Add DisableDeepCopy as list option to avoid deep copy during list

Signed-off-by: Siyu Wang <FillZpp.pub@gmail.com>

pkg/cache/internal/cache_reader.go

@@ -135,13 +135,31 @@ func (c *CacheReader) List(_ context.Context, out client.ObjectList, opts ...cli
 			}
 		}
 
-		outObj := obj.DeepCopyObject()
-		outObj.GetObjectKind().SetGroupVersionKind(c.groupVersionKind)
+		var outObj runtime.Object
+		if c.disableDeepCopy(obj, listOpts) {
+			outObj = obj
+		} else {
+			outObj = obj.DeepCopyObject()
+			outObj.GetObjectKind().SetGroupVersionKind(c.groupVersionKind)
+		}
 		runtimeObjs = append(runtimeObjs, outObj)
 	}
 	return apimeta.SetList(out, runtimeObjs)
 }
 
+// disableDeepCopy checks if this object need to skip deep copy.
+func (c *CacheReader) disableDeepCopy(obj runtime.Object, listOpts client.ListOptions) bool {
+	var disableDeepCopy bool
+	if listOpts.DisableDeepCopy != nil {
+		if listOpts.DisableDeepCopy.IgnoreGVK {
+			disableDeepCopy = true
+		} else if obj.GetObjectKind().GroupVersionKind() == c.groupVersionKind {
+			disableDeepCopy = true
+		}
+	}
+	return disableDeepCopy
+}
+
 // objectKeyToStorageKey converts an object key to store key.
 // It's akin to MetaNamespaceKeyFunc.  It's separate from
 // String to allow keeping the key format easily in sync with

pkg/cache/internal/cache_reader_test.go

@@ -0,0 +1,81 @@
+/*
+Copyright 2020 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package internal
+
+import (
+	"testing"
+
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
+	"k8s.io/apimachinery/pkg/runtime/schema"
+	"sigs.k8s.io/controller-runtime/pkg/client"
+	"sigs.k8s.io/controller-runtime/pkg/envtest/printer"
+)
+
+var (
+	targetGVK = schema.GroupVersionKind{Group: "test.kubebuilder.io", Version: "v1beta1", Kind: "SomeCR"}
+)
+
+func TestSource(t *testing.T) {
+	RegisterFailHandler(Fail)
+	suiteName := "Cache Internal Test Suite"
+	RunSpecsWithDefaultAndCustomReporters(t, suiteName, []Reporter{printer.NewlineReporter{}, printer.NewProwReporter(suiteName)})
+}
+
+var _ = Describe("Cache reader", func() {
+	Describe("Disable deep copy", func() {
+		var c *CacheReader
+		BeforeEach(func() {
+			c = &CacheReader{groupVersionKind: targetGVK}
+		})
+
+		objWithoutGVK := &unstructured.Unstructured{}
+		objWithGVK := &unstructured.Unstructured{}
+		objWithGVK.SetGroupVersionKind(targetGVK)
+
+		It("should deep copy for object without gvk if listOptions not set disableDeepCopy", func() {
+			listOps := client.ListOptions{}
+			Expect(c.disableDeepCopy(objWithoutGVK, listOps)).To(Equal(false))
+		})
+
+		It("should deep copy for object with gvk if listOptions not set disableDeepCopy", func() {
+			listOps := client.ListOptions{}
+			Expect(c.disableDeepCopy(objWithGVK, listOps)).To(Equal(false))
+		})
+
+		It("should deep copy for object without gvk if listOptions set disableDeepCopy and IgnoreGVK is false", func() {
+			listOps := client.ListOptions{DisableDeepCopy: &client.DisableDeepCopy{}}
+			Expect(c.disableDeepCopy(objWithoutGVK, listOps)).To(Equal(false))
+		})
+
+		It("should not deep copy for object with gvk if listOptions set disableDeepCopy and IgnoreGVK is false", func() {
+			listOps := client.ListOptions{DisableDeepCopy: &client.DisableDeepCopy{}}
+			Expect(c.disableDeepCopy(objWithGVK, listOps)).To(Equal(true))
+		})
+
+		It("should not deep copy for object without gvk if listOptions set disableDeepCopy and IgnoreGVK is true", func() {
+			listOps := client.ListOptions{DisableDeepCopy: &client.DisableDeepCopy{IgnoreGVK: true}}
+			Expect(c.disableDeepCopy(objWithoutGVK, listOps)).To(Equal(true))
+		})
+
+		It("should not deep copy for object with gvk if listOptions set disableDeepCopy and IgnoreGVK is true", func() {
+			listOps := client.ListOptions{DisableDeepCopy: &client.DisableDeepCopy{IgnoreGVK: true}}
+			Expect(c.disableDeepCopy(objWithGVK, listOps)).To(Equal(true))
+		})
+	})
+})

pkg/client/options.go

@@ -345,6 +345,9 @@ type ListOptions struct {
 	// that these may not be respected by all implementations of interface,
 	// and the LabelSelector, FieldSelector, Limit and Continue fields are ignored.
 	Raw *metav1.ListOptions
+
+	// DisableDeepCopy allows users to list objects without deep copy.
+	DisableDeepCopy *DisableDeepCopy
 }
 
 var _ ListOption = &ListOptions{}
@@ -521,6 +524,17 @@ func (c Continue) ApplyToList(opts *ListOptions) {
 	opts.Continue = string(c)
 }
 
+// DisableDeepCopy indicates not to deep copy objects during list objects in cache reader.
+type DisableDeepCopy struct {
+	// if IgnoreGVK is true, cache reader will always list without deep copy.
+	// Otherwise, it will only avoid deep copy for objects that already have correct groupVersionKind.
+	IgnoreGVK bool
+}
+
+func (d DisableDeepCopy) ApplyToList(opts *ListOptions) {
+	opts.DisableDeepCopy = &d
+}
+
 // }}}
 
 // {{{ Update Options