Merge pull request #115899 from odinuge/automated-cherry-pick-of-#115620-upstream-release-1.26

Automated cherry pick of #115620: client-go/cache: fix missing delete event on replace  (+ #116623)

Kubernetes-commit: d9a7f46fc5cac57240eaf531e15eabcacf2a2dc3

Author: k8s-publishing-bot

tools/cache/controller.go

@@ -353,17 +353,6 @@ func NewIndexerInformer(
 	return clientState, newInformer(lw, objType, resyncPeriod, h, clientState, nil)
 }
 
-// TransformFunc allows for transforming an object before it will be processed
-// and put into the controller cache and before the corresponding handlers will
-// be called on it.
-// TransformFunc (similarly to ResourceEventHandler functions) should be able
-// to correctly handle the tombstone of type cache.DeletedFinalStateUnknown
-//
-// The most common usage pattern is to clean-up some parts of the object to
-// reduce component memory usage if a given component doesn't care about them.
-// given controller doesn't care for them
-type TransformFunc func(interface{}) (interface{}, error)
-
 // NewTransformingInformer returns a Store and a controller for populating
 // the store while also providing event notifications. You should only used
 // the returned Store for Get/List operations; Add/Modify/Deletes will cause
@@ -411,19 +400,11 @@ func processDeltas(
 	// Object which receives event notifications from the given deltas
 	handler ResourceEventHandler,
 	clientState Store,
-	transformer TransformFunc,
 	deltas Deltas,
 ) error {
 	// from oldest to newest
 	for _, d := range deltas {
 		obj := d.Object
-		if transformer != nil {
-			var err error
-			obj, err = transformer(obj)
-			if err != nil {
-				return err
-			}
-		}
 
 		switch d.Type {
 		case Sync, Replaced, Added, Updated:
@@ -475,6 +456,7 @@ func newInformer(
 	fifo := NewDeltaFIFOWithOptions(DeltaFIFOOptions{
 		KnownObjects:          clientState,
 		EmitDeltaTypeReplaced: true,
+		Transformer:           transformer,
 	})
 
 	cfg := &Config{
@@ -486,7 +468,7 @@ func newInformer(
 
 		Process: func(obj interface{}) error {
 			if deltas, ok := obj.(Deltas); ok {
-				return processDeltas(h, clientState, transformer, deltas)
+				return processDeltas(h, clientState, deltas)
 			}
 			return errors.New("object given as Process argument is not Deltas")
 		},

tools/cache/controller_test.go

@@ -23,7 +23,7 @@ import (
 	"testing"
 	"time"
 
-	"k8s.io/api/core/v1"
+	v1 "k8s.io/api/core/v1"
 	apiequality "k8s.io/apimachinery/pkg/api/equality"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/runtime"
@@ -32,7 +32,7 @@ import (
 	"k8s.io/apimachinery/pkg/watch"
 	fcache "k8s.io/client-go/tools/cache/testing"
 
-	"github.com/google/gofuzz"
+	fuzz "github.com/google/gofuzz"
 )
 
 func Example() {

tools/cache/delta_fifo.go

@@ -51,6 +51,10 @@ type DeltaFIFOOptions struct {
 	// When true, `Replaced` events will be sent for items passed to a Replace() call.
 	// When false, `Sync` events will be sent instead.
 	EmitDeltaTypeReplaced bool
+
+	// If set, will be called for objects before enqueueing them. Please
+	// see the comment on TransformFunc for details.
+	Transformer TransformFunc
 }
 
 // DeltaFIFO is like FIFO, but differs in two ways.  One is that the
@@ -129,8 +133,32 @@ type DeltaFIFO struct {
 	// emitDeltaTypeReplaced is whether to emit the Replaced or Sync
 	// DeltaType when Replace() is called (to preserve backwards compat).
 	emitDeltaTypeReplaced bool
+
+	// Called with every object if non-nil.
+	transformer TransformFunc
 }
 
+// TransformFunc allows for transforming an object before it will be processed.
+// TransformFunc (similarly to ResourceEventHandler functions) should be able
+// to correctly handle the tombstone of type cache.DeletedFinalStateUnknown.
+//
+// New in v1.27: In such cases, the contained object will already have gone
+// through the transform object separately (when it was added / updated prior
+// to the delete), so the TransformFunc can likely safely ignore such objects
+// (i.e., just return the input object).
+//
+// The most common usage pattern is to clean-up some parts of the object to
+// reduce component memory usage if a given component doesn't care about them.
+//
+// New in v1.27: unless the object is a DeletedFinalStateUnknown, TransformFunc
+// sees the object before any other actor, and it is now safe to mutate the
+// object in place instead of making a copy.
+//
+// Note that TransformFunc is called while inserting objects into the
+// notification queue and is therefore extremely performance sensitive; please
+// do not do anything that will take a long time.
+type TransformFunc func(interface{}) (interface{}, error)
+
 // DeltaType is the type of a change (addition, deletion, etc)
 type DeltaType string
 
@@ -227,6 +255,7 @@ func NewDeltaFIFOWithOptions(opts DeltaFIFOOptions) *DeltaFIFO {
 		knownObjects: opts.KnownObjects,
 
 		emitDeltaTypeReplaced: opts.EmitDeltaTypeReplaced,
+		transformer:           opts.Transformer,
 	}
 	f.cond.L = &f.lock
 	return f
@@ -411,6 +440,21 @@ func (f *DeltaFIFO) queueActionLocked(actionType DeltaType, obj interface{}) err
 	if err != nil {
 		return KeyError{obj, err}
 	}
+
+	// Every object comes through this code path once, so this is a good
+	// place to call the transform func.  If obj is a
+	// DeletedFinalStateUnknown tombstone, then the containted inner object
+	// will already have gone through the transformer, but we document that
+	// this can happen. In cases involving Replace(), such an object can
+	// come through multiple times.
+	if f.transformer != nil {
+		var err error
+		obj, err = f.transformer(obj)
+		if err != nil {
+			return err
+		}
+	}
+
 	oldDeltas := f.items[id]
 	newDeltas := append(oldDeltas, Delta{actionType, obj})
 	newDeltas = dedupDeltas(newDeltas)
@@ -566,12 +610,11 @@ func (f *DeltaFIFO) Pop(process PopProcessFunc) (interface{}, error) {
 // using the Sync or Replace DeltaType and then (2) it does some deletions.
 // In particular: for every pre-existing key K that is not the key of
 // an object in `list` there is the effect of
-// `Delete(DeletedFinalStateUnknown{K, O})` where O is current object
-// of K.  If `f.knownObjects == nil` then the pre-existing keys are
-// those in `f.items` and the current object of K is the `.Newest()`
-// of the Deltas associated with K.  Otherwise the pre-existing keys
-// are those listed by `f.knownObjects` and the current object of K is
-// what `f.knownObjects.GetByKey(K)` returns.
+// `Delete(DeletedFinalStateUnknown{K, O})` where O is the latest known
+// object of K. The pre-existing keys are those in the union set of the keys in
+// `f.items` and `f.knownObjects` (if not nil). The last known object for key K is
+// the one present in the last delta in `f.items`. If there is no delta for K
+// in `f.items`, it is the object in `f.knownObjects`
 func (f *DeltaFIFO) Replace(list []interface{}, _ string) error {
 	f.lock.Lock()
 	defer f.lock.Unlock()
@@ -595,58 +638,56 @@ func (f *DeltaFIFO) Replace(list []interface{}, _ string) error {
 		}
 	}
 
-	if f.knownObjects == nil {
-		// Do deletion detection against our own list.
-		queuedDeletions := 0
-		for k, oldItem := range f.items {
-			if keys.Has(k) {
-				continue
-			}
-			// Delete pre-existing items not in the new list.
-			// This could happen if watch deletion event was missed while
-			// disconnected from apiserver.
-			var deletedObj interface{}
-			if n := oldItem.Newest(); n != nil {
-				deletedObj = n.Object
-			}
-			queuedDeletions++
-			if err := f.queueActionLocked(Deleted, DeletedFinalStateUnknown{k, deletedObj}); err != nil {
-				return err
-			}
-		}
-
-		if !f.populated {
-			f.populated = true
-			// While there shouldn't be any queued deletions in the initial
-			// population of the queue, it's better to be on the safe side.
-			f.initialPopulationCount = keys.Len() + queuedDeletions
-		}
-
-		return nil
-	}
-
-	// Detect deletions not already in the queue.
-	knownKeys := f.knownObjects.ListKeys()
+	// Do deletion detection against objects in the queue
 	queuedDeletions := 0
-	for _, k := range knownKeys {
+	for k, oldItem := range f.items {
 		if keys.Has(k) {
 			continue
 		}
-
-		deletedObj, exists, err := f.knownObjects.GetByKey(k)
-		if err != nil {
-			deletedObj = nil
-			klog.Errorf("Unexpected error %v during lookup of key %v, placing DeleteFinalStateUnknown marker without object", err, k)
-		} else if !exists {
-			deletedObj = nil
-			klog.Infof("Key %v does not exist in known objects store, placing DeleteFinalStateUnknown marker without object", k)
+		// Delete pre-existing items not in the new list.
+		// This could happen if watch deletion event was missed while
+		// disconnected from apiserver.
+		var deletedObj interface{}
+		if n := oldItem.Newest(); n != nil {
+			deletedObj = n.Object
+
+			// if the previous object is a DeletedFinalStateUnknown, we have to extract the actual Object
+			if d, ok := deletedObj.(DeletedFinalStateUnknown); ok {
+				deletedObj = d.Obj
+			}
 		}
 		queuedDeletions++
 		if err := f.queueActionLocked(Deleted, DeletedFinalStateUnknown{k, deletedObj}); err != nil {
 			return err
 		}
 	}
 
+	if f.knownObjects != nil {
+		// Detect deletions for objects not present in the queue, but present in KnownObjects
+		knownKeys := f.knownObjects.ListKeys()
+		for _, k := range knownKeys {
+			if keys.Has(k) {
+				continue
+			}
+			if len(f.items[k]) > 0 {
+				continue
+			}
+
+			deletedObj, exists, err := f.knownObjects.GetByKey(k)
+			if err != nil {
+				deletedObj = nil
+				klog.Errorf("Unexpected error %v during lookup of key %v, placing DeleteFinalStateUnknown marker without object", err, k)
+			} else if !exists {
+				deletedObj = nil
+				klog.Infof("Key %v does not exist in known objects store, placing DeleteFinalStateUnknown marker without object", k)
+			}
+			queuedDeletions++
+			if err := f.queueActionLocked(Deleted, DeletedFinalStateUnknown{k, deletedObj}); err != nil {
+				return err
+			}
+		}
+	}
+
 	if !f.populated {
 		f.populated = true
 		f.initialPopulationCount = keys.Len() + queuedDeletions