{"record":{"id":"1aca465002a02d53","repo":"GoogleCloudPlatform/microservices-demo","slug":"failed-to-get-user-cart-during-checkout-v","errorCode":null,"errorMessage":"failed to get user cart during checkout: %+v","messagePattern":"failed to get user cart during checkout: %\\+v","errorType":"exception","errorClass":null,"httpStatus":null,"severity":"error","filePath":"src/checkoutservice/main.go","lineNumber":327,"sourceCode":"\tout.orderItems = orderItems\n\treturn out, nil\n}\n\nfunc (cs *checkoutService) quoteShipping(ctx context.Context, address *pb.Address, items []*pb.CartItem) (*pb.Money, error) {\n\tshippingQuote, err := pb.NewShippingServiceClient(cs.shippingSvcConn).\n\t\tGetQuote(ctx, &pb.GetQuoteRequest{\n\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 {","sourceCodeStart":309,"sourceCodeEnd":345,"githubUrl":"https://github.com/GoogleCloudPlatform/microservices-demo/blob/72ba613a05f7fcee51cf1d0badff401b6ae7074d/src/checkoutservice/main.go#L309-L345","documentation":"getUserCart wraps a failed CartService.GetCart gRPC call with this message. Checkout could not read the user's cart, so the order cannot be built. Typical root causes are cart service unavailability or an invalid/empty user ID.","triggerScenarios":"pb.NewCartServiceClient(cs.cartSvcConn).GetCart(ctx, &pb.GetCartRequest{UserId: userID}) errors: cartservice down, unknown user ID rejected, or context deadline/cancellation.","commonSituations":"cartservice (often Redis-backed) crashed or lost its Redis connection; user ID empty because session/auth failed upstream; network policy blocking checkout->cart traffic.","solutions":["Check cartservice pods/logs and its Redis backend connectivity.","Verify userID is non-empty and valid before calling PlaceOrder (fail fast with InvalidArgument).","Check the gRPC status code: Unavailable -> retry with backoff; InvalidArgument -> fix the caller.","Confirm DNS/network policies allow checkoutservice to reach cartservice."],"exampleFix":"// before\ncart, err := pb.NewCartServiceClient(cs.cartSvcConn).GetCart(ctx, &pb.GetCartRequest{UserId: userID})\nif err != nil {\n\treturn nil, fmt.Errorf(\"failed to get user cart during checkout: %+v\", err)\n}\n// after\nif userID == \"\" {\n\treturn nil, status.Error(codes.InvalidArgument, \"user ID is required to fetch the cart\")\n}\ncart, err := pb.NewCartServiceClient(cs.cartSvcConn).GetCart(ctx, &pb.GetCartRequest{UserId: userID})\nif err != nil {\n\treturn nil, fmt.Errorf(\"failed to get user cart during checkout: %w\", err)\n}","handlingStrategy":"validation","validationCode":"if userID == \"\" {\n\treturn status.Error(codes.InvalidArgument, \"user ID is required\")\n}\n// optionally probe cart service health first\nresp, err := cartConn.Invoke(ctx, healthCheckMethod, ...) // or use grpc health protocol","typeGuard":"func isLoggedIn(userID string) bool {\n\treturn userID != \"\" // extend with session validation\n}","tryCatchPattern":"cart, err := cartClient.GetCart(ctx, req)\nif err != nil {\n\tif status.Code(err) == codes.Unavailable {\n\t\treturn retryWithBackoff(ctx, req)\n\t}\n\treturn fmt.Errorf(\"failed to get user cart during checkout: %w\", err)\n}","preventionTips":["Fail fast on empty user IDs","Keep Redis backing cartservice monitored","Add retries for Unavailable on the cart connection","Check cartservice readiness probes before deploys"],"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"}