try to update inventory on spawn

cmd/cart/main.go

@@ -71,6 +71,21 @@ type CartChangeEvent struct {
 	Mutations []actor.ApplyResult `json:"mutations"`
 }
 
+func matchesSkuAndLocation(update inventory.InventoryResult, item cart.CartItem) bool {
+	if string(update.SKU) == item.Sku {
+		if update.LocationID == "se" && item.StoreId == nil {
+			return true
+		}
+		if item.StoreId == nil {
+			return false
+		}
+		if *item.StoreId == string(update.LocationID) {
+			return true
+		}
+	}
+	return false
+}
+
 func main() {
 
 	controlPlaneConfig := actor.DefaultServerConfig()
@@ -129,8 +144,32 @@ func main() {
 			grainSpawns.Inc()
 			ret := cart.NewCartGrain(id, time.Now())
 			// Set baseline lastChange at spawn; replay may update it to last event timestamp.
+
 			inventoryPubSub.Subscribe(ret.HandleInventoryChange)
 			err := diskStorage.LoadEvents(ctx, id, ret)
+			if err == nil && inventoryService != nil {
+				refs := make([]*inventory.InventoryReference, 0)
+				for _, item := range ret.Items {
+					refs = append(refs, &inventory.InventoryReference{
+						SKU:        inventory.SKU(item.Sku),
+						LocationID: getLocationId(item),
+					})
+				}
+				_, span := tracer.Start(ctx, "update inventory")
+				defer span.End()
+				res, err := inventoryService.GetInventoryBatch(ctx, refs...)
+				if err != nil {
+					log.Printf("unable to update inventory %v", err)
+				} else {
+					for _, update := range res {
+						for _, item := range ret.Items {
+							if matchesSkuAndLocation(update, *item) {
+								item.Quantity = uint16(update.Quantity)
+							}
+						}
+					}
+				}
+			}
 
 			return ret, err
 		},