Checkout Flow¶

End-to-end order lifecycle from cart to shipment, with full observability at every step.

Flow¶

sequenceDiagram
    participant Browser
    participant Shop as Drone Shop
    participant CRM as Enterprise CRM
    participant ATP as Oracle ATP
    participant APM as OCI APM

    Browser->>Shop: POST /api/cart/add (product_id, quantity)
    Shop->>ATP: SELECT product (validate stock)
    Shop->>ATP: INSERT/UPDATE cart_items
    Shop-->>Browser: {status: "added"}
    Browser->>APM: RUM: shop.add_to_cart

    Browser->>Shop: POST /api/shop/checkout
    Shop->>APM: span: shop.checkout
    Shop->>ATP: SELECT cart_items + products
    Shop->>ATP: UPSERT customer
    Shop->>ATP: INSERT order + order_items
    Shop->>ATP: UPDATE products SET stock -= quantity
    Shop->>ATP: INSERT shipment
    Shop->>ATP: INSERT audit_log
    Shop->>ATP: DELETE cart_items (session cleanup)
    Shop->>CRM: POST /api/orders (sync via traceparent)
    Shop-->>Browser: {order_id, tracking_number, total}
    Browser->>APM: RUM: shop.checkout_complete

Pricing Logic¶

subtotal = SUM(price × quantity)
discount = apply_coupon(code, subtotal)
shipping = $0 if subtotal >= $5,000 else $149
total    = max(subtotal - discount, 0) + shipping

Observability at Each Step¶

Security Checks¶