serverless/docs/providers/aws/events/sns.md

Read this on the main serverless docs site

SNS

In the following example we create a new SNS topic with the name dispatch which is bound to the dispatcher function. The function will be called every time a message is sent to the dispatch topic.

functions:
  dispatcher:
    handler: dispatcher.dispatch
    events:
      - sns: dispatch

You're also able to add the same SNS topic to multiple functions:

functions:
  dispatcher:
    handler: dispatcher.dispatch
    events:
      - sns: dispatch
  dispatcher2:
    handler: dispatcher2.dispatch
    events:
      - sns: dispatch

This will run both functions for a message sent to the dispatch topic.

Creating the permission for a pre-existing topic

If you want to run a function from a preexisting SNS topic you need to connect the topic to a Lambda function yourself. By defining a topic arn inside of the SNS topic we're able to set up the Lambda Permission so SNS is allowed to call this function.

functions:
  dispatcher:
    handler: dispatcher.dispatch
    events:
      - sns: arn:xxx

Just make sure your function is already subscribed to the topic, as there's no way to add subscriptions to pre-existing topics in CF. The framework will just give permission to SNS to invoke the function.

Setting a display name

This event definition ensures that the aggregator function get's called every time a message is sent to the aggregate topic. Data aggregation pipeline will be shown in the AWS console so that the user can understand what the SNS topic is used for.

functions:
  aggregator:
    handler: aggregator.handler
    events:
      - sns:
          topicName: aggregate
          displayName: Data aggregation pipeline