This document discusses using AWS services like SNS and SQS to build a reliable e-commerce system. It presents several designs: 1. An initial "unreliable" design without messaging. 2. A design using SNS to pass order messages from the storefront to shipping and accounting. It explores SNS features like durable subscriptions and auto/client acknowledgement. 3. A refined design using SQS queues to ensure each order is processed by shipping exactly once before acknowledging completion. The goal is to prevent lost orders and ensure reliable fulfillment using AWS messaging services.

1. AWSKRUG #enterprise
AWS Messaging Service
• Simple Notification Service
• Simple Queue Service
• Simple Email Service(next Meetup)

2. Case Study - Internet Shopping Mall
• Requirements:
-- #1: Shopping mall name: Reliable E-Commerce
-- #2: Never loose purchase order

3. Reliable E-Commerce Design
StoreFront
Shipping
Accounting
Order
Order
Order
Order {orderId, accountId, orderItemNumber, creditCardNumber}
Order
Order

4. Un-Reliable E-Commerce
StoreFront
Shipping
Accounting
Order
Order
Order
Order
Order

5. Un-Reliable E-Commerce
StoreFront
Shipping
Accounting
Order
Order
Order
Order
Order

6. AWS Outage - March 2, 2018

7. Reliable E-Commerce Design #2
StoreFront
Shipping
Accounting
Order
Order
Order
Order

8. Simple Notification Service(SNS)
• Pub-Sub model(TIME magazine)
• Message Persistency
• Durable Subscription
• Guaranteed message delivery
• All subscribers receive the same message once
• Auto Acknowledge vs Client Acknowledge
• Support Pull(Sync) or Push(Async) delivery

9. Pub-Sub model(TIME magazine)
Publisher
(StoreFront)
Publishes
message
message #1
message #2
Subscriber #1
(Shipping)
Subscriber #2
(Accounting)
SNS Topic(Order)
message #2,#1
message #2, #1

10. Durable Subscription
Publisher
(StoreFront)
Publishes
message
message #1
message #2
Subscriber #1
(Shipping)
Subscriber #2
(Accounting)
SNS Topic(Order)
message #2, #1
Message #1 and #2 are persisted in SNS Topic(Order) to be delivered later for Accounting.

11. Auto ACK. vs Client ACK.
Publisher
Publishes
message #1
Subscriber
Subscriber
message #1
message #1
Publisher
Publishes
message #1
Auto ACKNOWLEDGE
Client ACKNOWLEDGE
ack #1

12. Pull(Sync) vs Push(Async) delivery
• Pull: Subscriber calls SNS Topic to get the
message out of SNS Topic
• Push: SNS Topic calls Subscriber(s) to push the
message to the Subscribers(s)
• Which one is better?

13. Reliable E-Commerce Design #2-B
StoreFront
Shipping
Accounting
Order
Order
Order
Order Shipping
Shipping

14. Pub-Sub model(TIME magazine)
Publisher
(StoreFront)
Publishes
message
message #1
message #2
Subscriber #1
(Shipping #1)
Subscriber #4
(Accounting)
SNS Topic(Order)
message #2,#1
message #2, #1
Subscriber #2
(Shipping #2)
Subscriber #3
(Shipping #3)
message #2,#1
message #2,#1
Order #1 and #2 are shipped three times.

15. Reliable E-Commerce Design #3
StoreFront
Shipping
Accounting
Order
Order
Order
Order
Order
Order
Shipping
Shipping

16. Simple Queue Service(SQS)
• Point-to-Point model(Bank Teller)
• Message Persistency
• Guaranteed message delivery
• Support Pull delivery
• One Receiver receives one unique message

17. Point-to-Point model(Bank Teller)
Sender
(SNS Topic)
Sends
message
Receiver#1
(Shipping)
Receiver #2
(Shipping)
message #1
message #2
Receiver #3
(Shipping)
Receiver #4
(Accounting)
message #3
message #3,#2, #1
Queue(Shipping)
Queue(Accounting)

18. Reliable E-Commerce Design #3
StoreFront
Shipping
Accounting
Order
Order
Order
Order
Order
Order
Shipping
Shipping