Parameters:

  VpcCIDR:
    Description: Please enter the IP range (CIDR notation) for this VPC
    Type: String
    Default: 10.10.0.0/16

  PublicSubnet1CIDR:
    Description: Please enter the IP range (CIDR notation) for the public subnet in the first Availability Zone
    Type: String
    Default: 10.10.10.0/24

  PublicSubnet2CIDR:
    Description: Please enter the IP range (CIDR notation) for the public subnet in the second Availability Zone
    Type: String
    Default: 10.10.11.0/24

  PrivateSubnet1CIDR:
    Description: Please enter the IP range (CIDR notation) for the private subnet in the first Availability Zone
    Type: String
    Default: 10.10.20.0/24

  PrivateSubnet2CIDR:
    Description: Please enter the IP range (CIDR notation) for the private subnet in the second Availability Zone
    Type: String
    Default: 10.10.21.0/24

  AllowedIP:
    Description: Allowed IP range
    Type: String
    Default: 0.0.0.0/0

  LatestLinux2AmiId:
    Description: Region specific image from the Parameter Store
    Type: 'AWS::SSM::Parameter::Value<AWS::EC2::Image::Id>'
    Default: '/aws/service/ami-amazon-linux-latest/amzn2-ami-hvm-x86_64-gp2'

  ResourceName:
    Type: String
    Default: int-alb-with-aws-ga
    Description: Prefix of Resources created for this workshop.

Metadata:
  AWS::CloudFormation::Interface:
    ParameterGroups:
      -
        Label:
          default: "Resource Configuration"
        Parameters:
          - ResourceName
    ParameterLabels:
      ResourceName:
        default: "Resource Prefix"

Resources:
  VPC:
    Type: AWS::EC2::VPC
    Properties:
      CidrBlock: !Ref VpcCIDR
      EnableDnsSupport: true
      EnableDnsHostnames: true
      Tags:
        - Key: Name
          Value: !Join [ -, [!Ref ResourceName, 'VPC'] ]

  InternetGateway:
    Type: AWS::EC2::InternetGateway
    Properties:
      Tags:
        - Key: Name
          Value: !Join [ -, [!Ref ResourceName, 'IGW'] ]

  InternetGatewayAttachment:
    Type: AWS::EC2::VPCGatewayAttachment
    Properties:
      InternetGatewayId: !Ref InternetGateway
      VpcId: !Ref VPC

  PublicSubnet1:
    Type: AWS::EC2::Subnet
    Properties:
      VpcId: !Ref VPC
      AvailabilityZone: !Select [ 0, !GetAZs '' ]
      CidrBlock: !Ref PublicSubnet1CIDR
      MapPublicIpOnLaunch: true
      Tags:
        - Key: Name
          Value: Public Subnet (AZ1)

  PublicSubnet2:
    Type: AWS::EC2::Subnet
    Properties:
      VpcId: !Ref VPC
      AvailabilityZone: !Select [ 1, !GetAZs  '' ]
      CidrBlock: !Ref PublicSubnet2CIDR
      MapPublicIpOnLaunch: true
      Tags:
        - Key: Name
          Value: Public Subnet (AZ2)

  PrivateSubnet1:
    Type: AWS::EC2::Subnet
    Properties:
      VpcId: !Ref VPC
      AvailabilityZone: !Select [ 0, !GetAZs  '' ]
      CidrBlock: !Ref PrivateSubnet1CIDR
      MapPublicIpOnLaunch: false
      Tags:
        - Key: Name
          Value: Private Subnet (AZ1)

  PrivateSubnet2:
    Type: AWS::EC2::Subnet
    Properties:
      VpcId: !Ref VPC
      AvailabilityZone: !Select [ 1, !GetAZs  '' ]
      CidrBlock: !Ref PrivateSubnet2CIDR
      MapPublicIpOnLaunch: false
      Tags:
        - Key: Name
          Value: Private Subnet (AZ2)

  NatGateway1EIP:
    Type: AWS::EC2::EIP
    DependsOn: InternetGatewayAttachment
    Properties:
      Domain: vpc

  NatGateway2EIP:
    Type: AWS::EC2::EIP
    DependsOn: InternetGatewayAttachment
    Properties:
      Domain: vpc

  NatGateway1:
    Type: AWS::EC2::NatGateway
    Properties:
      AllocationId: !GetAtt NatGateway1EIP.AllocationId
      SubnetId: !Ref PublicSubnet1

  NatGateway2:
    Type: AWS::EC2::NatGateway
    Properties:
      AllocationId: !GetAtt NatGateway2EIP.AllocationId
      SubnetId: !Ref PublicSubnet2

  PublicRouteTable:
    Type: AWS::EC2::RouteTable
    Properties:
      VpcId: !Ref VPC
      Tags:
        - Key: Name
          Value: Public Routes

  DefaultPublicRoute:
    Type: AWS::EC2::Route
    DependsOn: InternetGatewayAttachment
    Properties:
      RouteTableId: !Ref PublicRouteTable
      DestinationCidrBlock: 0.0.0.0/0
      GatewayId: !Ref InternetGateway

  PublicSubnet1RouteTableAssociation:
    Type: AWS::EC2::SubnetRouteTableAssociation
    Properties:
      RouteTableId: !Ref PublicRouteTable
      SubnetId: !Ref PublicSubnet1

  PublicSubnet2RouteTableAssociation:
    Type: AWS::EC2::SubnetRouteTableAssociation
    Properties:
      RouteTableId: !Ref PublicRouteTable
      SubnetId: !Ref PublicSubnet2


  PrivateRouteTable1:
    Type: AWS::EC2::RouteTable
    Properties:
      VpcId: !Ref VPC
      Tags:
        - Key: Name
          Value: Private Routes (AZ1)

  DefaultPrivateRoute1:
    Type: AWS::EC2::Route
    Properties:
      RouteTableId: !Ref PrivateRouteTable1
      DestinationCidrBlock: 0.0.0.0/0
      NatGatewayId: !Ref NatGateway1

  PrivateSubnet1RouteTableAssociation:
    Type: AWS::EC2::SubnetRouteTableAssociation
    Properties:
      RouteTableId: !Ref PrivateRouteTable1
      SubnetId: !Ref PrivateSubnet1

  PrivateRouteTable2:
    Type: AWS::EC2::RouteTable
    Properties:
      VpcId: !Ref VPC
      Tags:
        - Key: Name
          Value: Private Routes (AZ2)

  DefaultPrivateRoute2:
    Type: AWS::EC2::Route
    Properties:
      RouteTableId: !Ref PrivateRouteTable2
      DestinationCidrBlock: 0.0.0.0/0
      NatGatewayId: !Ref NatGateway2

  PrivateSubnet2RouteTableAssociation:
    Type: AWS::EC2::SubnetRouteTableAssociation
    Properties:
      RouteTableId: !Ref PrivateRouteTable2
      SubnetId: !Ref PrivateSubnet2

  WebServerPrefixList:
    Type: AWS::EC2::PrefixList
    Properties:
      PrefixListName: "WebServerPrefixList"
      AddressFamily: "IPv4"
      MaxEntries: 10
      Entries:
        - Cidr: !Ref AllowedIP
          Description: "AllowedIP"

  WebServerSecurityGroup:
    Type: AWS::EC2::SecurityGroup
    Properties:
      GroupName: "web-server-sg"
      GroupDescription: "Security Group for Web Servers"
      VpcId: !Ref VPC
      SecurityGroupIngress:
      - IpProtocol: tcp
        SourceSecurityGroupId: !Ref ALBSecurityGroup
        FromPort: 80
        ToPort: 80

  # Internal ALB
  InternalALBListener:
    Type: AWS::ElasticLoadBalancingV2::Listener
    Properties:
      DefaultActions:
        - Type: forward
          TargetGroupArn:
            Ref: WebServerTargetGroup
      LoadBalancerArn:
          Ref: InternalApplicationLoadBalancer
      Port: 80
      Protocol: HTTP

  InternalApplicationLoadBalancer:
    Type: AWS::ElasticLoadBalancingV2::LoadBalancer
    Properties:
      Scheme: internal
      Subnets:
      - Ref: PrivateSubnet1
      - Ref: PrivateSubnet2
      SecurityGroups:
      - Ref: ALBSecurityGroup

# Internal ALB Security Group with Allowed IP prefix
  ALBSecurityGroup:
    Type: AWS::EC2::SecurityGroup
    Properties:
        GroupDescription: 'int-alb-with-ga-sg'
        VpcId:
          Ref: VPC
        SecurityGroupIngress:
            - IpProtocol: tcp
              SourcePrefixListId: !Ref WebServerPrefixList
              FromPort: 80
              ToPort: 80

  WebServerTargetGroup:
    Type: AWS::ElasticLoadBalancingV2::TargetGroup
    Properties:
      HealthCheckIntervalSeconds: 5
      HealthCheckProtocol: HTTP
      HealthCheckTimeoutSeconds: 3
      HealthyThresholdCount: 3
      Matcher:
        HttpCode: '200'
      Name: WebServerTargetGroup
      Port: 80
      Protocol: HTTP
      TargetGroupAttributes:
      - Key: deregistration_delay.timeout_seconds
        Value: '10'
      UnhealthyThresholdCount: 3
      VpcId:
        Ref: 'VPC'

  LaunchConfigWebServer:
    Type: AWS::AutoScaling::LaunchConfiguration
    Properties:
      ImageId: !Ref LatestLinux2AmiId
      IamInstanceProfile: !Ref WebServerInstanceProfile
      SecurityGroups:
      - Ref: WebServerSecurityGroup
      InstanceType: t3.micro
      UserData: !Base64 |
        #!/bin/bash -x
        yum update -y
        yum install httpd -y
        sudo amazon-linux-extras install -y php7.2
        service httpd start
        chkconfig httpd on
        cd /var/www/html
        cat <<'EOT' >> /var/www/html/index.php
        <?php
        echo '<pre>';
        echo 'HTTP_X_FORWARDED_FOR: ';
        print_r($_SERVER['HTTP_X_FORWARDED_FOR']);
        echo '</pre>';
        exit;
        ?>
        EOT
      EbsOptimized: "true"


  AutoScalingWebServer:
    Type: AWS::AutoScaling::AutoScalingGroup
    Properties:
      VPCZoneIdentifier:
        - !Ref PrivateSubnet1
        - !Ref PrivateSubnet2
      LaunchConfigurationName: !Ref LaunchConfigWebServer
      MinSize: '1'
      MaxSize: '1'
      HealthCheckGracePeriod: 300
      MaxInstanceLifetime: 2592000
      TargetGroupARNs:
        - !Ref WebServerTargetGroup

  ### WebServer  IAM Role
  WebServerRole:
    Type: AWS::IAM::Role
    Properties:
      RoleName:
        Fn::Join:
          - '-'
          - ['webserver-role', !Ref "AWS::Region"]
      AssumeRolePolicyDocument:
        Version: 2012-10-17
        Statement:
          -
            Effect: Allow
            Principal:
              Service:
                - ec2.amazonaws.com
            Action:
              - sts:AssumeRole
      Path: /
      ManagedPolicyArns:
      - arn:aws:iam::aws:policy/service-role/AmazonEC2RoleforSSM
      Policies:
        -
          PolicyName: !Join [ -, ['webserver-policy', !Ref "AWS::Region"] ]
          PolicyDocument:
            Version: 2012-10-17
            Statement:
              -
                Effect: Allow
                Action:
                  - ssm:GetParameter
                  - ssm:GetParameters
                  - ssm:DescribeParameters
                Resource:
                  Fn::Join:
                  - ':'
                  - ["arn:aws:ssm", !Ref "AWS::Region", !Ref "AWS::AccountId", "*"]

  WebServerInstanceProfile:
    Type: AWS::IAM::InstanceProfile
    Properties:
      InstanceProfileName:
        Fn::Join:
          - '-'
          - ['webserver-profile', !Ref "AWS::Region"]
      Path: /
      Roles:
        - !Ref WebServerRole

  GlobalAccelerator:
    Type: AWS::GlobalAccelerator::Accelerator
    Properties:
      Name: WebGlobalAccelerator
      Enabled: true

  WebGAListener:
    Type: AWS::GlobalAccelerator::Listener
    Properties:
      AcceleratorArn: !Ref GlobalAccelerator
      Protocol: TCP
      PortRanges:
      - FromPort: 80
        ToPort: 80

  GlobalAcceleratorEndpointGroup:
    Type: AWS::GlobalAccelerator::EndpointGroup
    Properties:
      ListenerArn:
        Ref: WebGAListener
      EndpointGroupRegion:
        Ref: "AWS::Region"
      TrafficDialPercentage: 100
      EndpointConfigurations:
      - EndpointId: !Ref InternalApplicationLoadBalancer
        ClientIPPreservationEnabled: true
        Weight: 100

  GlobalAcceleratorSGCleanUp:
    Type: Custom::GlobalAcceleratorSGCleanUp
    Properties:
      ServiceToken:
       Fn::GetAtt:
          - "GlobalAcceleratorSGCleanUpLambda"
          - "Arn"

  GlobalAcceleratorSGCleanUpLambdaLogGroup:
    Type: AWS::Logs::LogGroup
    Properties:
      LogGroupName: /aws/lambda/GlobalAcceleratorSGCleanUpLambda
      RetentionInDays: 30

  GlobalAcceleratorSGCleanUpLambdaRole:
    Type: AWS::IAM::Role
    Properties:
      AssumeRolePolicyDocument:
        Version: '2012-10-17'
        Statement:
        - Effect: Allow
          Principal:
            Service:
            - lambda.amazonaws.com
          Action:
          - sts:AssumeRole
      Path: "/"
      Policies:
      - PolicyName: !Join [ -, ['cleanup-lambda-policy', !Ref "AWS::Region"] ]
        PolicyDocument:
          Version: '2012-10-17'
          Statement:
          - Effect: Allow
            Action:
            - logs:DescribeLogStreams
            - logs:CreateLogStream
            - logs:PutLogEvents
            - ec2:DescribeSecurityGroups
            - ec2:DeleteSecurityGroup
            - ec2:DescribeNetworkInterfaces
            Resource: '*'

  GlobalAcceleratorSGCleanUpLambda:
    Type: AWS::Lambda::Function
    Properties:
      FunctionName: GlobalAcceleratorSGCleanUpLambda
      Handler: "index.lambda_handler"
      Runtime: python3.7
      MemorySize: 128
      Timeout: 60
      Role: !GetAtt GlobalAcceleratorSGCleanUpLambdaRole.Arn
      Code:
        ZipFile: !Sub |
            import json, boto3, logging, os, urllib3
            import cfnresponse
            logger = logging.getLogger()
            logger.setLevel(logging.INFO)
            VPCID = os.environ['VPCID']

            def lambda_handler(event, context):
                logger.info("event: {}".format(event))
                try:
                    if event['RequestType'] == 'Delete':
                        ec2 = boto3.client('ec2')
                        response = ec2.describe_security_groups( Filters=[{'Name': 'vpc-id', 'Values': [ VPCID ]},{'Name': 'group-name', 'Values': [ 'GlobalAccelerator' ]}])
                        sg_id = response.get('SecurityGroups', [{}])[0].get('GroupId', '')
                        enis = list_network_interfaces(sg_id)
                        count = len(enis)
                        while True:
                         if count == 0:
                             ec2.delete_security_group(GroupId=sg_id)
                             break
                    elif event['RequestType'] == 'Create':
                        logger.info("event: {}".format(event))

                    sendResponseCfn(event, context, cfnresponse.SUCCESS)
                except Exception as e:
                    logger.info("Exception: {}".format(e))
                    sendResponseCfn(event, context, cfnresponse.FAILED)

            def sendResponseCfn(event, context, responseStatus):
                responseData = {}
                responseData['Data'] = {}
                cfnresponse.send(event, context, responseStatus, responseData, "CustomResourcePhysicalID")

            def list_network_interfaces(sg_id):
                # Retrieve the list network interfaces
                ec2 = boto3.client('ec2')
                try:
                    response = ec2.describe_network_interfaces( Filters=[{'Name': 'group-id', 'Values': [ sg_id ]}])
                    print(response)
                except ClientError as e:
                    logging.error(e)
                    return None
                return response['NetworkInterfaces']

      Environment:
        Variables:
          VPCID:
            !Ref VPC

Outputs:
  GlobalAcceleratorDNSName:
    Description: "The Domain Name System (DNS) name that Global Accelerator creates that points to your accelerator's static IP addresses."
    Value: !GetAtt GlobalAccelerator.DnsName