add grpc-proxy (github.com/mwitkow/grpc-proxy)

Signed-off-by: Adphi <philippe.adrien.nousse@gmail.com>

proxy/codec.go

@@ -0,0 +1,69 @@
+package proxy
+
+import (
+	"fmt"
+
+	"google.golang.org/grpc"
+	"google.golang.org/protobuf/proto"
+)
+
+// Codec returns a proxying grpc.Codec with the default protobuf codec as parent.
+//
+// See CodecWithParent.
+//
+// Deprecated: No longer necessary.
+func Codec() grpc.Codec {
+	return CodecWithParent(&protoCodec{})
+}
+
+// CodecWithParent returns a proxying grpc.Codec with a user provided codec as parent.
+//
+// Deprecated: No longer necessary.
+func CodecWithParent(fallback grpc.Codec) grpc.Codec {
+	return &rawCodec{fallback}
+}
+
+type rawCodec struct {
+	parentCodec grpc.Codec
+}
+
+type frame struct {
+	payload []byte
+}
+
+func (c *rawCodec) Marshal(v interface{}) ([]byte, error) {
+	out, ok := v.(*frame)
+	if !ok {
+		return c.parentCodec.Marshal(v)
+	}
+	return out.payload, nil
+
+}
+
+func (c *rawCodec) Unmarshal(data []byte, v interface{}) error {
+	dst, ok := v.(*frame)
+	if !ok {
+		return c.parentCodec.Unmarshal(data, v)
+	}
+	dst.payload = data
+	return nil
+}
+
+func (c *rawCodec) String() string {
+	return fmt.Sprintf("proxy>%s", c.parentCodec.String())
+}
+
+// protoCodec is a Codec implementation with protobuf. It is the default rawCodec for gRPC.
+type protoCodec struct{}
+
+func (protoCodec) Marshal(v interface{}) ([]byte, error) {
+	return proto.Marshal(v.(proto.Message))
+}
+
+func (protoCodec) Unmarshal(data []byte, v interface{}) error {
+	return proto.Unmarshal(data, v.(proto.Message))
+}
+
+func (protoCodec) String() string {
+	return "proto"
+}