From 00a491e0ceb34af56b292c8e19f762d64a86658e Mon Sep 17 00:00:00 2001
From: xigang <wangxigang2014@gmail.com>
Date: Thu, 12 Jun 2025 08:19:21 +0800
Subject: [PATCH] Add RealFIFOOptions struct to provide structured
 configuration for RealFIFO

Signed-off-by: xigang <wangxigang2014@gmail.com>

Kubernetes-commit: 26bbea8c07131080f763c4ccc1eda5daa66803a6
---
 tools/cache/controller.go      |  8 +++++--
 tools/cache/shared_informer.go |  6 ++++-
 tools/cache/the_real_fifo.go   | 42 ++++++++++++++++++++++++++++++----
 3 files changed, 49 insertions(+), 7 deletions(-)

diff --git a/tools/cache/controller.go b/tools/cache/controller.go
index 5f983b6b6..e8c99aa6a 100644
--- a/tools/cache/controller.go
+++ b/tools/cache/controller.go
@@ -19,13 +19,13 @@ package cache
 import (
 	"context"
 	"errors"
-	clientgofeaturegate "k8s.io/client-go/features"
 	"sync"
 	"time"
 
 	"k8s.io/apimachinery/pkg/runtime"
 	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
 	"k8s.io/apimachinery/pkg/util/wait"
+	clientgofeaturegate "k8s.io/client-go/features"
 	"k8s.io/utils/clock"
 )
 
@@ -598,7 +598,11 @@ func newInformer(clientState Store, options InformerOptions) Controller {
 
 	var fifo Queue
 	if clientgofeaturegate.FeatureGates().Enabled(clientgofeaturegate.InOrderInformers) {
-		fifo = NewRealFIFO(MetaNamespaceKeyFunc, clientState, options.Transform)
+		fifo = NewRealFIFOWithOptions(RealFIFOOptions{
+			KeyFunction:  MetaNamespaceKeyFunc,
+			KnownObjects: clientState,
+			Transformer:  options.Transform,
+		})
 	} else {
 		fifo = NewDeltaFIFOWithOptions(DeltaFIFOOptions{
 			KnownObjects:          clientState,
diff --git a/tools/cache/shared_informer.go b/tools/cache/shared_informer.go
index 99e5fcd18..959fb19ba 100644
--- a/tools/cache/shared_informer.go
+++ b/tools/cache/shared_informer.go
@@ -541,7 +541,11 @@ func (s *sharedIndexInformer) RunWithContext(ctx context.Context) {
 
 		var fifo Queue
 		if clientgofeaturegate.FeatureGates().Enabled(clientgofeaturegate.InOrderInformers) {
-			fifo = NewRealFIFO(MetaNamespaceKeyFunc, s.indexer, s.transform)
+			fifo = NewRealFIFOWithOptions(RealFIFOOptions{
+				KeyFunction:  MetaNamespaceKeyFunc,
+				KnownObjects: s.indexer,
+				Transformer:  s.transform,
+			})
 		} else {
 			fifo = NewDeltaFIFOWithOptions(DeltaFIFOOptions{
 				KnownObjects:          s.indexer,
diff --git a/tools/cache/the_real_fifo.go b/tools/cache/the_real_fifo.go
index ef322bea8..9295d3021 100644
--- a/tools/cache/the_real_fifo.go
+++ b/tools/cache/the_real_fifo.go
@@ -26,6 +26,25 @@ import (
 	utiltrace "k8s.io/utils/trace"
 )
 
+// RealFIFOOptions is the configuration parameters for RealFIFO.
+type RealFIFOOptions struct {
+	// KeyFunction is used to figure out what key an object should have. (It's
+	// exposed in the returned RealFIFO's keyOf() method, with additional
+	// handling around deleted objects and queue state).
+	// Optional, the default is MetaNamespaceKeyFunc.
+	KeyFunction KeyFunc
+
+	// KnownObjects is expected to return a list of keys that the consumer of
+	// this queue "knows about". It is used to decide which items are missing
+	// when Replace() is called; 'Deleted' deltas are produced for the missing items.
+	// KnownObjects is required.
+	KnownObjects KeyListerGetter
+
+	// If set, will be called for objects before enqueueing them. Please
+	// see the comment on TransformFunc for details.
+	Transformer TransformFunc
+}
+
 // RealFIFO is a Queue in which every notification from the Reflector is passed
 // in order to the Queue via Pop.
 // This means that it
@@ -398,16 +417,31 @@ func (f *RealFIFO) Transformer() TransformFunc {
 // NewRealFIFO returns a Store which can be used to queue up items to
 // process.
 func NewRealFIFO(keyFunc KeyFunc, knownObjects KeyListerGetter, transformer TransformFunc) *RealFIFO {
-	if knownObjects == nil {
+	return NewRealFIFOWithOptions(RealFIFOOptions{
+		KeyFunction:  keyFunc,
+		KnownObjects: knownObjects,
+		Transformer:  transformer,
+	})
+}
+
+// NewRealFIFOWithOptions returns a Queue which can be used to process changes to
+// items. See also the comment on RealFIFO.
+func NewRealFIFOWithOptions(opts RealFIFOOptions) *RealFIFO {
+	if opts.KeyFunction == nil {
+		opts.KeyFunction = MetaNamespaceKeyFunc
+	}
+
+	if opts.KnownObjects == nil {
 		panic("coding error: knownObjects must be provided")
 	}
 
 	f := &RealFIFO{
 		items:        make([]Delta, 0, 10),
-		keyFunc:      keyFunc,
-		knownObjects: knownObjects,
-		transformer:  transformer,
+		keyFunc:      opts.KeyFunction,
+		knownObjects: opts.KnownObjects,
+		transformer:  opts.Transformer,
 	}
+
 	f.cond.L = &f.lock
 	return f
 }