AWSTemplateFormatVersion: '2010-09-09'
Description: Deploy a service into an ECS cluster behind a public load balancer.
Parameters:
  LBServiceName:
    Type: String
    Default: gerrit-load-balancer
  ClusterStackName:
      Description: Stack name of the ECS cluster to deploy the services
      Type: String
      Default: gerrit-cluster
  EnvironmentName:
      Description: An environment name used to build the log stream names
      Type: String
      Default: test
  HAProxyDockerImage:
        Description: HAProxy Docker image
        Type: String
        Default: aws-gerrit/haproxy:latest
  SidecarDockerImage:
        Description: Syslog sidecar Docker image
        Type: String
        Default: aws-gerrit/syslog-sidecar:latest
  DockerRegistryUrl:
        Description: Docker registry URL
        Type: String
  DesiredCount:
        Description: How many instances of this task should we run across our cluster?
        Type: Number
        Default: 1
  HTTPGerritPort:
        Description: Gerrit HTTP port
        Type: Number
        Default: 8080
  SSHGerritPort:
        Description: Gerrit SSH port
        Type: Number
        Default: 29418
  HTTPContainerPort:
        Description: Gerrit HTTP port
        Type: Number
        Default: 80
  HTTPSHostPort:
        Description: Gerrit HTTPS port
        Type: Number
        Default: 443
  HTTPHostPort:
        Description: HAProxy HTTP port
        Type: Number
        Default: 80
  CertificateArn:
        Description: SSL Certificates ARN
        Type: String
  HostedZoneName:
        Description: The route53 HostedZoneName.
        Type: String
  Subdomain:
        Description: The subdomain of the Gerrit cluster
        Type: String
        Default: gerrit-dual-master
  GerritKeyPrefix:
        Description: Gerrit credentials keys prefix
        Type: String
  Master1ServiceStackName:
      Description: Stack name of the ECS Master Gerrit service
      Type: String
      Default: gerrit-service-master-1
  Master2ServiceStackName:
      Description: Stack name of the ECS Master Gerrit service
      Type: String
      Default: gerrit-service-master-2
  SyslogSidecarServiceName:
      Description: HAPRoxy Syslog Sidecar service name
      Type: String
      Default: gerrit-haproxy-sidecar

Resources:
    LBService:
        Type: AWS::ECS::Service
        DependsOn:
          - HTTPListener
        Properties:
            Cluster:
              Fn::ImportValue:
                  !Join [':', [!Ref 'ClusterStackName', 'ClusterName']]
            DesiredCount: !Ref DesiredCount
            TaskDefinition: !Ref TaskDefinition
            LoadBalancers:
                - ContainerName: !Ref LBServiceName
                  ContainerPort: !Ref HTTPContainerPort
                  TargetGroupArn: !Ref HTTPTargetGroup

    TaskDefinition:
        Type: AWS::ECS::TaskDefinition
        Properties:
            Family: !Sub '${LBServiceName}TaskDefinition'
            TaskRoleArn: !Ref ECSTaskExecutionRole
            ExecutionRoleArn: !Ref ECSTaskExecutionRole
            NetworkMode: bridge
            ContainerDefinitions:
                - Name: !Ref LBServiceName
                  Essential: true
                  Image: !Sub '${DockerRegistryUrl}/${HAProxyDockerImage}'
                  Environment:
                    - Name: GERRIT_MASTER_1_URL
                      Value:
                        Fn::ImportValue: !Join [':', [!Ref 'Master1ServiceStackName', 'PublicLoadBalancerDNSName']]
                    - Name: GERRIT_MASTER_2_URL
                      Value:
                        Fn::ImportValue: !Join [':', [!Ref 'Master2ServiceStackName', 'PublicLoadBalancerDNSName']]
                    - Name: SYSLOG_SIDECAR
                      Value: !Ref SyslogSidecarServiceName
                  Cpu: 1024
                  Memory: 2048
                  PortMappings:
                    - ContainerPort: !Ref HTTPContainerPort
                      HostPort: !Ref HTTPHostPort
                      Protocol: tcp
                  Links:
                    - !Ref SyslogSidecarServiceName
                  LogConfiguration:
                    LogDriver: awslogs
                    Options:
                        awslogs-group: !Ref ClusterStackName
                        awslogs-region: !Ref AWS::Region
                        awslogs-stream-prefix: !Ref EnvironmentName
                - Name: !Ref SyslogSidecarServiceName
                  Essential: true
                  Image: !Sub '${DockerRegistryUrl}/${SidecarDockerImage}'
                  Cpu: 256
                  Memory: 512
                  LogConfiguration:
                    LogDriver: awslogs
                    Options:
                        awslogs-group: !Ref ClusterStackName
                        awslogs-region: !Ref AWS::Region
                        awslogs-stream-prefix: !Ref EnvironmentName

    # This is a role which is used by the ECS tasks themselves.
    ECSTaskExecutionRole:
      Type: AWS::IAM::Role
      Properties:
        AssumeRolePolicyDocument:
          Statement:
          - Effect: Allow
            Principal:
              Service: [ecs-tasks.amazonaws.com]
            Action: ['sts:AssumeRole']
        Path: /
        Policies:
          - PolicyName: AmazonECSTaskExecutionRolePolicy
            PolicyDocument:
              Statement:
              - Effect: Allow
                Action:
                  # Allow the ECS Tasks to download images from ECR
                  - 'ecr:GetAuthorizationToken'
                  - 'ecr:BatchCheckLayerAvailability'
                  - 'ecr:GetDownloadUrlForLayer'
                  - 'ecr:BatchGetImage'
                  # Allow the ECS tasks to upload logs to CloudWatch
                  - 'logs:CreateLogStream'
                  - 'logs:PutLogEvents'
                Resource: '*'
          - PolicyName: AmazonECSTaskSecretManagerRolePolicy
            PolicyDocument:
              Statement:
              - Effect: Allow
                Action:
                  # Allow the ECS Tasks to get SSH Keys
                  - 'secretsmanager:GetSecretValue'
                  - 'kms:Decrypt'
                Resource: '*'

    LoadBalancer:
        Type: AWS::ElasticLoadBalancingV2::LoadBalancer
        Properties:
            Type: network
            Scheme: internet-facing
            Subnets:
              - Fn::ImportValue:
                  !Join [':', [!Ref 'ClusterStackName', 'PublicSubnetOne']]
            Tags:
                - Key: Name
                  Value: !Join ['-', [!Ref 'EnvironmentName', !Ref 'LBServiceName', 'alb']]

    HTTPTargetGroup:
        Type: AWS::ElasticLoadBalancingV2::TargetGroup
        DependsOn: LoadBalancer
        Properties:
            VpcId:
              Fn::ImportValue:
                  !Join [':', [!Ref 'ClusterStackName', 'VPCId']]
            Port: !Ref HTTPHostPort
            Protocol: TCP

    HTTPListener:
        Type: AWS::ElasticLoadBalancingV2::Listener
        DependsOn: LoadBalancer
        Properties:
            Certificates:
              - CertificateArn: !Ref CertificateArn
            DefaultActions:
            - Type: forward
              TargetGroupArn: !Ref HTTPTargetGroup
            LoadBalancerArn: !Ref LoadBalancer
            Port: !Ref HTTPSHostPort
            Protocol: TLS

Outputs:
  PublicLoadBalancerDNSName:
    Description: The DNS name of the external load balancer
    Value: !GetAtt 'LoadBalancer.DNSName'
    Export:
      Name: !Join [ ':', [ !Ref 'AWS::StackName', 'PublicLoadBalancerDNSName' ] ]
  CanonicalHostedZoneID:
    Description: Canonical Hosted Zone ID
    Value: !GetAtt 'LoadBalancer.CanonicalHostedZoneID'
    Export:
      Name: !Join [ ':', [ !Ref 'AWS::StackName', 'CanonicalHostedZoneID' ] ]
  PublicLoadBalancerUrl:
    Description: The url of the external load balancer
    Value: !Join ['', ['https://', !GetAtt 'LoadBalancer.DNSName']]
    Export:
      Name: !Join [ ':', [ !Ref 'AWS::StackName', 'PublicLoadBalancerUrl' ] ]
  HostedZoneName:
    Description: Route53 Hosted Zone name
    Value: !Ref HostedZoneName
    Export:
      Name: !Join [ ':', [ !Ref 'AWS::StackName', 'HostedZoneName' ] ]
  Subdomain:
    Description: Service DNS subdomain
    Value: !Ref Subdomain
    Export:
      Name: !Join [ ':', [ !Ref 'AWS::StackName', 'Subdomain' ] ]
  CanonicalWebUrl:
    Description: Canonical Web URL
    Value: !Sub 'https://${Subdomain}.${HostedZoneName}'
    Export:
      Name: !Join [ ':', [ !Ref 'AWS::StackName', 'CanonicalWebUrl' ] ]