let encoder handle unversioned objects

address lavalamp's comments

address lavalamp's comments

address lavalamp's comments

add a TODO based on lavalamp's comment

add a TODO based on lavalamp's comment

pkg/conversion/encode.go

@@ -19,6 +19,7 @@ package conversion
 import (
 	"encoding/json"
 	"fmt"
+	"path"
 )
 
 // EncodeToVersion turns the given api object into an appropriate JSON string.
@@ -52,6 +53,14 @@ import (
 func (s *Scheme) EncodeToVersion(obj interface{}, destVersion string) (data []byte, err error) {
 	obj = maybeCopy(obj)
 	v, _ := EnforcePtr(obj) // maybeCopy guarantees a pointer
+
+	// Don't encode an object defined in the unversioned package, unless if the
+	// destVersion is v1, encode it to v1 for backward compatibility.
+	pkg := path.Base(v.Type().PkgPath())
+	if pkg == "unversioned" && destVersion != "v1" {
+		return s.encodeUnversionedObject(obj)
+	}
+
 	if _, registered := s.typeToVersion[v.Type()]; !registered {
 		return nil, fmt.Errorf("type %v is not registered for %q and it will be impossible to Decode it, therefore Encode will refuse to encode it.", v.Type(), destVersion)
 	}
@@ -102,3 +111,21 @@ func (s *Scheme) EncodeToVersion(obj interface{}, destVersion string) (data []by
 
 	return data, nil
 }
+
+func (s *Scheme) encodeUnversionedObject(obj interface{}) (data []byte, err error) {
+	_, objKind, err := s.ObjectVersionAndKind(obj)
+	if err != nil {
+		return nil, err
+	}
+	if err = s.SetVersionAndKind("", objKind, obj); err != nil {
+		return nil, err
+	}
+	data, err = json.Marshal(obj)
+	if err != nil {
+		return nil, err
+	}
+	// Version and Kind should be blank in memory. Reset them, since it's
+	// possible that we modified a user object and not a copy above.
+	err = s.SetVersionAndKind("", "", obj)
+	return data, nil
+}

pkg/conversion/meta.go

@@ -19,6 +19,7 @@ package conversion
 import (
 	"encoding/json"
 	"fmt"
+	"path"
 	"reflect"
 )
 
@@ -77,6 +78,7 @@ func UpdateVersionAndKind(baseFields []string, versionField, version, kindField,
 	if err != nil {
 		return err
 	}
+	pkg := path.Base(v.Type().PkgPath())
 	t := v.Type()
 	name := t.Name()
 	if v.Kind() != reflect.Struct {
@@ -93,6 +95,15 @@ func UpdateVersionAndKind(baseFields []string, versionField, version, kindField,
 
 	field := v.FieldByName(kindField)
 	if !field.IsValid() {
+		// Types defined in the unversioned package are allowed to not have a
+		// kindField. Clients will have to know what they are based on the
+		// context.
+		// TODO: add some type trait here, or some way of indicating whether
+		// this feature is allowed on a per-type basis. Using package name is
+		// overly broad and a bit hacky.
+		if pkg == "unversioned" {
+			return nil
+		}
 		return fmt.Errorf("couldn't find %v field in %#v", kindField, v.Interface())
 	}
 	field.SetString(kind)

pkg/conversion/meta_test.go

@@ -17,8 +17,11 @@ limitations under the License.
 package conversion
 
 import (
+	"fmt"
 	"reflect"
 	"testing"
+
+	"k8s.io/kubernetes/pkg/api/unversioned"
 )
 
 func TestSimpleMetaFactoryInterpret(t *testing.T) {
@@ -72,6 +75,25 @@ func TestSimpleMetaFactoryUpdate(t *testing.T) {
 	}
 }
 
+// Test Updating objects that don't have a Kind field.
+func TestSimpleMetaFactoryUpdateNoKindField(t *testing.T) {
+	factory := SimpleMetaFactory{VersionField: "APIVersion", KindField: "Kind"}
+	// obj does not have a Kind field and is not defined in the unversioned package.
+	obj := struct {
+		SomeField string
+	}{"1"}
+	expectedError := fmt.Errorf("couldn't find %v field in %#v", factory.KindField, obj)
+	if err := factory.Update("test", "other", &obj); err == nil || expectedError.Error() != err.Error() {
+		t.Fatalf("expected error: %v, got: %v", expectedError, err)
+	}
+
+	// ListMeta does not have a Kind field, but is defined in the unversioned package.
+	listMeta := unversioned.ListMeta{}
+	if err := factory.Update("test", "other", &listMeta); err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+}
+
 func TestSimpleMetaFactoryUpdateStruct(t *testing.T) {
 	factory := SimpleMetaFactory{BaseFields: []string{"Test"}, VersionField: "V", KindField: "K"}
 

pkg/conversion/unversioned_test.go

@@ -0,0 +1,92 @@
+/*
+Copyright 2015 The Kubernetes Authors All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package conversion_test
+
+import (
+	"encoding/json"
+	"reflect"
+	"testing"
+
+	// TODO: Ideally we should create the necessary package structure in e.g.,
+	// pkg/conversion/test/... instead of importing pkg/api here.
+	"k8s.io/kubernetes/pkg/api"
+	"k8s.io/kubernetes/pkg/api/testapi"
+	"k8s.io/kubernetes/pkg/api/unversioned"
+	"k8s.io/kubernetes/pkg/runtime"
+)
+
+var status = &unversioned.Status{
+	Status:  unversioned.StatusFailure,
+	Code:    200,
+	Reason:  unversioned.StatusReasonUnknown,
+	Message: "",
+}
+
+func TestV1EncodeDecodeStatus(t *testing.T) {
+
+	v1Codec := testapi.Default.Codec()
+
+	encoded, err := v1Codec.Encode(status)
+	if err != nil {
+		t.Errorf("unexpected error: %v", err)
+	}
+	typeMeta := unversioned.TypeMeta{}
+	if err := json.Unmarshal(encoded, &typeMeta); err != nil {
+		t.Errorf("unexpected error: %v", err)
+	}
+	if typeMeta.Kind != "Status" {
+		t.Errorf("Kind is not set to \"Status\". Got %v", string(encoded))
+	}
+	if typeMeta.APIVersion != "v1" {
+		t.Errorf("APIVersion is not set to \"v1\". Got %v", string(encoded))
+	}
+	decoded, err := v1Codec.Decode(encoded)
+	if err != nil {
+		t.Errorf("unexpected error: %v", err)
+	}
+	if !reflect.DeepEqual(status, decoded) {
+		t.Errorf("expected: %v, got: %v", status, decoded)
+	}
+}
+
+func TestExperimentalEncodeDecodeStatus(t *testing.T) {
+	// TODO: caesarxuchao: use the testapi.Experimental.Codec() once the PR that
+	// moves experimental from v1 to v1alpha1 got merged.
+	// expCodec := testapi.Experimental.Codec()
+	expCodec := runtime.CodecFor(api.Scheme, "experimental/v1alpha1")
+	encoded, err := expCodec.Encode(status)
+	if err != nil {
+		t.Errorf("unexpected error: %v", err)
+	}
+	typeMeta := unversioned.TypeMeta{}
+	if err := json.Unmarshal(encoded, &typeMeta); err != nil {
+		t.Errorf("unexpected error: %v", err)
+	}
+	if typeMeta.Kind != "Status" {
+		t.Errorf("Kind is not set to \"Status\". Got %s", encoded)
+	}
+	if typeMeta.APIVersion != "" {
+		t.Errorf("APIVersion is not set to \"\". Got %s", encoded)
+	}
+	decoded, err := expCodec.Decode(encoded)
+	if err != nil {
+		t.Errorf("unexpected error: %v", err)
+	}
+	if !reflect.DeepEqual(status, decoded) {
+		t.Errorf("expected: %v, got: %v", status, decoded)
+	}
+}