template.yaml

AWSTemplateFormatVersion: "2010-09-09"
Transform: "AWS::Serverless-2016-10-31"

Description: Dynamic Scheduler

Parameters:
  EventBusName:
    Type: String
    Description: "The event bus name to connect the integration to"
    Default: "default"

Globals:
  Function:
    Runtime: "nodejs16.x"
    CodeUri: "./src"
    Timeout: 6
    Tracing: Active
    Environment:
      Variables:
        EVENT_BUS_NAME: !Ref EventBusName
        EVENT_SOURCE: !Sub "com.${AWS::StackName}"

Resources:

  ScheduleTable: 
    Type: AWS::DynamoDB::Table
    Properties: 
      TableName: !Ref AWS::StackName
      BillingMode: PAY_PER_REQUEST
      AttributeDefinitions:
        - AttributeName: "id"
          AttributeType: "S"
      KeySchema:
        - AttributeName: "id"
          KeyType: "HASH"

  StartFunction:
    Type: AWS::Serverless::Function
    Properties:
      FunctionName: !Sub "${AWS::StackName}-start"
      Handler: events/start.handler
      Environment:
        Variables:
          STATE_MACHINE_ARN: !Ref SchedulerStateMachine
          TABLE_NAME: !Ref ScheduleTable
      Policies:
        - DynamoDBCrudPolicy:
            TableName: !Ref ScheduleTable
        - EventBridgePutEventsPolicy:
            EventBusName: !Ref EventBusName
        - Statement:
            - Effect: Allow
              Action:
                - states:DescribeExecution
                - states:StopExecution
                - states:StartExecution
              Resource: '*'
      Events:
        EventReceived:
          Type: EventBridgeRule
          Properties:
            EventBusName: !Ref EventBusName
            Pattern:
              source:
                - !Sub "com.${AWS::StackName}"
              detail-type: 
                - "Schedule Start"

  TickFunction:
    Type: AWS::Serverless::Function
    Properties:
      FunctionName: !Sub "${AWS::StackName}-tick"
      Handler: events/tick.handler
      Environment:
        Variables:
          STATE_MACHINE_ARN: !Ref SchedulerStateMachine
          TABLE_NAME: !Ref ScheduleTable
      Policies:
        - DynamoDBCrudPolicy:
            TableName: !Ref ScheduleTable
        - EventBridgePutEventsPolicy:
            EventBusName: !Ref EventBusName
        - Statement:
            - Effect: Allow
              Action:
                - states:StartExecution
              Resource: '*'
      Events:
        EventReceived:
          Type: EventBridgeRule
          Properties:
            EventBusName: !Ref EventBusName
            Pattern:
              source:
                - !Sub "org.${AWS::StackName}"
              detail-type: 
                - "Schedule Tick"

  StopFunction:
    Type: AWS::Serverless::Function
    Properties:
      FunctionName: !Sub "${AWS::StackName}-stop"
      Handler: events/stop.handler
      Environment:
        Variables:
          STATE_MACHINE_ARN: !Ref SchedulerStateMachine
          TABLE_NAME: !Ref ScheduleTable
      Policies:
        - DynamoDBCrudPolicy:
            TableName: !Ref ScheduleTable
        - EventBridgePutEventsPolicy:
            EventBusName: !Ref EventBusName
        - Statement:
            - Effect: Allow
              Action:
                - states:DescribeExecution
                - states:StopExecution
              Resource: '*'
      Events:
        EventReceived:
          Type: EventBridgeRule
          Properties:
            EventBusName: !Ref EventBusName
            Pattern:
              detail-type: 
                - "Schedule Stop"

  SchedulerStateMachine:
    Type: AWS::Serverless::StateMachine
    Properties:
      Name: !Ref AWS::StackName
      DefinitionUri: states/scheduler.asl.yaml
      DefinitionSubstitutions:
        EventBusName: !Ref EventBusName
        EventSource: !Sub "org.${AWS::StackName}"
      Policies:
        - EventBridgePutEventsPolicy:
            EventBusName: !Ref EventBusName