AWSTemplateFormatVersion: '2010-09-09'
Transform: AWS::Serverless-2016-10-31
Description: >
  A Step Functions Workflow to start a new execution of a state machine directly from the task state of a running execution


Resources:
##########################################################################
#   CHILD and PARENT STEP FUNCTIONS                                      #
##########################################################################

  ChildStateMachine:
    Type: AWS::Serverless::StateMachine # More info about State Machine Resource: https://docs.aws.amazon.com/serverless-application-model/latest/developerguide/sam-resource-statemachine.html
    Properties:
      DefinitionUri: statemachine/childStateMachine.asl.json
      Type: EXPRESS
      Role: !GetAtt ChildStateMachineExecutionRole.Arn
      Logging:
        Destinations:
          - CloudWatchLogsLogGroup:
              LogGroupArn: !GetAtt ChildStateMachineLogGroup.Arn
        IncludeExecutionData: false
        Level: 'ALL'

  ParentStateMachine:
    Type: AWS::Serverless::StateMachine # More info about State Machine Resource: https://docs.aws.amazon.com/serverless-application-model/latest/developerguide/sam-resource-statemachine.html
    Properties:
      DefinitionUri: statemachine/parentStateMachine.asl.json
      DefinitionSubstitutions:
        ChildStateMachineArn: !GetAtt ChildStateMachine.Arn
      Role: !GetAtt ParentStateMachineExecutionRole.Arn
      Type: EXPRESS
      Logging:
        Destinations:
          - CloudWatchLogsLogGroup:
              LogGroupArn: !GetAtt ParentStateMachineLogGroup.Arn
        IncludeExecutionData: false
        Level: 'ALL'

##########################################################################
#  LOG GROUPS                                                            #
##########################################################################
  ParentStateMachineLogGroup:
    Type: AWS::Logs::LogGroup
    Properties:
      LogGroupName: !Join [ "/", [ "stepfunctions", !Ref AWS::StackName, "parentStateMachine"]]
  
  ChildStateMachineLogGroup:
    Type: AWS::Logs::LogGroup
    Properties:
      LogGroupName: !Join [ "/", [ "stepfunctions", !Ref AWS::StackName, "childStateMachine"]]


##########################################################################
#   Roles                                                               #
##########################################################################
  ChildStateMachineExecutionRole:
    Type: "AWS::IAM::Role"
    Properties:
      AssumeRolePolicyDocument:
        Version: "2012-10-17"
        Statement:
          - Effect: "Allow"
            Principal:
              Service:
                - !Sub states.${AWS::Region}.amazonaws.com
            Action: "sts:AssumeRole"
      Path: "/"
      Policies:
        -  PolicyName: LogPermissions
           PolicyDocument:
             Version: "2012-10-17"
             Statement:
              - Effect: Allow
                Action:
                  - "cloudwatch:*"
                  - "logs:*"
                Resource: "*"
                
  ParentStateMachineExecutionRole:
    Type: "AWS::IAM::Role"
    Properties:
      AssumeRolePolicyDocument:
        Version: "2012-10-17"
        Statement:
          - Effect: "Allow"
            Principal:
              Service:
                - !Sub states.${AWS::Region}.amazonaws.com
            Action: "sts:AssumeRole"
      Path: "/"
      Policies:
        - PolicyName: ChildStateMachineExecution
          PolicyDocument:
            Statement:
              - Effect: Allow
                Resource:
                  - !GetAtt ChildStateMachine.Arn
                Action:
                  - states:StartExecution
        -  PolicyName: LogPermissions
           PolicyDocument:
             Version: "2012-10-17"
             Statement:
              - Effect: Allow
                Action:
                  - "cloudwatch:*"
                  - "logs:*"
                Resource: "*"

Outputs:
  ParentStateMachineArn:
    Value: !GetAtt ParentStateMachine.Arn
    Description: ARN of the Parent State Machine
  ParentStateMachineLogGroupName:
    Value: !Ref ParentStateMachineLogGroup
    Description: Name of the Parent CloudWatch Log Group
  ChildStateMachineArn:
    Value: !GetAtt ChildStateMachine.Arn
    Description: ARN of the Child State Machine
  ChildStateMachineLogGroupName:
    Value: !Ref ChildStateMachineLogGroup
    Description: Name of the Parent CloudWatch Log Group