layer1: add namespace snapshot api step 1

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)