{"record":{"id":"6f4048bb5c7cdefa","repo":"GoogleCloudPlatform/microservices-demo","slug":"failed-to-empty-user-cart-during-checkout-v","errorCode":null,"errorMessage":"failed to empty user cart during checkout: %+v","messagePattern":"failed to empty user cart during checkout: %\\+v","errorType":"exception","errorClass":null,"httpStatus":null,"severity":"warning","filePath":"src/checkoutservice/main.go","lineNumber":334,"sourceCode":"\t\t\tAddress: address,\n\t\t\tItems:   items})\n\tif err != nil {\n\t\treturn nil, fmt.Errorf(\"failed to get shipping quote: %+v\", err)\n\t}\n\treturn shippingQuote.GetCostUsd(), nil\n}\n\nfunc (cs *checkoutService) getUserCart(ctx context.Context, userID string) ([]*pb.CartItem, error) {\n\tcart, err := pb.NewCartServiceClient(cs.cartSvcConn).GetCart(ctx, &pb.GetCartRequest{UserId: userID})\n\tif err != nil {\n\t\treturn nil, fmt.Errorf(\"failed to get user cart during checkout: %+v\", err)\n\t}\n\treturn cart.GetItems(), nil\n}\n\nfunc (cs *checkoutService) emptyUserCart(ctx context.Context, userID string) error {\n\tif _, err := pb.NewCartServiceClient(cs.cartSvcConn).EmptyCart(ctx, &pb.EmptyCartRequest{UserId: userID}); err != nil {\n\t\treturn fmt.Errorf(\"failed to empty user cart during checkout: %+v\", err)\n\t}\n\treturn nil\n}\n\nfunc (cs *checkoutService) prepOrderItems(ctx context.Context, items []*pb.CartItem, userCurrency string) ([]*pb.OrderItem, error) {\n\tout := make([]*pb.OrderItem, len(items))\n\tcl := pb.NewProductCatalogServiceClient(cs.productCatalogSvcConn)\n\n\tfor i, item := range items {\n\t\tproduct, err := cl.GetProduct(ctx, &pb.GetProductRequest{Id: item.GetProductId()})\n\t\tif err != nil {\n\t\t\treturn nil, fmt.Errorf(\"failed to get product #%q\", item.GetProductId())\n\t\t}\n\t\tprice, err := cs.convertCurrency(ctx, product.GetPriceUsd(), userCurrency)\n\t\tif err != nil {\n\t\t\treturn nil, fmt.Errorf(\"failed to convert price of %q to %s\", item.GetProductId(), userCurrency)\n\t\t}\n\t\tout[i] = &pb.OrderItem{","sourceCodeStart":316,"sourceCodeEnd":352,"githubUrl":"https://github.com/GoogleCloudPlatform/microservices-demo/blob/72ba613a05f7fcee51cf1d0badff401b6ae7074d/src/checkoutservice/main.go#L316-L352","documentation":"emptyUserCart wraps a failed CartService.EmptyCart gRPC call with this message. PlaceOrder calls this after placing the order to clear the cart; failure means the cart may still contain items (a duplicate-order risk on retry) even though checkout partially succeeded.","triggerScenarios":"pb.NewCartServiceClient(cs.cartSvcConn).EmptyCart(ctx, &pb.EmptyCartRequest{UserId: userID}) returns an error: cartservice unavailable, Redis backend down, or invalid user ID.","commonSituations":"cartservice or Redis briefly unavailable right after order placement; stale connection after cartservice restart; this error surfacing after the order already succeeded, confusing clients.","solutions":["Check cartservice and Redis health in logs/pod status.","Retry EmptyCart with backoff since it is idempotent (clearing an already-empty cart is safe).","Consider whether order success should not be masked by cart-empty failure; report cart-clear errors separately.","Verify the userID passed matches the one used for GetCart."],"exampleFix":"// before\nif _, err := pb.NewCartServiceClient(cs.cartSvcConn).EmptyCart(ctx, &pb.EmptyCartRequest{UserId: userID}); err != nil {\n\treturn fmt.Errorf(\"failed to empty user cart during checkout: %+v\", err)\n}\n// after\nif _, err := pb.NewCartServiceClient(cs.cartSvcConn).EmptyCart(ctx, &pb.EmptyCartRequest{UserId: userID}); err != nil {\n\tlog.Printf(\"warning: order placed but cart could not be emptied for %s: %v\", userID, err)\n\treturn fmt.Errorf(\"failed to empty user cart during checkout: %w\", err)\n}","handlingStrategy":"retry","validationCode":"if userID == \"\" {\n\treturn status.Error(codes.InvalidArgument, \"user ID is required\")\n}","typeGuard":null,"tryCatchPattern":"// EmptyCart is idempotent: safe to retry\nerr := retry(3, time.Second, func() error {\n\t_, err := cartClient.EmptyCart(ctx, &pb.EmptyCartRequest{UserId: userID})\n\treturn err\n})\nif err != nil {\n\tlog.Printf(\"order placed but cart not emptied for %s: %v\", userID, err)\n}","preventionTips":["Treat cart clearing as best-effort: don't fail an already-placed order","Retry idempotent calls with backoff","Monitor Redis health behind cartservice","Use the same userID used for GetCart"],"tags":["grpc","cart","redis","microservices"],"backgroundTag":"downstream-grpc-call-failed","analyzedSha":"72ba613a05f7fcee51cf1d0badff401b6ae7074d","analyzedAt":"2026-09-02T01:15:09.673Z","contentChangedAt":null,"schemaVersion":2},"datasetVersion":"2026-09-09T06:17:21.866Z"}