Merge pull request #50325 from p0lyn0mial/sample_server_ban_flunder_plugin_get_name

Automatic merge from submit-queue

Small improvement in ban flunder admission plugin.

**What this PR does / why we need it**:
After the changes a name will be taken directly from meta field.
Previously a name was taken via attributes.GetName() method,
which in turns derived a name from a URL address.
This didn't work as we don't allow to pass a name when POSTing a resource.

#47868

**Release note**:

```
NONE
```

staging/src/k8s.io/sample-apiserver/pkg/admission/plugin/banflunder/BUILD

@@ -11,6 +11,7 @@ go_library(
     srcs = ["admission.go"],
     deps = [
         "//vendor/k8s.io/apimachinery/pkg/api/errors:go_default_library",
+        "//vendor/k8s.io/apimachinery/pkg/api/meta:go_default_library",
         "//vendor/k8s.io/apimachinery/pkg/labels:go_default_library",
         "//vendor/k8s.io/apiserver/pkg/admission:go_default_library",
         "//vendor/k8s.io/sample-apiserver/pkg/admission/wardleinitializer:go_default_library",

staging/src/k8s.io/sample-apiserver/pkg/admission/plugin/banflunder/admission.go

@@ -21,6 +21,7 @@ import (
 	"io"
 
 	"k8s.io/apimachinery/pkg/api/errors"
+	"k8s.io/apimachinery/pkg/api/meta"
 	"k8s.io/apimachinery/pkg/labels"
 	"k8s.io/apiserver/pkg/admission"
 	"k8s.io/sample-apiserver/pkg/admission/wardleinitializer"
@@ -52,7 +53,12 @@ func (d *disallowFlunder) Admit(a admission.Attributes) error {
 		return nil
 	}
 
-	flunderName := a.GetName()
+	metaAccessor, err := meta.Accessor(a.GetObject())
+	if err != nil {
+		return err
+	}
+	flunderName := metaAccessor.GetName()
+
 	fischers, err := d.lister.List(labels.Everything())
 	if err != nil {
 		return err

staging/src/k8s.io/sample-apiserver/pkg/admission/plugin/banflunder/admission_test.go

@@ -135,7 +135,7 @@ func TestBanflunderAdmissionPlugin(t *testing.T) {
 				nil,
 				scenario.admissionInputKind,
 				scenario.admissionInput.ObjectMeta.Namespace,
-				scenario.admissionInput.ObjectMeta.Name,
+				"",
 				scenario.admissionInputResource,
 				"",
 				admission.Create,