%YAML 1.1

# Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
# SPDX-License-Identifier: MIT

---

AWSTemplateFormatVersion: 2010-09-09

Description: dcv-fleet

Metadata:
  AWS::CloudFormation::Interface:
    ParameterGroups:
      - Label:
          default: DCV Fleet Parameters
        Parameters:
          - DcvCluster
          - DcvFleet
          - Enabled
          - InstanceType
          - RootVolumeSize
          - ScalingPolicy
          - MinSize
          - MaxSize
          - MaxVirtualSessionsPerServer
          - BillingTagName
          - BillingTagValue

Parameters:
  DcvCluster:
    Type: String
    AllowedPattern: ^[a-zA-Z][a-zA-Z0-9-]+$
    Default: dcv-cluster
    AllowedValues:
     - dcv-cluster
  DcvFleet:
    Type: String
    Description: "Please don't use spaces"
    Default: linux_instances
  Enabled:
    Type: String
    AllowedValues: [true]
    Default: true
  InstanceType:
    Type: String
    Default: g4dn.xlarge
  RootVolumeSize:
    Type: Number
    Default: 35
    MinValue: 35
  ScalingPolicy:
    Type: String
    Default: StepScaling
    AllowedValues:
      - StepScaling
  MinSize:
    Type: Number
    MinValue: 1
  MaxSize:
    Type: Number
  MaxVirtualSessionsPerServer:
    Type: Number
    Default: 1
    AllowedValues: [1]
  BillingTagName:
    Type: String
  BillingTagValue:
    Type: String


Conditions:
  Enabled: !Equals [true, !Ref Enabled]
  SimpleScaling: !And
    - !Condition Enabled
    - !Equals [SimpleScaling, !Ref ScalingPolicy]
  StepScaling: !And
    - !Condition Enabled
    - !Equals [StepScaling, !Ref ScalingPolicy]
  Step01: !Or [!Condition Step02, !Equals [1, !Ref MinSize]]
  Step02: !Or [!Condition Step03, !Equals [2, !Ref MinSize]]
  Step03: !Or [!Condition Step04, !Equals [3, !Ref MinSize]]
  Step04: !Or [!Condition Step05, !Equals [4, !Ref MinSize]]
  Step05: !Or [!Condition Step06, !Equals [5, !Ref MinSize]]
  Step06: !Or [!Condition Step07, !Equals [6, !Ref MinSize]]
  Step07: !Or [!Condition Step08, !Equals [7, !Ref MinSize]]
  Step08: !Or [!Condition Step09, !Equals [8, !Ref MinSize]]
  Step09: !Or [!Condition Step10, !Equals [9, !Ref MinSize]]
  Step10: !And
    - !Not [!Equals [1, !Ref MinSize]]
    - !Not [!Equals [2, !Ref MinSize]]
    - !Not [!Equals [3, !Ref MinSize]]
    - !Not [!Equals [4, !Ref MinSize]]
    - !Not [!Equals [5, !Ref MinSize]]
    - !Not [!Equals [6, !Ref MinSize]]
    - !Not [!Equals [7, !Ref MinSize]]
    - !Not [!Equals [8, !Ref MinSize]]
    - !Not [!Equals [9, !Ref MinSize]]

Resources:

  LaunchTemplate:
    Type: AWS::EC2::LaunchTemplate
    Properties:
      LaunchTemplateData:
        BlockDeviceMappings:
          - DeviceName: /dev/sda1
            Ebs:
              VolumeSize: !Ref RootVolumeSize
              VolumeType: gp3
              DeleteOnTermination: true
              Encrypted: true
        IamInstanceProfile:
          Arn: '{{resolve:ssm:/dcv/Role}}'
        ImageId: '{{resolve:ssm:/dcv/linux/AmiIdVdi}}'
        InstanceType: !Ref InstanceType
        Monitoring:
          Enabled: true
        NetworkInterfaces:
          - DeviceIndex: 0
            Groups:
              - '{{resolve:ssm:/dcv/Sg}}'
        TagSpecifications:
          - ResourceType: instance
            Tags:
              - Key: Name
                Value: !Sub '${DcvCluster}-DcvServer'
              - Key: dcv:cluster
                Value: !Ref DcvCluster
              - Key: dcv:fleet
                Value: !Ref DcvFleet
              - Key: dcv:max-virtual-sessions
                Value: !Ref MaxVirtualSessionsPerServer
              - Key: !Ref BillingTagName
                Value: !Ref BillingTagValue
          - ResourceType: volume
            Tags:
              - Key: Name
                Value: !Sub '${DcvCluster}-DcvServer'
              - Key: dcv:cluster
                Value: !Ref DcvCluster
              - Key: dcv:fleet
                Value: !Ref DcvFleet
              - Key: !Ref BillingTagName
                Value: !Ref BillingTagValue
        UserData:
          Fn::Base64: !Sub |
            #!/bin/bash
            
            #Configure default region for the AWS cli
            aws configure set region ${AWS::Region}
            
            sleep 30
            
            # Retrieve the required parameters
            export StackName=${AWS::StackName}
            export RegionName=${AWS::Region}
            export DcvFleet=${DcvFleet}
            export InstanceType=${InstanceType}

            LinuxUserdata=$(aws ssm get-parameter --name "/dcv/linux/Userdata" --output text --query Parameter.Value)

            while [ ! -f /tmp/linux.sh ]
            do
              sleep 2
              aws s3 cp "$LinuxUserdata" /tmp/linux.sh
            done
            
            chmod +x /tmp/linux.sh
            
            bash /tmp/linux.sh
            
            rm -f /tmp/linux.sh
            


      TagSpecifications:
        - ResourceType: launch-template
          Tags:
            - Key: Name
              Value: !Sub '${DcvCluster}-DcvFleet'
            - Key: dcv:cluster
              Value: !Ref DcvCluster
            - Key: dcv:fleet
              Value: !Ref DcvFleet

  AutoScalingGroup:
    Type: AWS::AutoScaling::AutoScalingGroup
    CreationPolicy:
      ResourceSignal:
        Count: !Ref MinSize
        Timeout: PT30M
    Properties:
      DesiredCapacity: !Ref MinSize
      MaxSize: !Ref MaxSize
      MinSize: !Ref MinSize
      LaunchTemplate:
        LaunchTemplateId: !Ref LaunchTemplate
        Version: !GetAtt LaunchTemplate.LatestVersionNumber
      MetricsCollection:
        - Granularity: 1Minute
      VPCZoneIdentifier: 
        - '{{resolve:ssm:/dcv/VdiSubnetId}}'
      Tags:
        - PropagateAtLaunch: false
          Key: Name
          Value: !Sub '${DcvCluster}-DcvFleet'
        - PropagateAtLaunch: false
          Key: dcv:cluster
          Value: !Ref DcvCluster
        - PropagateAtLaunch: false
          Key: dcv:fleet
          Value: !Ref DcvFleet
        - PropagateAtLaunch: false
          Key: dcv:type
          Value: dcvserver
          
  StepScalingScaleOutPolicy:
    Type: AWS::AutoScaling::ScalingPolicy
    Condition: StepScaling
    Properties:
      AdjustmentType: ChangeInCapacity
      AutoScalingGroupName: !Ref AutoScalingGroup
      EstimatedInstanceWarmup: 300
      MetricAggregationType: Average
      PolicyType: StepScaling
      StepAdjustments:
        - !If
          - Step01
          - MetricIntervalUpperBound: -1
            MetricIntervalLowerBound: !If [Step02, -2, !Ref 'AWS::NoValue']
            ScalingAdjustment: 1
          - !Ref 'AWS::NoValue'
        - !If
          - Step02
          - MetricIntervalUpperBound: -2
            MetricIntervalLowerBound: !If [Step03, -3, !Ref 'AWS::NoValue']
            ScalingAdjustment: 2
          - !Ref 'AWS::NoValue'
        - !If
          - Step03
          - MetricIntervalUpperBound: -3
            MetricIntervalLowerBound: !If [Step04, -4, !Ref 'AWS::NoValue']
            ScalingAdjustment: 3
          - !Ref 'AWS::NoValue'
        - !If
          - Step04
          - MetricIntervalUpperBound: -4
            MetricIntervalLowerBound: !If [Step05, -5, !Ref 'AWS::NoValue']
            ScalingAdjustment: 4
          - !Ref 'AWS::NoValue'
        - !If
          - Step05
          - MetricIntervalUpperBound: -5
            MetricIntervalLowerBound: !If [Step06, -6, !Ref 'AWS::NoValue']
            ScalingAdjustment: 5
          - !Ref 'AWS::NoValue'
        - !If
          - Step06
          - MetricIntervalUpperBound: -6
            MetricIntervalLowerBound: !If [Step07, -7, !Ref 'AWS::NoValue']
            ScalingAdjustment: 6
          - !Ref 'AWS::NoValue'
        - !If
          - Step07
          - MetricIntervalUpperBound: -7
            MetricIntervalLowerBound: !If [Step08, -8, !Ref 'AWS::NoValue']
            ScalingAdjustment: 7
          - !Ref 'AWS::NoValue'
        - !If
          - Step08
          - MetricIntervalUpperBound: -8
            MetricIntervalLowerBound: !If [Step09, -9, !Ref 'AWS::NoValue']
            ScalingAdjustment: 8
          - !Ref 'AWS::NoValue'
        - !If
          - Step09
          - MetricIntervalUpperBound: -9
            MetricIntervalLowerBound: !If [Step10, -10, !Ref 'AWS::NoValue']
            ScalingAdjustment: 9
          - !Ref 'AWS::NoValue'
        - !If
          - Step10
          - MetricIntervalUpperBound: -10
            MetricIntervalLowerBound: !Ref 'AWS::NoValue'
            ScalingAdjustment: 10
          - !Ref 'AWS::NoValue'

  StepScalingScaleInPolicy:
    Type: AWS::AutoScaling::ScalingPolicy
    Condition: StepScaling
    Properties:
      AdjustmentType: ChangeInCapacity
      AutoScalingGroupName: !Ref AutoScalingGroup
      EstimatedInstanceWarmup: 60
      MetricAggregationType: Average
      PolicyType: StepScaling
      StepAdjustments:
        - MetricIntervalLowerBound: 1
          MetricIntervalUpperBound: 2
          ScalingAdjustment: -1
        - MetricIntervalLowerBound: 2
          MetricIntervalUpperBound: 3
          ScalingAdjustment: -2
        - MetricIntervalLowerBound: 3
          MetricIntervalUpperBound: 4
          ScalingAdjustment: -3
        - MetricIntervalLowerBound: 4
          MetricIntervalUpperBound: 5
          ScalingAdjustment: -4
        - MetricIntervalLowerBound: 5
          MetricIntervalUpperBound: 6
          ScalingAdjustment: -5
        - MetricIntervalLowerBound: 6
          MetricIntervalUpperBound: 7
          ScalingAdjustment: -6
        - MetricIntervalLowerBound: 7
          MetricIntervalUpperBound: 8
          ScalingAdjustment: -7
        - MetricIntervalLowerBound: 8
          MetricIntervalUpperBound: 9
          ScalingAdjustment: -8
        - MetricIntervalLowerBound: 9
          MetricIntervalUpperBound: 10
          ScalingAdjustment: -9
        - MetricIntervalLowerBound: 10
          MetricIntervalUpperBound: !Ref 'AWS::NoValue'
          ScalingAdjustment: -10

  SimpleScalingScaleOutPolicy:
    Type: AWS::AutoScaling::ScalingPolicy
    Condition: SimpleScaling
    Properties:
      AdjustmentType: ChangeInCapacity
      AutoScalingGroupName: !Ref AutoScalingGroup
      Cooldown: '1800'
      PolicyType: SimpleScaling
      ScalingAdjustment: 1

  SimpleScalingScaleInPolicy:
    Type: AWS::AutoScaling::ScalingPolicy
    Condition: SimpleScaling
    Properties:
      AdjustmentType: ChangeInCapacity
      AutoScalingGroupName: !Ref AutoScalingGroup
      Cooldown: '60'
      PolicyType: SimpleScaling
      ScalingAdjustment: -1

  ScaleOutAlarm:
    Type: AWS::CloudWatch::Alarm
    Condition: Enabled
    Properties:
      ActionsEnabled: !Ref Enabled
      AlarmActions:
        - !If [SimpleScaling, !Ref SimpleScalingScaleOutPolicy, !Ref StepScalingScaleOutPolicy]
      AlarmDescription: !Sub 'scale-out strategy for dcv fleet ${AutoScalingGroup}'
      AlarmName: !Sub '${DcvCluster}-${DcvFleet}-ScaleOut'
      ComparisonOperator: LessThanThreshold
      DatapointsToAlarm: 1
      Dimensions:
        - Name: DCV Cluster
          Value: !Ref DcvCluster
        - Name: Fleet Name
          Value: !Ref AutoScalingGroup
      EvaluationPeriods: 1
      MetricName: idle_servers
      Namespace: DCV AutoScaling
      Period: 60
      Statistic: Average
      Threshold: !If [Enabled, !Ref MinSize, 0]
      TreatMissingData: missing
      Unit: Count

  ScaleInAlarm:
    Type: AWS::CloudWatch::Alarm
    Condition: Enabled
    Properties:
      ActionsEnabled: !Ref Enabled
      AlarmActions:
        - !If [SimpleScaling, !Ref SimpleScalingScaleInPolicy, !Ref StepScalingScaleInPolicy]
      AlarmDescription: !Sub 'scale-in strategy for dcv fleet ${AutoScalingGroup}'
      AlarmName: !Sub '${DcvCluster}-${DcvFleet}-ScaleIn'
      ComparisonOperator: GreaterThanThreshold
      DatapointsToAlarm: 1
      Dimensions:
        - Name: DCV Cluster
          Value: !Ref DcvCluster
        - Name: Fleet Name
          Value: !Ref AutoScalingGroup
      EvaluationPeriods: 1
      MetricName: idle_servers
      Namespace: DCV AutoScaling
      Period: 60
      Statistic: Average
      Threshold: !If [Enabled, !Ref MinSize, 0]
      TreatMissingData: missing
      Unit: Count

Outputs:
  LaunchTemplateId:
    Value: !Ref LaunchTemplate
  AutoScalingGroup:
    Value: !Ref AutoScalingGroup

...