pause

Documentation

Overview

Package pause implements a controller pattern for temporarily stopping reconciliation of a resource (but not the entire controller).

When a specific label is added to the resource, the controller sees it and adds a `Paused` condition to the Status of the object, and refuses to process it further until it is un-paused (by removal of the label).

There is also a `SelfPause` handler that can be used if the controller detects a state that it can't easily recover without human intervention. For example, when a required Job has failed after all of its retries, or an external resource (like a Database) is in a bad state, and it is unreasonable to continuously poll for changes. SelfPause should be used sparingly, a controller should almost always prefer to backoff/retry.

Index

• Constants
• func IsPaused(object metav1.Object, pausedLabelKey string) bool
• func NewPausedCondition(pausedLabelKey string) metav1.Condition
• func NewSelfPausedCondition(pausedLabelKey string) metav1.Condition
• type Handler
  • func NewPauseContextHandler[K HasStatusConditions](ctrls *typedctx.Key[queue.Interface], pausedLabelKey string, ...) *Handler[K]
  • func (p *Handler[K]) Handle(ctx context.Context)
• type HasStatusConditions
• type SelfPauseHandler
  • func NewSelfPauseHandler[K HasStatusConditions](ctrls *typedctx.Key[queue.Interface], pausedLabelKey string, ...) *SelfPauseHandler[K]
  • func (p *SelfPauseHandler[K]) Handle(ctx context.Context)

Examples

• NewPauseContextHandler

Constants

const ConditionTypePaused = "Paused"

Functions

func IsPaused

func IsPaused(object metav1.Object, pausedLabelKey string) bool

func NewPausedCondition

func NewPausedCondition(pausedLabelKey string) metav1.Condition

func NewSelfPausedCondition

func NewSelfPausedCondition(pausedLabelKey string) metav1.Condition

Types

type Handler

type Handler[K HasStatusConditions] struct {
	PausedLabelKey string
	Object         *typedctx.DefaultingKey[K]
	PatchStatus    func(ctx context.Context, patch K) error
	Next           handler.ContextHandler
	// contains filtered or unexported fields
}

func NewPauseContextHandler

func NewPauseContextHandler[K HasStatusConditions](ctrls *typedctx.Key[queue.Interface],
	pausedLabelKey string,
	object *typedctx.DefaultingKey[K],
	patchStatus func(ctx context.Context, patch K) error,
	next handler.ContextHandler,
) *Handler[K]

Example

queueOperations := queue.NewQueueOperationsCtx()
ctxObject := typedctx.WithDefault[*MyObject](&MyObject{
	TypeMeta:   metav1.TypeMeta{},
	ObjectMeta: metav1.ObjectMeta{Name: "test", Namespace: "test"},
})

ctx, cancel := context.WithCancel(context.Background())
defer cancel()
pauseHandler := handler.NewHandler(NewPauseContextHandler(
	queueOperations.Key,
	"example.com/paused",
	ctxObject,
	func(ctx context.Context, patch *MyObject) error {
		// update status
		return nil
	},
	handler.NoopHandler,
), "checkPause")
pauseHandler.Handle(ctx)

func (*Handler[K]) Handle

func (p *Handler[K]) Handle(ctx context.Context)

type HasStatusConditions

type HasStatusConditions interface {
	comparable
	metav1.Object
	FindStatusCondition(conditionType string) *metav1.Condition
	SetStatusCondition(metav1.Condition)
	RemoveStatusCondition(conditionType string)
	GetStatusConditions() *[]metav1.Condition
}

HasStatusConditions is an interface that any object implementing standard condition accessors will satisfy.

type SelfPauseHandler

type SelfPauseHandler[K HasStatusConditions] struct {
	CtxKey         *typedctx.DefaultingKey[K]
	PausedLabelKey string
	OwnerUID       types.UID
	Patch          func(ctx context.Context, patch K) error
	PatchStatus    func(ctx context.Context, patch K) error
	// contains filtered or unexported fields
}

SelfPauseHandler is used when the controller pauses itself. This is only used when the controller has no good way to tell when the bad state has been resolved (i.e. an external resource is behaving poorly).

func NewSelfPauseHandler

func NewSelfPauseHandler[K HasStatusConditions](ctrls *typedctx.Key[queue.Interface],
	pausedLabelKey string,
	contextKey *typedctx.DefaultingKey[K],
	patch, patchStatus func(ctx context.Context, patch K) error,
) *SelfPauseHandler[K]

func (*SelfPauseHandler[K]) Handle

func (p *SelfPauseHandler[K]) Handle(ctx context.Context)