Merge pull request #529 from lavalamp/recursiveApiObj

Add APIObject for generic inclusion of API objects

pkg/api/apiobj.go

@@ -0,0 +1,90 @@
+/*
+Copyright 2014 Google Inc. 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 api
+
+import (
+	"gopkg.in/v1/yaml"
+)
+
+// Encode()/Decode() are the canonical way of converting an API object to/from
+// wire format. This file provides utility functions which permit doing so
+// recursively, such that API objects of types known only at run time can be
+// embedded within other API types.
+
+// UnmarshalJSON implements the json.Unmarshaler interface.
+func (a *APIObject) UnmarshalJSON(b []byte) error {
+	// Handle JSON's "null": Decode() doesn't expect it.
+	if len(b) == 4 && string(b) == "null" {
+		a.Object = nil
+		return nil
+	}
+
+	obj, err := Decode(b)
+	if err != nil {
+		return err
+	}
+	a.Object = obj
+	return nil
+}
+
+// MarshalJSON implements the json.Marshaler interface.
+func (a APIObject) MarshalJSON() ([]byte, error) {
+	if a.Object == nil {
+		// Encode unset/nil objects as JSON's "null".
+		return []byte("null"), nil
+	}
+
+	return Encode(a.Object)
+}
+
+// SetYAML implements the yaml.Setter interface.
+func (a *APIObject) SetYAML(tag string, value interface{}) bool {
+	if value == nil {
+		a.Object = nil
+		return true
+	}
+	// Why does the yaml package send value as a map[interface{}]interface{}?
+	// It's especially frustrating because encoding/json does the right thing
+	// by giving a []byte. So here we do the embarrasing thing of re-encode and
+	// de-encode the right way.
+	// TODO: Write a version of Decode that uses reflect to turn this value
+	// into an API object.
+	b, err := yaml.Marshal(value)
+	if err != nil {
+		panic("yaml can't reverse it's own object")
+	}
+	obj, err := Decode(b)
+	if err != nil {
+		return false
+	}
+	a.Object = obj
+	return true
+}
+
+// GetYAML implements the yaml.Getter interface.
+func (a APIObject) GetYAML() (tag string, value interface{}) {
+	if a.Object == nil {
+		value = "null"
+		return
+	}
+	// Encode returns JSON, which is conveniently a subset of YAML.
+	v, err := Encode(a.Object)
+	if err != nil {
+		panic("impossible to encode API object!")
+	}
+	return tag, v
+}

pkg/api/apiobj_test.go

@@ -0,0 +1,72 @@
+/*
+Copyright 2014 Google Inc. 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 api
+
+import (
+	"encoding/json"
+	"reflect"
+	"testing"
+)
+
+func TestAPIObject(t *testing.T) {
+	type EmbeddedTest struct {
+		JSONBase    `yaml:",inline" json:",inline"`
+		Object      APIObject `yaml:"object,omitempty" json:"object,omitempty"`
+		EmptyObject APIObject `yaml:"emptyObject,omitempty" json:"emptyObject,omitempty"`
+	}
+
+	AddKnownTypes(EmbeddedTest{})
+
+	outer := &EmbeddedTest{
+		JSONBase: JSONBase{ID: "outer"},
+		Object: APIObject{
+			&EmbeddedTest{
+				JSONBase: JSONBase{ID: "inner"},
+			},
+		},
+	}
+
+	wire, err := Encode(outer)
+	if err != nil {
+		t.Fatalf("Unexpected encode error '%v'", err)
+	}
+
+	t.Logf("Wire format is:\n%v\n", string(wire))
+
+	decoded, err := Decode(wire)
+	if err != nil {
+		t.Fatalf("Unexpected decode error %v", err)
+	}
+
+	if e, a := outer, decoded; !reflect.DeepEqual(e, a) {
+		t.Errorf("Expected: %#v but got %#v", e, a)
+	}
+
+	// test JSON decoding, too, since api.Decode uses yaml unmarshalling.
+	var decodedViaJSON EmbeddedTest
+	err = json.Unmarshal(wire, &decodedViaJSON)
+	if err != nil {
+		t.Fatalf("Unexpected decode error %v", err)
+	}
+
+	// Things that Decode would have done for us:
+	decodedViaJSON.Kind = ""
+
+	if e, a := outer, &decodedViaJSON; !reflect.DeepEqual(e, a) {
+		t.Errorf("Expected: %#v but got %#v", e, a)
+	}
+}

pkg/api/helper.go

@@ -66,7 +66,7 @@ func FindJSONBaseRO(obj interface{}) (JSONBase, error) {
 		v = v.Elem()
 	}
 	if v.Kind() != reflect.Struct {
-		return JSONBase{}, fmt.Errorf("expected struct, but got %v", v.Type().Name())
+		return JSONBase{}, fmt.Errorf("expected struct, but got %v (%#v)", v.Type().Name(), v.Interface())
 	}
 	jsonBase := v.FieldByName("JSONBase")
 	if !jsonBase.IsValid() {
@@ -125,7 +125,7 @@ func nameAndJSONBase(obj interface{}) (string, *JSONBase, error) {
 	v = v.Elem()
 	name := v.Type().Name()
 	if v.Kind() != reflect.Struct {
-		return "", nil, fmt.Errorf("expected struct, but got %v", name)
+		return "", nil, fmt.Errorf("expected struct, but got %v: %v (%#v)", v.Kind(), v.Type().Name(), v.Interface())
 	}
 	jsonBase := v.FieldByName("JSONBase")
 	if !jsonBase.IsValid() {

pkg/api/types.go

@@ -66,7 +66,7 @@ type Volume struct {
 	// Source represents the location and type of a volume to mount.
 	// This is optional for now. If not specified, the Volume is implied to be an EmptyDir.
 	// This implied behavior is deprecated and will be removed in a future version.
-        Source *VolumeSource `yaml:"source" json:"source"`
+	Source *VolumeSource `yaml:"source" json:"source"`
 }
 
 type VolumeSource struct {
@@ -86,7 +86,7 @@ type HostDirectory struct {
 	Path string `yaml:"path" json:"path"`
 }
 
-type EmptyDirectory struct {}
+type EmptyDirectory struct{}
 
 // Port represents a network port in a single container
 type Port struct {
@@ -345,6 +345,16 @@ type WatchEvent struct {
 	// The type of the watch event; added, modified, or deleted.
 	Type watch.EventType
 
-	// An object which can be decoded via api.Decode
-	EmbeddedObject []byte
+	// For added or modified objects, this is the new object; for deleted objects,
+	// it's the state of the object immediately prior to its deletion.
+	Object APIObject
+}
+
+// APIObject has appropriate encoder and decoder functions, such that on the wire, it's
+// stored as a []byte, but in memory, the contained object is accessable as an interface{}
+// via the Get() function. Only objects having a JSONBase may be stored via APIObject.
+// The purpose of this is to allow an API object of type known only at runtime to be
+// embedded within other API objects.
+type APIObject struct {
+	Object interface{}
 }

pkg/api/validation_test.go

@@ -208,7 +208,7 @@ func TestValidateManifest(t *testing.T) {
 			Version: "v1beta1",
 			ID:      "abc",
 			Volumes: []Volume{{Name: "vol1", Source: &VolumeSource{HostDirectory: &HostDirectory{"/mnt/vol1"}}},
-			                  {Name: "vol2", Source: &VolumeSource{HostDirectory: &HostDirectory{"/mnt/vol2"}}}},
+				{Name: "vol2", Source: &VolumeSource{HostDirectory: &HostDirectory{"/mnt/vol2"}}}},
 			Containers: []Container{
 				{
 					Name:       "abc",

pkg/apiserver/apiserver.go

@@ -503,14 +503,9 @@ func (w *WatchServer) HandleWS(ws *websocket.Conn) {
 				// End of results.
 				return
 			}
-			wireFormat, err := api.Encode(event.Object)
-			if err != nil {
-				glog.Errorf("error encoding %#v: %v", event.Object, err)
-				return
-			}
-			err = websocket.JSON.Send(ws, &api.WatchEvent{
-				Type:           event.Type,
-				EmbeddedObject: wireFormat,
+			err := websocket.JSON.Send(ws, &api.WatchEvent{
+				Type:   event.Type,
+				Object: api.APIObject{event.Object},
 			})
 			if err != nil {
 				// Client disconnect.
@@ -555,14 +550,9 @@ func (self *WatchServer) ServeHTTP(w http.ResponseWriter, req *http.Request) {
 				// End of results.
 				return
 			}
-			wireFormat, err := api.Encode(event.Object)
-			if err != nil {
-				glog.Errorf("error encoding %#v: %v", event.Object, err)
-				return
-			}
-			err = encoder.Encode(&api.WatchEvent{
-				Type:           event.Type,
-				EmbeddedObject: wireFormat,
+			err := encoder.Encode(&api.WatchEvent{
+				Type:   event.Type,
+				Object: api.APIObject{event.Object},
 			})
 			if err != nil {
 				// Client disconnect.

pkg/apiserver/apiserver_test.go

@@ -595,12 +595,8 @@ func TestWatchWebsocket(t *testing.T) {
 		if got.Type != action {
 			t.Errorf("Unexpected type: %v", got.Type)
 		}
-		apiObj, err := api.Decode(got.EmbeddedObject)
-		if err != nil {
-			t.Fatalf("Unexpected error: %v", err)
-		}
-		if !reflect.DeepEqual(object, apiObj) {
-			t.Errorf("Expected %v, got %v", object, apiObj)
+		if e, a := object, got.Object.Object; !reflect.DeepEqual(e, a) {
+			t.Errorf("Expected %v, got %v", e, a)
 		}
 	}
 
@@ -654,12 +650,8 @@ func TestWatchHTTP(t *testing.T) {
 		if got.Type != action {
 			t.Errorf("Unexpected type: %v", got.Type)
 		}
-		apiObj, err := api.Decode(got.EmbeddedObject)
-		if err != nil {
-			t.Fatalf("Unexpected error: %v", err)
-		}
-		if !reflect.DeepEqual(object, apiObj) {
-			t.Errorf("Expected %v, got %v", object, apiObj)
+		if e, a := object, got.Object.Object; !reflect.DeepEqual(e, a) {
+			t.Errorf("Expected %v, got %v", e, a)
 		}
 	}