AWSTemplateFormatVersion: '2010-09-09'
Transform: AWS::Serverless-2016-10-31
Description: Serverless patterns - Amazon API Gateway to AWS Lambda to Amazon DynamoDB
Parameters:
  DynamoDBTableName:
    Type: String
    Default: DemoStreamDynamoDBToLambda
    Description: Enter a name for the Kinesis Data Stream.
Resources:
  ProducerFunction:
    Type: AWS::Serverless::Function
    Properties:
      FunctionName: ProducerFunction
      Handler: apiHandler.lambda_handler
      Runtime: python3.9
      CodeUri: src/
      Policies:
        DynamoDBCrudPolicy:
          TableName: !Ref DynamoDBTable
      Events:
        ApiEvent:
          Type: Api
          Properties:
            Path: /
            Method: POST
  DynamoDBTable:
    Type: AWS::DynamoDB::Table
    Properties:
      AttributeDefinitions: 
        - AttributeName: id
          AttributeType: S
      KeySchema: 
        - AttributeName: id
          KeyType: HASH
      ProvisionedThroughput: 
        ReadCapacityUnits: 5
        WriteCapacityUnits: 5
      StreamSpecification:
        StreamViewType: NEW_IMAGE
      TableName: !Ref DynamoDBTableName
    
        
  ConsumerFunction:
    Type: AWS::Serverless::Function
    Properties:
      FunctionName: ConsumerFunction
      Handler: messageHandler.lambda_handler
      Runtime: python3.9
      CodeUri: src/
      Policies: 
      - DynamoDBStreamReadPolicy:
          TableName: !Ref DynamoDBTableName
          StreamName: !Select [3, !Split ["/", !GetAtt DynamoDBTable.StreamArn]]      
      Events:
        Stream:
          Type: DynamoDB
          Properties:
            Stream: !GetAtt DynamoDBTable.StreamArn
            StartingPosition: LATEST
            BatchSize: 100

Outputs:
  EndpointUrl:
    Description: 'HTTP REST endpoint URL'
    Value: !Sub 'https://${ServerlessRestApi}.execute-api.${AWS::Region}.amazonaws.com/Prod'