Implement PostUploadPackWithSidechannel using sidechannel protocol

Issue: https://gitlab.com/gitlab-com/gl-infra/scalability/-/issues/1219
Changelog: added

3 files changed, 292 insertions, 80 deletions

diff --git a/proto/go/gitalypb/smarthttp.pb.go b/proto/go/gitalypb/smarthttp.pb.go
index bbedd31b2..e7ec4a48a 100644
--- a/proto/go/gitalypb/smarthttp.pb.go
+++ b/proto/go/gitalypb/smarthttp.pb.go
@@ -255,6 +255,110 @@ func (x *PostUploadPackResponse) GetData() []byte {
 	return nil
 }
 
+type PostUploadPackWithSidechannelRequest struct {
+	state         protoimpl.MessageState
+	sizeCache     protoimpl.SizeCache
+	unknownFields protoimpl.UnknownFields
+
+	// repository should only be present in the first message of the stream
+	Repository *Repository `protobuf:"bytes,1,opt,name=repository,proto3" json:"repository,omitempty"`
+	// Parameters to use with git -c (key=value pairs)
+	GitConfigOptions []string `protobuf:"bytes,2,rep,name=git_config_options,json=gitConfigOptions,proto3" json:"git_config_options,omitempty"`
+	// Git protocol version
+	GitProtocol string `protobuf:"bytes,3,opt,name=git_protocol,json=gitProtocol,proto3" json:"git_protocol,omitempty"`
+}
+
+func (x *PostUploadPackWithSidechannelRequest) Reset() {
+	*x = PostUploadPackWithSidechannelRequest{}
+	if protoimpl.UnsafeEnabled {
+		mi := &file_smarthttp_proto_msgTypes[4]
+		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+		ms.StoreMessageInfo(mi)
+	}
+}
+
+func (x *PostUploadPackWithSidechannelRequest) String() string {
+	return protoimpl.X.MessageStringOf(x)
+}
+
+func (*PostUploadPackWithSidechannelRequest) ProtoMessage() {}
+
+func (x *PostUploadPackWithSidechannelRequest) ProtoReflect() protoreflect.Message {
+	mi := &file_smarthttp_proto_msgTypes[4]
+	if protoimpl.UnsafeEnabled && x != nil {
+		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+		if ms.LoadMessageInfo() == nil {
+			ms.StoreMessageInfo(mi)
+		}
+		return ms
+	}
+	return mi.MessageOf(x)
+}
+
+// Deprecated: Use PostUploadPackWithSidechannelRequest.ProtoReflect.Descriptor instead.
+func (*PostUploadPackWithSidechannelRequest) Descriptor() ([]byte, []int) {
+	return file_smarthttp_proto_rawDescGZIP(), []int{4}
+}
+
+func (x *PostUploadPackWithSidechannelRequest) GetRepository() *Repository {
+	if x != nil {
+		return x.Repository
+	}
+	return nil
+}
+
+func (x *PostUploadPackWithSidechannelRequest) GetGitConfigOptions() []string {
+	if x != nil {
+		return x.GitConfigOptions
+	}
+	return nil
+}
+
+func (x *PostUploadPackWithSidechannelRequest) GetGitProtocol() string {
+	if x != nil {
+		return x.GitProtocol
+	}
+	return ""
+}
+
+type PostUploadPackWithSidechannelResponse struct {
+	state         protoimpl.MessageState
+	sizeCache     protoimpl.SizeCache
+	unknownFields protoimpl.UnknownFields
+}
+
+func (x *PostUploadPackWithSidechannelResponse) Reset() {
+	*x = PostUploadPackWithSidechannelResponse{}
+	if protoimpl.UnsafeEnabled {
+		mi := &file_smarthttp_proto_msgTypes[5]
+		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+		ms.StoreMessageInfo(mi)
+	}
+}
+
+func (x *PostUploadPackWithSidechannelResponse) String() string {
+	return protoimpl.X.MessageStringOf(x)
+}
+
+func (*PostUploadPackWithSidechannelResponse) ProtoMessage() {}
+
+func (x *PostUploadPackWithSidechannelResponse) ProtoReflect() protoreflect.Message {
+	mi := &file_smarthttp_proto_msgTypes[5]
+	if protoimpl.UnsafeEnabled && x != nil {
+		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
+		if ms.LoadMessageInfo() == nil {
+			ms.StoreMessageInfo(mi)
+		}
+		return ms
+	}
+	return mi.MessageOf(x)
+}
+
+// Deprecated: Use PostUploadPackWithSidechannelResponse.ProtoReflect.Descriptor instead.
+func (*PostUploadPackWithSidechannelResponse) Descriptor() ([]byte, []int) {
+	return file_smarthttp_proto_rawDescGZIP(), []int{5}
+}
+
 type PostReceivePackRequest struct {
 	state         protoimpl.MessageState
 	sizeCache     protoimpl.SizeCache
@@ -278,7 +382,7 @@ type PostReceivePackRequest struct {
 func (x *PostReceivePackRequest) Reset() {
 	*x = PostReceivePackRequest{}
 	if protoimpl.UnsafeEnabled {
-		mi := &file_smarthttp_proto_msgTypes[4]
+		mi := &file_smarthttp_proto_msgTypes[6]
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		ms.StoreMessageInfo(mi)
 	}
@@ -291,7 +395,7 @@ func (x *PostReceivePackRequest) String() string {
 func (*PostReceivePackRequest) ProtoMessage() {}
 
 func (x *PostReceivePackRequest) ProtoReflect() protoreflect.Message {
-	mi := &file_smarthttp_proto_msgTypes[4]
+	mi := &file_smarthttp_proto_msgTypes[6]
 	if protoimpl.UnsafeEnabled && x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -304,7 +408,7 @@ func (x *PostReceivePackRequest) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use PostReceivePackRequest.ProtoReflect.Descriptor instead.
 func (*PostReceivePackRequest) Descriptor() ([]byte, []int) {
-	return file_smarthttp_proto_rawDescGZIP(), []int{4}
+	return file_smarthttp_proto_rawDescGZIP(), []int{6}
 }
 
 func (x *PostReceivePackRequest) GetRepository() *Repository {
@@ -368,7 +472,7 @@ type PostReceivePackResponse struct {
 func (x *PostReceivePackResponse) Reset() {
 	*x = PostReceivePackResponse{}
 	if protoimpl.UnsafeEnabled {
-		mi := &file_smarthttp_proto_msgTypes[5]
+		mi := &file_smarthttp_proto_msgTypes[7]
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		ms.StoreMessageInfo(mi)
 	}
@@ -381,7 +485,7 @@ func (x *PostReceivePackResponse) String() string {
 func (*PostReceivePackResponse) ProtoMessage() {}
 
 func (x *PostReceivePackResponse) ProtoReflect() protoreflect.Message {
-	mi := &file_smarthttp_proto_msgTypes[5]
+	mi := &file_smarthttp_proto_msgTypes[7]
 	if protoimpl.UnsafeEnabled && x != nil {
 		ms := protoimpl.X.MessageStateOf(protoimpl.Pointer(x))
 		if ms.LoadMessageInfo() == nil {
@@ -394,7 +498,7 @@ func (x *PostReceivePackResponse) ProtoReflect() protoreflect.Message {
 
 // Deprecated: Use PostReceivePackResponse.ProtoReflect.Descriptor instead.
 func (*PostReceivePackResponse) Descriptor() ([]byte, []int) {
-	return file_smarthttp_proto_rawDescGZIP(), []int{5}
+	return file_smarthttp_proto_rawDescGZIP(), []int{7}
 }
 
 func (x *PostReceivePackResponse) GetData() []byte {
@@ -437,54 +541,76 @@ var file_smarthttp_proto_rawDesc = []byte{
 	0x63, 0x6f, 0x6c, 0x22, 0x2c, 0x0a, 0x16, 0x50, 0x6f, 0x73, 0x74, 0x55, 0x70, 0x6c, 0x6f, 0x61,
 	0x64, 0x50, 0x61, 0x63, 0x6b, 0x52, 0x65, 0x73, 0x70, 0x6f, 0x6e, 0x73, 0x65, 0x12, 0x12, 0x0a,
 	0x04, 0x64, 0x61, 0x74, 0x61, 0x18, 0x01, 0x20, 0x01, 0x28, 0x0c, 0x52, 0x04, 0x64, 0x61, 0x74,
-	0x61, 0x22, 0x92, 0x02, 0x0a, 0x16, 0x50, 0x6f, 0x73, 0x74, 0x52, 0x65, 0x63, 0x65, 0x69, 0x76,
-	0x65, 0x50, 0x61, 0x63, 0x6b, 0x52, 0x65, 0x71, 0x75, 0x65, 0x73, 0x74, 0x12, 0x38, 0x0a, 0x0a,
-	0x72, 0x65, 0x70, 0x6f, 0x73, 0x69, 0x74, 0x6f, 0x72, 0x79, 0x18, 0x01, 0x20, 0x01, 0x28, 0x0b,
-	0x32, 0x12, 0x2e, 0x67, 0x69, 0x74, 0x61, 0x6c, 0x79, 0x2e, 0x52, 0x65, 0x70, 0x6f, 0x73, 0x69,
-	0x74, 0x6f, 0x72, 0x79, 0x42, 0x04, 0x98, 0xc6, 0x2c, 0x01, 0x52, 0x0a, 0x72, 0x65, 0x70, 0x6f,
-	0x73, 0x69, 0x74, 0x6f, 0x72, 0x79, 0x12, 0x12, 0x0a, 0x04, 0x64, 0x61, 0x74, 0x61, 0x18, 0x02,
-	0x20, 0x01, 0x28, 0x0c, 0x52, 0x04, 0x64, 0x61, 0x74, 0x61, 0x12, 0x13, 0x0a, 0x05, 0x67, 0x6c,
-	0x5f, 0x69, 0x64, 0x18, 0x03, 0x20, 0x01, 0x28, 0x09, 0x52, 0x04, 0x67, 0x6c, 0x49, 0x64, 0x12,
-	0x23, 0x0a, 0x0d, 0x67, 0x6c, 0x5f, 0x72, 0x65, 0x70, 0x6f, 0x73, 0x69, 0x74, 0x6f, 0x72, 0x79,
-	0x18, 0x04, 0x20, 0x01, 0x28, 0x09, 0x52, 0x0c, 0x67, 0x6c, 0x52, 0x65, 0x70, 0x6f, 0x73, 0x69,
-	0x74, 0x6f, 0x72, 0x79, 0x12, 0x1f, 0x0a, 0x0b, 0x67, 0x6c, 0x5f, 0x75, 0x73, 0x65, 0x72, 0x6e,
-	0x61, 0x6d, 0x65, 0x18, 0x05, 0x20, 0x01, 0x28, 0x09, 0x52, 0x0a, 0x67, 0x6c, 0x55, 0x73, 0x65,
-	0x72, 0x6e, 0x61, 0x6d, 0x65, 0x12, 0x21, 0x0a, 0x0c, 0x67, 0x69, 0x74, 0x5f, 0x70, 0x72, 0x6f,
-	0x74, 0x6f, 0x63, 0x6f, 0x6c, 0x18, 0x06, 0x20, 0x01, 0x28, 0x09, 0x52, 0x0b, 0x67, 0x69, 0x74,
-	0x50, 0x72, 0x6f, 0x74, 0x6f, 0x63, 0x6f, 0x6c, 0x12, 0x2c, 0x0a, 0x12, 0x67, 0x69, 0x74, 0x5f,
-	0x63, 0x6f, 0x6e, 0x66, 0x69, 0x67, 0x5f, 0x6f, 0x70, 0x74, 0x69, 0x6f, 0x6e, 0x73, 0x18, 0x07,
-	0x20, 0x03, 0x28, 0x09, 0x52, 0x10, 0x67, 0x69, 0x74, 0x43, 0x6f, 0x6e, 0x66, 0x69, 0x67, 0x4f,
-	0x70, 0x74, 0x69, 0x6f, 0x6e, 0x73, 0x22, 0x2d, 0x0a, 0x17, 0x50, 0x6f, 0x73, 0x74, 0x52, 0x65,
-	0x63, 0x65, 0x69, 0x76, 0x65, 0x50, 0x61, 0x63, 0x6b, 0x52, 0x65, 0x73, 0x70, 0x6f, 0x6e, 0x73,
-	0x65, 0x12, 0x12, 0x0a, 0x04, 0x64, 0x61, 0x74, 0x61, 0x18, 0x01, 0x20, 0x01, 0x28, 0x0c, 0x52,
-	0x04, 0x64, 0x61, 0x74, 0x61, 0x32, 0xf6, 0x02, 0x0a, 0x10, 0x53, 0x6d, 0x61, 0x72, 0x74, 0x48,
-	0x54, 0x54, 0x50, 0x53, 0x65, 0x72, 0x76, 0x69, 0x63, 0x65, 0x12, 0x51, 0x0a, 0x12, 0x49, 0x6e,
-	0x66, 0x6f, 0x52, 0x65, 0x66, 0x73, 0x55, 0x70, 0x6c, 0x6f, 0x61, 0x64, 0x50, 0x61, 0x63, 0x6b,
-	0x12, 0x17, 0x2e, 0x67, 0x69, 0x74, 0x61, 0x6c, 0x79, 0x2e, 0x49, 0x6e, 0x66, 0x6f, 0x52, 0x65,
-	0x66, 0x73, 0x52, 0x65, 0x71, 0x75, 0x65, 0x73, 0x74, 0x1a, 0x18, 0x2e, 0x67, 0x69, 0x74, 0x61,
-	0x6c, 0x79, 0x2e, 0x49, 0x6e, 0x66, 0x6f, 0x52, 0x65, 0x66, 0x73, 0x52, 0x65, 0x73, 0x70, 0x6f,
-	0x6e, 0x73, 0x65, 0x22, 0x06, 0xfa, 0x97, 0x28, 0x02, 0x08, 0x02, 0x30, 0x01, 0x12, 0x52, 0x0a,
-	0x13, 0x49, 0x6e, 0x66, 0x6f, 0x52, 0x65, 0x66, 0x73, 0x52, 0x65, 0x63, 0x65, 0x69, 0x76, 0x65,
-	0x50, 0x61, 0x63, 0x6b, 0x12, 0x17, 0x2e, 0x67, 0x69, 0x74, 0x61, 0x6c, 0x79, 0x2e, 0x49, 0x6e,
-	0x66, 0x6f, 0x52, 0x65, 0x66, 0x73, 0x52, 0x65, 0x71, 0x75, 0x65, 0x73, 0x74, 0x1a, 0x18, 0x2e,
+	0x61, 0x22, 0xb1, 0x01, 0x0a, 0x24, 0x50, 0x6f, 0x73, 0x74, 0x55, 0x70, 0x6c, 0x6f, 0x61, 0x64,
+	0x50, 0x61, 0x63, 0x6b, 0x57, 0x69, 0x74, 0x68, 0x53, 0x69, 0x64, 0x65, 0x63, 0x68, 0x61, 0x6e,
+	0x6e, 0x65, 0x6c, 0x52, 0x65, 0x71, 0x75, 0x65, 0x73, 0x74, 0x12, 0x38, 0x0a, 0x0a, 0x72, 0x65,
+	0x70, 0x6f, 0x73, 0x69, 0x74, 0x6f, 0x72, 0x79, 0x18, 0x01, 0x20, 0x01, 0x28, 0x0b, 0x32, 0x12,
+	0x2e, 0x67, 0x69, 0x74, 0x61, 0x6c, 0x79, 0x2e, 0x52, 0x65, 0x70, 0x6f, 0x73, 0x69, 0x74, 0x6f,
+	0x72, 0x79, 0x42, 0x04, 0x98, 0xc6, 0x2c, 0x01, 0x52, 0x0a, 0x72, 0x65, 0x70, 0x6f, 0x73, 0x69,
+	0x74, 0x6f, 0x72, 0x79, 0x12, 0x2c, 0x0a, 0x12, 0x67, 0x69, 0x74, 0x5f, 0x63, 0x6f, 0x6e, 0x66,
+	0x69, 0x67, 0x5f, 0x6f, 0x70, 0x74, 0x69, 0x6f, 0x6e, 0x73, 0x18, 0x02, 0x20, 0x03, 0x28, 0x09,
+	0x52, 0x10, 0x67, 0x69, 0x74, 0x43, 0x6f, 0x6e, 0x66, 0x69, 0x67, 0x4f, 0x70, 0x74, 0x69, 0x6f,
+	0x6e, 0x73, 0x12, 0x21, 0x0a, 0x0c, 0x67, 0x69, 0x74, 0x5f, 0x70, 0x72, 0x6f, 0x74, 0x6f, 0x63,
+	0x6f, 0x6c, 0x18, 0x03, 0x20, 0x01, 0x28, 0x09, 0x52, 0x0b, 0x67, 0x69, 0x74, 0x50, 0x72, 0x6f,
+	0x74, 0x6f, 0x63, 0x6f, 0x6c, 0x22, 0x27, 0x0a, 0x25, 0x50, 0x6f, 0x73, 0x74, 0x55, 0x70, 0x6c,
+	0x6f, 0x61, 0x64, 0x50, 0x61, 0x63, 0x6b, 0x57, 0x69, 0x74, 0x68, 0x53, 0x69, 0x64, 0x65, 0x63,
+	0x68, 0x61, 0x6e, 0x6e, 0x65, 0x6c, 0x52, 0x65, 0x73, 0x70, 0x6f, 0x6e, 0x73, 0x65, 0x22, 0x92,
+	0x02, 0x0a, 0x16, 0x50, 0x6f, 0x73, 0x74, 0x52, 0x65, 0x63, 0x65, 0x69, 0x76, 0x65, 0x50, 0x61,
+	0x63, 0x6b, 0x52, 0x65, 0x71, 0x75, 0x65, 0x73, 0x74, 0x12, 0x38, 0x0a, 0x0a, 0x72, 0x65, 0x70,
+	0x6f, 0x73, 0x69, 0x74, 0x6f, 0x72, 0x79, 0x18, 0x01, 0x20, 0x01, 0x28, 0x0b, 0x32, 0x12, 0x2e,
+	0x67, 0x69, 0x74, 0x61, 0x6c, 0x79, 0x2e, 0x52, 0x65, 0x70, 0x6f, 0x73, 0x69, 0x74, 0x6f, 0x72,
+	0x79, 0x42, 0x04, 0x98, 0xc6, 0x2c, 0x01, 0x52, 0x0a, 0x72, 0x65, 0x70, 0x6f, 0x73, 0x69, 0x74,
+	0x6f, 0x72, 0x79, 0x12, 0x12, 0x0a, 0x04, 0x64, 0x61, 0x74, 0x61, 0x18, 0x02, 0x20, 0x01, 0x28,
+	0x0c, 0x52, 0x04, 0x64, 0x61, 0x74, 0x61, 0x12, 0x13, 0x0a, 0x05, 0x67, 0x6c, 0x5f, 0x69, 0x64,
+	0x18, 0x03, 0x20, 0x01, 0x28, 0x09, 0x52, 0x04, 0x67, 0x6c, 0x49, 0x64, 0x12, 0x23, 0x0a, 0x0d,
+	0x67, 0x6c, 0x5f, 0x72, 0x65, 0x70, 0x6f, 0x73, 0x69, 0x74, 0x6f, 0x72, 0x79, 0x18, 0x04, 0x20,
+	0x01, 0x28, 0x09, 0x52, 0x0c, 0x67, 0x6c, 0x52, 0x65, 0x70, 0x6f, 0x73, 0x69, 0x74, 0x6f, 0x72,
+	0x79, 0x12, 0x1f, 0x0a, 0x0b, 0x67, 0x6c, 0x5f, 0x75, 0x73, 0x65, 0x72, 0x6e, 0x61, 0x6d, 0x65,
+	0x18, 0x05, 0x20, 0x01, 0x28, 0x09, 0x52, 0x0a, 0x67, 0x6c, 0x55, 0x73, 0x65, 0x72, 0x6e, 0x61,
+	0x6d, 0x65, 0x12, 0x21, 0x0a, 0x0c, 0x67, 0x69, 0x74, 0x5f, 0x70, 0x72, 0x6f, 0x74, 0x6f, 0x63,
+	0x6f, 0x6c, 0x18, 0x06, 0x20, 0x01, 0x28, 0x09, 0x52, 0x0b, 0x67, 0x69, 0x74, 0x50, 0x72, 0x6f,
+	0x74, 0x6f, 0x63, 0x6f, 0x6c, 0x12, 0x2c, 0x0a, 0x12, 0x67, 0x69, 0x74, 0x5f, 0x63, 0x6f, 0x6e,
+	0x66, 0x69, 0x67, 0x5f, 0x6f, 0x70, 0x74, 0x69, 0x6f, 0x6e, 0x73, 0x18, 0x07, 0x20, 0x03, 0x28,
+	0x09, 0x52, 0x10, 0x67, 0x69, 0x74, 0x43, 0x6f, 0x6e, 0x66, 0x69, 0x67, 0x4f, 0x70, 0x74, 0x69,
+	0x6f, 0x6e, 0x73, 0x22, 0x2d, 0x0a, 0x17, 0x50, 0x6f, 0x73, 0x74, 0x52, 0x65, 0x63, 0x65, 0x69,
+	0x76, 0x65, 0x50, 0x61, 0x63, 0x6b, 0x52, 0x65, 0x73, 0x70, 0x6f, 0x6e, 0x73, 0x65, 0x12, 0x12,
+	0x0a, 0x04, 0x64, 0x61, 0x74, 0x61, 0x18, 0x01, 0x20, 0x01, 0x28, 0x0c, 0x52, 0x04, 0x64, 0x61,
+	0x74, 0x61, 0x32, 0xfd, 0x03, 0x0a, 0x10, 0x53, 0x6d, 0x61, 0x72, 0x74, 0x48, 0x54, 0x54, 0x50,
+	0x53, 0x65, 0x72, 0x76, 0x69, 0x63, 0x65, 0x12, 0x51, 0x0a, 0x12, 0x49, 0x6e, 0x66, 0x6f, 0x52,
+	0x65, 0x66, 0x73, 0x55, 0x70, 0x6c, 0x6f, 0x61, 0x64, 0x50, 0x61, 0x63, 0x6b, 0x12, 0x17, 0x2e,
 	0x67, 0x69, 0x74, 0x61, 0x6c, 0x79, 0x2e, 0x49, 0x6e, 0x66, 0x6f, 0x52, 0x65, 0x66, 0x73, 0x52,
-	0x65, 0x73, 0x70, 0x6f, 0x6e, 0x73, 0x65, 0x22, 0x06, 0xfa, 0x97, 0x28, 0x02, 0x08, 0x02, 0x30,
-	0x01, 0x12, 0x5b, 0x0a, 0x0e, 0x50, 0x6f, 0x73, 0x74, 0x55, 0x70, 0x6c, 0x6f, 0x61, 0x64, 0x50,
-	0x61, 0x63, 0x6b, 0x12, 0x1d, 0x2e, 0x67, 0x69, 0x74, 0x61, 0x6c, 0x79, 0x2e, 0x50, 0x6f, 0x73,
-	0x74, 0x55, 0x70, 0x6c, 0x6f, 0x61, 0x64, 0x50, 0x61, 0x63, 0x6b, 0x52, 0x65, 0x71, 0x75, 0x65,
-	0x73, 0x74, 0x1a, 0x1e, 0x2e, 0x67, 0x69, 0x74, 0x61, 0x6c, 0x79, 0x2e, 0x50, 0x6f, 0x73, 0x74,
-	0x55, 0x70, 0x6c, 0x6f, 0x61, 0x64, 0x50, 0x61, 0x63, 0x6b, 0x52, 0x65, 0x73, 0x70, 0x6f, 0x6e,
-	0x73, 0x65, 0x22, 0x06, 0xfa, 0x97, 0x28, 0x02, 0x08, 0x02, 0x28, 0x01, 0x30, 0x01, 0x12, 0x5e,
-	0x0a, 0x0f, 0x50, 0x6f, 0x73, 0x74, 0x52, 0x65, 0x63, 0x65, 0x69, 0x76, 0x65, 0x50, 0x61, 0x63,
-	0x6b, 0x12, 0x1e, 0x2e, 0x67, 0x69, 0x74, 0x61, 0x6c, 0x79, 0x2e, 0x50, 0x6f, 0x73, 0x74, 0x52,
-	0x65, 0x63, 0x65, 0x69, 0x76, 0x65, 0x50, 0x61, 0x63, 0x6b, 0x52, 0x65, 0x71, 0x75, 0x65, 0x73,
-	0x74, 0x1a, 0x1f, 0x2e, 0x67, 0x69, 0x74, 0x61, 0x6c, 0x79, 0x2e, 0x50, 0x6f, 0x73, 0x74, 0x52,
-	0x65, 0x63, 0x65, 0x69, 0x76, 0x65, 0x50, 0x61, 0x63, 0x6b, 0x52, 0x65, 0x73, 0x70, 0x6f, 0x6e,
-	0x73, 0x65, 0x22, 0x06, 0xfa, 0x97, 0x28, 0x02, 0x08, 0x01, 0x28, 0x01, 0x30, 0x01, 0x42, 0x34,
-	0x5a, 0x32, 0x67, 0x69, 0x74, 0x6c, 0x61, 0x62, 0x2e, 0x63, 0x6f, 0x6d, 0x2f, 0x67, 0x69, 0x74,
-	0x6c, 0x61, 0x62, 0x2d, 0x6f, 0x72, 0x67, 0x2f, 0x67, 0x69, 0x74, 0x61, 0x6c, 0x79, 0x2f, 0x76,
-	0x31, 0x34, 0x2f, 0x70, 0x72, 0x6f, 0x74, 0x6f, 0x2f, 0x67, 0x6f, 0x2f, 0x67, 0x69, 0x74, 0x61,
-	0x6c, 0x79, 0x70, 0x62, 0x62, 0x06, 0x70, 0x72, 0x6f, 0x74, 0x6f, 0x33,
+	0x65, 0x71, 0x75, 0x65, 0x73, 0x74, 0x1a, 0x18, 0x2e, 0x67, 0x69, 0x74, 0x61, 0x6c, 0x79, 0x2e,
+	0x49, 0x6e, 0x66, 0x6f, 0x52, 0x65, 0x66, 0x73, 0x52, 0x65, 0x73, 0x70, 0x6f, 0x6e, 0x73, 0x65,
+	0x22, 0x06, 0xfa, 0x97, 0x28, 0x02, 0x08, 0x02, 0x30, 0x01, 0x12, 0x52, 0x0a, 0x13, 0x49, 0x6e,
+	0x66, 0x6f, 0x52, 0x65, 0x66, 0x73, 0x52, 0x65, 0x63, 0x65, 0x69, 0x76, 0x65, 0x50, 0x61, 0x63,
+	0x6b, 0x12, 0x17, 0x2e, 0x67, 0x69, 0x74, 0x61, 0x6c, 0x79, 0x2e, 0x49, 0x6e, 0x66, 0x6f, 0x52,
+	0x65, 0x66, 0x73, 0x52, 0x65, 0x71, 0x75, 0x65, 0x73, 0x74, 0x1a, 0x18, 0x2e, 0x67, 0x69, 0x74,
+	0x61, 0x6c, 0x79, 0x2e, 0x49, 0x6e, 0x66, 0x6f, 0x52, 0x65, 0x66, 0x73, 0x52, 0x65, 0x73, 0x70,
+	0x6f, 0x6e, 0x73, 0x65, 0x22, 0x06, 0xfa, 0x97, 0x28, 0x02, 0x08, 0x02, 0x30, 0x01, 0x12, 0x5b,
+	0x0a, 0x0e, 0x50, 0x6f, 0x73, 0x74, 0x55, 0x70, 0x6c, 0x6f, 0x61, 0x64, 0x50, 0x61, 0x63, 0x6b,
+	0x12, 0x1d, 0x2e, 0x67, 0x69, 0x74, 0x61, 0x6c, 0x79, 0x2e, 0x50, 0x6f, 0x73, 0x74, 0x55, 0x70,
+	0x6c, 0x6f, 0x61, 0x64, 0x50, 0x61, 0x63, 0x6b, 0x52, 0x65, 0x71, 0x75, 0x65, 0x73, 0x74, 0x1a,
+	0x1e, 0x2e, 0x67, 0x69, 0x74, 0x61, 0x6c, 0x79, 0x2e, 0x50, 0x6f, 0x73, 0x74, 0x55, 0x70, 0x6c,
+	0x6f, 0x61, 0x64, 0x50, 0x61, 0x63, 0x6b, 0x52, 0x65, 0x73, 0x70, 0x6f, 0x6e, 0x73, 0x65, 0x22,
+	0x06, 0xfa, 0x97, 0x28, 0x02, 0x08, 0x02, 0x28, 0x01, 0x30, 0x01, 0x12, 0x84, 0x01, 0x0a, 0x1d,
+	0x50, 0x6f, 0x73, 0x74, 0x55, 0x70, 0x6c, 0x6f, 0x61, 0x64, 0x50, 0x61, 0x63, 0x6b, 0x57, 0x69,
+	0x74, 0x68, 0x53, 0x69, 0x64, 0x65, 0x63, 0x68, 0x61, 0x6e, 0x6e, 0x65, 0x6c, 0x12, 0x2c, 0x2e,
+	0x67, 0x69, 0x74, 0x61, 0x6c, 0x79, 0x2e, 0x50, 0x6f, 0x73, 0x74, 0x55, 0x70, 0x6c, 0x6f, 0x61,
+	0x64, 0x50, 0x61, 0x63, 0x6b, 0x57, 0x69, 0x74, 0x68, 0x53, 0x69, 0x64, 0x65, 0x63, 0x68, 0x61,
+	0x6e, 0x6e, 0x65, 0x6c, 0x52, 0x65, 0x71, 0x75, 0x65, 0x73, 0x74, 0x1a, 0x2d, 0x2e, 0x67, 0x69,
+	0x74, 0x61, 0x6c, 0x79, 0x2e, 0x50, 0x6f, 0x73, 0x74, 0x55, 0x70, 0x6c, 0x6f, 0x61, 0x64, 0x50,
+	0x61, 0x63, 0x6b, 0x57, 0x69, 0x74, 0x68, 0x53, 0x69, 0x64, 0x65, 0x63, 0x68, 0x61, 0x6e, 0x6e,
+	0x65, 0x6c, 0x52, 0x65, 0x73, 0x70, 0x6f, 0x6e, 0x73, 0x65, 0x22, 0x06, 0xfa, 0x97, 0x28, 0x02,
+	0x08, 0x02, 0x12, 0x5e, 0x0a, 0x0f, 0x50, 0x6f, 0x73, 0x74, 0x52, 0x65, 0x63, 0x65, 0x69, 0x76,
+	0x65, 0x50, 0x61, 0x63, 0x6b, 0x12, 0x1e, 0x2e, 0x67, 0x69, 0x74, 0x61, 0x6c, 0x79, 0x2e, 0x50,
+	0x6f, 0x73, 0x74, 0x52, 0x65, 0x63, 0x65, 0x69, 0x76, 0x65, 0x50, 0x61, 0x63, 0x6b, 0x52, 0x65,
+	0x71, 0x75, 0x65, 0x73, 0x74, 0x1a, 0x1f, 0x2e, 0x67, 0x69, 0x74, 0x61, 0x6c, 0x79, 0x2e, 0x50,
+	0x6f, 0x73, 0x74, 0x52, 0x65, 0x63, 0x65, 0x69, 0x76, 0x65, 0x50, 0x61, 0x63, 0x6b, 0x52, 0x65,
+	0x73, 0x70, 0x6f, 0x6e, 0x73, 0x65, 0x22, 0x06, 0xfa, 0x97, 0x28, 0x02, 0x08, 0x01, 0x28, 0x01,
+	0x30, 0x01, 0x42, 0x34, 0x5a, 0x32, 0x67, 0x69, 0x74, 0x6c, 0x61, 0x62, 0x2e, 0x63, 0x6f, 0x6d,
+	0x2f, 0x67, 0x69, 0x74, 0x6c, 0x61, 0x62, 0x2d, 0x6f, 0x72, 0x67, 0x2f, 0x67, 0x69, 0x74, 0x61,
+	0x6c, 0x79, 0x2f, 0x76, 0x31, 0x34, 0x2f, 0x70, 0x72, 0x6f, 0x74, 0x6f, 0x2f, 0x67, 0x6f, 0x2f,
+	0x67, 0x69, 0x74, 0x61, 0x6c, 0x79, 0x70, 0x62, 0x62, 0x06, 0x70, 0x72, 0x6f, 0x74, 0x6f, 0x33,
 }
 
 var (
@@ -499,33 +625,38 @@ func file_smarthttp_proto_rawDescGZIP() []byte {
 	return file_smarthttp_proto_rawDescData
 }
 
-var file_smarthttp_proto_msgTypes = make([]protoimpl.MessageInfo, 6)
+var file_smarthttp_proto_msgTypes = make([]protoimpl.MessageInfo, 8)
 var file_smarthttp_proto_goTypes = []interface{}{
-	(*InfoRefsRequest)(nil),         // 0: gitaly.InfoRefsRequest
-	(*InfoRefsResponse)(nil),        // 1: gitaly.InfoRefsResponse
-	(*PostUploadPackRequest)(nil),   // 2: gitaly.PostUploadPackRequest
-	(*PostUploadPackResponse)(nil),  // 3: gitaly.PostUploadPackResponse
-	(*PostReceivePackRequest)(nil),  // 4: gitaly.PostReceivePackRequest
-	(*PostReceivePackResponse)(nil), // 5: gitaly.PostReceivePackResponse
-	(*Repository)(nil),              // 6: gitaly.Repository
+	(*InfoRefsRequest)(nil),                       // 0: gitaly.InfoRefsRequest
+	(*InfoRefsResponse)(nil),                      // 1: gitaly.InfoRefsResponse
+	(*PostUploadPackRequest)(nil),                 // 2: gitaly.PostUploadPackRequest
+	(*PostUploadPackResponse)(nil),                // 3: gitaly.PostUploadPackResponse
+	(*PostUploadPackWithSidechannelRequest)(nil),  // 4: gitaly.PostUploadPackWithSidechannelRequest
+	(*PostUploadPackWithSidechannelResponse)(nil), // 5: gitaly.PostUploadPackWithSidechannelResponse
+	(*PostReceivePackRequest)(nil),                // 6: gitaly.PostReceivePackRequest
+	(*PostReceivePackResponse)(nil),               // 7: gitaly.PostReceivePackResponse
+	(*Repository)(nil),                            // 8: gitaly.Repository
 }
 var file_smarthttp_proto_depIdxs = []int32{
-	6, // 0: gitaly.InfoRefsRequest.repository:type_name -> gitaly.Repository
-	6, // 1: gitaly.PostUploadPackRequest.repository:type_name -> gitaly.Repository
-	6, // 2: gitaly.PostReceivePackRequest.repository:type_name -> gitaly.Repository
-	0, // 3: gitaly.SmartHTTPService.InfoRefsUploadPack:input_type -> gitaly.InfoRefsRequest
-	0, // 4: gitaly.SmartHTTPService.InfoRefsReceivePack:input_type -> gitaly.InfoRefsRequest
-	2, // 5: gitaly.SmartHTTPService.PostUploadPack:input_type -> gitaly.PostUploadPackRequest
-	4, // 6: gitaly.SmartHTTPService.PostReceivePack:input_type -> gitaly.PostReceivePackRequest
-	1, // 7: gitaly.SmartHTTPService.InfoRefsUploadPack:output_type -> gitaly.InfoRefsResponse
-	1, // 8: gitaly.SmartHTTPService.InfoRefsReceivePack:output_type -> gitaly.InfoRefsResponse
-	3, // 9: gitaly.SmartHTTPService.PostUploadPack:output_type -> gitaly.PostUploadPackResponse
-	5, // 10: gitaly.SmartHTTPService.PostReceivePack:output_type -> gitaly.PostReceivePackResponse
-	7, // [7:11] is the sub-list for method output_type
-	3, // [3:7] is the sub-list for method input_type
-	3, // [3:3] is the sub-list for extension type_name
-	3, // [3:3] is the sub-list for extension extendee
-	0, // [0:3] is the sub-list for field type_name
+	8, // 0: gitaly.InfoRefsRequest.repository:type_name -> gitaly.Repository
+	8, // 1: gitaly.PostUploadPackRequest.repository:type_name -> gitaly.Repository
+	8, // 2: gitaly.PostUploadPackWithSidechannelRequest.repository:type_name -> gitaly.Repository
+	8, // 3: gitaly.PostReceivePackRequest.repository:type_name -> gitaly.Repository
+	0, // 4: gitaly.SmartHTTPService.InfoRefsUploadPack:input_type -> gitaly.InfoRefsRequest
+	0, // 5: gitaly.SmartHTTPService.InfoRefsReceivePack:input_type -> gitaly.InfoRefsRequest
+	2, // 6: gitaly.SmartHTTPService.PostUploadPack:input_type -> gitaly.PostUploadPackRequest
+	4, // 7: gitaly.SmartHTTPService.PostUploadPackWithSidechannel:input_type -> gitaly.PostUploadPackWithSidechannelRequest
+	6, // 8: gitaly.SmartHTTPService.PostReceivePack:input_type -> gitaly.PostReceivePackRequest
+	1, // 9: gitaly.SmartHTTPService.InfoRefsUploadPack:output_type -> gitaly.InfoRefsResponse
+	1, // 10: gitaly.SmartHTTPService.InfoRefsReceivePack:output_type -> gitaly.InfoRefsResponse
+	3, // 11: gitaly.SmartHTTPService.PostUploadPack:output_type -> gitaly.PostUploadPackResponse
+	5, // 12: gitaly.SmartHTTPService.PostUploadPackWithSidechannel:output_type -> gitaly.PostUploadPackWithSidechannelResponse
+	7, // 13: gitaly.SmartHTTPService.PostReceivePack:output_type -> gitaly.PostReceivePackResponse
+	9, // [9:14] is the sub-list for method output_type
+	4, // [4:9] is the sub-list for method input_type
+	4, // [4:4] is the sub-list for extension type_name
+	4, // [4:4] is the sub-list for extension extendee
+	0, // [0:4] is the sub-list for field type_name
 }
 
 func init() { file_smarthttp_proto_init() }
@@ -585,7 +716,7 @@ func file_smarthttp_proto_init() {
 			}
 		}
 		file_smarthttp_proto_msgTypes[4].Exporter = func(v interface{}, i int) interface{} {
-			switch v := v.(*PostReceivePackRequest); i {
+			switch v := v.(*PostUploadPackWithSidechannelRequest); i {
 			case 0:
 				return &v.state
 			case 1:
@@ -597,6 +728,30 @@ func file_smarthttp_proto_init() {
 			}
 		}
 		file_smarthttp_proto_msgTypes[5].Exporter = func(v interface{}, i int) interface{} {
+			switch v := v.(*PostUploadPackWithSidechannelResponse); i {
+			case 0:
+				return &v.state
+			case 1:
+				return &v.sizeCache
+			case 2:
+				return &v.unknownFields
+			default:
+				return nil
+			}
+		}
+		file_smarthttp_proto_msgTypes[6].Exporter = func(v interface{}, i int) interface{} {
+			switch v := v.(*PostReceivePackRequest); i {
+			case 0:
+				return &v.state
+			case 1:
+				return &v.sizeCache
+			case 2:
+				return &v.unknownFields
+			default:
+				return nil
+			}
+		}
+		file_smarthttp_proto_msgTypes[7].Exporter = func(v interface{}, i int) interface{} {
 			switch v := v.(*PostReceivePackResponse); i {
 			case 0:
 				return &v.state
@@ -615,7 +770,7 @@ func file_smarthttp_proto_init() {
 			GoPackagePath: reflect.TypeOf(x{}).PkgPath(),
 			RawDescriptor: file_smarthttp_proto_rawDesc,
 			NumEnums:      0,
-			NumMessages:   6,
+			NumMessages:   8,
 			NumExtensions: 0,
 			NumServices:   1,
 		},
diff --git a/proto/go/gitalypb/smarthttp_grpc.pb.go b/proto/go/gitalypb/smarthttp_grpc.pb.go
index da3528e32..523303520 100644
--- a/proto/go/gitalypb/smarthttp_grpc.pb.go
+++ b/proto/go/gitalypb/smarthttp_grpc.pb.go
@@ -28,6 +28,8 @@ type SmartHTTPServiceClient interface {
 	InfoRefsReceivePack(ctx context.Context, in *InfoRefsRequest, opts ...grpc.CallOption) (SmartHTTPService_InfoRefsReceivePackClient, error)
 	// Request and response body for POST /upload-pack
 	PostUploadPack(ctx context.Context, opts ...grpc.CallOption) (SmartHTTPService_PostUploadPackClient, error)
+	// Request and response body for POST /upload-pack using sidechannel protocol
+	PostUploadPackWithSidechannel(ctx context.Context, in *PostUploadPackWithSidechannelRequest, opts ...grpc.CallOption) (*PostUploadPackWithSidechannelResponse, error)
 	// Request and response body for POST /receive-pack
 	PostReceivePack(ctx context.Context, opts ...grpc.CallOption) (SmartHTTPService_PostReceivePackClient, error)
 }
@@ -135,6 +137,15 @@ func (x *smartHTTPServicePostUploadPackClient) Recv() (*PostUploadPackResponse,
 	return m, nil
 }
 
+func (c *smartHTTPServiceClient) PostUploadPackWithSidechannel(ctx context.Context, in *PostUploadPackWithSidechannelRequest, opts ...grpc.CallOption) (*PostUploadPackWithSidechannelResponse, error) {
+	out := new(PostUploadPackWithSidechannelResponse)
+	err := c.cc.Invoke(ctx, "/gitaly.SmartHTTPService/PostUploadPackWithSidechannel", in, out, opts...)
+	if err != nil {
+		return nil, err
+	}
+	return out, nil
+}
+
 func (c *smartHTTPServiceClient) PostReceivePack(ctx context.Context, opts ...grpc.CallOption) (SmartHTTPService_PostReceivePackClient, error) {
 	stream, err := c.cc.NewStream(ctx, &SmartHTTPService_ServiceDesc.Streams[3], "/gitaly.SmartHTTPService/PostReceivePack", opts...)
 	if err != nil {
@@ -180,6 +191,8 @@ type SmartHTTPServiceServer interface {
 	InfoRefsReceivePack(*InfoRefsRequest, SmartHTTPService_InfoRefsReceivePackServer) error
 	// Request and response body for POST /upload-pack
 	PostUploadPack(SmartHTTPService_PostUploadPackServer) error
+	// Request and response body for POST /upload-pack using sidechannel protocol
+	PostUploadPackWithSidechannel(context.Context, *PostUploadPackWithSidechannelRequest) (*PostUploadPackWithSidechannelResponse, error)
 	// Request and response body for POST /receive-pack
 	PostReceivePack(SmartHTTPService_PostReceivePackServer) error
 	mustEmbedUnimplementedSmartHTTPServiceServer()
@@ -198,6 +211,9 @@ func (UnimplementedSmartHTTPServiceServer) InfoRefsReceivePack(*InfoRefsRequest,
 func (UnimplementedSmartHTTPServiceServer) PostUploadPack(SmartHTTPService_PostUploadPackServer) error {
 	return status.Errorf(codes.Unimplemented, "method PostUploadPack not implemented")
 }
+func (UnimplementedSmartHTTPServiceServer) PostUploadPackWithSidechannel(context.Context, *PostUploadPackWithSidechannelRequest) (*PostUploadPackWithSidechannelResponse, error) {
+	return nil, status.Errorf(codes.Unimplemented, "method PostUploadPackWithSidechannel not implemented")
+}
 func (UnimplementedSmartHTTPServiceServer) PostReceivePack(SmartHTTPService_PostReceivePackServer) error {
 	return status.Errorf(codes.Unimplemented, "method PostReceivePack not implemented")
 }
@@ -282,6 +298,24 @@ func (x *smartHTTPServicePostUploadPackServer) Recv() (*PostUploadPackRequest, e
 	return m, nil
 }
 
+func _SmartHTTPService_PostUploadPackWithSidechannel_Handler(srv interface{}, ctx context.Context, dec func(interface{}) error, interceptor grpc.UnaryServerInterceptor) (interface{}, error) {
+	in := new(PostUploadPackWithSidechannelRequest)
+	if err := dec(in); err != nil {
+		return nil, err
+	}
+	if interceptor == nil {
+		return srv.(SmartHTTPServiceServer).PostUploadPackWithSidechannel(ctx, in)
+	}
+	info := &grpc.UnaryServerInfo{
+		Server:     srv,
+		FullMethod: "/gitaly.SmartHTTPService/PostUploadPackWithSidechannel",
+	}
+	handler := func(ctx context.Context, req interface{}) (interface{}, error) {
+		return srv.(SmartHTTPServiceServer).PostUploadPackWithSidechannel(ctx, req.(*PostUploadPackWithSidechannelRequest))
+	}
+	return interceptor(ctx, in, info, handler)
+}
+
 func _SmartHTTPService_PostReceivePack_Handler(srv interface{}, stream grpc.ServerStream) error {
 	return srv.(SmartHTTPServiceServer).PostReceivePack(&smartHTTPServicePostReceivePackServer{stream})
 }
@@ -314,7 +348,12 @@ func (x *smartHTTPServicePostReceivePackServer) Recv() (*PostReceivePackRequest,
 var SmartHTTPService_ServiceDesc = grpc.ServiceDesc{
 	ServiceName: "gitaly.SmartHTTPService",
 	HandlerType: (*SmartHTTPServiceServer)(nil),
-	Methods:     []grpc.MethodDesc{},
+	Methods: []grpc.MethodDesc{
+		{
+			MethodName: "PostUploadPackWithSidechannel",
+			Handler:    _SmartHTTPService_PostUploadPackWithSidechannel_Handler,
+		},
+	},
 	Streams: []grpc.StreamDesc{
 		{
 			StreamName:    "InfoRefsUploadPack",
diff --git a/proto/smarthttp.proto b/proto/smarthttp.proto
index 26d057685..f9e3977d6 100644
--- a/proto/smarthttp.proto
+++ b/proto/smarthttp.proto
@@ -33,6 +33,13 @@ service SmartHTTPService {
     };
   }
 
+  // Request and response body for POST /upload-pack using sidechannel protocol
+  rpc PostUploadPackWithSidechannel(PostUploadPackWithSidechannelRequest) returns (PostUploadPackWithSidechannelResponse) {
+    option (op_type) = {
+      op: ACCESSOR
+    };
+  }
+
   // Request and response body for POST /receive-pack
   rpc PostReceivePack(stream PostReceivePackRequest) returns (stream PostReceivePackResponse) {
     option (op_type) = {
@@ -71,6 +78,17 @@ message PostUploadPackResponse {
   bytes data = 1;
 }
 
+message PostUploadPackWithSidechannelRequest {
+  // repository should only be present in the first message of the stream
+  Repository repository = 1 [(target_repository)=true];
+  // Parameters to use with git -c (key=value pairs)
+  repeated string git_config_options = 2;
+  // Git protocol version
+  string git_protocol = 3;
+}
+
+message PostUploadPackWithSidechannelResponse { }
+
 message PostReceivePackRequest {
   // repository should only be present in the first message of the stream
   Repository repository = 1 [(target_repository)=true];