feat(utils): add RPC API utils for SFU and Go SDK (#1215)

* feat(utils): add RPC API utils for SFU and Go SDK

* rename with data channel prefix

* cleanup

Author: anunaym14

utils/data_channel_rpc.go

@@ -0,0 +1,103 @@
+package utils
+
+import (
+	"fmt"
+	"time"
+
+	"github.com/livekit/psrpc"
+)
+
+type DataChannelRpcErrorCode uint32
+
+const (
+	DataChannelRpcApplicationError DataChannelRpcErrorCode = 1500 + iota
+	DataChannelRpcConnectionTimeout
+	DataChannelRpcResponseTimeout
+	DataChannelRpcRecipientDisconnected
+	DataChannelRpcResponsePayloadTooLarge
+	DataChannelRpcSendFailed
+)
+
+const (
+	DataChannelRpcUnsupportedMethod DataChannelRpcErrorCode = 1400 + iota
+	DataChannelRpcRecipientNotFound
+	DataChannelRpcRequestPayloadTooLarge
+	DataChannelRpcUnsupportedServer
+	DataChannelRpcUnsupportedVersion
+)
+
+const (
+	DataChannelRpcMaxRoundTripLatency    = 2000 * time.Millisecond
+	DataChannelRpcMaxMessageBytes        = 256
+	DataChannelRpcMaxDataBytes           = 15360 // 15KiB
+	DataChannelRpcMaxPayloadBytes        = 15360 // 15KiB
+	DataChannelRpcDefaultResponseTimeout = 10000 * time.Millisecond
+)
+
+var dataChannelRpcErrorMessages = map[DataChannelRpcErrorCode]string{
+	DataChannelRpcApplicationError:        "Application error in method handler",
+	DataChannelRpcConnectionTimeout:       "Connection timeout",
+	DataChannelRpcResponseTimeout:         "Response timeout",
+	DataChannelRpcRecipientDisconnected:   "Recipient disconnected",
+	DataChannelRpcResponsePayloadTooLarge: "Response payload too large",
+	DataChannelRpcSendFailed:              "Failed to send",
+
+	DataChannelRpcUnsupportedMethod:      "Method not supported at destination",
+	DataChannelRpcRecipientNotFound:      "Recipient not found",
+	DataChannelRpcRequestPayloadTooLarge: "Request payload too large",
+	DataChannelRpcUnsupportedServer:      "RPC not supported by server",
+	DataChannelRpcUnsupportedVersion:     "Unsupported RPC version",
+}
+
+type DataChannelRpcError struct {
+	Code    DataChannelRpcErrorCode
+	Message string
+	Data    string
+}
+
+func (e *DataChannelRpcError) Error() string {
+	return fmt.Sprintf("RpcError %d: %s", e.Code, e.Message)
+}
+
+func (e *DataChannelRpcError) PsrpcError() psrpc.Error {
+	switch e.Code {
+	case DataChannelRpcApplicationError:
+		return psrpc.NewErrorf(psrpc.Internal, e.Message, "data", e.Data)
+	case DataChannelRpcConnectionTimeout:
+		return psrpc.NewErrorf(psrpc.DeadlineExceeded, e.Message, "data", e.Data)
+	case DataChannelRpcResponseTimeout:
+		return psrpc.NewErrorf(psrpc.DeadlineExceeded, e.Message, "data", e.Data)
+	case DataChannelRpcRecipientDisconnected:
+		return psrpc.NewErrorf(psrpc.Unavailable, e.Message, "data", e.Data)
+	case DataChannelRpcResponsePayloadTooLarge:
+		return psrpc.NewErrorf(psrpc.MalformedResponse, e.Message, "data", e.Data)
+	case DataChannelRpcSendFailed:
+		return psrpc.NewErrorf(psrpc.Internal, e.Message, "data", e.Data)
+	case DataChannelRpcUnsupportedMethod:
+		return psrpc.NewErrorf(psrpc.InvalidArgument, e.Message, "data", e.Data)
+	case DataChannelRpcRecipientNotFound:
+		return psrpc.NewErrorf(psrpc.NotFound, e.Message, "data", e.Data)
+	case DataChannelRpcRequestPayloadTooLarge:
+		return psrpc.NewErrorf(psrpc.MalformedRequest, e.Message, "data", e.Data)
+	case DataChannelRpcUnsupportedServer:
+		return psrpc.NewErrorf(psrpc.Unimplemented, e.Message, "data", e.Data)
+	case DataChannelRpcUnsupportedVersion:
+		return psrpc.NewErrorf(psrpc.Unimplemented, e.Message, "data", e.Data)
+	default:
+		return psrpc.NewErrorf(psrpc.Internal, e.Message, "data", e.Data)
+	}
+}
+
+func DataChannelRpcErrorFromBuiltInCodes(code DataChannelRpcErrorCode, data *string) *DataChannelRpcError {
+	return &DataChannelRpcError{Code: code, Message: dataChannelRpcErrorMessages[code], Data: *data}
+}
+
+type DataChannelRpcPendingAckHandler struct {
+	Resolve             func()
+	ParticipantIdentity string
+}
+
+type DataChannelRpcPendingResponseHandler struct {
+	Resolve             func(payload string, err *DataChannelRpcError)
+	ParticipantIdentity string
+}