Add a method for encoding directly to a io.Writer and use it for HTTPx

Author: brendandburns

hack/benchmark-integration.sh

@@ -28,16 +28,18 @@ cleanup() {
   kube::log::status "Benchmark cleanup complete"
 }
 
+ARGS="-bench-pods 3000 -bench-tasks 100 -bench-tasks 10"
+
 runTests() {
   kube::etcd::start
   kube::log::status "Running benchmarks"
-  KUBE_GOFLAGS="-tags 'benchmark no-docker' -bench . -benchtime 1s -cpu 4" \
+  KUBE_GOFLAGS="-tags 'benchmark no-docker' -bench . -benchmem -benchtime 1s -cpu 4" \
     KUBE_RACE="-race" \
     KUBE_TEST_API_VERSIONS="v1" \
     KUBE_TIMEOUT="-timeout 10m" \
     KUBE_TEST_ETCD_PREFIXES="registry"\
     ETCD_CUSTOM_PREFIX="None" \
-    KUBE_TEST_ARGS="-bench-quiet 0 -bench-pods 30 -bench-tasks 1"\
+    KUBE_TEST_ARGS="${ARGS}" \
     "${KUBE_ROOT}/hack/test-go.sh" test/integration
   cleanup
 }

pkg/api/meta/restmapper_test.go

@@ -18,6 +18,7 @@ package meta
 
 import (
 	"errors"
+	"io"
 	"testing"
 
 	"k8s.io/kubernetes/pkg/runtime"
@@ -29,6 +30,10 @@ func (fakeCodec) Encode(runtime.Object) ([]byte, error) {
 	return []byte{}, nil
 }
 
+func (fakeCodec) EncodeToStream(runtime.Object, io.Writer) error {
+	return nil
+}
+
 func (fakeCodec) Decode([]byte) (runtime.Object, error) {
 	return nil, nil
 }

pkg/apiserver/apiserver.go

@@ -380,24 +380,32 @@ func isPrettyPrint(req *http.Request) bool {
 
 // writeJSON renders an object as JSON to the response.
 func writeJSON(statusCode int, codec runtime.Codec, object runtime.Object, w http.ResponseWriter, pretty bool) {
+	w.Header().Set("Content-Type", "application/json")
+	// We send the status code before we encode the object, so if we error, the status code stays but there will
+	// still be an error object.  This seems ok, the alternative is to validate the object before
+	// encoding, but this really should never happen, so it's wasted compute for every API request.
+	w.WriteHeader(statusCode)
+	if pretty {
+		prettyJSON(codec, object, w)
+		return
+	}
+	err := codec.EncodeToStream(object, w)
+	if err != nil {
+		errorJSONFatal(err, codec, w)
+	}
+}
+
+func prettyJSON(codec runtime.Codec, object runtime.Object, w http.ResponseWriter) {
+	formatted := &bytes.Buffer{}
 	output, err := codec.Encode(object)
 	if err != nil {
 		errorJSONFatal(err, codec, w)
-		return
 	}
-	if pretty {
-		// PR #2243: Pretty-print JSON by default.
-		formatted := &bytes.Buffer{}
-		err = json.Indent(formatted, output, "", "  ")
-		if err != nil {
-			errorJSONFatal(err, codec, w)
-			return
-		}
-		output = formatted.Bytes()
+	if err := json.Indent(formatted, output, "", "  "); err != nil {
+		errorJSONFatal(err, codec, w)
+		return
 	}
-	w.Header().Set("Content-Type", "application/json")
-	w.WriteHeader(statusCode)
-	w.Write(output)
+	w.Write(formatted.Bytes())
 }
 
 // errorJSON renders an error to the response. Returns the HTTP status code of the error.

pkg/apiserver/apiserver_test.go

@@ -2432,9 +2432,8 @@ func expectApiStatus(t *testing.T, method, url string, data []byte, code int) *u
 		return nil
 	}
 	var status unversioned.Status
-	_, err = extractBody(response, &status)
-	if err != nil {
-		t.Fatalf("unexpected error on %s %s: %v", method, url, err)
+	if body, err := extractBody(response, &status); err != nil {
+		t.Fatalf("unexpected error on %s %s: %v\nbody:\n%s", method, url, err, body)
 		return nil
 	}
 	if code != response.StatusCode {
@@ -2470,7 +2469,10 @@ func TestWriteJSONDecodeError(t *testing.T) {
 		writeJSON(http.StatusOK, codec, &UnregisteredAPIObject{"Undecodable"}, w, false)
 	}))
 	defer server.Close()
-	status := expectApiStatus(t, "GET", server.URL, nil, http.StatusInternalServerError)
+	// We send a 200 status code before we encode the object, so we expect OK, but there will
+	// still be an error object.  This seems ok, the alternative is to validate the object before
+	// encoding, but this really should never happen, so it's wasted compute for every API request.
+	status := expectApiStatus(t, "GET", server.URL, nil, http.StatusOK)
 	if status.Reason != unversioned.StatusReasonUnknown {
 		t.Errorf("unexpected reason %#v", status)
 	}

pkg/conversion/encode.go

@@ -17,8 +17,10 @@ limitations under the License.
 package conversion
 
 import (
+	"bytes"
 	"encoding/json"
 	"fmt"
+	"io"
 	"path"
 )
 
@@ -51,65 +53,79 @@ import (
 // config files.
 //
 func (s *Scheme) EncodeToVersion(obj interface{}, destVersion string) (data []byte, err error) {
+	buff := &bytes.Buffer{}
+	if err := s.EncodeToVersionStream(obj, destVersion, buff); err != nil {
+		return nil, err
+	}
+	return buff.Bytes(), nil
+}
+
+func (s *Scheme) EncodeToVersionStream(obj interface{}, destVersion string, stream io.Writer) 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)
+		// TODO: convert this to streaming too
+		data, err := s.encodeUnversionedObject(obj)
+		if err != nil {
+			return err
+		}
+		_, err = stream.Write(data)
+		return err
 	}
 
 	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)
+		return 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)
 	}
 
 	objVersion, objKind, err := s.ObjectVersionAndKind(obj)
 	if err != nil {
-		return nil, err
+		return err
 	}
 
 	// Perform a conversion if necessary.
 	if objVersion != destVersion {
 		objOut, err := s.NewObject(destVersion, objKind)
 		if err != nil {
-			return nil, err
+			return err
 		}
 		flags, meta := s.generateConvertMeta(objVersion, destVersion, obj)
 		err = s.converter.Convert(obj, objOut, flags, meta)
 		if err != nil {
-			return nil, err
+			return err
 		}
 		obj = objOut
 	}
 
 	// ensure the output object name comes from the destination type
 	_, objKind, err = s.ObjectVersionAndKind(obj)
 	if err != nil {
-		return nil, err
+		return err
 	}
 
 	// Version and Kind should be set on the wire.
 	err = s.SetVersionAndKind(destVersion, objKind, obj)
 	if err != nil {
-		return nil, err
+		return err
 	}
 
 	// To add metadata, do some simple surgery on the JSON.
-	data, err = json.Marshal(obj)
-	if err != nil {
-		return nil, err
+	encoder := json.NewEncoder(stream)
+	if err := encoder.Encode(obj); err != nil {
+		return 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)
 	if err != nil {
-		return nil, err
+		return err
 	}
 
-	return data, nil
+	return nil
 }
 
 func (s *Scheme) encodeUnversionedObject(obj interface{}) (data []byte, err error) {

pkg/registry/thirdpartyresourcedata/codec.go

@@ -20,6 +20,7 @@ import (
 	"bytes"
 	"encoding/json"
 	"fmt"
+	"io"
 	"strings"
 
 	"k8s.io/kubernetes/pkg/api/latest"
@@ -219,40 +220,49 @@ const template = `{
   "items": [ %s ]
 }`
 
-func encodeToJSON(obj *experimental.ThirdPartyResourceData) ([]byte, error) {
+func encodeToJSON(obj *experimental.ThirdPartyResourceData, stream io.Writer) error {
 	var objOut interface{}
 	if err := json.Unmarshal(obj.Data, &objOut); err != nil {
-		return nil, err
+		return err
 	}
 	objMap, ok := objOut.(map[string]interface{})
 	if !ok {
-		return nil, fmt.Errorf("unexpected type: %v", objOut)
+		return fmt.Errorf("unexpected type: %v", objOut)
 	}
 	objMap["metadata"] = obj.ObjectMeta
-	return json.Marshal(objMap)
+	encoder := json.NewEncoder(stream)
+	return encoder.Encode(objMap)
+}
+
+func (t *thirdPartyResourceDataCodec) Encode(obj runtime.Object) ([]byte, error) {
+	buff := &bytes.Buffer{}
+	if err := t.EncodeToStream(obj, buff); err != nil {
+		return nil, err
+	}
+	return buff.Bytes(), nil
 }
 
-func (t *thirdPartyResourceDataCodec) Encode(obj runtime.Object) (data []byte, err error) {
+func (t *thirdPartyResourceDataCodec) EncodeToStream(obj runtime.Object, stream io.Writer) (err error) {
 	switch obj := obj.(type) {
 	case *experimental.ThirdPartyResourceData:
-		return encodeToJSON(obj)
+		return encodeToJSON(obj, stream)
 	case *experimental.ThirdPartyResourceDataList:
 		// TODO: There must be a better way to do this...
-		buff := &bytes.Buffer{}
 		dataStrings := make([]string, len(obj.Items))
 		for ix := range obj.Items {
-			data, err := encodeToJSON(&obj.Items[ix])
+			buff := &bytes.Buffer{}
+			err := encodeToJSON(&obj.Items[ix], buff)
 			if err != nil {
-				return nil, err
+				return err
 			}
-			dataStrings[ix] = string(data)
+			dataStrings[ix] = buff.String()
 		}
-		fmt.Fprintf(buff, template, t.kind+"List", strings.Join(dataStrings, ","))
-		return buff.Bytes(), nil
+		fmt.Fprintf(stream, template, t.kind+"List", strings.Join(dataStrings, ","))
+		return nil
 	case *unversioned.Status:
-		return t.delegate.Encode(obj)
+		return t.delegate.EncodeToStream(obj, stream)
 	default:
-		return nil, fmt.Errorf("unexpected object to encode: %#v", obj)
+		return fmt.Errorf("unexpected object to encode: %#v", obj)
 	}
 }
 

pkg/runtime/codec.go

@@ -17,6 +17,8 @@ limitations under the License.
 package runtime
 
 import (
+	"io"
+
 	"k8s.io/kubernetes/pkg/util/yaml"
 )
 
@@ -78,6 +80,10 @@ func (c *codecWrapper) Encode(obj Object) ([]byte, error) {
 	return c.EncodeToVersion(obj, c.version)
 }
 
+func (c *codecWrapper) EncodeToStream(obj Object, stream io.Writer) error {
+	return c.EncodeToVersionStream(obj, c.version, stream)
+}
+
 // TODO: Make this behaviour default when we move everyone away from
 // the unversioned types.
 //

pkg/runtime/interfaces.go

@@ -16,6 +16,10 @@ limitations under the License.
 
 package runtime
 
+import (
+	"io"
+)
+
 // ObjectScheme represents common conversions between formal external API versions
 // and the internal Go structs. ObjectScheme is typically used with ObjectCodec to
 // transform internal Go structs into serialized versions. There may be many valid
@@ -45,6 +49,7 @@ type Decoder interface {
 // Encoder defines methods for serializing API objects into bytes
 type Encoder interface {
 	Encode(obj Object) (data []byte, err error)
+	EncodeToStream(obj Object, stream io.Writer) error
 }
 
 // Codec defines methods for serializing and deserializing API objects.
@@ -67,6 +72,7 @@ type ObjectEncoder interface {
 	// to a specified output version. An error is returned if the object
 	// cannot be converted for any reason.
 	EncodeToVersion(obj Object, outVersion string) ([]byte, error)
+	EncodeToVersionStream(obj Object, outVersion string, stream io.Writer) error
 }
 
 // ObjectConvertor converts an object to a different version.

pkg/runtime/scheme.go

@@ -19,6 +19,7 @@ package runtime
 import (
 	"encoding/json"
 	"fmt"
+	"io"
 	"net/url"
 	"reflect"
 
@@ -434,6 +435,10 @@ func (s *Scheme) EncodeToVersion(obj Object, destVersion string) (data []byte, e
 	return s.raw.EncodeToVersion(obj, destVersion)
 }
 
+func (s *Scheme) EncodeToVersionStream(obj Object, destVersion string, stream io.Writer) error {
+	return s.raw.EncodeToVersionStream(obj, destVersion, stream)
+}
+
 // Decode converts a YAML or JSON string back into a pointer to an api object.
 // Deduces the type based upon the APIVersion and Kind fields, which are set
 // by Encode. Only versioned objects (APIVersion != "") are accepted. The object

pkg/runtime/scheme_test.go

@@ -246,13 +246,16 @@ func TestExtensionMapping(t *testing.T) {
 	}{
 		{
 			&InternalExtensionType{Extension: runtime.EmbeddedObject{Object: &ExtensionA{TestString: "foo"}}},
-			`{"kind":"ExtensionType","apiVersion":"testExternal","extension":{"kind":"A","testString":"foo"}}`,
+			`{"kind":"ExtensionType","apiVersion":"testExternal","extension":{"kind":"A","testString":"foo"}}
+`,
 		}, {
 			&InternalExtensionType{Extension: runtime.EmbeddedObject{Object: &ExtensionB{TestString: "bar"}}},
-			`{"kind":"ExtensionType","apiVersion":"testExternal","extension":{"kind":"B","testString":"bar"}}`,
+			`{"kind":"ExtensionType","apiVersion":"testExternal","extension":{"kind":"B","testString":"bar"}}
+`,
 		}, {
 			&InternalExtensionType{Extension: runtime.EmbeddedObject{Object: nil}},
-			`{"kind":"ExtensionType","apiVersion":"testExternal","extension":null}`,
+			`{"kind":"ExtensionType","apiVersion":"testExternal","extension":null}
+`,
 		},
 	}
 
@@ -261,7 +264,7 @@ func TestExtensionMapping(t *testing.T) {
 		if err != nil {
 			t.Errorf("unexpected error '%v' (%#v)", err, item.obj)
 		} else if e, a := item.encoded, string(gotEncoded); e != a {
-			t.Errorf("expected %v, got %v", e, a)
+			t.Errorf("expected\n%#v\ngot\n%#v\n", e, a)
 		}
 
 		gotDecoded, err := scheme.Decode([]byte(item.encoded))