Overview

The Basket Service provides an API for creating, revising, and removing items from a User’s basket.

Capabilities

• Users will be able to store their cart and count of each item.
• Users will be able to add/remove items from the cart
• Users will be able to modify the count of each item in the cart
• Users will be able to clear their cart
• Users will be able to see the number of their cart items on the navbar
• Users will be able to store their wishlist
• Users will be able to move items from their wishlist to their basket
• Users should be able to add/remove items from their wishlist
• The basket should be limited to store a specified number of items
• The basket should be limited to store a specific measurement size
• Basket is cleared when the user generates an order
• Items stay in the basket for 30 days, then they are moved to the wishlist
• A visitor logging in will merge baskets

Service API

Commands	Queries	Events
saveToBasket()	getCart()	Cart Item Added
removeFromBasket()	getCartCount()	Cart Item Removed
clearCart()		Cart Item Edited
		Cart Cleared

Non-Functional Requirements

• The system should be able to store 10M baskets.
• The latency to access a basket should be:
  • P90 – 50ms
  • P99 – 100ms
  • P100 – 500ms
• The baskets history needs to be stored in DWH (redshift).

Observability

Key Metrics

• items_added_to_basket
• checked_out_baskets
• baskets_cleared
• users_logged_in
• items_removed_from_basket
• items_moved_to_wishlist

Health Check Endpoint

/actuator/health

Implementation

System Architecture

Database Queries

• findItemsByUserId()
• findItemByUserIdAndItemId()
• saveItem()
• deleteItem()

Primary Database Schema

Partition Key

• UserPrefix_UserId
  • UserPrefix: Identifies type of User. (OMNI / VISI)
  • UserId: Account User ID or user session ID is not logged in.

Sort Key

• ItemId

Attributes

• Quantity
• QuantityUnits
• UserId
• UserType
• CreatedBy
• CreatedAt
• UpdatedBy
• UpdatedAt
• IPAddress
• isDeleted

Partiton Key	Sort Key	Attributes
UserPrefix_UserId	ItemId	Quantity	QuantityUnits	UserId	CreatedBy	CreatedAt	UpdatedBy	UpdatedAt	IPAddress	isDeleted

Dependencies

Invokes

• Wishlist Service
  • saveItem()

Subscribes

• Catalog Service

  • Item Removed

• Purchase Service

  • Order Placed

• Authentication Service

  • Authorization Token
  • Session ID