AWSTemplateFormatVersion: '2010-09-09'
Description: 'CloudFormation Template to create the DMS replication instance, endpoints, and tasks'

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# Parameters 
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Parameters:

  ParentVPCStack:
    Description: 'Provide Stack name of parent VPC stack based on VPC-3AZs yaml template. Refer Cloudformation dashboard in AWS Console to get this.'
    Type: String
    MinLength: '1'
    MaxLength: '128'
    AllowedPattern: '^[a-zA-Z]+[0-9a-zA-Z\-]*$'
     
  DMSInstanceClass:
    Description: Replication Instance Type
    Type: String
    Default: dms.r5.large
    AllowedValues: 
      - dms.r5.large 
      - dms.r5.xlarge
      - dms.r5.2xlarge
      - dms.r5.4xlarge
      - dms.r5.8xlarge
      - dms.r5.12xlarge
      - dms.r5.16xlarge
      - dms.r5.24xlarge

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# Mandatory tags that will be added to all resources that support tags
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  EnvironmentStage:
    Type: String
    Description: The environment tag is used to designate the Environment Stage of the associated AWS resource.
    AllowedValues:
      - dev
      - test
      - pre-prod
      - prod
    Default: dev
    
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# Conditions
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Conditions:

  IsProd: !Equals [!Ref EnvironmentStage, 'prod']
  MultiAZ: !Or [!Equals [!Ref EnvironmentStage, 'pre-prod'], Condition: IsProd]
  
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# Resources 
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Resources:
        
  ReplicationSubnetGroup:
    Type: AWS::DMS::ReplicationSubnetGroup
    Properties:
      ReplicationSubnetGroupDescription: !Ref 'AWS::StackName'
      SubnetIds: !Split [',', {'Fn::ImportValue': !Sub '${ParentVPCStack}-SubnetsPrivate'}] 

  DMSSecurityGroup:
    Type: AWS::EC2::SecurityGroup
    Properties:
      GroupDescription: !Ref 'AWS::StackName'
      VpcId: {'Fn::ImportValue': !Sub '${ParentVPCStack}-VPC'}
      Tags:
        - Key: Name
          Value: !Sub '${AWS::StackName}-DMSSecurityGroup' 

  ReplicationInstance:
    Type: AWS::DMS::ReplicationInstance
    Properties:
      MultiAZ: !If [MultiAZ, true, false]
      PubliclyAccessible: true
      ReplicationInstanceClass: !Ref DMSInstanceClass
      ReplicationSubnetGroupIdentifier: !Ref ReplicationSubnetGroup
      VpcSecurityGroupIds:
        - !Ref DMSSecurityGroup

Outputs:
  ReplicationInstanceArn:
    Value: !Ref ReplicationInstance

  DMSSecurityGroupID:
    Description: Use this Security Group to reference incoming traffic from RDS instance
    Value: !Ref DMSSecurityGroup
    Export:
      Name: !Sub '${AWS::StackName}-DMSSecurityGroupID'