Merge pull request #51727 from juanvallejo/jvallejo/ensure-unstructured-objects-kubectl-get

Automatic merge from submit-queue (batch tested with PRs 51031, 51705, 51888, 51727, 51684). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>..

ensure unstructured resources in kubectl get

Related downstream issue: https://github.com/openshift/origin/issues/16064

Ensure we are dealing with unstructured objects before attempting to
compose into an unstructured list.

`$ kubectl get ...` [assumes all resources returned from a resource builder are unstructured objects](https://github.com/kubernetes/kubernetes/blob/master/pkg/kubectl/cmd/get.go#L355). This leads to a panic when dealing with non-unstructured objects.
This patch ensures we are dealing with unstructured objects before attempting to
compose into an unstructured list.

**Release note**:
```release-note
NONE
```

cc @fabianofranz @kubernetes/sig-cli-misc

pkg/kubectl/cmd/get.go

@@ -17,6 +17,7 @@ limitations under the License.
 package cmd
 
 import (
+	"encoding/json"
 	"fmt"
 	"io"
 	"strings"
@@ -26,11 +27,13 @@ import (
 
 	kapierrors "k8s.io/apimachinery/pkg/api/errors"
 	"k8s.io/apimachinery/pkg/api/meta"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
 	"k8s.io/apimachinery/pkg/runtime"
 	utilerrors "k8s.io/apimachinery/pkg/util/errors"
 	"k8s.io/apimachinery/pkg/util/sets"
 	"k8s.io/apimachinery/pkg/watch"
+	"k8s.io/kubernetes/pkg/api"
 	"k8s.io/kubernetes/pkg/kubectl"
 	"k8s.io/kubernetes/pkg/kubectl/cmd/templates"
 	cmdutil "k8s.io/kubernetes/pkg/kubectl/cmd/util"
@@ -354,17 +357,32 @@ func RunGet(f cmdutil.Factory, out, errOut io.Writer, cmd *cobra.Command, args [
 		var obj runtime.Object
 		if !singleItemImplied || len(infos) > 1 {
 			// we have more than one item, so coerce all items into a list
-			list := &unstructured.UnstructuredList{
-				Object: map[string]interface{}{
-					"kind":       "List",
-					"apiVersion": "v1",
-					"metadata":   map[string]interface{}{},
+			// we have more than one item, so coerce all items into a list.
+			// we don't want an *unstructured.Unstructured list yet, as we
+			// may be dealing with non-unstructured objects. Compose all items
+			// into an api.List, and then decode using an unstructured scheme.
+			list := api.List{
+				TypeMeta: metav1.TypeMeta{
+					Kind:       "List",
+					APIVersion: "v1",
 				},
+				ListMeta: metav1.ListMeta{},
 			}
 			for _, info := range infos {
-				list.Items = append(list.Items, *info.Object.(*unstructured.Unstructured))
+				list.Items = append(list.Items, info.Object)
 			}
-			obj = list
+
+			listData, err := json.Marshal(list)
+			if err != nil {
+				return err
+			}
+
+			converted, err := runtime.Decode(unstructured.UnstructuredJSONScheme, listData)
+			if err != nil {
+				return err
+			}
+
+			obj = converted
 		} else {
 			obj = infos[0].Object
 		}

pkg/kubectl/cmd/get_test.go

@@ -575,6 +575,83 @@ func TestGetListComponentStatus(t *testing.T) {
 	}
 }
 
+func TestGetMixedGenericObjects(t *testing.T) {
+	initTestErrorHandler(t)
+
+	// ensure that a runtime.Object without
+	// an ObjectMeta field is handled properly
+	structuredObj := &metav1.Status{
+		TypeMeta: metav1.TypeMeta{
+			Kind:       "Status",
+			APIVersion: "v1",
+		},
+		Status:  "Success",
+		Message: "",
+		Reason:  "",
+		Code:    0,
+	}
+
+	f, tf, codec, _ := cmdtesting.NewAPIFactory()
+	tf.Printer = &testPrinter{GenericPrinter: true}
+	tf.UnstructuredClient = &fake.RESTClient{
+		APIRegistry:          api.Registry,
+		NegotiatedSerializer: unstructuredSerializer,
+		Client: fake.CreateHTTPClient(func(req *http.Request) (*http.Response, error) {
+			switch req.URL.Path {
+			case "/namespaces/test/pods":
+				return &http.Response{StatusCode: 200, Header: defaultHeader(), Body: objBody(codec, structuredObj)}, nil
+			default:
+				t.Fatalf("request url: %#v,and request: %#v", req.URL, req)
+				return nil, nil
+			}
+		}),
+	}
+	tf.Namespace = "test"
+	tf.ClientConfig = &restclient.Config{ContentConfig: restclient.ContentConfig{GroupVersion: &api.Registry.GroupOrDie(api.GroupName).GroupVersion}}
+	buf := bytes.NewBuffer([]byte{})
+	errBuf := bytes.NewBuffer([]byte{})
+
+	cmd := NewCmdGet(f, buf, errBuf)
+	cmd.SetOutput(buf)
+	cmd.Flags().Set("output", "json")
+	cmd.Run(cmd, []string{"pods"})
+
+	if len(buf.String()) == 0 {
+		t.Error("unexpected empty output")
+	}
+
+	actual := tf.Printer.(*testPrinter).Objects
+	fn := func(obj runtime.Object) unstructured.Unstructured {
+		data, err := runtime.Encode(api.Codecs.LegacyCodec(schema.GroupVersion{Version: "v1"}), obj)
+		if err != nil {
+			panic(err)
+		}
+		out := &unstructured.Unstructured{Object: make(map[string]interface{})}
+		if err := encjson.Unmarshal(data, &out.Object); err != nil {
+			panic(err)
+		}
+		return *out
+	}
+
+	expected := &unstructured.UnstructuredList{
+		Object: map[string]interface{}{"kind": "List", "apiVersion": "v1", "metadata": map[string]interface{}{"selfLink": "", "resourceVersion": ""}},
+		Items: []unstructured.Unstructured{
+			fn(structuredObj),
+		},
+	}
+	actualBytes, err := encjson.Marshal(actual[0])
+	if err != nil {
+		t.Fatal(err)
+	}
+	expectedBytes, err := encjson.Marshal(expected)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if string(actualBytes) != string(expectedBytes) {
+		t.Errorf("expectedBytes: %s,but actualBytes: %s", expectedBytes, actualBytes)
+	}
+}
+
 func TestGetMultipleTypeObjects(t *testing.T) {
 	pods, svc, _ := testData()
 
@@ -649,11 +726,11 @@ func TestGetMultipleTypeObjectsAsList(t *testing.T) {
 	fn := func(obj runtime.Object) unstructured.Unstructured {
 		data, err := runtime.Encode(api.Codecs.LegacyCodec(schema.GroupVersion{Version: "v1"}), obj)
 		if err != nil {
-			panic(err)
+			t.Fatal(err)
 		}
 		out := &unstructured.Unstructured{Object: make(map[string]interface{})}
 		if err := encjson.Unmarshal(data, &out.Object); err != nil {
-			panic(err)
+			t.Fatal(err)
 		}
 		return *out
 	}