Documentation

Overview

    Package predicate defines Predicates used by Controllers to filter Events before they are provided to EventHandlers.

    Index

    Examples

    Constants

    This section is empty.

    Variables

    This section is empty.

    Functions

    This section is empty.

    Types

    type AnnotationChangedPredicate

    type AnnotationChangedPredicate struct {
    	Funcs
    }

      AnnotationChangedPredicate implements a default update predicate function on annotation change.

      This predicate will skip update events that have no change in the object's annotation. It is intended to be used in conjunction with the GenerationChangedPredicate, as in the following example:

      Controller.Watch(

      &source.Kind{Type: v1.MyCustomKind},
      &handler.EnqueueRequestForObject{},
      predicate.Or(predicate.GenerationChangedPredicate{}, predicate.AnnotationChangedPredicate{}))
      

      This is mostly useful for controllers that needs to trigger both when the resource's generation is incremented (i.e., when the resource' .spec changes), or an annotation changes (e.g., for a staging/alpha API).

      func (AnnotationChangedPredicate) Update

        Update implements default UpdateEvent filter for validating annotation change

        type Funcs

        type Funcs struct {
        	// Create returns true if the Create event should be processed
        	CreateFunc func(event.CreateEvent) bool
        
        	// Delete returns true if the Delete event should be processed
        	DeleteFunc func(event.DeleteEvent) bool
        
        	// Update returns true if the Update event should be processed
        	UpdateFunc func(event.UpdateEvent) bool
        
        	// Generic returns true if the Generic event should be processed
        	GenericFunc func(event.GenericEvent) bool
        }

          Funcs is a function that implements Predicate.

          Example

            This example creates a new Predicate to drop Update Events where the Generation has not changed.

            Output:
            
            

            func NewPredicateFuncs

            func NewPredicateFuncs(filter func(object client.Object) bool) Funcs

              NewPredicateFuncs returns a predicate funcs that applies the given filter function on CREATE, UPDATE, DELETE and GENERIC events. For UPDATE events, the filter is applied to the new object.

              func (Funcs) Create

              func (p Funcs) Create(e event.CreateEvent) bool

                Create implements Predicate

                func (Funcs) Delete

                func (p Funcs) Delete(e event.DeleteEvent) bool

                  Delete implements Predicate

                  func (Funcs) Generic

                  func (p Funcs) Generic(e event.GenericEvent) bool

                    Generic implements Predicate

                    func (Funcs) Update

                    func (p Funcs) Update(e event.UpdateEvent) bool

                      Update implements Predicate

                      type GenerationChangedPredicate

                      type GenerationChangedPredicate struct {
                      	Funcs
                      }

                        GenerationChangedPredicate implements a default update predicate function on Generation change.

                        This predicate will skip update events that have no change in the object's metadata.generation field. The metadata.generation field of an object is incremented by the API server when writes are made to the spec field of an object. This allows a controller to ignore update events where the spec is unchanged, and only the metadata and/or status fields are changed.

                        For CustomResource objects the Generation is only incremented when the status subresource is enabled.

                        Caveats:

                        * The assumption that the Generation is incremented only on writing to the spec does not hold for all APIs. E.g For Deployment objects the Generation is also incremented on writes to the metadata.annotations field. For object types other than CustomResources be sure to verify which fields will trigger a Generation increment when they are written to.

                        * With this predicate, any update events with writes only to the status field will not be reconciled. So in the event that the status block is overwritten or wiped by someone else the controller will not self-correct to restore the correct status.

                        func (GenerationChangedPredicate) Update

                          Update implements default UpdateEvent filter for validating generation change

                          type LabelChangedPredicate

                          type LabelChangedPredicate struct {
                          	Funcs
                          }

                            LabelChangedPredicate implements a default update predicate function on label change.

                            This predicate will skip update events that have no change in the object's label. It is intended to be used in conjunction with the GenerationChangedPredicate, as in the following example:

                            Controller.Watch(

                            &source.Kind{Type: v1.MyCustomKind},
                            &handler.EnqueueRequestForObject{},
                            predicate.Or(predicate.GenerationChangedPredicate{}, predicate.LabelChangedPredicate{}))
                            

                            This will be helpful when object's labels is carrying some extra specification information beyond object's spec, and the controller will be triggered if any valid spec change (not only in spec, but also in labels) happens.

                            func (LabelChangedPredicate) Update

                              Update implements default UpdateEvent filter for checking label change

                              type Predicate

                              type Predicate interface {
                              	// Create returns true if the Create event should be processed
                              	Create(event.CreateEvent) bool
                              
                              	// Delete returns true if the Delete event should be processed
                              	Delete(event.DeleteEvent) bool
                              
                              	// Update returns true if the Update event should be processed
                              	Update(event.UpdateEvent) bool
                              
                              	// Generic returns true if the Generic event should be processed
                              	Generic(event.GenericEvent) bool
                              }

                                Predicate filters events before enqueuing the keys.

                                func And

                                func And(predicates ...Predicate) Predicate

                                  And returns a composite predicate that implements a logical AND of the predicates passed to it.

                                  func LabelSelectorPredicate

                                  func LabelSelectorPredicate(s metav1.LabelSelector) (Predicate, error)

                                    LabelSelectorPredicate constructs a Predicate from a LabelSelector. Only objects matching the LabelSelector will be admitted.

                                    func Or

                                    func Or(predicates ...Predicate) Predicate

                                      Or returns a composite predicate that implements a logical OR of the predicates passed to it.

                                      type ResourceVersionChangedPredicate

                                      type ResourceVersionChangedPredicate struct {
                                      	Funcs
                                      }

                                        ResourceVersionChangedPredicate implements a default update predicate function on resource version change

                                        func (ResourceVersionChangedPredicate) Update

                                          Update implements default UpdateEvent filter for validating resource version change