Simple Notification Service (SNS)¶

Overview¶

• Pub/Sub service.
• Allows multiple subscribers to receive a message from the SNS topic (queue).
• Event Producer only sends a message to one SNS topic.
• One or more Event Recievers (subscriptions) listen to the SNS topic.
• Each subscription to the topic will get all messages. Messages can optionally be filtered.
• Up to 10million subscriptions per topic.
• Up to 100,000 topics.
• Subscribers can be SQS, HTTP/HTTPS, Lambda, Email, SMS messages or Mobile notifications.
• Most AWS services can send data to SNS for notifications.

Subscription Protocols¶

• HTTP
• HTTPS
• Email
• Email-JSON
• Amazon SQS
• Amazone Lambda

Publishing¶

Topic Publish (Using the SDK)¶

• Create a topic.
• Create a subscription(s).
• Publish 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 etc.

Security¶

Encryption¶

• Encryption during transit via HTTPS.
• Encryption at rest using KMS.
• Client-side encryption if desired.

Access Controls¶

• IAM policies regulat access to the SNS API.
• SNS Access Policies, similar to S3 Bucket Policies for cross-account access to SNS topips, or allowing other service to write to an SNS topic.

SNS + SQS Fan Out Pattern¶

• Push a message to SNS, and it will be recieved by all SQS queues that are subscribers.
• Fully de-coupled, no data loss.
• SQS allows data persistence, delayed processing and retries of work.
• Easy to add more SQS subscribers over time. Useful for micro-services.
• SQS Queue accesspolicy needs to allow SNS to write.
• SNS can't send messages to SQS FIFO queues.

S3 Events to Multiple Queues¶

• Can only have on S3 Event rule for the same event type (eg: object create) & prefix (eg: images).
• Use Fan-out pattern to send the same S3 event to many SQS queues.