暂存一下,防止丢失

internal/application/cardobservation/traffic.go

@@ -0,0 +1,86 @@
+package cardobservation
+
+import (
+	"context"
+	"strconv"
+	"time"
+
+	"gorm.io/gorm"
+	"gorm.io/gorm/clause"
+
+	domain "github.com/break/junhong_cmp_fiber/internal/domain/cardobservation"
+	"github.com/break/junhong_cmp_fiber/internal/model"
+	"github.com/break/junhong_cmp_fiber/pkg/errors"
+)
+
+// TrafficIncrementedEvent 是卡流量正增量的可靠领域事实。
+type TrafficIncrementedEvent struct {
+	EventID       string    `json:"event_id"`
+	CardID        uint      `json:"card_id"`
+	IncrementMB   float64   `json:"increment_mb"`
+	ObservedAt    time.Time `json:"observed_at"`
+	Source        string    `json:"source"`
+	Scene         string    `json:"scene"`
+	RequestID     string    `json:"request_id,omitempty"`
+	CorrelationID string    `json:"correlation_id,omitempty"`
+}
+
+// ApplyTrafficObservation 串行应用流量读数，并在正增量时同事务写 Outbox。
+func (s *Service) ApplyTrafficObservation(ctx context.Context, observation domain.TrafficObservation) (domain.TrafficDecision, error) {
+	if s == nil || s.db == nil || s.eventWriter == nil {
+		return domain.TrafficDecision{}, errors.New(errors.CodeInternalError, "卡流量观测能力未完整配置")
+	}
+	var decision domain.TrafficDecision
+	err := s.db.WithContext(ctx).Transaction(func(tx *gorm.DB) error {
+		var card model.IotCard
+		if err := tx.Clauses(clause.Locking{Strength: "UPDATE"}).Where("id = ?", observation.CardID).First(&card).Error; err != nil {
+			if err == gorm.ErrRecordNotFound {
+				return errors.New(errors.CodeNotFound, "IoT卡不存在")
+			}
+			return errors.Wrap(errors.CodeDatabaseError, err, "锁定IoT卡流量事实失败")
+		}
+		nextDecision, decisionErr := domain.ApplyTraffic(domain.CardTrafficSnapshot{
+			CardID: card.ID, DataUsageMB: card.DataUsageMB, CurrentMonthUsageMB: card.CurrentMonthUsageMB,
+			CurrentMonthStartDate: card.CurrentMonthStartDate, LastMonthTotalMB: card.LastMonthTotalMB,
+			LastGatewayReadingMB: card.LastGatewayReadingMB,
+		}, observation)
+		if decisionErr != nil {
+			return decisionErr
+		}
+		decision = nextDecision
+		updates := map[string]any{
+			"last_data_check_at": observation.Metadata.ObservedAt, "last_sync_time": observation.Metadata.ObservedAt,
+			"current_month_start_date": decision.CurrentMonthStartDate, "last_month_total_mb": decision.LastMonthTotalMB,
+			"current_month_usage_mb": decision.CurrentMonthUsageMB, "data_usage_mb": decision.DataUsageMB,
+		}
+		if decision.ReadingAccepted {
+			updates["last_gateway_reading_mb"] = decision.LastGatewayReadingMB
+		}
+		result := tx.Model(&model.IotCard{}).
+			Where("id = ? AND last_gateway_reading_mb = ?", card.ID, card.LastGatewayReadingMB).
+			Updates(updates)
+		if result.Error != nil {
+			return errors.Wrap(errors.CodeDatabaseError, result.Error, "更新卡流量事实失败")
+		}
+		if result.RowsAffected != 1 {
+			return errors.New(errors.CodeConflict, "卡流量基线已被其他请求更新")
+		}
+		if decision.IncrementMB <= 0 {
+			return nil
+		}
+		eventID := "card-traffic:" + strconv.FormatUint(uint64(card.ID), 10) + ":" + observation.Metadata.ObservationID + ":incremented"
+		return s.eventWriter.AppendTraffic(ctx, tx, TrafficIncrementedEvent{
+			EventID: eventID, CardID: card.ID, IncrementMB: decision.IncrementMB,
+			ObservedAt: observation.Metadata.ObservedAt, Source: observation.Metadata.Source,
+			Scene: observation.Metadata.Scene, RequestID: observation.Metadata.RequestID,
+			CorrelationID: observation.Metadata.CorrelationID,
+		})
+	})
+	if err != nil {
+		return domain.TrafficDecision{}, err
+	}
+	if s.cache != nil {
+		s.cache.Invalidate(ctx, observation.CardID)
+	}
+	return decision, nil
+}