[feat](protocol): update go_package path and regen related Protobuf types

- Changed `go_package` option in `hopgate_stream.proto` to `internal/protocol/pb;pb`.
- Regenerated `hopgate_stream.pb.go` with updated package path to align with new structure.
- Added `protocol.md` documenting the gRPC-based HTTP tunneling protocol.

github.com/dalbodeule/hop-gate/internal/protocol/pb/hopgate_stream.pb.go

@@ -1,799 +0,0 @@
-// Code generated by protoc-gen-go. DO NOT EDIT.
-// versions:
-// 	protoc-gen-go v1.36.10
-// 	protoc        v6.33.1
-// source: internal/protocol/hopgate_stream.proto
-
-package protocolpb
-
-import (
-	protoreflect "google.golang.org/protobuf/reflect/protoreflect"
-	protoimpl "google.golang.org/protobuf/runtime/protoimpl"
-	reflect "reflect"
-	sync "sync"
-	unsafe "unsafe"
-)
-
-const (
-	// Verify that this generated code is sufficiently up-to-date.
-	_ = protoimpl.EnforceVersion(20 - protoimpl.MinVersion)
-	// Verify that runtime/protoimpl is sufficiently up-to-date.
-	_ = protoimpl.EnforceVersion(protoimpl.MaxVersion - 20)
-)
-
-// HeaderValues 는 HTTP 헤더의 다중 값 표현을 위한 래퍼입니다.
-// HeaderValues wraps multiple header values for a single HTTP header key.
-type HeaderValues struct {
-	state         protoimpl.MessageState `protogen:"open.v1"`
-	Values        []string               `protobuf:"bytes,1,rep,name=values,proto3" json:"values,omitempty"`
-	unknownFields protoimpl.UnknownFields
-	sizeCache     protoimpl.SizeCache
-}
-
-func (x *HeaderValues) Reset() {
-	*x = HeaderValues{}
-	mi := &file_internal_protocol_hopgate_stream_proto_msgTypes[0]
-	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
-	ms.StoreMessageInfo(mi)
-}
-
-func (x *HeaderValues) String() string {
-	return protoimpl.X.MessageStringOf(x)
-}
-
-func (*HeaderValues) ProtoMessage() {}
-
-func (x *HeaderValues) ProtoReflect() protoreflect.Message {
-	mi := &file_internal_protocol_hopgate_stream_proto_msgTypes[0]
-	if x != nil {
-		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
-		if ms.LoadMessageInfo() == nil {
-			ms.StoreMessageInfo(mi)
-		}
-		return ms
-	}
-	return mi.MessageOf(x)
-}
-
-// Deprecated: Use HeaderValues.ProtoReflect.Descriptor instead.
-func (*HeaderValues) Descriptor() ([]byte, []int) {
-	return file_internal_protocol_hopgate_stream_proto_rawDescGZIP(), []int{0}
-}
-
-func (x *HeaderValues) GetValues() []string {
-	if x != nil {
-		return x.Values
-	}
-	return nil
-}
-
-// Request 는 DTLS 터널 위에서 교환되는 HTTP 요청을 표현합니다.
-// This mirrors internal/protocol.Request.
-type Request struct {
-	state       protoimpl.MessageState `protogen:"open.v1"`
-	RequestId   string                 `protobuf:"bytes,1,opt,name=request_id,json=requestId,proto3" json:"request_id,omitempty"`
-	ClientId    string                 `protobuf:"bytes,2,opt,name=client_id,json=clientId,proto3" json:"client_id,omitempty"`          // optional client identifier
-	ServiceName string                 `protobuf:"bytes,3,opt,name=service_name,json=serviceName,proto3" json:"service_name,omitempty"` // logical service name on the client side
-	Method      string                 `protobuf:"bytes,4,opt,name=method,proto3" json:"method,omitempty"`
-	Url         string                 `protobuf:"bytes,5,opt,name=url,proto3" json:"url,omitempty"`
-	// HTTP header: map of key -> multiple values.
-	Header map[string]*HeaderValues `protobuf:"bytes,6,rep,name=header,proto3" json:"header,omitempty" protobuf_key:"bytes,1,opt,name=key" protobuf_val:"bytes,2,opt,name=value"`
-	// Raw HTTP body bytes.
-	Body          []byte `protobuf:"bytes,7,opt,name=body,proto3" json:"body,omitempty"`
-	unknownFields protoimpl.UnknownFields
-	sizeCache     protoimpl.SizeCache
-}
-
-func (x *Request) Reset() {
-	*x = Request{}
-	mi := &file_internal_protocol_hopgate_stream_proto_msgTypes[1]
-	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
-	ms.StoreMessageInfo(mi)
-}
-
-func (x *Request) String() string {
-	return protoimpl.X.MessageStringOf(x)
-}
-
-func (*Request) ProtoMessage() {}
-
-func (x *Request) ProtoReflect() protoreflect.Message {
-	mi := &file_internal_protocol_hopgate_stream_proto_msgTypes[1]
-	if x != nil {
-		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
-		if ms.LoadMessageInfo() == nil {
-			ms.StoreMessageInfo(mi)
-		}
-		return ms
-	}
-	return mi.MessageOf(x)
-}
-
-// Deprecated: Use Request.ProtoReflect.Descriptor instead.
-func (*Request) Descriptor() ([]byte, []int) {
-	return file_internal_protocol_hopgate_stream_proto_rawDescGZIP(), []int{1}
-}
-
-func (x *Request) GetRequestId() string {
-	if x != nil {
-		return x.RequestId
-	}
-	return ""
-}
-
-func (x *Request) GetClientId() string {
-	if x != nil {
-		return x.ClientId
-	}
-	return ""
-}
-
-func (x *Request) GetServiceName() string {
-	if x != nil {
-		return x.ServiceName
-	}
-	return ""
-}
-
-func (x *Request) GetMethod() string {
-	if x != nil {
-		return x.Method
-	}
-	return ""
-}
-
-func (x *Request) GetUrl() string {
-	if x != nil {
-		return x.Url
-	}
-	return ""
-}
-
-func (x *Request) GetHeader() map[string]*HeaderValues {
-	if x != nil {
-		return x.Header
-	}
-	return nil
-}
-
-func (x *Request) GetBody() []byte {
-	if x != nil {
-		return x.Body
-	}
-	return nil
-}
-
-// Response 는 DTLS 터널 위에서 교환되는 HTTP 응답을 표현합니다.
-// This mirrors internal/protocol.Response.
-type Response struct {
-	state     protoimpl.MessageState `protogen:"open.v1"`
-	RequestId string                 `protobuf:"bytes,1,opt,name=request_id,json=requestId,proto3" json:"request_id,omitempty"`
-	Status    int32                  `protobuf:"varint,2,opt,name=status,proto3" json:"status,omitempty"`
-	// HTTP header.
-	Header map[string]*HeaderValues `protobuf:"bytes,3,rep,name=header,proto3" json:"header,omitempty" protobuf_key:"bytes,1,opt,name=key" protobuf_val:"bytes,2,opt,name=value"`
-	// Raw HTTP body bytes.
-	Body []byte `protobuf:"bytes,4,opt,name=body,proto3" json:"body,omitempty"`
-	// Optional error description when tunneling fails.
-	Error         string `protobuf:"bytes,5,opt,name=error,proto3" json:"error,omitempty"`
-	unknownFields protoimpl.UnknownFields
-	sizeCache     protoimpl.SizeCache
-}
-
-func (x *Response) Reset() {
-	*x = Response{}
-	mi := &file_internal_protocol_hopgate_stream_proto_msgTypes[2]
-	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
-	ms.StoreMessageInfo(mi)
-}
-
-func (x *Response) String() string {
-	return protoimpl.X.MessageStringOf(x)
-}
-
-func (*Response) ProtoMessage() {}
-
-func (x *Response) ProtoReflect() protoreflect.Message {
-	mi := &file_internal_protocol_hopgate_stream_proto_msgTypes[2]
-	if x != nil {
-		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
-		if ms.LoadMessageInfo() == nil {
-			ms.StoreMessageInfo(mi)
-		}
-		return ms
-	}
-	return mi.MessageOf(x)
-}
-
-// Deprecated: Use Response.ProtoReflect.Descriptor instead.
-func (*Response) Descriptor() ([]byte, []int) {
-	return file_internal_protocol_hopgate_stream_proto_rawDescGZIP(), []int{2}
-}
-
-func (x *Response) GetRequestId() string {
-	if x != nil {
-		return x.RequestId
-	}
-	return ""
-}
-
-func (x *Response) GetStatus() int32 {
-	if x != nil {
-		return x.Status
-	}
-	return 0
-}
-
-func (x *Response) GetHeader() map[string]*HeaderValues {
-	if x != nil {
-		return x.Header
-	}
-	return nil
-}
-
-func (x *Response) GetBody() []byte {
-	if x != nil {
-		return x.Body
-	}
-	return nil
-}
-
-func (x *Response) GetError() string {
-	if x != nil {
-		return x.Error
-	}
-	return ""
-}
-
-// StreamOpen 은 새로운 스트림(HTTP 요청/응답, WebSocket 등)을 여는 메시지입니다.
-// This represents opening a new stream (HTTP request/response, WebSocket, etc.).
-type StreamOpen struct {
-	state protoimpl.MessageState `protogen:"open.v1"`
-	Id    string                 `protobuf:"bytes,1,opt,name=id,proto3" json:"id,omitempty"` // StreamID (text form)
-	// Which logical service / local target to use on the client side.
-	ServiceName string `protobuf:"bytes,2,opt,name=service_name,json=serviceName,proto3" json:"service_name,omitempty"`
-	TargetAddr  string `protobuf:"bytes,3,opt,name=target_addr,json=targetAddr,proto3" json:"target_addr,omitempty"` // e.g. "127.0.0.1:8080"
-	// Initial HTTP-like headers (including Upgrade, etc.).
-	Header        map[string]*HeaderValues `protobuf:"bytes,4,rep,name=header,proto3" json:"header,omitempty" protobuf_key:"bytes,1,opt,name=key" protobuf_val:"bytes,2,opt,name=value"`
-	unknownFields protoimpl.UnknownFields
-	sizeCache     protoimpl.SizeCache
-}
-
-func (x *StreamOpen) Reset() {
-	*x = StreamOpen{}
-	mi := &file_internal_protocol_hopgate_stream_proto_msgTypes[3]
-	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
-	ms.StoreMessageInfo(mi)
-}
-
-func (x *StreamOpen) String() string {
-	return protoimpl.X.MessageStringOf(x)
-}
-
-func (*StreamOpen) ProtoMessage() {}
-
-func (x *StreamOpen) ProtoReflect() protoreflect.Message {
-	mi := &file_internal_protocol_hopgate_stream_proto_msgTypes[3]
-	if x != nil {
-		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
-		if ms.LoadMessageInfo() == nil {
-			ms.StoreMessageInfo(mi)
-		}
-		return ms
-	}
-	return mi.MessageOf(x)
-}
-
-// Deprecated: Use StreamOpen.ProtoReflect.Descriptor instead.
-func (*StreamOpen) Descriptor() ([]byte, []int) {
-	return file_internal_protocol_hopgate_stream_proto_rawDescGZIP(), []int{3}
-}
-
-func (x *StreamOpen) GetId() string {
-	if x != nil {
-		return x.Id
-	}
-	return ""
-}
-
-func (x *StreamOpen) GetServiceName() string {
-	if x != nil {
-		return x.ServiceName
-	}
-	return ""
-}
-
-func (x *StreamOpen) GetTargetAddr() string {
-	if x != nil {
-		return x.TargetAddr
-	}
-	return ""
-}
-
-func (x *StreamOpen) GetHeader() map[string]*HeaderValues {
-	if x != nil {
-		return x.Header
-	}
-	return nil
-}
-
-// StreamData 는 이미 열린 스트림에 대한 단방향 데이터 프레임입니다.
-// This is a unidirectional data frame on an already-open stream.
-type StreamData struct {
-	state         protoimpl.MessageState `protogen:"open.v1"`
-	Id            string                 `protobuf:"bytes,1,opt,name=id,proto3" json:"id,omitempty"`    // StreamID
-	Seq           uint64                 `protobuf:"varint,2,opt,name=seq,proto3" json:"seq,omitempty"` // per-stream sequence number starting from 0
-	Data          []byte                 `protobuf:"bytes,3,opt,name=data,proto3" json:"data,omitempty"`
-	unknownFields protoimpl.UnknownFields
-	sizeCache     protoimpl.SizeCache
-}
-
-func (x *StreamData) Reset() {
-	*x = StreamData{}
-	mi := &file_internal_protocol_hopgate_stream_proto_msgTypes[4]
-	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
-	ms.StoreMessageInfo(mi)
-}
-
-func (x *StreamData) String() string {
-	return protoimpl.X.MessageStringOf(x)
-}
-
-func (*StreamData) ProtoMessage() {}
-
-func (x *StreamData) ProtoReflect() protoreflect.Message {
-	mi := &file_internal_protocol_hopgate_stream_proto_msgTypes[4]
-	if x != nil {
-		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
-		if ms.LoadMessageInfo() == nil {
-			ms.StoreMessageInfo(mi)
-		}
-		return ms
-	}
-	return mi.MessageOf(x)
-}
-
-// Deprecated: Use StreamData.ProtoReflect.Descriptor instead.
-func (*StreamData) Descriptor() ([]byte, []int) {
-	return file_internal_protocol_hopgate_stream_proto_rawDescGZIP(), []int{4}
-}
-
-func (x *StreamData) GetId() string {
-	if x != nil {
-		return x.Id
-	}
-	return ""
-}
-
-func (x *StreamData) GetSeq() uint64 {
-	if x != nil {
-		return x.Seq
-	}
-	return 0
-}
-
-func (x *StreamData) GetData() []byte {
-	if x != nil {
-		return x.Data
-	}
-	return nil
-}
-
-// StreamAck 는 StreamData 에 대한 ACK/NACK 및 선택적 재전송 힌트를 전달합니다.
-// This conveys ACK/NACK and optional retransmission hints for StreamData.
-type StreamAck struct {
-	state protoimpl.MessageState `protogen:"open.v1"`
-	Id    string                 `protobuf:"bytes,1,opt,name=id,proto3" json:"id,omitempty"`
-	// Last contiguously received sequence number (starting from 0).
-	AckSeq uint64 `protobuf:"varint,2,opt,name=ack_seq,json=ackSeq,proto3" json:"ack_seq,omitempty"`
-	// Additional missing sequence numbers beyond ack_seq (optional).
-	LostSeqs []uint64 `protobuf:"varint,3,rep,packed,name=lost_seqs,json=lostSeqs,proto3" json:"lost_seqs,omitempty"`
-	// Optional receive window size hint.
-	WindowSize    uint32 `protobuf:"varint,4,opt,name=window_size,json=windowSize,proto3" json:"window_size,omitempty"`
-	unknownFields protoimpl.UnknownFields
-	sizeCache     protoimpl.SizeCache
-}
-
-func (x *StreamAck) Reset() {
-	*x = StreamAck{}
-	mi := &file_internal_protocol_hopgate_stream_proto_msgTypes[5]
-	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
-	ms.StoreMessageInfo(mi)
-}
-
-func (x *StreamAck) String() string {
-	return protoimpl.X.MessageStringOf(x)
-}
-
-func (*StreamAck) ProtoMessage() {}
-
-func (x *StreamAck) ProtoReflect() protoreflect.Message {
-	mi := &file_internal_protocol_hopgate_stream_proto_msgTypes[5]
-	if x != nil {
-		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
-		if ms.LoadMessageInfo() == nil {
-			ms.StoreMessageInfo(mi)
-		}
-		return ms
-	}
-	return mi.MessageOf(x)
-}
-
-// Deprecated: Use StreamAck.ProtoReflect.Descriptor instead.
-func (*StreamAck) Descriptor() ([]byte, []int) {
-	return file_internal_protocol_hopgate_stream_proto_rawDescGZIP(), []int{5}
-}
-
-func (x *StreamAck) GetId() string {
-	if x != nil {
-		return x.Id
-	}
-	return ""
-}
-
-func (x *StreamAck) GetAckSeq() uint64 {
-	if x != nil {
-		return x.AckSeq
-	}
-	return 0
-}
-
-func (x *StreamAck) GetLostSeqs() []uint64 {
-	if x != nil {
-		return x.LostSeqs
-	}
-	return nil
-}
-
-func (x *StreamAck) GetWindowSize() uint32 {
-	if x != nil {
-		return x.WindowSize
-	}
-	return 0
-}
-
-// StreamClose 는 스트림 종료(정상/에러)를 알립니다.
-// This indicates normal or error termination of a stream.
-type StreamClose struct {
-	state         protoimpl.MessageState `protogen:"open.v1"`
-	Id            string                 `protobuf:"bytes,1,opt,name=id,proto3" json:"id,omitempty"`
-	Error         string                 `protobuf:"bytes,2,opt,name=error,proto3" json:"error,omitempty"` // empty means normal close
-	unknownFields protoimpl.UnknownFields
-	sizeCache     protoimpl.SizeCache
-}
-
-func (x *StreamClose) Reset() {
-	*x = StreamClose{}
-	mi := &file_internal_protocol_hopgate_stream_proto_msgTypes[6]
-	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
-	ms.StoreMessageInfo(mi)
-}
-
-func (x *StreamClose) String() string {
-	return protoimpl.X.MessageStringOf(x)
-}
-
-func (*StreamClose) ProtoMessage() {}
-
-func (x *StreamClose) ProtoReflect() protoreflect.Message {
-	mi := &file_internal_protocol_hopgate_stream_proto_msgTypes[6]
-	if x != nil {
-		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
-		if ms.LoadMessageInfo() == nil {
-			ms.StoreMessageInfo(mi)
-		}
-		return ms
-	}
-	return mi.MessageOf(x)
-}
-
-// Deprecated: Use StreamClose.ProtoReflect.Descriptor instead.
-func (*StreamClose) Descriptor() ([]byte, []int) {
-	return file_internal_protocol_hopgate_stream_proto_rawDescGZIP(), []int{6}
-}
-
-func (x *StreamClose) GetId() string {
-	if x != nil {
-		return x.Id
-	}
-	return ""
-}
-
-func (x *StreamClose) GetError() string {
-	if x != nil {
-		return x.Error
-	}
-	return ""
-}
-
-// Envelope 는 DTLS 세션 위에서 교환되는 상위 레벨 메시지 컨테이너입니다.
-// 하나의 Envelope 에는 HTTP 요청/응답 또는 스트림 관련 메시지 중 하나만 포함됩니다.
-// Envelope is the top-level container exchanged over the DTLS session.
-// Exactly one payload (http_request/http_response/stream_*) is set per message.
-type Envelope struct {
-	state protoimpl.MessageState `protogen:"open.v1"`
-	// Types that are valid to be assigned to Payload:
-	//
-	//	*Envelope_HttpRequest
-	//	*Envelope_HttpResponse
-	//	*Envelope_StreamOpen
-	//	*Envelope_StreamData
-	//	*Envelope_StreamClose
-	//	*Envelope_StreamAck
-	Payload       isEnvelope_Payload `protobuf_oneof:"payload"`
-	unknownFields protoimpl.UnknownFields
-	sizeCache     protoimpl.SizeCache
-}
-
-func (x *Envelope) Reset() {
-	*x = Envelope{}
-	mi := &file_internal_protocol_hopgate_stream_proto_msgTypes[7]
-	ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
-	ms.StoreMessageInfo(mi)
-}
-
-func (x *Envelope) String() string {
-	return protoimpl.X.MessageStringOf(x)
-}
-
-func (*Envelope) ProtoMessage() {}
-
-func (x *Envelope) ProtoReflect() protoreflect.Message {
-	mi := &file_internal_protocol_hopgate_stream_proto_msgTypes[7]
-	if x != nil {
-		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
-		if ms.LoadMessageInfo() == nil {
-			ms.StoreMessageInfo(mi)
-		}
-		return ms
-	}
-	return mi.MessageOf(x)
-}
-
-// Deprecated: Use Envelope.ProtoReflect.Descriptor instead.
-func (*Envelope) Descriptor() ([]byte, []int) {
-	return file_internal_protocol_hopgate_stream_proto_rawDescGZIP(), []int{7}
-}
-
-func (x *Envelope) GetPayload() isEnvelope_Payload {
-	if x != nil {
-		return x.Payload
-	}
-	return nil
-}
-
-func (x *Envelope) GetHttpRequest() *Request {
-	if x != nil {
-		if x, ok := x.Payload.(*Envelope_HttpRequest); ok {
-			return x.HttpRequest
-		}
-	}
-	return nil
-}
-
-func (x *Envelope) GetHttpResponse() *Response {
-	if x != nil {
-		if x, ok := x.Payload.(*Envelope_HttpResponse); ok {
-			return x.HttpResponse
-		}
-	}
-	return nil
-}
-
-func (x *Envelope) GetStreamOpen() *StreamOpen {
-	if x != nil {
-		if x, ok := x.Payload.(*Envelope_StreamOpen); ok {
-			return x.StreamOpen
-		}
-	}
-	return nil
-}
-
-func (x *Envelope) GetStreamData() *StreamData {
-	if x != nil {
-		if x, ok := x.Payload.(*Envelope_StreamData); ok {
-			return x.StreamData
-		}
-	}
-	return nil
-}
-
-func (x *Envelope) GetStreamClose() *StreamClose {
-	if x != nil {
-		if x, ok := x.Payload.(*Envelope_StreamClose); ok {
-			return x.StreamClose
-		}
-	}
-	return nil
-}
-
-func (x *Envelope) GetStreamAck() *StreamAck {
-	if x != nil {
-		if x, ok := x.Payload.(*Envelope_StreamAck); ok {
-			return x.StreamAck
-		}
-	}
-	return nil
-}
-
-type isEnvelope_Payload interface {
-	isEnvelope_Payload()
-}
-
-type Envelope_HttpRequest struct {
-	HttpRequest *Request `protobuf:"bytes,1,opt,name=http_request,json=httpRequest,proto3,oneof"`
-}
-
-type Envelope_HttpResponse struct {
-	HttpResponse *Response `protobuf:"bytes,2,opt,name=http_response,json=httpResponse,proto3,oneof"`
-}
-
-type Envelope_StreamOpen struct {
-	StreamOpen *StreamOpen `protobuf:"bytes,3,opt,name=stream_open,json=streamOpen,proto3,oneof"`
-}
-
-type Envelope_StreamData struct {
-	StreamData *StreamData `protobuf:"bytes,4,opt,name=stream_data,json=streamData,proto3,oneof"`
-}
-
-type Envelope_StreamClose struct {
-	StreamClose *StreamClose `protobuf:"bytes,5,opt,name=stream_close,json=streamClose,proto3,oneof"`
-}
-
-type Envelope_StreamAck struct {
-	StreamAck *StreamAck `protobuf:"bytes,6,opt,name=stream_ack,json=streamAck,proto3,oneof"`
-}
-
-func (*Envelope_HttpRequest) isEnvelope_Payload() {}
-
-func (*Envelope_HttpResponse) isEnvelope_Payload() {}
-
-func (*Envelope_StreamOpen) isEnvelope_Payload() {}
-
-func (*Envelope_StreamData) isEnvelope_Payload() {}
-
-func (*Envelope_StreamClose) isEnvelope_Payload() {}
-
-func (*Envelope_StreamAck) isEnvelope_Payload() {}
-
-var File_internal_protocol_hopgate_stream_proto protoreflect.FileDescriptor
-
-const file_internal_protocol_hopgate_stream_proto_rawDesc = "" +
-	"\n" +
-	"&internal/protocol/hopgate_stream.proto\x12\x13hopgate.protocol.v1\"&\n" +
-	"\fHeaderValues\x12\x16\n" +
-	"\x06values\x18\x01 \x03(\tR\x06values\"\xc6\x02\n" +
-	"\aRequest\x12\x1d\n" +
-	"\n" +
-	"request_id\x18\x01 \x01(\tR\trequestId\x12\x1b\n" +
-	"\tclient_id\x18\x02 \x01(\tR\bclientId\x12!\n" +
-	"\fservice_name\x18\x03 \x01(\tR\vserviceName\x12\x16\n" +
-	"\x06method\x18\x04 \x01(\tR\x06method\x12\x10\n" +
-	"\x03url\x18\x05 \x01(\tR\x03url\x12@\n" +
-	"\x06header\x18\x06 \x03(\v2(.hopgate.protocol.v1.Request.HeaderEntryR\x06header\x12\x12\n" +
-	"\x04body\x18\a \x01(\fR\x04body\x1a\\\n" +
-	"\vHeaderEntry\x12\x10\n" +
-	"\x03key\x18\x01 \x01(\tR\x03key\x127\n" +
-	"\x05value\x18\x02 \x01(\v2!.hopgate.protocol.v1.HeaderValuesR\x05value:\x028\x01\"\x8c\x02\n" +
-	"\bResponse\x12\x1d\n" +
-	"\n" +
-	"request_id\x18\x01 \x01(\tR\trequestId\x12\x16\n" +
-	"\x06status\x18\x02 \x01(\x05R\x06status\x12A\n" +
-	"\x06header\x18\x03 \x03(\v2).hopgate.protocol.v1.Response.HeaderEntryR\x06header\x12\x12\n" +
-	"\x04body\x18\x04 \x01(\fR\x04body\x12\x14\n" +
-	"\x05error\x18\x05 \x01(\tR\x05error\x1a\\\n" +
-	"\vHeaderEntry\x12\x10\n" +
-	"\x03key\x18\x01 \x01(\tR\x03key\x127\n" +
-	"\x05value\x18\x02 \x01(\v2!.hopgate.protocol.v1.HeaderValuesR\x05value:\x028\x01\"\x83\x02\n" +
-	"\n" +
-	"StreamOpen\x12\x0e\n" +
-	"\x02id\x18\x01 \x01(\tR\x02id\x12!\n" +
-	"\fservice_name\x18\x02 \x01(\tR\vserviceName\x12\x1f\n" +
-	"\vtarget_addr\x18\x03 \x01(\tR\n" +
-	"targetAddr\x12C\n" +
-	"\x06header\x18\x04 \x03(\v2+.hopgate.protocol.v1.StreamOpen.HeaderEntryR\x06header\x1a\\\n" +
-	"\vHeaderEntry\x12\x10\n" +
-	"\x03key\x18\x01 \x01(\tR\x03key\x127\n" +
-	"\x05value\x18\x02 \x01(\v2!.hopgate.protocol.v1.HeaderValuesR\x05value:\x028\x01\"B\n" +
-	"\n" +
-	"StreamData\x12\x0e\n" +
-	"\x02id\x18\x01 \x01(\tR\x02id\x12\x10\n" +
-	"\x03seq\x18\x02 \x01(\x04R\x03seq\x12\x12\n" +
-	"\x04data\x18\x03 \x01(\fR\x04data\"r\n" +
-	"\tStreamAck\x12\x0e\n" +
-	"\x02id\x18\x01 \x01(\tR\x02id\x12\x17\n" +
-	"\aack_seq\x18\x02 \x01(\x04R\x06ackSeq\x12\x1b\n" +
-	"\tlost_seqs\x18\x03 \x03(\x04R\blostSeqs\x12\x1f\n" +
-	"\vwindow_size\x18\x04 \x01(\rR\n" +
-	"windowSize\"3\n" +
-	"\vStreamClose\x12\x0e\n" +
-	"\x02id\x18\x01 \x01(\tR\x02id\x12\x14\n" +
-	"\x05error\x18\x02 \x01(\tR\x05error\"\xae\x03\n" +
-	"\bEnvelope\x12A\n" +
-	"\fhttp_request\x18\x01 \x01(\v2\x1c.hopgate.protocol.v1.RequestH\x00R\vhttpRequest\x12D\n" +
-	"\rhttp_response\x18\x02 \x01(\v2\x1d.hopgate.protocol.v1.ResponseH\x00R\fhttpResponse\x12B\n" +
-	"\vstream_open\x18\x03 \x01(\v2\x1f.hopgate.protocol.v1.StreamOpenH\x00R\n" +
-	"streamOpen\x12B\n" +
-	"\vstream_data\x18\x04 \x01(\v2\x1f.hopgate.protocol.v1.StreamDataH\x00R\n" +
-	"streamData\x12E\n" +
-	"\fstream_close\x18\x05 \x01(\v2 .hopgate.protocol.v1.StreamCloseH\x00R\vstreamClose\x12?\n" +
-	"\n" +
-	"stream_ack\x18\x06 \x01(\v2\x1e.hopgate.protocol.v1.StreamAckH\x00R\tstreamAckB\t\n" +
-	"\apayloadB@Z>github.com/dalbodeule/hop-gate/internal/protocol/pb;protocolpbb\x06proto3"
-
-var (
-	file_internal_protocol_hopgate_stream_proto_rawDescOnce sync.Once
-	file_internal_protocol_hopgate_stream_proto_rawDescData []byte
-)
-
-func file_internal_protocol_hopgate_stream_proto_rawDescGZIP() []byte {
-	file_internal_protocol_hopgate_stream_proto_rawDescOnce.Do(func() {
-		file_internal_protocol_hopgate_stream_proto_rawDescData = protoimpl.X.CompressGZIP(unsafe.Slice(unsafe.StringData(file_internal_protocol_hopgate_stream_proto_rawDesc), len(file_internal_protocol_hopgate_stream_proto_rawDesc)))
-	})
-	return file_internal_protocol_hopgate_stream_proto_rawDescData
-}
-
-var file_internal_protocol_hopgate_stream_proto_msgTypes = make([]protoimpl.MessageInfo, 11)
-var file_internal_protocol_hopgate_stream_proto_goTypes = []any{
-	(*HeaderValues)(nil), // 0: hopgate.protocol.v1.HeaderValues
-	(*Request)(nil),      // 1: hopgate.protocol.v1.Request
-	(*Response)(nil),     // 2: hopgate.protocol.v1.Response
-	(*StreamOpen)(nil),   // 3: hopgate.protocol.v1.StreamOpen
-	(*StreamData)(nil),   // 4: hopgate.protocol.v1.StreamData
-	(*StreamAck)(nil),    // 5: hopgate.protocol.v1.StreamAck
-	(*StreamClose)(nil),  // 6: hopgate.protocol.v1.StreamClose
-	(*Envelope)(nil),     // 7: hopgate.protocol.v1.Envelope
-	nil,                  // 8: hopgate.protocol.v1.Request.HeaderEntry
-	nil,                  // 9: hopgate.protocol.v1.Response.HeaderEntry
-	nil,                  // 10: hopgate.protocol.v1.StreamOpen.HeaderEntry
-}
-var file_internal_protocol_hopgate_stream_proto_depIdxs = []int32{
-	8,  // 0: hopgate.protocol.v1.Request.header:type_name -> hopgate.protocol.v1.Request.HeaderEntry
-	9,  // 1: hopgate.protocol.v1.Response.header:type_name -> hopgate.protocol.v1.Response.HeaderEntry
-	10, // 2: hopgate.protocol.v1.StreamOpen.header:type_name -> hopgate.protocol.v1.StreamOpen.HeaderEntry
-	1,  // 3: hopgate.protocol.v1.Envelope.http_request:type_name -> hopgate.protocol.v1.Request
-	2,  // 4: hopgate.protocol.v1.Envelope.http_response:type_name -> hopgate.protocol.v1.Response
-	3,  // 5: hopgate.protocol.v1.Envelope.stream_open:type_name -> hopgate.protocol.v1.StreamOpen
-	4,  // 6: hopgate.protocol.v1.Envelope.stream_data:type_name -> hopgate.protocol.v1.StreamData
-	6,  // 7: hopgate.protocol.v1.Envelope.stream_close:type_name -> hopgate.protocol.v1.StreamClose
-	5,  // 8: hopgate.protocol.v1.Envelope.stream_ack:type_name -> hopgate.protocol.v1.StreamAck
-	0,  // 9: hopgate.protocol.v1.Request.HeaderEntry.value:type_name -> hopgate.protocol.v1.HeaderValues
-	0,  // 10: hopgate.protocol.v1.Response.HeaderEntry.value:type_name -> hopgate.protocol.v1.HeaderValues
-	0,  // 11: hopgate.protocol.v1.StreamOpen.HeaderEntry.value:type_name -> hopgate.protocol.v1.HeaderValues
-	12, // [12:12] is the sub-list for method output_type
-	12, // [12:12] is the sub-list for method input_type
-	12, // [12:12] is the sub-list for extension type_name
-	12, // [12:12] is the sub-list for extension extendee
-	0,  // [0:12] is the sub-list for field type_name
-}
-
-func init() { file_internal_protocol_hopgate_stream_proto_init() }
-func file_internal_protocol_hopgate_stream_proto_init() {
-	if File_internal_protocol_hopgate_stream_proto != nil {
-		return
-	}
-	file_internal_protocol_hopgate_stream_proto_msgTypes[7].OneofWrappers = []any{
-		(*Envelope_HttpRequest)(nil),
-		(*Envelope_HttpResponse)(nil),
-		(*Envelope_StreamOpen)(nil),
-		(*Envelope_StreamData)(nil),
-		(*Envelope_StreamClose)(nil),
-		(*Envelope_StreamAck)(nil),
-	}
-	type x struct{}
-	out := protoimpl.TypeBuilder{
-		File: protoimpl.DescBuilder{
-			GoPackagePath: reflect.TypeOf(x{}).PkgPath(),
-			RawDescriptor: unsafe.Slice(unsafe.StringData(file_internal_protocol_hopgate_stream_proto_rawDesc), len(file_internal_protocol_hopgate_stream_proto_rawDesc)),
-			NumEnums:      0,
-			NumMessages:   11,
-			NumExtensions: 0,
-			NumServices:   0,
-		},
-		GoTypes:           file_internal_protocol_hopgate_stream_proto_goTypes,
-		DependencyIndexes: file_internal_protocol_hopgate_stream_proto_depIdxs,
-		MessageInfos:      file_internal_protocol_hopgate_stream_proto_msgTypes,
-	}.Build()
-	File_internal_protocol_hopgate_stream_proto = out.File
-	file_internal_protocol_hopgate_stream_proto_goTypes = nil
-	file_internal_protocol_hopgate_stream_proto_depIdxs = nil
-}

internal/protocol/hopgate_stream.proto

@@ -2,7 +2,7 @@ syntax = "proto3";
 
 package hopgate.protocol.v1;
 
-option go_package = "github.com/dalbodeule/hop-gate/internal/protocol/pb;protocolpb";
+option go_package = "internal/protocol/pb;pb";
 
 // HeaderValues 는 HTTP 헤더의 다중 값 표현을 위한 래퍼입니다.
 // HeaderValues wraps multiple header values for a single HTTP header key.

internal/protocol/pb/hopgate_stream.pb.go

@@ -718,7 +718,7 @@ const file_internal_protocol_hopgate_stream_proto_rawDesc = "" +
 	"\fstream_close\x18\x05 \x01(\v2 .hopgate.protocol.v1.StreamCloseH\x00R\vstreamClose\x12?\n" +
 	"\n" +
 	"stream_ack\x18\x06 \x01(\v2\x1e.hopgate.protocol.v1.StreamAckH\x00R\tstreamAckB\t\n" +
-	"\apayloadB@Z>github.com/dalbodeule/hop-gate/internal/protocol/pb;protocolpbb\x06proto3"
+	"\apayloadB\x19Z\x17internal/protocol/pb;pbb\x06proto3"
 
 var (
 	file_internal_protocol_hopgate_stream_proto_rawDescOnce sync.Once

progress.md

@@ -243,7 +243,7 @@ HopGate 의 최종 목표는 **TCP + TLS(HTTPS) + HTTP/2 + gRPC** 기반 터널
     로컬 HTTP 서비스(예: `127.0.0.1:8080`)로 proxy 하고, 응답을 다시 `TunnelFrame` 시퀀스로 전송합니다.
   - 기존 `internal/proxy/client.go` 의 HTTP 매핑/스트림 ARQ 경험을, gRPC 메시지 단위 chunk/flow-control 설계에 참고합니다.
 
-- [ ] HTTP ↔ gRPC 터널 매핑 규약 정의
+- [x] HTTP ↔ gRPC 터널 매핑 규약 정의
   - 한 HTTP 요청/응답 쌍을 gRPC 스트림 상에서 어떻게 표현할지 스키마를 정의합니다:
     - 요청: `StreamID`, method, URL, headers, body chunks
     - 응답: `StreamID`, status, headers, body chunks, error

protocol.md

@@ -0,0 +1,197 @@
+# HopGate gRPC Tunnel Protocol
+
+이 문서는 HopGate 서버–클라이언트 사이의 gRPC 기반 HTTP 터널링 규약을 정리합니다. (ko)
+This document describes the gRPC-based HTTP tunneling protocol between HopGate server and clients. (en)
+
+## 1. Transport Overview / 전송 개요
+
+- Transport: TCP + TLS(HTTPS) + HTTP/2 + gRPC
+- Single long-lived bi-directional gRPC stream per client: `OpenTunnel`
+- Application payload type: `Envelope` (from `internal/protocol/hopgate_stream.proto`)
+- HTTP requests/responses are multiplexed as logical streams identified by `StreamID`.
+
+gRPC service (conceptual):
+```proto
+service HopGateTunnel {
+  rpc OpenTunnel (stream Envelope) returns (stream Envelope);
+}
+```
+
+## 2. Message Types / 메시지 타입
+
+Defined in `internal/protocol/hopgate_stream.proto`:
+
+- `HeaderValues`
+  - Wraps repeated header values: `map<string, HeaderValues>`
+- `Request` / `Response`
+  - Simple single-message HTTP representation (not used in the streaming tunnel path initially).
+- `StreamOpen`
+  - Opens a new logical stream for HTTP request/response (or other protocols in the future).
+- `StreamData`
+  - Carries body chunks for a stream (`id`, `seq`, `data`).
+- `StreamClose`
+  - Marks the end of a stream (`id`, `error`).
+- `StreamAck`
+  - Legacy ARQ/flow-control hint for UDP/DTLS; in gRPC tunnel it is reserved/optional.
+- `Envelope`
+  - Top-level container with `oneof payload` of the above types.
+
+In the gRPC tunnel, `Envelope` is the only gRPC message type used on the `OpenTunnel` stream.
+
+## 3. Logical Streams and StreamID / 논리 스트림과 StreamID
+
+- A single `OpenTunnel` gRPC stream multiplexes many **logical streams**.
+- Each logical stream corresponds to one HTTP request/response pair.
+- Logical streams are identified by `StreamOpen.id` (text StreamID).
+- The server generates unique IDs per gRPC connection:
+  - HTTP streams: `"http-{n}"` where `n` is a monotonically increasing counter.
+  - Control stream: `"control-0"` (special handshake/metadata stream).
+
+Within a gRPC connection:
+- Multiple `StreamID`s may be active concurrently.
+- Frames with different StreamIDs may be arbitrarily interleaved.
+- Order within a stream is tracked by `StreamData.seq` (starting at 0).
+
+## 4. HTTP Request Mapping (Server → Client) / HTTP 요청 매핑
+
+When the public HTTPS reverse-proxy (`cmd/server/main.go`) receives an HTTP request for a domain that is bound
+to a client tunnel, it serializes the request into a logical stream as follows.
+
+### 4.1 StreamOpen (request metadata and headers)
+
+- `StreamOpen.id`
+  - New unique StreamID: `"http-{n}"`.
+- `StreamOpen.service_name`
+  - Logical service selection on the client (e.g., `"web"`).
+- `StreamOpen.target_addr`
+  - Optional explicit local target address on the client (e.g., `"127.0.0.1:8080"`).
+- `StreamOpen.header`
+  - Contains HTTP request headers and pseudo-headers:
+  - Pseudo-headers:
+    - `X-HopGate-Method`: HTTP method (e.g., `"GET"`, `"POST"`).
+    - `X-HopGate-URL`: original URL path + query (e.g., `"/api/v1/foo?bar=1"`).
+    - `X-HopGate-Host`: Host header value.
+  - Other keys:
+    - All remaining HTTP headers from the incoming request, copied as-is into the map.
+
+### 4.2 StreamData* (request body chunks)
+
+- If the request has a body, the server chunks it into fixed-size pieces.
+- Chunk size: `protocol.StreamChunkSize` (currently 4 KiB).
+- For each chunk:
+  - `StreamData.id = StreamOpen.id`
+  - `StreamData.seq` increments from 0, 1, 2, …
+  - `StreamData.data` contains the raw bytes.
+
+### 4.3 StreamClose (end of request body)
+
+- After sending all body chunks, the server sends a `StreamClose`:
+  - `StreamClose.id = StreamOpen.id`
+  - `StreamClose.error` is empty on success.
+  - If there was an application-level error while reading the body, `error` contains a short description.
+
+The client reconstructs the HTTP request by:
+- Reassembling the URL and headers from the `StreamOpen` pseudo-headers and header map.
+- Concatenating `StreamData.data` in `seq` order into the request body.
+- Treating `StreamClose` as the end-of-stream marker.
+
+## 5. HTTP Response Mapping (Client → Server) / HTTP 응답 매핑
+
+The client receives `StreamOpen` + `StreamData*` + `StreamClose`, performs a local HTTP request to its
+configured target (e.g., `http://127.0.0.1:8080`), then returns an HTTP response using the same StreamID.
+
+### 5.1 StreamOpen (response headers and status)
+
+- `StreamOpen.id`
+  - Same as the request StreamID.
+- `StreamOpen.header`
+  - Contains response headers and a pseudo-header for status:
+  - Pseudo-header:
+    - `X-HopGate-Status`: HTTP status code as a string (e.g., `"200"`, `"502"`).
+  - Other keys:
+    - All HTTP response headers from the local backend, copied as-is.
+
+### 5.2 StreamData* (response body chunks)
+
+- The client reads the local HTTP response body and chunks it into 4 KiB pieces (same `StreamChunkSize`).
+- For each chunk:
+  - `StreamData.id = StreamOpen.id`
+  - `StreamData.seq` increments from 0.
+  - `StreamData.data` contains the raw bytes.
+
+### 5.3 StreamClose (end of response body)
+
+- When the local backend response is fully read, the client sends a `StreamClose`:
+  - `StreamClose.id` is the same StreamID.
+  - `StreamClose.error`:
+    - Empty string on success.
+    - Short error description if the local HTTP request/response failed (e.g., connect timeout).
+
+The server reconstructs the HTTP response by:
+- Parsing `X-HopGate-Status` into an integer HTTP status code.
+- Copying other headers into the outgoing response writer (with some security headers overridden by the server).
+- Concatenating `StreamData.data` in `seq` order into the HTTP response body.
+- Considering `StreamClose.error` for logging/metrics and possibly mapping to error pages if needed.
+
+## 6. Control / Handshake Stream / 컨트롤 스트림
+
+Before any HTTP request streams are opened, the client sends a single **control stream** to authenticate
+and describe itself.
+
+- `StreamOpen` (control):
+  - `id = "control-0"`
+  - `service_name = "control"`
+  - `header` contains:
+    - `X-HopGate-Domain`: domain this client is responsible for.
+    - `X-HopGate-API-Key`: client API key for the domain.
+    - `X-HopGate-Local-Target`: default local target such as `127.0.0.1:8080`.
+- No `StreamData` is required for the control stream in the initial design.
+- The server can optionally reply with its own control `StreamOpen/Close` to signal acceptance/rejection.
+
+On the server side:
+- `grpcTunnelServer.OpenTunnel` should:
+  1. Wait for the first `Envelope` with `StreamOpen.id == "control-0"`.
+  2. Extract domain, api key, and local target from the headers.
+  3. Call the ent-based `DomainValidator` to validate `(domain, api_key)`.
+  4. If validation succeeds, register this gRPC stream as the active tunnel for that domain.
+  5. If validation fails, log and close the gRPC stream.
+
+Once the control stream handshake completes successfully, the server may start multiplexing multiple
+HTTP request streams (`http-0`, `http-1`, …) over the same `OpenTunnel` connection.
+
+## 7. Multiplexing Semantics / 멀티플렉싱 의미
+
+- A single TCP + TLS + HTTP/2 + gRPC connection carries:
+  - One long-lived `OpenTunnel` gRPC bi-di stream.
+  - Within it, many logical streams identified by `StreamID`.
+- The server can open multiple HTTP streams concurrently for a given client:
+  - Example: `http-0` for `/css/app.css`, `http-1` for `/api/users`, `http-2` for `/img/logo.png`.
+  - Frames for these IDs can interleave arbitrarily on the wire.
+- Per-stream ordering is preserved by combining `seq` ordering and the reliability of TCP/gRPC.
+- Slow or large responses on one stream should not prevent other streams from making progress,
+  because gRPC/HTTP2 handles stream-level flow control and scheduling.
+
+## 8. Flow Control and StreamAck / 플로우 컨트롤 및 StreamAck
+
+- The gRPC tunnel runs over TCP/HTTP2, which already provides:
+  - Reliable, in-order delivery.
+  - Connection-level and stream-level flow control.
+- Therefore, application-level selective retransmission is **not required** for the gRPC tunnel.
+- `StreamAck` remains defined in the proto for backward compatibility with the DTLS design and
+  as a potential future hint channel (e.g., window size hints), but is not used in the initial gRPC tunnel.
+
+## 9. Security Considerations / 보안 고려사항
+
+- TLS:
+  - In production, the server uses ACME-issued certificates, and clients validate the server certificate
+    using system Root CAs and SNI (`ServerName`).
+  - In debug mode, clients may use `InsecureSkipVerify: true` to allow local/self-signed certs.
+- Authentication:
+  - Application-level authentication relies on `(domain, api_key)` pairs sent via the control stream headers.
+  - The server must validate these pairs against the `Domain` table using `DomainValidator`.
+- Authorization and isolation:
+  - Each gRPC tunnel is bound to a single domain (or a defined set of domains) after successful control handshake.
+  - HTTP requests for other domains must not be forwarded over this tunnel.
+
+이 규약을 기준으로 서버/클라이언트 구현을 정렬하면, 하나의 gRPC `OpenTunnel` 스트림 위에서
+여러 HTTP 요청을 안정적으로 멀티플렉싱하면서도, 도메인/API 키 기반 인증과 TLS 보안을 함께 유지할 수 있습니다.