA certificate for the Kapi of the shoot identified by
	// shootNamespace, so it can later be retrieved via GetShootCACertificate(). Passing certificate=nil deletes the record,
	// if one exists.
	SetShootCACertificate(shootNamespace string, certificate []byte)
	// AddKapiWatcher subscribes an event handler which gets called when there is a change in the ShootKapi objects on
	// record in the registry.
	// If shouldNotifyOfPreexisting is true, a KapiEventCreate event will be delivered to the watcher for each ShootKapi
	// which is already in the registry at the time of the call. If false, the watcher will only be notified of subsequent
	// changes.
	//
	// IMPORTANT:
	// If a goroutine exists which could hold a given lock while calling a method on a given InputDataRegistry instance,
	// then it is illegal for any KapiWatcher registered on that instance to block, even indirectly, on that same lock.
	// The KapiWatcher is still allowed to e.g. create a separate goroutine which blocks in the lock, as long as it doesn't
	// block waiting on the goroutine.
	AddKapiWatcher(watcher *KapiWatcher, shouldNotifyOfPreexisting bool)
	// RemoveKapiWatcher removes the event watcher, registered by a prior AddKapiWatcher call.
	// The watcher pointer must have the same value as the one provided to said AddKapiWatcher() call.
	// Returns false, if the specified watcher has never been added to the registry, or was already removed.
	RemoveKapiWatcher(watcher *KapiWatcher) bool
}

type InputDataSource interface {
	// GetShootKapis lists the known Kapi pods for the shoot identified by shootNamespace. Returns nil if the shoot
	// is unknown to InputDataSource at the time of the call.
	GetShootKapis(shootNamespace string) []ShootKapi

	// AddKapiWatcher subscribes an event handler which gets called when there is a change in the ShootKapi objects on
	// record in the InputDataSource.
	// If shouldNotifyOfPreexisting is true, a KapiEventCreate event will be delivered to the watcher for each ShootKapi
	// which is already in the InputDataSource at the time of the call. If false, the watcher will only be notified of
	// future changes.
	//
	// IMPORTANT:
	// If a goroutine exists which could hold a given lock while calling a method on a given InputDataSource instance,
	// then it is illegal for any KapiWatcher registered on that instance to block, even indirectly, on that same lock.
	// The KapiWatcher is still allowed to e.g. create a separate goroutine which blocks in the lock, as long as it
	// doesn't block waiting on the goroutine.
	AddKapiWatcher(watcher *KapiWatcher, shouldNotifyOfPreexisting bool)

	// RemoveKapiWatcher removes the event watcher, registered by a prior AddKapiWatcher call.
	// The watcher pointer must have the same value as the one provided to said AddKapiWatcher() call.
	// Returns false, if the specified watcher has never been added to the InputDataSource, or was already removed.
	RemoveKapiWatcher(watcher *KapiWatcher) bool
}

type KapiData struct {
	PodLabels             map[string]string // The K8s labels on the pod object
	MetricsUrl            string            // The URL where metrics for the pod can be scraped
	TotalRequestCountNew  int64             // Most recent value for the number of Kapi requests to this pod, since the pod started.
	MetricsTimeNew        time.Time         // The point in time to which TotalRequestCountNew refers. Zero when the metrics sample is unavailable.
	TotalRequestCountOld  int64             // The previous value of TotalRequestCountNew. Enables rate-of-change calculations.
	MetricsTimeOld        time.Time         // The point in time to which TotalRequestCountOld refers. Zero when the metrics sample is unavailable.
	PodUID                types.UID
	LastMetricsScrapeTime time.Time // The start time of the most recent metrics scrape for the Kapi.
	FaultCount            int       // Number of consecutive failed attempt to obtain metrics for this pod. Reset to zero upon success.
	// contains filtered or unexported fields
}

type KapiEventType int

type KapiWatcher func(kapi ShootKapi, event KapiEventType)

type ShootKapi interface {
	ShootNamespace() string       // ShootNamespace and PodName are immutable and together serve as ID
	PodName() string              // ShootNamespace and PodName are immutable and together serve as ID
	PodLabels() map[string]string // The K8s labels on the pod object
	TotalRequestCountNew() int64  // Most recent value for the number of Kapi requests to this pod, since the pod started.
	TotalRequestCountOld() int64  // The previous value of TotalRequestCountNew. Enables rate-of-change calculations.
	MetricsTimeNew() time.Time    // The point in time to which TotalRequestCountNew refers. Zero when the metrics sample is unavailable.
	MetricsTimeOld() time.Time    // The point in time to which TotalRequestCountOld refers. Zero when the metrics sample is unavailable.
	PodUID() types.UID
}