GoogleCloudPlatform/microservices-demo · warning

failed to empty user cart during checkout: %+v

Error message

failed to empty user cart during checkout: %+v

What it means

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.

Source

Thrown at src/checkoutservice/main.go:334

			Address: address,
			Items:   items})
	if err != nil {
		return nil, fmt.Errorf("failed to get shipping quote: %+v", err)
	}
	return shippingQuote.GetCostUsd(), nil
}

func (cs *checkoutService) getUserCart(ctx context.Context, userID string) ([]*pb.CartItem, error) {
	cart, err := pb.NewCartServiceClient(cs.cartSvcConn).GetCart(ctx, &pb.GetCartRequest{UserId: userID})
	if err != nil {
		return nil, fmt.Errorf("failed to get user cart during checkout: %+v", err)
	}
	return cart.GetItems(), nil
}

func (cs *checkoutService) emptyUserCart(ctx context.Context, userID string) error {
	if _, err := pb.NewCartServiceClient(cs.cartSvcConn).EmptyCart(ctx, &pb.EmptyCartRequest{UserId: userID}); err != nil {
		return fmt.Errorf("failed to empty user cart during checkout: %+v", err)
	}
	return nil
}

func (cs *checkoutService) prepOrderItems(ctx context.Context, items []*pb.CartItem, userCurrency string) ([]*pb.OrderItem, error) {
	out := make([]*pb.OrderItem, len(items))
	cl := pb.NewProductCatalogServiceClient(cs.productCatalogSvcConn)

	for i, item := range items {
		product, err := cl.GetProduct(ctx, &pb.GetProductRequest{Id: item.GetProductId()})
		if err != nil {
			return nil, fmt.Errorf("failed to get product #%q", item.GetProductId())
		}
		price, err := cs.convertCurrency(ctx, product.GetPriceUsd(), userCurrency)
		if err != nil {
			return nil, fmt.Errorf("failed to convert price of %q to %s", item.GetProductId(), userCurrency)
		}
		out[i] = &pb.OrderItem{

View on GitHub (pinned to 72ba613a05)

Solutions

1. Check cartservice and Redis health in logs/pod status.
2. Retry EmptyCart with backoff since it is idempotent (clearing an already-empty cart is safe).
3. Consider whether order success should not be masked by cart-empty failure; report cart-clear errors separately.
4. Verify the userID passed matches the one used for GetCart.

Example fix

// before
if _, err := pb.NewCartServiceClient(cs.cartSvcConn).EmptyCart(ctx, &pb.EmptyCartRequest{UserId: userID}); err != nil {
	return fmt.Errorf("failed to empty user cart during checkout: %+v", err)
}
// after
if _, err := pb.NewCartServiceClient(cs.cartSvcConn).EmptyCart(ctx, &pb.EmptyCartRequest{UserId: userID}); err != nil {
	log.Printf("warning: order placed but cart could not be emptied for %s: %v", userID, err)
	return fmt.Errorf("failed to empty user cart during checkout: %w", err)
}

if userID == "" {
	return status.Error(codes.InvalidArgument, "user ID is required")
}

// EmptyCart is idempotent: safe to retry
err := retry(3, time.Second, func() error {
	_, err := cartClient.EmptyCart(ctx, &pb.EmptyCartRequest{UserId: userID})
	return err
})
if err != nil {
	log.Printf("order placed but cart not emptied for %s: %v", userID, err)
}

When it happens

Trigger: pb.NewCartServiceClient(cs.cartSvcConn).EmptyCart(ctx, &pb.EmptyCartRequest{UserId: userID}) returns an error: cartservice unavailable, Redis backend down, or invalid user ID.

Common situations: cartservice or Redis briefly unavailable right after order placement; stale connection after cartservice restart; this error surfacing after the order already succeeded, confusing clients.

Related errors

• failed to get user cart during checkout: %+v
• could not retrieve cart
• failed to add to cart
• failed to empty cart
• FAILED_PRECONDITION

AI-assisted analysis of GoogleCloudPlatform/microservices-demo@72ba613a05 (2026-09-02). Data as JSON: /api/errors/6f4048bb5c7cdefa. Report an issue: GitHub.