---
AWSTemplateFormatVersion: 2010-09-09

Description: Reference Architecture to host Moodle on AWS - Creates EFS file system

Metadata:

  AWS::CloudFormation::Interface:

    ParameterGroups:
    - Label:
        default: Amazon EFS Parameters
      Parameters:
        - Growth
        - InstanceType
        - EC2KeyName
        - PerformanceMode
        - EncrpytedBoolean
        - SecurityGroup
        - NumberOfSubnets
        - Subnet
    ParameterLabels:
      EncrpytedBoolean:
        default: Encryption state
      Growth:
        default: Add data (GiB)
      InstanceType:
        default: Instance Type
      EC2KeyName:
        default: Existing Key Pair
      NumberOfSubnets:
        default: Number of subnets
      PerformanceMode:
        default: Performance Mode
      SecurityGroup:
        default: EFS Security Group
      Subnet:
        default: Subnets

Parameters:

  EncrpytedBoolean:
    AllowedValues:
      - True
      - False
    Default: True
    Description: Create an encrypted Amazon EFS file system.
    Type: String
  Growth:
    ConstraintDescription: Must be an integer.
    Default: 0
    Description: Amount of dummy data (GiB) to add to the file system (max 6144 GiB). Amazon EFS storage charges apply. 
    MaxValue: 6144
    MinValue: 0
    Type: Number
  InstanceType:
    AllowedValues:
      - t2.medium 
      - t2.large 
      - t2.xlarge 
      - t2.2xlarge 
      - m4.large 
      - m4.xlarge 
      - m4.2xlarge 
      - m4.4xlarge 
      - m4.10xlarge 
      - m4.16xlarge 
      - m5.large 
      - m5.xlarge 
      - m5.2xlarge 
      - m5.4xlarge 
      - m5.12xlarge 
      - m5.24xlarge 
      - c4.large 
      - c4.xlarge 
      - c4.2xlarge 
      - c4.4xlarge 
      - c4.8xlarge 
      - c5.large 
      - c5.xlarge 
      - c5.2xlarge 
      - c5.4xlarge 
      - c5.9xlarge 
      - c5.18xlarge
      - r4.large 
      - r4.xlarge 
      - r4.2xlarge 
      - r4.4xlarge 
      - r4.8xlarge 
      - r4.16xlarge 
      - r5.large
      - r5.2xlarge
      - r5.4xlarge
      - r5.8xlarge
      - r5.12xlarge
      - r5.16xlarge
      - r5.24xlarge
    ConstraintDescription: Must be a valid Amazon EC2 instance type.
    Default: r4.large
    Description: The Amazon EC2 instance type that adds data to the file system.
    Type: String
  EC2KeyName:
    Description: Name of an existing EC2 key pair
    Type: AWS::EC2::KeyPair::KeyName
  NumberOfSubnets:
    AllowedValues:
    - 2
    - 3
    - 4
    - 5
    - 6
    Default: 3
    Description: Number of subnets. This must match your selections in the list of Subnets below.
    Type: String 
  PerformanceMode:
    AllowedValues:
      - generalPurpose
      - maxIO
    Default: generalPurpose
    Description: Select the performance mode of the file system.
    Type: String
  SecurityGroup:
    Description: Select the Amazon EFS security group.
    Type: AWS::EC2::SecurityGroup::Id   
  Subnet:
    Description: Select existing subnets.
    Type: List<AWS::EC2::Subnet::Id>
  LatestAmiId :
    Type : AWS::SSM::Parameter::Value<AWS::EC2::Image::Id>
    Default: /aws/service/ami-amazon-linux-latest/amzn-ami-hvm-x86_64-gp2
    

Conditions:
  
  NumberOfSubnets1:
      !Equals [ 1, !Ref NumberOfSubnets ]
  NumberOfSubnets2:
      !Equals [ 2, !Ref NumberOfSubnets ]
  NumberOfSubnets3:
      !Equals [ 3, !Ref NumberOfSubnets ]
  NumberOfSubnets4:
      !Equals [ 4, !Ref NumberOfSubnets ]
  NumberOfSubnets5:
      !Equals [ 5, !Ref NumberOfSubnets ]
  NumberOfSubnets6:
      !Equals [ 6, !Ref NumberOfSubnets ]
  Subnet0: !Or
    - !Condition NumberOfSubnets1
    - !Condition NumberOfSubnets2
    - !Condition NumberOfSubnets3
    - !Condition NumberOfSubnets4
    - !Condition NumberOfSubnets5
    - !Condition NumberOfSubnets6
  Subnet1: !Or
    - !Condition NumberOfSubnets2
    - !Condition NumberOfSubnets3
    - !Condition NumberOfSubnets4
    - !Condition NumberOfSubnets5
    - !Condition NumberOfSubnets6
  Subnet2: !Or
    - !Condition NumberOfSubnets3
    - !Condition NumberOfSubnets4
    - !Condition NumberOfSubnets5
    - !Condition NumberOfSubnets6
  Subnet3: !Or
    - !Condition NumberOfSubnets4
    - !Condition NumberOfSubnets5
    - !Condition NumberOfSubnets6
  Subnet4: !Or
    - !Condition NumberOfSubnets5
    - !Condition NumberOfSubnets6
  Subnet5: !Condition NumberOfSubnets6


Resources:

  ElasticFileSystem:
    Type: AWS::EFS::FileSystem
    Properties:
      Encrypted: !Ref EncrpytedBoolean
      FileSystemTags:
        - Key: Name
          Value: !Join [ '', [ 'Moodle / ', !Ref 'AWS::StackName' ] ]
      PerformanceMode: !Ref PerformanceMode
  ElasticFileSystemMountTarget0:
    Condition: Subnet0
    Type: AWS::EFS::MountTarget
    Properties:
      FileSystemId: !Ref ElasticFileSystem
      SecurityGroups:
      - !Ref SecurityGroup
      SubnetId: !Select [ 0, !Ref Subnet ]
  ElasticFileSystemMountTarget1:
    Condition: Subnet1
    Type: AWS::EFS::MountTarget
    Properties:
      FileSystemId: !Ref ElasticFileSystem
      SecurityGroups:
      - !Ref SecurityGroup
      SubnetId: !Select [ 1, !Ref Subnet ]
  ElasticFileSystemMountTarget2:
    Condition: Subnet2
    Type: AWS::EFS::MountTarget
    Properties:
      FileSystemId: !Ref ElasticFileSystem
      SecurityGroups:
      - !Ref SecurityGroup
      SubnetId: !Select [ 2, !Ref Subnet ]
  ElasticFileSystemMountTarget3:
    Condition: Subnet3
    Type: AWS::EFS::MountTarget
    Properties:
      FileSystemId: !Ref ElasticFileSystem
      SecurityGroups:
      - !Ref SecurityGroup
      SubnetId: !Select [ 3, !Ref Subnet ]
  ElasticFileSystemMountTarget4:
    Condition: Subnet4
    Type: AWS::EFS::MountTarget
    Properties:
      FileSystemId: !Ref ElasticFileSystem
      SecurityGroups:
      - !Ref SecurityGroup
      SubnetId: !Select [ 4, !Ref Subnet ]
  ElasticFileSystemMountTarget5:
    Condition: Subnet5
    Type: AWS::EFS::MountTarget
    Properties:
      FileSystemId: !Ref ElasticFileSystem
      SecurityGroups:
      - !Ref SecurityGroup
      SubnetId: !Select [ 5, !Ref Subnet ]
  InstanceProfile:
    Type: AWS::IAM::InstanceProfile
    Properties:
      Path: /
      Roles:
      - !Ref InstanceRole
  InstanceRole:
    Type: AWS::IAM::Role
    Properties:
      AssumeRolePolicyDocument:
        Version: 2012-10-17
        Statement:
        - Effect: Allow
          Principal:
            Service:
            - ec2.amazonaws.com.cn
          Action:
          - sts:AssumeRole
      Path: /
      Policies:
      - PolicyName: efs-create-file-system-with-storage
        PolicyDocument:
          Version: 2012-10-17
          Statement:
          - Effect: Allow
            Action:
              - autoscaling:DescribeAutoScalingGroups
              - autoscaling:DescribeAutoScalingInstances
              - autoscaling:DescribePolicies
              - autoscaling:UpdateAutoScalingGroup
            Resource: 'arn:aws-cn:autoscaling:*:*:*:*'
  AutoScalingGroup:
    Type: AWS::AutoScaling::AutoScalingGroup
    Properties:
      Cooldown: 60
      HealthCheckGracePeriod: 120
      HealthCheckType: EC2
      LaunchConfigurationName: !Ref LaunchConfiguration
      MaxSize: 1
      MinSize: 0
      DesiredCapacity: 1
      Tags:
        - Key: Name
          Value: !Join [ '', [ 'EFS ', !Ref ElasticFileSystem, ' data load... will auto terminate.' ] ]
          PropagateAtLaunch: true
      VPCZoneIdentifier:
        !If
          [ NumberOfSubnets1,
          [ !Select [ 0, !Ref Subnet ] ],
          !If
            [ NumberOfSubnets2,
            [ !Select [ 0, !Ref Subnet ], !Select [ 1, !Ref Subnet ] ],
            !If
              [ NumberOfSubnets3,
              [ !Select [ 0, !Ref Subnet ], !Select [ 1, !Ref Subnet ], !Select [ 2, !Ref Subnet ] ],
              !If
                [ NumberOfSubnets4,
                [ !Select [ 0, !Ref Subnet ], !Select [ 1, !Ref Subnet ], !Select [ 2, !Ref Subnet ], !Select [ 3, !Ref Subnet ] ],
                !If
                  [ NumberOfSubnets5,
                  [ !Select [ 0, !Ref Subnet ], !Select [ 1, !Ref Subnet ], !Select [ 2, !Ref Subnet ], !Select [ 3, !Ref Subnet ], !Select [ 4, !Ref Subnet ] ],
                  [ !Select [ 0, !Ref Subnet ], !Select [ 1, !Ref Subnet ], !Select [ 2, !Ref Subnet ], !Select [ 3, !Ref Subnet ], !Select [ 4, !Ref Subnet ], !Select [ 5, !Ref Subnet ] ]
                  ]
                ]
              ]
            ]
          ]
    CreationPolicy:
      ResourceSignal:
        Count: 0
        Timeout: PT12H
    UpdatePolicy:
      AutoScalingReplacingUpdate:
        WillReplace: true
  AutoScalingPolicy:
    Type: AWS::AutoScaling::ScalingPolicy
    Properties:
      AdjustmentType: ChangeInCapacity
      AutoScalingGroupName: !Ref AutoScalingGroup
      Cooldown: 60
      PolicyType: SimpleScaling
      ScalingAdjustment: 1
  LaunchConfiguration:
    Type: AWS::AutoScaling::LaunchConfiguration
    Metadata:
      AWS::CloudFormation::Init:
        configSets:
          efs_init:
            - install_efs_utils
            - efs-add-storage        
        efs-add-storage:
          packages:
            yum:
              #Only needed to set permissions on the moodle folder
              httpd: []
          files:              
            /tmp/efs-add-storage.sh:
              content: !Sub |
                #!/bin/bash -x

                FILE_SYSTEM_ID=$1
                DATA_DIRECTORY=$2
                GROWTH=$3

                if [ $# -lt 3 ]; then
                  echo "Invalid # of arguments. Require: file system id, data directory, file system growth (GiB) "
                  exit 0
                fi

                # get region from instance meta-data
                availabilityzone=$(curl -s http://169.254.169.254/latest/meta-data/placement/availability-zone)
                region=${!availabilityzone:0:-1}

                # get instance id
                instance_id=$(curl -s http://169.254.169.254/latest/meta-data/instance-id)

                # get autoscaling group name
                asg_name=$(aws autoscaling describe-auto-scaling-instances --instance-ids $instance_id --region $region --output text --query 'AutoScalingInstances[0].AutoScalingGroupName')

                # set the number of threads to the number of vcpus
                threads=$(( $(nproc --all) * 8 ))

                # wait for file system DNS name to be propagated
                results=1
                while [[ $results != 0 ]]; do
                  nslookup $FILE_SYSTEM_ID.efs.$region.amazonaws.com.cn
                  results=$?
                  if [[ results = 1 ]]; then
                    sleep 30
                  fi
                done

                # mount file system
                sudo mkdir -p /$FILE_SYSTEM_ID
                sudo chown ec2-user:ec2-user /$FILE_SYSTEM_ID
                sudo mount -t efs $FILE_SYSTEM_ID:/ /$FILE_SYSTEM_ID
                #Create directories for Moodle
                sudo mkdir -p /$FILE_SYSTEM_ID/data
                sudo mkdir -p /$FILE_SYSTEM_ID/cache
                sudo mkdir -p /$FILE_SYSTEM_ID/temp
                chown apache:apache /$FILE_SYSTEM_ID/data/
                chown apache:apache /$FILE_SYSTEM_ID/cache/
                chown apache:apache /$FILE_SYSTEM_ID/temp/

                # create data directory if not exists
                sudo mkdir -p /$FILE_SYSTEM_ID/$DATA_DIRECTORY
                sudo chown ec2-user:ec2-user /$FILE_SYSTEM_ID/$DATA_DIRECTORY

                # dd 1GiB files to file system to match DATA_SIZE
                files=$GROWTH
                if [ $(( $files / $threads )) == 0 ];
                  then
                    runs=0
                    parallel_threads=$(( $files % $threads ))
                  else
                    runs=$(( $files / $threads ))
                    parallel_threads=$threads
                fi
                while [ $runs -ge 0 ]; do
                  if [ $runs == 0 ];
                    then
                      parallel_threads=$(( $files % $threads ))
                      seq 0 $(( $parallel_threads - 1 )) | parallel --will-cite -j $parallel_threads --compress dd if=/dev/zero of=/$FILE_SYSTEM_ID/$DATA_DIRECTORY/1G-dd-$(date +%Y%m%d%H%M%S.%3N)-{} bs=1M count=1024 oflag=sync
                      runs=$(($runs-1))
                    else
                      seq 0 $(( $parallel_threads - 1 )) | parallel --will-cite -j $parallel_threads --compress dd if=/dev/zero of=/$FILE_SYSTEM_ID/$DATA_DIRECTORY/1G-dd-$(date +%Y%m%d%H%M%S.%3N)-{} bs=1M count=1024 oflag=sync
                      runs=$(($runs-1))
                  fi
                done

                # set ASG to zero which terminates instance
                aws autoscaling update-auto-scaling-group --auto-scaling-group-name $asg_name --desired-capacity 0 --region $region

              mode: 000777
              owner: root
              group: root             
        
        install_efs_utils:
          packages:
            yum:
              git: []
              rpm-build: []
          files:
            /tmp/install_efs_utils.sh:
              content: !Sub |
                #!/bin/bash -xe
                git clone https://github.com/aws/efs-utils.git
                cd efs-utils
                make rpm
                yum -y install build/amazon-efs-utils*rpm
              mode: 000500
              owner: root
              group: root
          commands:
            install_efs_utils:
              command: ./install_efs_utils.sh
              cwd: /tmp
              ignoreErrors: false

    Properties:
      BlockDeviceMappings:
        - DeviceName: /dev/xvda
          Ebs:
            DeleteOnTermination: true
            VolumeSize: 10
            VolumeType: gp2
      IamInstanceProfile: !Ref InstanceProfile
      ImageId: !Ref LatestAmiId
      InstanceMonitoring: true
      InstanceType: !Ref InstanceType
      KeyName: !Ref EC2KeyName
      SecurityGroups:
      - !Ref SecurityGroup
      UserData:
        "Fn::Base64":
          !Join [
            "",[
            "#cloud-config\n",
            "repo_update: true\n",
            "repo_upgrade: all\n",
            "\n",
            "packages:\n",
            "- parallel\n",
            "\n",
            "runcmd:\n",
            "- yum --enablerepo=epel install nload -y\n",
            "- ntpstat\n",
            "- /opt/aws/bin/cfn-init --configsets efs_init --verbose --stack ", !Ref 'AWS::StackName', " --resource LaunchConfiguration --region ", !Ref 'AWS::Region',"\n",
            "- /tmp/efs-add-storage.sh ", !Ref ElasticFileSystem, " throughput_data ", !Ref Growth,"\n",
            "- /opt/aws/bin/cfn-signal -e $? --stack ", !Ref 'AWS::StackName', " --resource AutoScalingGroup --region ", !Ref 'AWS::Region',"\n"
            ]
          ]
  EfsSizeMonitorFunction:
    Metadata:
      cfn_nag:
        rules_to_suppress:
          - id: W58
            reason: Attached AWS-managed Policies
    Type: AWS::Lambda::Function
    Properties: 
      Code:
        ZipFile: !Sub |
          import boto3
          import os
          import sys

          def handler(event, context):
              if not os.environ.get('filesystemid'):
                  print "Unable to get the environment variable filesystemid"
                  sys.exit(1)
              else:
                  filesystemid = os.environ.get('filesystemid')

              if not os.environ.get('region'):
                  print "Unable to get the environment variable region"
                  sys.exit(1)
              else:
                  region = os.environ.get('region')

              def efs_get_size():
                  client = boto3.client('efs')
                  response = client.describe_file_systems(FileSystemId=filesystemid)
                  k = response['FileSystems'][0]['SizeInBytes']['Value']
                  return k

              def cloudwatch_put_metric():
                  client = boto3.client('cloudwatch')
                  client.put_metric_data(
                      MetricData=[
                          {
                              'MetricName': 'SizeInBytes',
                              'Dimensions': [
                                  {
                                      'Name': 'FileSystemId',
                                      'Value': filesystemid
                                  },
                              ],
                              'Unit': 'None',
                              'Value': efs_get_size()
                          },
                      ],
                      Namespace='Custom/EFS'
                  )
                  print('CloudWatch metric SizeInBytes sucessfully updated.')

              cloudwatch_put_metric()
      Description: Lambda function to update the SizeInBytes EFS CloudWatch metric
      Environment:
        Variables:
          filesystemid: !Ref ElasticFileSystem
          region: !Ref 'AWS::Region'
      FunctionName: !Join [ '', [ 'efs-', !Ref ElasticFileSystem, '-size-monitor' ] ]
      Handler: index.handler
      Role: !GetAtt LambdaRole.Arn
      Runtime: python2.7
      Timeout: 60
  LambdaRole:
    Type: AWS::IAM::Role
    Properties:
      AssumeRolePolicyDocument:
        Version: 2012-10-17
        Statement:
        - Effect: Allow
          Principal:
            Service:
            - lambda.amazonaws.com
          Action:
          - sts:AssumeRole
      Path: /
      ManagedPolicyArns:
        - arn:aws-cn:iam::aws:policy/CloudWatchFullAccess
        - arn:aws-cn:iam::aws:policy/AmazonElasticFileSystemReadOnlyAccess
  EfsLambdaPermission: 
    Type: AWS::Lambda::Permission
    Properties: 
      FunctionName: !Ref EfsSizeMonitorFunction
      Action: lambda:InvokeFunction
      Principal: events.amazonaws.com
      SourceArn: !GetAtt EfsSizeMonitorEvent.Arn
  EfsSizeMonitorEvent:
    Type: AWS::Events::Rule
    Properties: 
      Description: Scheduled event to update SizeInBytes EFS CloudWatch metric
      Name: !Join [ '', [ 'efs-', !Ref ElasticFileSystem, '-size-monitor-scheduled-event' ] ]
      ScheduleExpression: rate(1 minute)
      State: ENABLED
      Targets:
        - Arn: !GetAtt EfsSizeMonitorFunction.Arn
          Id: 1

Outputs:
  ElasticFileSystem:
    Value: !Ref ElasticFileSystem
  ElasticFileSystemDnsName:
    Description: DNS name for the Amazon EFS file system.
    Value: !Join [ '.', [ !Ref ElasticFileSystem, 'efs', !Ref 'AWS::Region', 'amazonaws', 'com.cn' ] ]