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Amazon SNS

Updated Jul 26, 2020 ·
NOTES

This is not an exhaustive documentation of all the existing AWS Services. These are summarized notes that I used for the AWS Certifications.

To see the complete documentation, please go to: AWS documentation

Simple Notification Service (SNS)​

Features:

  • Pub/Sub model
  • The event produces only sends messages to one SNS topic.
  • Each subscriber to the topic will get all the messages be default (we can filter them, if we want).
  • We can have up to 10 million subscribers per topic.
  • We cave up to 100K topics.
  • Subscribers to the topic can be:
    • SQS
    • HTTP/HTTPS
    • Lambda
    • Emails
    • SMS messages
    • Mobile Notifications

Integrations​

  • CloudWatch (for alarms)

  • Auto Scaling Groups notifications

  • S3 (bucket events)

  • CloudFormation (state changes)

Publishing events​

  • How to publish?

    • In order to publish we must create a topic using the SDK.
    • We may create one or many subscriptions.
    • We publish data to the topic.

  • Direct Publish (for mobile apps SDK)

    • Create a platform application.

    • Create a platform endpoint.

    • Publish to the platform endpoint.

    • Works with Google GCM, Apple APNS, Amazon ADM.

SNS + SQS Fan Out​

Features:

  • Send a message to multiple SQS queues using SNS.
  • Push one in SNS, receive in all SQS queues which are subscribers.
  • Fully decouples, no data loss.
  • SQS allows for data persistance, delayed processing and retries of work.
  • Ability to add more SQS subscribers over time.
  • SQS queues must have an allow access policy for SNS to be able to write to the queues.
  • SNS cannot send messages to SQS FIFO queues (AWS limitation)!

Use case:

  • Send S3 events to multiple queues.

  • For the same combination of even type and prefix we can only have one S3 Event rule.

  • In case we want to send the same S3 event to many SQS queues, we must use SNS fan-out.