feat(go): reuse parsed fields across projections

go/vehicle-gateway/internal/realtime/kv.go

@@ -26,33 +26,27 @@ func BuildFieldsEnvelope(env envelope.FrameEnvelope) (envelope.FrameEnvelope, bo
 	if !envelope.IsRealtimeTelemetryFrame(env) {
 		return envelope.FrameEnvelope{}, false
 	}
-	rows := realtimeKVFields(env, env.Parsed)
-	fields := make(map[string]any, len(rows))
-	for _, row := range rows {
-		key := row.Domain
-		if strings.TrimSpace(row.Field) != "" {
-			key += "." + row.Field
-		}
-		fields[key] = row.Value
-	}
-	if len(fields) == 0 {
+	fields, fieldTypes, ok := ParsedFieldsForEnvelope(env)
+	if !ok {
 		return envelope.FrameEnvelope{}, false
 	}
 	out := envelope.FrameEnvelope{
-		EventID:        env.StableEventID() + ":fields",
-		TraceID:        env.TraceID,
-		Protocol:       env.Protocol,
-		MessageID:      env.MessageID,
-		Sequence:       env.Sequence,
-		VIN:            env.VIN,
-		VehicleKeyHint: env.VehicleKeyHint,
-		Phone:          env.Phone,
-		DeviceID:       env.DeviceID,
-		Plate:          env.Plate,
-		SourceEndpoint: env.SourceEndpoint,
-		EventTimeMS:    env.EventTimeMS,
-		ReceivedAtMS:   env.ReceivedAtMS,
-		Fields:         fields,
+		EventID:          env.StableEventID() + ":fields",
+		TraceID:          env.TraceID,
+		Protocol:         env.Protocol,
+		MessageID:        env.MessageID,
+		Sequence:         env.Sequence,
+		VIN:              env.VIN,
+		VehicleKeyHint:   env.VehicleKeyHint,
+		Phone:            env.Phone,
+		DeviceID:         env.DeviceID,
+		Plate:            env.Plate,
+		SourceEndpoint:   env.SourceEndpoint,
+		EventTimeMS:      env.EventTimeMS,
+		ReceivedAtMS:     env.ReceivedAtMS,
+		Fields:           fields,
+		ParsedFields:     fields,
+		ParsedFieldTypes: fieldTypes,
 		Parsed: map[string]any{
 			"source_event_id": env.StableEventID(),
 			"field_mapping":   realtimeFieldMappingVersion,
@@ -62,6 +56,91 @@ func BuildFieldsEnvelope(env envelope.FrameEnvelope) (envelope.FrameEnvelope, bo
 	return out, true
 }
 
+func EnsureParsedFields(env *envelope.FrameEnvelope) bool {
+	if env == nil {
+		return false
+	}
+	if len(env.ParsedFields) > 0 {
+		if env.ParsedFieldTypes == nil {
+			env.ParsedFieldTypes = inferParsedFieldTypes(env.ParsedFields)
+		}
+		return true
+	}
+	fields, fieldTypes, ok := ParsedFieldsForEnvelope(*env)
+	if !ok {
+		return false
+	}
+	env.ParsedFields = fields
+	env.ParsedFieldTypes = fieldTypes
+	return true
+}
+
+func ParsedFieldsForEnvelope(env envelope.FrameEnvelope) (map[string]any, map[string]string, bool) {
+	if len(env.ParsedFields) > 0 {
+		fields := cloneAnyMap(env.ParsedFields)
+		fieldTypes := cloneStringMap(env.ParsedFieldTypes)
+		if len(fieldTypes) == 0 {
+			fieldTypes = inferParsedFieldTypes(fields)
+		}
+		return fields, fieldTypes, true
+	}
+	rows := realtimeKVFields(env, env.Parsed)
+	if len(rows) == 0 {
+		return nil, nil, false
+	}
+	fields := make(map[string]any, len(rows))
+	fieldTypes := make(map[string]string, len(rows))
+	for _, row := range rows {
+		key := realtimeKVFieldPath(row.Domain, row.Field)
+		if key == "" {
+			continue
+		}
+		fields[key] = row.Value
+		fieldTypes[key] = row.ValueType
+	}
+	if len(fields) == 0 {
+		return nil, nil, false
+	}
+	return fields, fieldTypes, true
+}
+
+func inferParsedFieldTypes(fields map[string]any) map[string]string {
+	if len(fields) == 0 {
+		return nil
+	}
+	out := make(map[string]string, len(fields))
+	for key, value := range fields {
+		_, valueType, ok := stringifyKVValue(value)
+		if !ok {
+			continue
+		}
+		out[key] = valueType
+	}
+	return out
+}
+
+func cloneAnyMap(in map[string]any) map[string]any {
+	if len(in) == 0 {
+		return nil
+	}
+	out := make(map[string]any, len(in))
+	for key, value := range in {
+		out[key] = value
+	}
+	return out
+}
+
+func cloneStringMap(in map[string]string) map[string]string {
+	if len(in) == 0 {
+		return nil
+	}
+	out := make(map[string]string, len(in))
+	for key, value := range in {
+		out[key] = value
+	}
+	return out
+}
+
 type protocolFieldMapping struct {
 	Prefix       string
 	GBDataUnits  bool