Merge NamespaceExists into NamespaceLifecycle

This commit merges the NamespaceExists admission controller
into the NamespaceLifecycle admission controller.

New tests were added to the NamespaceLifecycle addmission controller
tests, and the test case was fixed so that it runs without panicing.

Additionally, the NamespaceExists admission controller was marked as
deprecated in the docs.

Closes #12053

plugin/pkg/admission/namespace/lifecycle/admission_test.go

@@ -17,12 +17,15 @@ limitations under the License.
 package lifecycle
 
 import (
+	"fmt"
 	"testing"
 
 	"k8s.io/kubernetes/pkg/admission"
 	"k8s.io/kubernetes/pkg/api"
 	"k8s.io/kubernetes/pkg/client/unversioned/cache"
 	"k8s.io/kubernetes/pkg/client/unversioned/testclient"
+	"k8s.io/kubernetes/pkg/runtime"
+	"k8s.io/kubernetes/pkg/watch"
 )
 
 // TestAdmission
@@ -36,14 +39,37 @@ func TestAdmission(t *testing.T) {
 			Phase: api.NamespaceActive,
 		},
 	}
-	store := cache.NewStore(cache.IndexFuncToKeyFuncAdapter(cache.MetaNamespaceIndexFunc))
+
+	reactFunc := func(action testclient.Action) (runtime.Object, error) {
+		switch {
+		case action.Matches("get", "namespaces"):
+			if getAction, ok := action.(testclient.GetAction); ok && getAction.GetName() == namespaceObj.Name {
+				return namespaceObj, nil
+			}
+		case action.Matches("list", "namespaces"):
+			return &api.NamespaceList{Items: []api.Namespace{*namespaceObj}}, nil
+
+		}
+
+		return nil, fmt.Errorf("No result for action %v", action)
+	}
+
+	store := cache.NewStore(cache.MetaNamespaceKeyFunc)
 	store.Add(namespaceObj)
-	mockClient := &testclient.Fake{}
+	fakeWatch := watch.NewFake()
+	mockClient := &testclient.Fake{Watch: fakeWatch, ReactFn: reactFunc}
 	lfhandler := NewLifecycle(mockClient).(*lifecycle)
 	lfhandler.store = store
 	handler := admission.NewChainHandler(lfhandler)
 	pod := api.Pod{
-		ObjectMeta: api.ObjectMeta{Name: "123", Namespace: namespaceObj.Namespace},
+		ObjectMeta: api.ObjectMeta{Name: "123", Namespace: namespaceObj.Name},
+		Spec: api.PodSpec{
+			Volumes:    []api.Volume{{Name: "vol"}},
+			Containers: []api.Container{{Name: "ctr", Image: "image"}},
+		},
+	}
+	badPod := api.Pod{
+		ObjectMeta: api.ObjectMeta{Name: "456", Namespace: "doesnotexist"},
 		Spec: api.PodSpec{
 			Volumes:    []api.Volume{{Name: "vol"}},
 			Containers: []api.Container{{Name: "ctr", Image: "image"}},
@@ -88,4 +114,19 @@ func TestAdmission(t *testing.T) {
 		t.Errorf("Did not expect an error %v", err)
 	}
 
+	// verify create/update/delete of object in non-existant namespace throws error
+	err = handler.Admit(admission.NewAttributesRecord(&badPod, "Pod", badPod.Namespace, badPod.Name, "pods", "", admission.Create, nil))
+	if err == nil {
+		t.Errorf("Expected an aerror that objects cannot be created in non-existant namespaces", err)
+	}
+
+	err = handler.Admit(admission.NewAttributesRecord(&badPod, "Pod", badPod.Namespace, badPod.Name, "pods", "", admission.Update, nil))
+	if err == nil {
+		t.Errorf("Expected an aerror that objects cannot be updated in non-existant namespaces", err)
+	}
+
+	err = handler.Admit(admission.NewAttributesRecord(&badPod, "Pod", badPod.Namespace, badPod.Name, "pods", "", admission.Delete, nil))
+	if err == nil {
+		t.Errorf("Expected an aerror that objects cannot be deleted in non-existant namespaces", err)
+	}
 }