Ref: https://learn.cantrill.io/courses/1820301/lectures/41301398

• Summary:
• Contents:

Amazon SNS - Overview

• 🔧 Serverless PUB-SUB messaging service
  • Coordinates sending & delivery of messages to multiple destinations (subscribers)
  • Messages are ≤ 256kB payloads
    • 💡 don't remember the max, but understand you can't send large files with SNS
• Public → NW connectivity with public endpoint
• Used heavily across AWS for notifications → e.g. CW, CFN…

Amazon SNS - Architecture

Diagram: https://github.com/acantril/aws-sa-associate-saac03/blob/main/1600-SERVERLESS_and_APPLICATION_SERVICES/00_LEARNINGAIDS/SNS-1.png

• Regionally resilient → HA, scalable, and durable within a region
• Secure → supports SSE (server-side encryption)
• SNS Topic: base entity of SNS
  • Contains configuration & permissions
  • 1-to-many communication
    • A Publisher sends messages to a topic
    • Topics have subscribers which receive messages
  • Examples of supported subscribers/destinations: HTTP(S), email (-JSON), SQS, mobile push notifications, SMS messages, Lambda…
  • Entities can be both a publisher and a subscriber (e.g. APIs)
• Topic policy: resource policy containing permissions of the SNS topic
  • R/W permissions to topic
  • Can configure cross-account access
• Other configurations
  • Filters: filter messages → only those relevant to the subscriber are delivered
  • Delivery Status → confirm delivery of messages to subscriber(s)
    • supports statuses for HTTP(S), Lambda, SQS…
  • Delivery Retries → reliable delivery: retry until message delivered successfully
• Fanout architecture: single SNS topic with multiple SQS queues as subscribers
  • Allows creating multiple related workloads (e.g. processing diff sizes or bitrates for CatTube videos)
  • 💡 Learn this architecture. Will feature in the exam