fix: avoid concurrent map operations for valid owner changes

For controllers that themselves start other controllers, concurrent maps
operations can happen when using the "valid owner change" feature. This
change will get rid of these concurrent map operations by using a
sync.Map instead.

Signed-off-by: Donnie Adams <donnie@acorn.io>

pkg/apply/apply.go

@@ -3,6 +3,7 @@ package apply
 import (
 	"context"
 	"fmt"
+	"sync"
 
 	"k8s.io/apimachinery/pkg/runtime/schema"
 	kclient "sigs.k8s.io/controller-runtime/pkg/client"
@@ -17,11 +18,11 @@ var (
 	// values that are allowed to change.  The key is in the format of
 	// "oldValue => newValue"
 	// subcontext and the value is the old subcontext name.
-	validOwnerChange = map[string]bool{}
+	validOwnerChange = sync.Map{}
 )
 
 func AddValidOwnerChange(oldSubcontext, newSubContext string) {
-	validOwnerChange[fmt.Sprintf("%s => %s", oldSubcontext, newSubContext)] = true
+	validOwnerChange.Store(fmt.Sprintf("%s => %s", oldSubcontext, newSubContext), struct{}{})
 }
 
 type Apply interface {

pkg/apply/desiredset_process.go

@@ -277,12 +277,14 @@ func (a *apply) process(debugID string, set labels.Selector, gvk schema.GroupVer
 func isAllowOwnerTransition(existingObj, newObj kclient.Object) bool {
 	existingAnno := existingObj.GetAnnotations()
 	newAnno := newObj.GetAnnotations()
-	return newAnno[LabelSubContext] != "" &&
-		(existingAnno[LabelGVK] == "" || existingAnno[LabelGVK] == newAnno[LabelGVK]) &&
-		(existingAnno[LabelNamespace] == "" || existingAnno[LabelNamespace] == newAnno[LabelNamespace]) &&
-		(existingAnno[LabelName] == "" || existingAnno[LabelName] == newAnno[LabelName]) &&
-		validOwnerChange[fmt.Sprintf("%s => %s", existingAnno[LabelSubContext], newAnno[LabelSubContext])]
-
+	if newAnno[LabelSubContext] == "" ||
+		(existingAnno[LabelGVK] != "" && existingAnno[LabelGVK] != newAnno[LabelGVK]) ||
+		(existingAnno[LabelNamespace] != "" && existingAnno[LabelNamespace] != newAnno[LabelNamespace]) ||
+		(existingAnno[LabelName] != "" && existingAnno[LabelName] != newAnno[LabelName]) {
+		return false
+	}
+	_, ok := validOwnerChange.Load(fmt.Sprintf("%s => %s", existingAnno[LabelSubContext], newAnno[LabelSubContext]))
+	return ok
 }
 
 // isAssigningSubContext is checking to see if an existing managed object