feat: Optionally enable namespacesync using a flag

Author: dlipovetsky

cmd/main.go

@@ -147,30 +147,37 @@ func main() {
 		os.Exit(1)
 	}
 
-	unstructuredCachingClient, err := client.New(mgr.GetConfig(), client.Options{
-		HTTPClient: mgr.GetHTTPClient(),
-		Cache: &client.CacheOptions{
-			Reader:       mgr.GetCache(),
-			Unstructured: true,
-		},
-	})
-	if err != nil {
-		setupLog.Error(err, "unable to create unstructured caching client")
-		os.Exit(1)
-	}
-
-	if err := (&namespacesync.Reconciler{
-		Client:                      mgr.GetClient(),
-		UnstructuredCachingClient:   unstructuredCachingClient,
-		SourceClusterClassNamespace: namespacesyncOptions.SourceNamespace,
-		TargetNamespaceFilter:       namespacesync.NamespaceHasLabelKey(namespacesyncOptions.TargetNamespaceLabelKey),
-	}).SetupWithManager(
-		signalCtx,
-		mgr,
-		controller.Options{MaxConcurrentReconciles: namespacesyncOptions.Concurrency},
-	); err != nil {
-		setupLog.Error(err, "unable to create controller", "controller", "namespacesync.Reconciler")
-		os.Exit(1)
+	if namespacesyncOptions.Enabled {
+		if namespacesyncOptions.SourceNamespace == "" || namespacesyncOptions.TargetNamespaceLabelKey == "" {
+			setupLog.Error(nil, "Namespace Sync is enabled, but source namespace and/or target namespace label key are not configured.") //nolint:lll // Usage string is wrapped in the terminal.
+			os.Exit(1)
+		}
+
+		unstructuredCachingClient, err := client.New(mgr.GetConfig(), client.Options{
+			HTTPClient: mgr.GetHTTPClient(),
+			Cache: &client.CacheOptions{
+				Reader:       mgr.GetCache(),
+				Unstructured: true,
+			},
+		})
+		if err != nil {
+			setupLog.Error(err, "unable to create unstructured caching client")
+			os.Exit(1)
+		}
+
+		if err := (&namespacesync.Reconciler{
+			Client:                      mgr.GetClient(),
+			UnstructuredCachingClient:   unstructuredCachingClient,
+			SourceClusterClassNamespace: namespacesyncOptions.SourceNamespace,
+			TargetNamespaceFilter:       namespacesync.NamespaceHasLabelKey(namespacesyncOptions.TargetNamespaceLabelKey),
+		}).SetupWithManager(
+			signalCtx,
+			mgr,
+			controller.Options{MaxConcurrentReconciles: namespacesyncOptions.Concurrency},
+		); err != nil {
+			setupLog.Error(err, "unable to create controller", "controller", "namespacesync.Reconciler")
+			os.Exit(1)
+		}
 	}
 
 	if err := mgr.Start(signalCtx); err != nil {

pkg/controllers/namespacesync/flags.go

@@ -5,16 +5,23 @@ package namespacesync
 
 import (
 	"github.com/spf13/pflag"
-	corev1 "k8s.io/api/core/v1"
 )
 
 type Options struct {
+	Enabled                 bool
 	Concurrency             int
 	SourceNamespace         string
 	TargetNamespaceLabelKey string
 }
 
 func (o *Options) AddFlags(flags *pflag.FlagSet) {
+	pflag.CommandLine.BoolVar(
+		&o.Enabled,
+		"namespacesync-enabled",
+		false,
+		"Enable copying of ClusterClasses and Templates from a source namespace to one or more target namespaces.",
+	)
+
 	pflag.CommandLine.IntVar(
 		&o.Concurrency,
 		"namespacesync-concurrency",