User Creates Order (v1.0.0)

Flow for when a user creates an order

Flow Order Lifecycle Checkout

Flow of feature

This flow describes the process when a user creates an order, including the steps that the system takes to validate the order and process the payment. The flow starts with the user initiating checkout with items in their basket. The system then validates the basket contents and availability, and if all is well, it publishes a UserCheckedOutIntegrationEvent.

This event is then picked up by the Ordering Service, which then sends a PlaceOrderCommand to the Finance Service. The Finance Service processes the order, checks the payment and inventory, and if all is well, it then publishes an OrderPlacedIntegrationEvent. This event is then picked up by the Notification Service, which sends a confirmation email to the customer with the order details.

Key Steps in the Order Creation Flow

  1. Basket Checkout

    • User initiates checkout with items in their basket
    • System validates basket contents and availability
    • UserCheckedOutIntegrationEvent is published

  2. Order Processing

    • Finance service receives checkout event
    • Order state machine transitions to Placed state
    • Basket deletion is requested via PlaceOrderCommand

  3. Basket Cleanup

    • Basket service processes deletion request
    • On success: BasketDeletedCompleteIntegrationEvent is published
    • On failure: BasketDeletedFailedIntegrationEvent is published

  4. Order Completion

    • Finance service processes basket deletion result
    • Order state transitions to Completed or Failed
    • Appropriate notifications are triggered

Error Handling

The flow includes robust error handling mechanisms:

  • Basket Deletion Failures: Handled through the Failed state in the order state machine
  • Transient Errors: Automatic retry mechanisms are implemented
  • Data Consistency: Ensured through the saga pattern implementation

Business Rules

The order creation process enforces several important business rules:

  • Orders must have valid payment information
  • Inventory must be available for all items
  • User must have a valid account
  • Order total must match basket total
  • Basket must be successfully deleted to complete the order

Performance Considerations

  • The order creation flow is designed for high throughput
  • Asynchronous processing ensures system responsiveness
  • Database operations are optimized for minimal contention
  • Event-driven architecture enables horizontal scaling