feat(go): add nats fast writer

go/vehicle-gateway/cmd/nats-fast-writer/main_test.go

@@ -0,0 +1,73 @@
+package main
+
+import (
+	"context"
+	"errors"
+	"testing"
+
+	"lingniu-vehicle-ingest/go/vehicle-gateway/internal/envelope"
+)
+
+func TestProcessFastMessageWritesTDengineAndRedisBeforeAck(t *testing.T) {
+	env := envelope.FrameEnvelope{Protocol: envelope.ProtocolGB32960, VIN: "VIN001", EventID: "evt-1"}
+	payload, err := env.MarshalJSONBytes()
+	if err != nil {
+		t.Fatal(err)
+	}
+	appender := &recordingFastAppender{}
+	updater := &recordingFastUpdater{}
+	ackCount := 0
+	msg := &fastMessage{data: payload, ack: func() error {
+		ackCount++
+		return nil
+	}}
+
+	if err := processFastMessage(context.Background(), appender, updater, msg); err != nil {
+		t.Fatalf("processFastMessage() error = %v", err)
+	}
+	if appender.count != 1 || updater.count != 1 || ackCount != 1 {
+		t.Fatalf("appends=%d updates=%d acks=%d", appender.count, updater.count, ackCount)
+	}
+}
+
+func TestProcessFastMessageDoesNotAckWhenRedisFails(t *testing.T) {
+	env := envelope.FrameEnvelope{Protocol: envelope.ProtocolJT808, VIN: "VIN001", EventID: "evt-2"}
+	payload, err := env.MarshalJSONBytes()
+	if err != nil {
+		t.Fatal(err)
+	}
+	appender := &recordingFastAppender{}
+	updater := &recordingFastUpdater{err: errors.New("redis down")}
+	ackCount := 0
+	msg := &fastMessage{data: payload, ack: func() error {
+		ackCount++
+		return nil
+	}}
+
+	if err := processFastMessage(context.Background(), appender, updater, msg); err == nil {
+		t.Fatal("processFastMessage() error = nil, want redis failure")
+	}
+	if ackCount != 0 {
+		t.Fatalf("ack count = %d, want 0", ackCount)
+	}
+}
+
+type recordingFastAppender struct {
+	count int
+	err   error
+}
+
+func (a *recordingFastAppender) AppendAll(context.Context, envelope.FrameEnvelope) error {
+	a.count++
+	return a.err
+}
+
+type recordingFastUpdater struct {
+	count int
+	err   error
+}
+
+func (u *recordingFastUpdater) FastUpdate(context.Context, envelope.FrameEnvelope) error {
+	u.count++
+	return u.err
+}