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AWSTemplateFormatVersion: 2010-09-09
Description: Service Catalog AutoScaling Product
Parameters:
  ALBTargetGroupStack:
    Description: ALB Target Group ARN
    Type: String
  AppInstanceType:
    Description: EC2 instance type
    Type: String
    Default: t2.medium
  AppEC2IAMRole:
    Description: The name of EC2 Instance profile
    Type: String
    Default: ''
  AppHealthCheckGracePeriod:
    Description: Number of seconds after instance launch ALB begins health checks
    Type: Number
    MinValue: 40
    MaxValue: 5000
    Default: 300
    ConstraintDescription: Value must be between 40-5000 seconds
  HealthCheckType:
    Description: The service you want the health status from, Amazon EC2 or Elastic Load Balancer
    Type: String
    Default: ELB
    AllowedValues:
      - ELB
      - EC2
  AppMinCount:
    Description: 'Minimum EC2 Instances count'
    Type: Number
    MinValue: 0
    MaxValue: 5
    Default: 1
  AppMaxCount:
    Description: 'Maximum EC2 Instances count'
    Type: Number
    MinValue: 0
    MaxValue: 10
    Default: 1
  SNSTopicARN:
    Description: Notification Topic ARN
    Type: String
    Default: ''
  SNSTopicStackName:
    Description: Notification Topic Service Catalog SNS Stack
    Type: String
    Default: ''
  EnableScalePolicy:
    Description: Enable Auto Scaling Policy
    Type: String
    Default: false
    AllowedValues:
      - true
      - false
  ScaleOutCooldown:
    Description: The amount of time, in seconds, after a scale-out activity completes before another scale-out activity can start.
    Type: String
    Default: 3600
  ScaleOutAdjustment:
    Description: The number of instances by which to scale-out
    Type: Number
    MinValue: 1
    MaxValue: 5
    Default: 1
  ScaleInCooldown:
    Description: The amount of time, in seconds, after a scale-in activity completes before another scale in activity can start
    Type: String
    Default: 1200
  ScaleInAdjustment:
    Description: The number of instances by which to scale-in
    Type: Number
    MinValue: -5
    MaxValue: -1
    Default: -1
  ImageId:
    Description: ImageId
    Type: String
  SecurityGroupIds:
    Description: VPC Security Groups Ids as comma separated list
    Type: CommaDelimitedList
  SubnetIds:
    Description: VPC Subnets Ids as comma separated list
    Type: CommaDelimitedList
  UserData:
    Description: User Data
    Type: String
    Default: ''
  KeyName:
    Description: User Data
    Type: String
    Default: ''
  Tags:
    Description: The tags to be applied to the resource.
    Type: String
    Default: ''

Conditions:
  IsMinZero: !Equals [!Ref AppMinCount, 0]
  IsSNSStack: !Not [!Equals [!Ref SNSTopicStackName, ""]]
  IsSNSArn: !Not [!Equals [!Ref SNSTopicARN, ""]]
  EnablePolicy: !Equals [!Ref EnableScalePolicy, true]
  HasEC2Role: !Not [!Equals [!Ref AppEC2IAMRole, ""]]
  HasUserData: !Not [!Equals [!Ref UserData, ""]]
  HasKeyName: !Not [!Equals [!Ref KeyName, ""]]
  HasTags: !Not [!Equals [!Ref Tags, '']]

Resources:
  GetTags:
    Type: "Custom::ResourceCompliance"
    Condition : HasTags
    Version: "1.0"
    Properties:
      ServiceToken: !Sub 'arn:aws:lambda:${AWS::Region}:${AWS::AccountId}:function:sc-resource-compliance'
      Action:
        Name: json
        Parameters:
          JSON: !Ref Tags
          Type: Tags
  LaunchConfig:
    Type: 'AWS::AutoScaling::LaunchConfiguration'
    Properties:
      InstanceMonitoring: true
      ImageId: !Ref ImageId
      SecurityGroups: !Ref SecurityGroupIds
      InstanceType: !Ref AppInstanceType
      IamInstanceProfile:
        !If
          - HasEC2Role
          - !Sub 'arn:aws:iam::${AWS::AccountId}:instance-profile/${AppEC2IAMRole}'
          - !Ref AWS::NoValue
      KeyName: !If [HasKeyName, !Ref KeyName, !Ref "AWS::NoValue"]
      UserData:
        !If
          - HasUserData
          - !Ref UserData
          - !Ref AWS::NoValue

  AppASG:
    Type: 'AWS::AutoScaling::AutoScalingGroup'
    Properties:
      NotificationConfigurations:
        - !If
            - IsSNSArn
            - TopicARN:
                !Ref SNSTopicARN
              NotificationTypes:
                - autoscaling:EC2_INSTANCE_LAUNCH
                - autoscaling:EC2_INSTANCE_LAUNCH_ERROR
                - autoscaling:EC2_INSTANCE_TERMINATE
                - autoscaling:EC2_INSTANCE_TERMINATE_ERROR
            - !If
              - IsSNSStack
              - TopicARN:
                  Fn::ImportValue:
                      !Sub "${SNSTopicStackName}-SNSArn"
                NotificationTypes:
                  - autoscaling:EC2_INSTANCE_LAUNCH
                  - autoscaling:EC2_INSTANCE_LAUNCH_ERROR
                  - autoscaling:EC2_INSTANCE_TERMINATE
                  - autoscaling:EC2_INSTANCE_TERMINATE_ERROR
              - !Ref "AWS::NoValue"
      TerminationPolicies:
        - OldestInstance
      DesiredCapacity: !If [IsMinZero, 1, !Ref AppMinCount]
      HealthCheckGracePeriod: !Ref AppHealthCheckGracePeriod
      HealthCheckType: !Ref HealthCheckType
      TargetGroupARNs:
        - Fn::ImportValue:
            !Sub "${ALBTargetGroupStack}-ALBTargetId"
      LaunchConfigurationName: !Ref LaunchConfig
      MaxSize: !Ref AppMaxCount
      MetricsCollection:
        - Granularity: 1Minute
      MinSize: !Ref AppMinCount
      VPCZoneIdentifier: !Ref SubnetIds
      Tags: !If [HasTags, !GetAtt GetTags.Json, !Ref "AWS::NoValue"]
  ScaleOutPolicy:
    Condition: EnablePolicy
    Type: 'AWS::AutoScaling::ScalingPolicy'
    Properties:
      AdjustmentType: ChangeInCapacity
      AutoScalingGroupName: !Ref AppASG
      Cooldown: !Ref ScaleOutCooldown
      ScalingAdjustment: !Ref ScaleOutAdjustment
      PolicyType: SimpleScaling
  ScaleInPolicy:
    Condition: EnablePolicy
    Type: 'AWS::AutoScaling::ScalingPolicy'
    Properties:
      AdjustmentType: ChangeInCapacity
      AutoScalingGroupName: !Ref AppASG
      Cooldown: !Ref ScaleInCooldown
      ScalingAdjustment: !Ref ScaleInAdjustment
      PolicyType: SimpleScaling
Outputs:
  AppASGName:
    Value: !Ref AppASG
    Export:
      Name: !Sub ${AWS::StackName}-AppASGName
  ScaleOutPolicy:
    Value: !Ref ScaleOutPolicy
    Condition : EnablePolicy
    Export:
      Name: !Sub ${AWS::StackName}-ScaleOutPolicy
  ScaleInPolicy:
    Value: !Ref ScaleInPolicy
    Condition : EnablePolicy
    Export:
      Name: !Sub ${AWS::StackName}-ScaleInPolicy