feat(go): add nats kafka ingest bridge

go/vehicle-gateway/internal/eventbus/nats_sink.go

@@ -0,0 +1,117 @@
+package eventbus
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"time"
+
+	"github.com/nats-io/nats.go"
+
+	"lingniu-vehicle-ingest/go/vehicle-gateway/internal/envelope"
+)
+
+type NATSConfig struct {
+	URL            string
+	Name           string
+	RawSubjects    map[envelope.Protocol]string
+	UnifiedSubject string
+}
+
+type NATSSink struct {
+	conn           *nats.Conn
+	publisher      natsPublisher
+	rawSubjects    map[envelope.Protocol]string
+	unifiedSubject string
+}
+
+type NATSPublishOption = nats.PubOpt
+
+type natsPublisher interface {
+	Publish(context.Context, string, []byte, ...NATSPublishOption) error
+}
+
+func NewNATSSink(cfg NATSConfig) (*NATSSink, error) {
+	if cfg.URL == "" {
+		return nil, errors.New("nats url is required")
+	}
+	name := cfg.Name
+	if name == "" {
+		name = "lingniu-vehicle-gateway"
+	}
+	conn, err := nats.Connect(cfg.URL, nats.Name(name), nats.Timeout(5*time.Second))
+	if err != nil {
+		return nil, err
+	}
+	js, err := conn.JetStream()
+	if err != nil {
+		conn.Close()
+		return nil, err
+	}
+	sink := newNATSSinkWithPublisher(natsJetStreamPublisher{js: js}, cfg)
+	sink.conn = conn
+	return sink, nil
+}
+
+func newNATSSinkWithPublisher(publisher natsPublisher, cfg NATSConfig) *NATSSink {
+	rawSubjects := map[envelope.Protocol]string{
+		envelope.ProtocolGB32960:    "vehicle.raw.gb32960.v1",
+		envelope.ProtocolJT808:      "vehicle.raw.jt808.v1",
+		envelope.ProtocolYutongMQTT: "vehicle.raw.yutong-mqtt.v1",
+	}
+	for protocol, subject := range cfg.RawSubjects {
+		if subject != "" {
+			rawSubjects[protocol] = subject
+		}
+	}
+	unifiedSubject := cfg.UnifiedSubject
+	if unifiedSubject == "" {
+		unifiedSubject = "vehicle.event.unified.v1"
+	}
+	return &NATSSink{
+		publisher:      publisher,
+		rawSubjects:    rawSubjects,
+		unifiedSubject: unifiedSubject,
+	}
+}
+
+func (s *NATSSink) PublishRaw(ctx context.Context, env envelope.FrameEnvelope) error {
+	subject, ok := s.rawSubjects[env.Protocol]
+	if !ok || subject == "" {
+		return fmt.Errorf("raw subject not configured for protocol %s", env.Protocol)
+	}
+	return s.publish(ctx, subject, env)
+}
+
+func (s *NATSSink) PublishUnified(ctx context.Context, env envelope.FrameEnvelope) error {
+	if s.unifiedSubject == "" {
+		return errors.New("unified subject is empty")
+	}
+	return s.publish(ctx, s.unifiedSubject, env)
+}
+
+func (s *NATSSink) Close() error {
+	if s == nil || s.conn == nil {
+		return nil
+	}
+	_ = s.conn.Drain()
+	s.conn.Close()
+	return nil
+}
+
+func (s *NATSSink) publish(ctx context.Context, subject string, env envelope.FrameEnvelope) error {
+	payload, err := env.MarshalJSONBytes()
+	if err != nil {
+		return err
+	}
+	return s.publisher.Publish(ctx, subject, payload, nats.MsgId(env.StableEventID()))
+}
+
+type natsJetStreamPublisher struct {
+	js nats.JetStreamContext
+}
+
+func (p natsJetStreamPublisher) Publish(ctx context.Context, subject string, data []byte, opts ...NATSPublishOption) error {
+	_, err := p.js.Publish(subject, data, append(opts, nats.Context(ctx))...)
+	return err
+}

go/vehicle-gateway/internal/eventbus/nats_sink_test.go

@@ -0,0 +1,55 @@
+package eventbus
+
+import (
+	"context"
+	"encoding/json"
+	"testing"
+
+	"lingniu-vehicle-ingest/go/vehicle-gateway/internal/envelope"
+)
+
+func TestNATSSinkRoutesRawAndUnifiedSubjects(t *testing.T) {
+	publisher := &recordingNATSPublisher{}
+	sink := newNATSSinkWithPublisher(publisher, NATSConfig{
+		RawSubjects: map[envelope.Protocol]string{
+			envelope.ProtocolJT808: "vehicle.raw.jt808.v1",
+		},
+		UnifiedSubject: "vehicle.event.unified.v1",
+	})
+	env := envelope.FrameEnvelope{Protocol: envelope.ProtocolJT808, Phone: "13307795425", MessageID: "0x0200"}
+
+	if err := sink.PublishRaw(context.Background(), env); err != nil {
+		t.Fatalf("PublishRaw() error = %v", err)
+	}
+	if err := sink.PublishUnified(context.Background(), env); err != nil {
+		t.Fatalf("PublishUnified() error = %v", err)
+	}
+
+	if got, want := publisher.messages[0].subject, "vehicle.raw.jt808.v1"; got != want {
+		t.Fatalf("raw subject = %q, want %q", got, want)
+	}
+	if got, want := publisher.messages[1].subject, "vehicle.event.unified.v1"; got != want {
+		t.Fatalf("unified subject = %q, want %q", got, want)
+	}
+	var decoded envelope.FrameEnvelope
+	if err := json.Unmarshal(publisher.messages[0].data, &decoded); err != nil {
+		t.Fatalf("raw payload is not envelope json: %v", err)
+	}
+	if decoded.Phone != "13307795425" {
+		t.Fatalf("decoded phone = %q", decoded.Phone)
+	}
+}
+
+type recordingNATSPublisher struct {
+	messages []recordedNATSMessage
+}
+
+type recordedNATSMessage struct {
+	subject string
+	data    []byte
+}
+
+func (p *recordingNATSPublisher) Publish(_ context.Context, subject string, data []byte, _ ...NATSPublishOption) error {
+	p.messages = append(p.messages, recordedNATSMessage{subject: subject, data: append([]byte(nil), data...)})
+	return nil
+}