l-38

vendor/sigs.k8s.io/controller-runtime/pkg/builder/controller.go

@@ -75,11 +75,13 @@ type ForInput struct {
 	err              error
 }
 
+// For 方法监控的对象只能是一个
 // For defines the type of Object being *reconciled*, and configures the ControllerManagedBy to respond to create / delete /
 // update events by *reconciling the object*.
 // This is the equivalent of calling
 // Watches(&source.Kind{Type: apiType}, &handler.EnqueueRequestForObject{}).
 func (blder *Builder) For(object client.Object, opts ...ForOption) *Builder {
+	// 如果已经存在就报错退出，完成了之间空一个对象的逻辑
 	if blder.forInput.object != nil {
 		blder.forInput.err = fmt.Errorf("For(...) should only be called once, could not assign multiple objects for reconciliation")
 		return blder
@@ -173,6 +175,7 @@ func (blder *Builder) Complete(r reconcile.Reconciler) error {
 
 // Build builds the Application Controller and returns the Controller it created.
 func (blder *Builder) Build(r reconcile.Reconciler) (controller.Controller, error) {
+	// 异常检查，保证后续的执行不会产生空指针的 panic
 	if r == nil {
 		return nil, fmt.Errorf("must provide a non-nil Reconciler")
 	}