template.yaml

AWSTemplateFormatVersion: "2010-09-09"
Transform: AWS::Serverless-2016-10-31
Description: >
  lambda-iot-rule

Parameters:
  PublishTopic:
    Type: String
    Default: "topic_1"
    Description: (Required) Provide a topic to publish on. The default will publish on topic_1
  SubscribeTopic:
    Type: String
    Default: "topic_2"
    Description: (Required) Provide a topic for the IoT rule to query. The default will trigger on any message published to topic_2
    
Resources:
  TopicSubscriber:
    Type: AWS::Serverless::Function
    Properties:
      Handler: app.handler
      Runtime: nodejs10.x
      CodeUri: src/topicSubscriber/
      Policies:
        - DynamoDBCrudPolicy:
            TableName: !Ref MyTable
      Environment:
        Variables:
          TABLE_NAME: !Ref MyTable
      Events:
        IoT:
          Type: IoTRule
          Properties:
            AwsIotSqlVersion: 2016-03-23
            Sql: !Sub "SELECT * FROM '${SubscribeTopic}'"
  TopicPublisher:
    Type: AWS::Serverless::Function
    Properties:
      Handler: app.handler
      Runtime: nodejs10.x
      CodeUri: src/topicPublisher/
      Policies:
        - Version: '2012-10-17' 
          Statement:
            - Effect: Allow
              Action:
                - iot:Publish
                - iot:DescribeEndpoint
              Resource: '*'
      Environment:
        Variables:
          PUBLISH_TOPIC: !Ref PublishTopic
      Events:
        PostResource:
          Type: Api
          Properties:
            Path: /publish
            Method: post
  
  MyTable:
    Type: AWS::Serverless::SimpleTable

Outputs:
  ApiURL:
    Description: "API endpoint URL for Prod environment"
    Value: !Sub "https://${ServerlessRestApi}.execute-api.${AWS::Region}.amazonaws.com/Prod/"