controller

type Config struct {
	// Handler is the controller handler.
	Handler Handler
	// Retriever is the controller retriever.
	Retriever Retriever
	// Leader elector will be used to use only one instance, if no set it will be
	// leader election will be ignored
	LeaderElector leaderelection.Runner
	// MetricsRecorder will record the controller metrics.
	MetricsRecorder MetricsRecorder
	// Logger will log messages of the controller.
	Logger log.Logger

	// name of the controller.
	Name string
	// ConcurrentWorkers is the number of concurrent workers the controller will have running processing events.
	ConcurrentWorkers int
	// ResyncInterval is the interval the controller will process all the selected resources.
	ResyncInterval time.Duration
	// ProcessingJobRetries is the number of times the job will try to reprocess the event before returning a real error.
	ProcessingJobRetries int
	// DisableResync will disable resyncing, if disabled the controller only will react on event updates and resync
	// all when it runs for the first time.
	// This is useful for secondary resource controllers (e.g pod controller of a primary controller based on deployments).
	DisableResync bool
}

type Controller interface {
	// Run runs the controller and blocks until the context is `Done`.
	Run(ctx context.Context) error
}

type Handler interface {
	Handle(context.Context, runtime.Object) error
}

type HandlerFunc func(context.Context, runtime.Object) error

type MetricsRecorder interface {
	// IncResourceEvent increments in one the metric records of a queued event.
	IncResourceEventQueued(ctx context.Context, controller string, isRequeue bool)
	// ObserveResourceInQueueDuration measures how long takes to dequeue a queued object. If the object is already in queue
	// it will be measured once, since the first time it was added to the queue.
	ObserveResourceInQueueDuration(ctx context.Context, controller string, queuedAt time.Time)
	// ObserveResourceProcessingDuration measures how long it takes to process a resources (handling).
	ObserveResourceProcessingDuration(ctx context.Context, controller string, success bool, startProcessingAt time.Time)
	// RegisterResourceQueueLengthFunc will register a function that will be called
	// by the metrics recorder to get the length of a queue at a given point in time.
	RegisterResourceQueueLengthFunc(controller string, f func(context.Context) int) error
}

type Retriever interface {
	List(ctx context.Context, options metav1.ListOptions) (runtime.Object, error)
	Watch(ctx context.Context, options metav1.ListOptions) (watch.Interface, error)
}