layer1: add namespace snapshot api step 1

pkg/utils/informer.go

@@ -23,7 +23,7 @@ import (
 
 func GetInformersForNamespaces(client versioned.Interface, defaultSync time.Duration, kind string) map[string]cache.SharedIndexInformer {
 	informers := make(map[string]cache.SharedIndexInformer)
-	for _, ns := range DefaultNSResolver().FissionResourceNS {
+	for _, ns := range DefaultNSResolver().Snapshot() {
 		factory := genInformer.NewFilteredSharedInformerFactory(client, defaultSync, ns, nil).Core().V1()
 		switch kind {
 		case fv1.CanaryConfigResource:
@@ -52,7 +52,7 @@ func GetInformersForNamespaces(client versioned.Interface, defaultSync time.Dura
 func GetK8sInformersForNamespaces(client kubernetes.Interface, defaultSync time.Duration, kind string) map[string]cache.SharedIndexInformer {
 	informers := make(map[string]cache.SharedIndexInformer)
 	namespaces := DefaultNSResolver()
-	for _, ns := range namespaces.FissionNSWithOptions(WithBuilderNs(), WithFunctionNs(), WithDefaultNs()) {
+	for _, ns := range namespaces.SnapshotWithOptions(WithBuilderNs(), WithFunctionNs(), WithDefaultNs()) {
 		factory := k8sInformers.NewSharedInformerFactoryWithOptions(client, defaultSync, k8sInformers.WithNamespace(ns))
 		switch kind {
 		case fv1.Deployments:
@@ -77,7 +77,7 @@ func GetK8sInformersForNamespaces(client kubernetes.Interface, defaultSync time.
 func GetInformerEventChecker(ctx context.Context, client kubernetes.Interface, reason string) map[string]cache.SharedInformer {
 	informers := make(map[string]cache.SharedInformer)
 	namespaces := DefaultNSResolver()
-	for _, ns := range namespaces.FissionNSWithOptions(WithBuilderNs(), WithFunctionNs(), WithDefaultNs()) {
+	for _, ns := range namespaces.SnapshotWithOptions(WithBuilderNs(), WithFunctionNs(), WithDefaultNs()) {
 		informers[ns] = cache.NewSharedInformer(
 			&cache.ListWatch{
 				ListFunc: func(options metav1.ListOptions) (runtime.Object, error) {
@@ -100,7 +100,7 @@ func GetInformerFactoryByExecutor(client kubernetes.Interface, labels labels.Sel
 	informerFactory := make(map[string]k8sInformers.SharedInformerFactory)
 
 	namespaces := DefaultNSResolver()
-	for _, ns := range namespaces.FissionNSWithOptions(WithBuilderNs(), WithFunctionNs(), WithDefaultNs()) {
+	for _, ns := range namespaces.SnapshotWithOptions(WithBuilderNs(), WithFunctionNs(), WithDefaultNs()) {
 		factory := k8sInformers.NewSharedInformerFactoryWithOptions(client, defaultResync,
 			k8sInformers.WithTweakListOptions(func(options *metav1.ListOptions) {
 				options.LabelSelector = labels.String()

pkg/utils/namespace.go

@@ -2,6 +2,7 @@ package utils
 
 import (
 	"os"
+	"sort"
 	"strings"
 	"sync"
 
@@ -96,10 +97,23 @@ func (nsr *NamespaceResolver) AddNamespace(ns string) bool {
 		return false
 	}
 	nsr.FissionResourceNS[ns] = ns
-	nsr.Logger.Info("dynamically added namespace to resolver", zap.String("namespace", ns))
+	if nsr.Logger != nil {
+		nsr.Logger.Info("dynamically added namespace to resolver", zap.String("namespace", ns))
+	}
 	return true
 }
 
+// Snapshot returns a stable copy of the currently registered resource namespaces.
+// The returned slice is detached from the internal mutable map and safe to iterate.
+func (nsr *NamespaceResolver) Snapshot() []string {
+	nsr.mu.RLock()
+	defer nsr.mu.RUnlock()
+
+	namespaces := listNamespaces(nsr.FissionResourceNS)
+	sort.Strings(namespaces)
+	return namespaces
+}
+
 func (nsr *NamespaceResolver) FissionNSWithOptions(option ...option) map[string]string {
 	var options options
 	for _, opt := range option {
@@ -122,10 +136,20 @@ func (nsr *NamespaceResolver) FissionNSWithOptions(option ...option) map[string]
 	if options.defaultNs && nsr.DefaultNamespace != "" {
 		fissionResourceNS[nsr.DefaultNamespace] = nsr.DefaultNamespace
 	}
-	nsr.Logger.Debug("fission resource namespaces", zap.Any("namespaces", listNamespaces(fissionResourceNS)))
+	if nsr.Logger != nil {
+		nsr.Logger.Debug("fission resource namespaces", zap.Any("namespaces", listNamespaces(fissionResourceNS)))
+	}
 	return fissionResourceNS
 }
 
+// SnapshotWithOptions returns a stable slice copy of Fission namespaces after applying
+// optional builder/function/default namespace expansion.
+func (nsr *NamespaceResolver) SnapshotWithOptions(option ...option) []string {
+	namespaces := listNamespaces(nsr.FissionNSWithOptions(option...))
+	sort.Strings(namespaces)
+	return namespaces
+}
+
 func GetNamespaces() map[string]string {
 	namespaces := make(map[string]string)
 

pkg/utils/namespace_test.go

@@ -2,6 +2,7 @@ package utils
 
 import (
 	"os"
+	"reflect"
 	"testing"
 )
 
@@ -177,6 +178,44 @@ func TestNamespaceResolver(t *testing.T) {
 		}
 	})
 
+	t.Run("Snapshot returns stable copy", func(t *testing.T) {
+		nsr := &NamespaceResolver{
+			FissionResourceNS: map[string]string{
+				"ns-b": "ns-b",
+				"ns-a": "ns-a",
+			},
+		}
+
+		snapshot := nsr.Snapshot()
+		expected := []string{"ns-a", "ns-b"}
+		if !reflect.DeepEqual(expected, snapshot) {
+			t.Fatalf("expected snapshot %v, got %v", expected, snapshot)
+		}
+
+		snapshot[0] = "mutated"
+		if nsr.FissionResourceNS["ns-a"] != "ns-a" {
+			t.Fatalf("snapshot mutated internal namespace map")
+		}
+	})
+
+	t.Run("SnapshotWithOptions includes expanded namespaces once", func(t *testing.T) {
+		nsr := &NamespaceResolver{
+			FunctionNamespace: "fn-ns",
+			BuilderNamespace:  "builder-ns",
+			DefaultNamespace:  "default",
+			FissionResourceNS: map[string]string{
+				"default": "default",
+				"user-ns": "user-ns",
+			},
+		}
+
+		snapshot := nsr.SnapshotWithOptions(WithBuilderNs(), WithFunctionNs(), WithDefaultNs())
+		expected := []string{"builder-ns", "default", "fn-ns", "user-ns"}
+		if !reflect.DeepEqual(expected, snapshot) {
+			t.Fatalf("expected snapshot with options %v, got %v", expected, snapshot)
+		}
+	})
+
 	t.Run("getNamespace", func(t *testing.T) {
 		for _, test := range []struct {
 			name                string