---
AWSTemplateFormatVersion: 2010-09-09


Parameters:
  Name:
    Type: String

  LaunchType:
    Type: String
    Default: Fargate
    AllowedValues:
      - Fargate
      - EC2

  ECSImageId:
    Type: AWS::SSM::Parameter::Value<AWS::EC2::Image::Id>
    Description: Use an Image from SSM Parameter Store
    Default: /aws/service/ecs/optimized-ami/amazon-linux-2/recommended/image_id

  InstanceType:
    Type: String
    Default: t3.medium

  ClusterSize:
    Type: Number
    Default: 2

  Subnets:
    Type: List<AWS::EC2::Subnet::Id>

  SourceSecurityGroup:
    Type: AWS::EC2::SecurityGroup::Id

  VpcId:
    Type: AWS::EC2::VPC::Id


Conditions:
  EC2: !Equals [ !Ref LaunchType, "EC2" ]

Resources:
  ECSRole:
    Type: AWS::IAM::Role
    Condition: EC2
    Properties:
      Path: /
      AssumeRolePolicyDocument:
        Statement:
          - Action: sts:AssumeRole
            Effect: Allow
            Principal:
              Service: ec2.amazonaws.com
      ManagedPolicyArns:
        - arn:aws:iam::aws:policy/service-role/AmazonEC2ContainerServiceforEC2Role

  InstanceProfile:
    Type: AWS::IAM::InstanceProfile
    Condition: EC2
    Properties:
      Path: /
      Roles:
        - !Ref ECSRole

  SecurityGroup:
    Type: "AWS::EC2::SecurityGroup"
    Condition: EC2
    Properties:
      GroupDescription: !Sub ${Name}-hosts
      SecurityGroupIngress:
        - SourceSecurityGroupId: !Ref SourceSecurityGroup
          IpProtocol: -1
      VpcId: !Ref VpcId

  Cluster:
    Type: AWS::ECS::Cluster
    Properties:
      ClusterName: !Ref Name

  AutoScalingGroup:
    Type: AWS::AutoScaling::AutoScalingGroup
    Condition: EC2
    Properties:
      VPCZoneIdentifier: !Ref Subnets
      LaunchConfigurationName: !Ref LaunchConfiguration
      MinSize: !Ref ClusterSize
      MaxSize: !Ref ClusterSize
      DesiredCapacity: !Ref ClusterSize
      Tags: 
        - Key: Name
          Value: !Sub ${Name} - ECS Host
          PropagateAtLaunch: true
    CreationPolicy:
      ResourceSignal:
        Timeout: PT15M
    UpdatePolicy:
      AutoScalingRollingUpdate:
        MinInstancesInService: 1
        MaxBatchSize: 1
        PauseTime: PT15M
        WaitOnResourceSignals: true

  LaunchConfiguration:
    Type: AWS::AutoScaling::LaunchConfiguration
    Condition: EC2
    Metadata:
      AWS::CloudFormation::Init:
        config:
          commands:
            01_add_instance_to_cluster:
                command: !Sub echo ECS_CLUSTER=${Cluster} > /etc/ecs/ecs.config
          files:
            "/etc/cfn/cfn-hup.conf":
              mode: 000400
              owner: root
              group: root
              content: !Sub |
                [main]
                stack=${AWS::StackId}
                region=${AWS::Region}
            "/etc/cfn/hooks.d/cfn-auto-reloader.conf":
              content: !Sub |
                [cfn-auto-reloader-hook]
                triggers=post.update
                path=Resources.ContainerInstances.Metadata.AWS::CloudFormation::Init
                action=/opt/aws/bin/cfn-init -v --region ${AWS::Region} --stack ${AWS::StackName} --resource LaunchConfiguration
          services:
            sysvinit:
              cfn-hup:
                enabled: true
                ensureRunning: true
                files:
                  - /etc/cfn/cfn-hup.conf
                  - /etc/cfn/hooks.d/cfn-auto-reloader.conf
    Properties:
      ImageId: !Ref ECSImageId
      InstanceType: !Ref InstanceType
      IamInstanceProfile: !Ref InstanceProfile
      SecurityGroups:
        - !Ref SecurityGroup
      UserData:
        "Fn::Base64": !Sub |
          #!/bin/bash
          yum install -y aws-cfn-bootstrap
          /opt/aws/bin/cfn-init -v --region ${AWS::Region} --stack ${AWS::StackName} --resource LaunchConfiguration
          /opt/aws/bin/cfn-signal -e $? --region ${AWS::Region} --stack ${AWS::StackName} --resource AutoScalingGroup


Outputs:
  ClusterName:
      Value: !Ref Cluster