feat!: replace msgpack with protobuf for all NATS messages

BREAKING CHANGE: All NATS message serialization now uses Protocol Buffers.
- Added proto/messages/v1/messages.proto with 22 message types
- Generated Go code at gen/messagespb/
- messages/ package now exports type aliases to proto types
- natsutil.Publish/Request/Decode use proto.Marshal/Unmarshal
- Removed legacy MessageHandler, OnMessage, wrapMapHandler
- TypedMessageHandler now returns (proto.Message, error)
- EffectiveQuery is now a free function: messages.EffectiveQuery(req)
- Removed msgpack dependency entirely

natsutil/natsutil_test.go

@@ -3,254 +3,212 @@ package natsutil
 import (
 	"testing"
 
-	"github.com/vmihailenco/msgpack/v5"
+	"google.golang.org/protobuf/proto"
+
+	pb "git.daviestechlabs.io/daviestechlabs/handler-base/gen/messagespb"
 )
 
 // ────────────────────────────────────────────────────────────────────────────
-// DecodeMsgpackMap tests
+// Decode tests
 // ────────────────────────────────────────────────────────────────────────────
 
-func TestDecodeMsgpackMap_Roundtrip(t *testing.T) {
-	orig := map[string]any{
-		"request_id": "req-001",
-		"user_id":    "user-42",
-		"premium":    true,
-		"top_k":      int64(10), // msgpack decodes ints as int64
+func TestDecode_ChatRequest_Roundtrip(t *testing.T) {
+	orig := &pb.ChatRequest{
+		RequestId: "req-001",
+		UserId:    "user-42",
+		Premium:   true,
+		TopK:      10,
 	}
-	data, err := msgpack.Marshal(orig)
+	data, err := proto.Marshal(orig)
 	if err != nil {
 		t.Fatal(err)
 	}
 
-	decoded, err := DecodeMsgpackMap(data)
-	if err != nil {
+	var decoded pb.ChatRequest
+	if err := Decode(data, &decoded); err != nil {
 		t.Fatal(err)
 	}
 
-	if decoded["request_id"] != "req-001" {
-		t.Errorf("request_id = %v", decoded["request_id"])
+	if decoded.GetRequestId() != "req-001" {
+		t.Errorf("RequestId = %v", decoded.GetRequestId())
 	}
-	if decoded["premium"] != true {
-		t.Errorf("premium = %v", decoded["premium"])
+	if decoded.GetUserId() != "user-42" {
+		t.Errorf("UserId = %v", decoded.GetUserId())
+	}
+	if decoded.GetPremium() != true {
+		t.Errorf("Premium = %v", decoded.GetPremium())
+	}
+	if decoded.GetTopK() != 10 {
+		t.Errorf("TopK = %v", decoded.GetTopK())
 	}
 }
 
-func TestDecodeMsgpackMap_Empty(t *testing.T) {
-	data, _ := msgpack.Marshal(map[string]any{})
-	m, err := DecodeMsgpackMap(data)
+func TestDecode_EmptyMessage(t *testing.T) {
+	data, err := proto.Marshal(&pb.ChatRequest{})
 	if err != nil {
 		t.Fatal(err)
 	}
-	if len(m) != 0 {
-		t.Errorf("expected empty map, got %v", m)
+	var decoded pb.ChatRequest
+	if err := Decode(data, &decoded); err != nil {
+		t.Fatal(err)
+	}
+	if decoded.GetRequestId() != "" {
+		t.Errorf("expected empty RequestId, got %q", decoded.GetRequestId())
 	}
 }
 
-func TestDecodeMsgpackMap_InvalidData(t *testing.T) {
-	_, err := DecodeMsgpackMap([]byte{0xFF, 0xFE})
+func TestDecode_InvalidData(t *testing.T) {
+	err := Decode([]byte{0xFF, 0xFE}, &pb.ChatRequest{})
 	if err == nil {
-		t.Error("expected error for invalid msgpack data")
+		t.Error("expected error for invalid protobuf data")
 	}
 }
 
 // ────────────────────────────────────────────────────────────────────────────
-// DecodeMsgpack (typed struct) tests
+// Typed struct roundtrip tests
 // ────────────────────────────────────────────────────────────────────────────
 
-type testMessage struct {
-	RequestID string `msgpack:"request_id"`
-	UserID    string `msgpack:"user_id"`
-	Count     int    `msgpack:"count"`
-	Active    bool   `msgpack:"active"`
-}
-
-func TestDecodeMsgpackTyped_Roundtrip(t *testing.T) {
-	orig := testMessage{
-		RequestID: "req-typed-001",
-		UserID:    "user-7",
-		Count:     42,
-		Active:    true,
+func TestDecode_VoiceResponse_Roundtrip(t *testing.T) {
+	orig := &pb.VoiceResponse{
+		RequestId:     "vr-001",
+		Response:      "The capital of France is Paris.",
+		Transcription: "What is the capital of France?",
 	}
-	data, err := msgpack.Marshal(orig)
+	data, err := proto.Marshal(orig)
 	if err != nil {
 		t.Fatal(err)
 	}
 
-	// Simulate nats.Msg data decoding.
-	var decoded testMessage
-	if err := msgpack.Unmarshal(data, &decoded); err != nil {
+	var decoded pb.VoiceResponse
+	if err := Decode(data, &decoded); err != nil {
 		t.Fatal(err)
 	}
 
-	if decoded.RequestID != orig.RequestID {
-		t.Errorf("RequestID = %q, want %q", decoded.RequestID, orig.RequestID)
+	if decoded.GetRequestId() != orig.GetRequestId() {
+		t.Errorf("RequestId = %q, want %q", decoded.GetRequestId(), orig.GetRequestId())
 	}
-	if decoded.Count != orig.Count {
-		t.Errorf("Count = %d, want %d", decoded.Count, orig.Count)
+	if decoded.GetResponse() != orig.GetResponse() {
+		t.Errorf("Response = %q, want %q", decoded.GetResponse(), orig.GetResponse())
 	}
-	if decoded.Active != orig.Active {
-		t.Errorf("Active = %v, want %v", decoded.Active, orig.Active)
+	if decoded.GetTranscription() != orig.GetTranscription() {
+		t.Errorf("Transcription = %q, want %q", decoded.GetTranscription(), orig.GetTranscription())
 	}
 }
 
-// TestTypedStructDecodesMapEncoding verifies that a typed struct can be
-// decoded from data that was encoded as map[string]any (backwards compat).
-func TestTypedStructDecodesMapEncoding(t *testing.T) {
-	// Encode as map (the old way).
-	mapData := map[string]any{
-		"request_id": "req-compat",
-		"user_id":    "user-compat",
-		"count":      int64(99),
-		"active":     false,
+func TestDecode_ErrorResponse_Roundtrip(t *testing.T) {
+	orig := &pb.ErrorResponse{
+		Error:   true,
+		Message: "something broke",
+		Type:    "InternalError",
 	}
-	data, err := msgpack.Marshal(mapData)
+	data, err := proto.Marshal(orig)
 	if err != nil {
 		t.Fatal(err)
 	}
 
-	// Decode into typed struct (the new way).
-	var msg testMessage
-	if err := msgpack.Unmarshal(data, &msg); err != nil {
+	var decoded pb.ErrorResponse
+	if err := Decode(data, &decoded); err != nil {
 		t.Fatal(err)
 	}
 
-	if msg.RequestID != "req-compat" {
-		t.Errorf("RequestID = %q", msg.RequestID)
+	if !decoded.GetError() {
+		t.Error("expected Error=true")
 	}
-	if msg.Count != 99 {
-		t.Errorf("Count = %d, want 99", msg.Count)
+	if decoded.GetMessage() != "something broke" {
+		t.Errorf("Message = %q", decoded.GetMessage())
+	}
+	if decoded.GetType() != "InternalError" {
+		t.Errorf("Type = %q", decoded.GetType())
 	}
 }
 
 // ────────────────────────────────────────────────────────────────────────────
-// Binary data tests (audio []byte in msgpack)
+// Binary data tests (audio []byte in protobuf)
 // ────────────────────────────────────────────────────────────────────────────
 
-type audioMessage struct {
-	SessionID string `msgpack:"session_id"`
-	Audio     []byte `msgpack:"audio"`
-	SampleRate int   `msgpack:"sample_rate"`
-}
-
 func TestBinaryDataRoundtrip(t *testing.T) {
 	audio := make([]byte, 32768)
 	for i := range audio {
 		audio[i] = byte(i % 256)
 	}
 
-	orig := audioMessage{
-		SessionID:  "sess-audio-001",
+	orig := &pb.TTSAudioChunk{
+		SessionId:  "sess-audio-001",
 		Audio:      audio,
 		SampleRate: 24000,
 	}
-	data, err := msgpack.Marshal(orig)
+	data, err := proto.Marshal(orig)
 	if err != nil {
 		t.Fatal(err)
 	}
 
-	var decoded audioMessage
-	if err := msgpack.Unmarshal(data, &decoded); err != nil {
+	var decoded pb.TTSAudioChunk
+	if err := Decode(data, &decoded); err != nil {
 		t.Fatal(err)
 	}
 
-	if len(decoded.Audio) != len(orig.Audio) {
-		t.Fatalf("audio len = %d, want %d", len(decoded.Audio), len(orig.Audio))
+	if len(decoded.GetAudio()) != len(orig.GetAudio()) {
+		t.Fatalf("audio len = %d, want %d", len(decoded.GetAudio()), len(orig.GetAudio()))
 	}
-	for i := range decoded.Audio {
-		if decoded.Audio[i] != orig.Audio[i] {
-			t.Fatalf("audio[%d] = %d, want %d", i, decoded.Audio[i], orig.Audio[i])
+	for i := range decoded.GetAudio() {
+		if decoded.GetAudio()[i] != orig.GetAudio()[i] {
+			t.Fatalf("audio[%d] = %d, want %d", i, decoded.GetAudio()[i], orig.GetAudio()[i])
 		}
 	}
 }
 
-// TestBinaryVsBase64Size shows the wire-size win of raw bytes vs base64 string.
-func TestBinaryVsBase64Size(t *testing.T) {
+// TestProtoWireSize shows protobuf wire size for binary payloads.
+func TestProtoWireSize(t *testing.T) {
 	audio := make([]byte, 16384)
 
-	// Old approach: base64 string in map.
-	import_b64 := make([]byte, (len(audio)*4+2)/3) // approximate base64 size
-	mapMsg := map[string]any{
-		"session_id": "sess-1",
-		"audio_b64":  string(import_b64),
-	}
-	mapData, _ := msgpack.Marshal(mapMsg)
-
-	// New approach: raw bytes in struct.
-	structMsg := audioMessage{
-		SessionID: "sess-1",
+	msg := &pb.TTSAudioChunk{
+		SessionId: "sess-1",
 		Audio:     audio,
 	}
-	structData, _ := msgpack.Marshal(structMsg)
+	data, _ := proto.Marshal(msg)
 
-	t.Logf("base64-in-map: %d bytes, raw-bytes-in-struct: %d bytes (%.0f%% smaller)",
-		len(mapData), len(structData),
-		100*(1-float64(len(structData))/float64(len(mapData))))
+	t.Logf("TTSAudioChunk with 16KB audio: %d bytes on wire", len(data))
 }
 
 // ────────────────────────────────────────────────────────────────────────────
 // Benchmarks
 // ────────────────────────────────────────────────────────────────────────────
 
-func BenchmarkEncodeMap(b *testing.B) {
-	data := map[string]any{
-		"request_id": "req-bench",
-		"user_id":    "user-bench",
-		"message":    "What is the weather today?",
-		"premium":    true,
-		"top_k":      10,
+func BenchmarkEncode_ChatRequest(b *testing.B) {
+	data := &pb.ChatRequest{
+		RequestId: "req-bench",
+		UserId:    "user-bench",
+		Message:   "What is the weather today?",
+		Premium:   true,
+		TopK:      10,
 	}
 	for b.Loop() {
-		_, _ = msgpack.Marshal(data)
+		_, _ = proto.Marshal(data)
 	}
 }
 
-func BenchmarkEncodeStruct(b *testing.B) {
-	data := testMessage{
-		RequestID: "req-bench",
-		UserID:    "user-bench",
-		Count:     10,
-		Active:    true,
-	}
-	for b.Loop() {
-		_, _ = msgpack.Marshal(data)
-	}
-}
-
-func BenchmarkDecodeMap(b *testing.B) {
-	raw, _ := msgpack.Marshal(map[string]any{
-		"request_id": "req-bench",
-		"user_id":    "user-bench",
-		"message":    "What is the weather today?",
-		"premium":    true,
-		"top_k":      10,
+func BenchmarkDecode_ChatRequest(b *testing.B) {
+	raw, _ := proto.Marshal(&pb.ChatRequest{
+		RequestId: "req-bench",
+		UserId:    "user-bench",
+		Message:   "What is the weather today?",
+		Premium:   true,
+		TopK:      10,
 	})
 	for b.Loop() {
-		var m map[string]any
-		_ = msgpack.Unmarshal(raw, &m)
+		var m pb.ChatRequest
+		_ = Decode(raw, &m)
 	}
 }
 
-func BenchmarkDecodeStruct(b *testing.B) {
-	raw, _ := msgpack.Marshal(testMessage{
-		RequestID: "req-bench",
-		UserID:    "user-bench",
-		Count:     10,
-		Active:    true,
-	})
-	for b.Loop() {
-		var m testMessage
-		_ = msgpack.Unmarshal(raw, &m)
-	}
-}
-
-func BenchmarkDecodeAudio32KB(b *testing.B) {
-	raw, _ := msgpack.Marshal(audioMessage{
-		SessionID:  "s1",
+func BenchmarkDecode_Audio32KB(b *testing.B) {
+	raw, _ := proto.Marshal(&pb.TTSAudioChunk{
+		SessionId:  "s1",
 		Audio:      make([]byte, 32768),
 		SampleRate: 24000,
 	})
 	for b.Loop() {
-		var m audioMessage
-		_ = msgpack.Unmarshal(raw, &m)
+		var m pb.TTSAudioChunk
+		_ = Decode(raw, &m)
 	}
 }