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

Read this on the main serverless docs site

DynamoDB / Kinesis Streams

This setup specifies that the compute function should be triggered whenever the corresponding DynamoDB table is modified (e.g. a new entry is added).

Note: The stream event will hook up your existing streams to a Lambda function. Serverless won't create a new stream for you.

functions:
  compute:
    handler: handler.compute
    events:
      - stream: arn:aws:dynamodb:region:XXXXXX:table/foo/stream/1970-01-01T00:00:00.000
      - stream:
          arn:
            Fn::GetAtt:
              - MyKinesisStream
              - Arn

Setting the BatchSize and StartingPosition

This configuration sets up a disabled Kinesis stream event for the preprocess function which has a batch size of 100. The starting position is LATEST.

Note: The stream event will hook up your existing streams to a Lambda function. Serverless won't create a new stream for you.

functions:
  preprocess:
    handler: handler.preprocess
    events:
      - stream:
          arn: arn:aws:kinesis:region:XXXXXX:stream/foo
          batchSize: 100
          startingPosition: LATEST
          enabled: false