Using AWS Lambda with Amazon Cognito

The Amazon Cognito Events feature enables you to run Lambda functions in response to events in Amazon Cognito. Amazon Cognito provides authentication, authorization, and user management for your web and mobile apps. You can invoke a Lambda function in response to important events in Amazon Cognito. For example, using the Sync Trigger events, you can invoke a Lambda function that is published each time a dataset is synchronized. To learn more and walk through an example, see Introducing Amazon Cognito Events: Sync Triggers in the Mobile Development blog.

Example Amazon Cognito message event

{
  "datasetName": "datasetName",
  "eventType": "SyncTrigger",
  "region": "us-east-1",
  "identityId": "identityId",
  "datasetRecords": {
    "SampleKey2": {
      "newValue": "newValue2",
      "oldValue": "oldValue2",
      "op": "replace"
    },
    "SampleKey1": {
      "newValue": "newValue1",
      "oldValue": "oldValue1",
      "op": "replace"
    }
  },
  "identityPoolId": "identityPoolId",
  "version": 2
}

You configure event source mapping using Amazon Cognito event subscription configuration. For information about event source mapping and a sample event, see Amazon Cognito events in the Amazon Cognito Developer Guide.