AWSTemplateFormatVersion: '2010-09-09'
Description: Gerrit master launch configuration and autoscaling group
Parameters:
  EC2AMI:
    Description: AMI ID for the EC2 instance hosting gerrit masters
    Type: String
  InstanceType:
    Description: EC2 instance type
    Type: String
    AllowedValues: [t2.micro, t2.small, t2.medium, t2.large, m3.medium, m3.large,
                    m3.xlarge, m3.2xlarge, m4.large, m4.xlarge, m4.2xlarge, m4.4xlarge, m4.10xlarge,
                    c4.large, c4.xlarge, c4.2xlarge, c4.4xlarge, c4.8xlarge, c3.large, c3.xlarge,
                    c3.2xlarge, c3.4xlarge, c3.8xlarge, r3.large, r3.xlarge, r3.2xlarge, r3.4xlarge,
                    r3.8xlarge, i2.xlarge, i2.2xlarge, i2.4xlarge, i2.8xlarge]
    ConstraintDescription: Please choose a valid instance type.
  ECSKeyName:
    Type: String
    Description: EC2 key pair name the cluter's instances
  EnvironmentName:
    Description: An environment name used to build the log stream names
    Type: String
  ECSCluster:
    Description: The ECSCluster reference name to register gerrit masters to
    Type: String
  EC2SecurityGroup:
    Description: security groups to assign to the instances in the Auto Scaling group hosting gerrit masters
    Type: String
  EC2InstanceProfile:
    Description: The Amazon Resource Name (ARN) of the instance profile associated with the IAM role for the EC2 instances running gerrit masters
    Type: String
  GerritInstanceNumber:
    Description: Whether this is master1 or master2
    Type: Number
    AllowedValues: [1,2]
  FileSystem:
    Description: The ID of the filesystem to share git data between gerrit master instances
    Type: String
  SubnetId:
    Description: The subnet ID where gerrit master in the Auto Scaling group can be created
    Type: String
  LogGroupName:
    Description: The log group name
    Type: String
  MasterMaxCount:
    Description: The maximum number of EC2 instances in the master autoscaling group
    Type: Number

Resources:
  MasterECSAutoScalingGroup:
    Type: AWS::AutoScaling::AutoScalingGroup
    Properties:
      VPCZoneIdentifier:
        - !Ref SubnetId
      LaunchConfigurationName: !Ref 'MasterLaunchConfiguration'
      MinSize: '1'
      MaxSize: !Ref MasterMaxCount
      DesiredCapacity: '1'
    CreationPolicy:
      ResourceSignal:
        Timeout: PT15M
    UpdatePolicy:
      AutoScalingReplacingUpdate:
        WillReplace: 'true'

  MasterLaunchConfiguration:
    Type: AWS::AutoScaling::LaunchConfiguration
    Properties:
      ImageId: !Ref 'EC2AMI'
      SecurityGroups: [!Ref 'EC2SecurityGroup']
      InstanceType: !Ref 'InstanceType'
      IamInstanceProfile: !Ref 'EC2InstanceProfile'
      KeyName: !Ref ECSKeyName
      UserData:
        Fn::Base64: !Sub |
          #!/bin/bash -xe
          export MASTER_ID=master-${GerritInstanceNumber}
          echo ECS_CLUSTER=${ECSCluster} >> /etc/ecs/ecs.config
          echo ECS_INSTANCE_ATTRIBUTES={\"target_group\":\"$MASTER_ID\"} >> /etc/ecs/ecs.config

          yum install -y aws-cfn-bootstrap nfs-utils wget

          # EFS setting
          DIR_TGT=/mnt/efs/gerrit-shared
          mkdir -p $DIR_TGT
          EC2_REGION=${AWS::Region}
          # 169.254.169.254 link-local address, valid only from the instance, to retrieve meta-data information.
          EC2_AVAIL_ZONE=`curl -s http://169.254.169.254/latest/meta-data/placement/availability-zone`
          EFS_FILE_SYSTEM_ID=${FileSystem}
          DIR_SRC=$EC2_AVAIL_ZONE.$EFS_FILE_SYSTEM_ID.efs.$EC2_REGION.amazonaws.com

          touch /home/ec2-user/echo.res
          echo $MASTER_ID >> /home/ec2-user/echo.res
          echo $EFS_FILE_SYSTEM_ID >> /home/ec2-user/echo.res
          echo $EC2_AVAIL_ZONE >> /home/ec2-user/echo.res
          echo $EC2_REGION >> /home/ec2-user/echo.res
          echo $DIR_SRC >> /home/ec2-user/echo.res
          echo $DIR_TGT >> /home/ec2-user/echo.res
          MAX_RETRIES=20
          for i in $(seq 1 $MAX_RETRIES); do
            echo "Mounting EFS volume ($i/$MAX_RETRIES)..."
            `mount -t nfs4 -o nfsvers=4.1,hard,timeo=600,retrans=2 $DIR_SRC:/ $DIR_TGT >> /home/ec2-user/echo.res` \
              && s=0 && break || s=$? && sleep 5;
          done; (exit $s)
          mkdir -p $DIR_TGT/git
          mkdir -p $DIR_TGT/high-availability
          chown -R 1000:1000 $DIR_TGT
          cp -p /etc/fstab /etc/fstab.back-$(date +%F)
          echo -e \"$DIR_SRC:/ \t\t $DIR_TGT \t\t nfs \t\t defaults \t\t 0 \t\t 0\" | tee -a /etc/fstab
          # Get the CloudWatch Logs agent
          echo -e "
            {\"logs\":
              {\"logs_collected\":
                {\"files\":
                  {\"collect_list\":
                    [
                      {\"file_path\": \"/var/lib/docker/volumes/gerrit-logs-$MASTER_ID/_data/replication_log\",
                      \"log_group_name\": \"${LogGroupName}\",
                      \"log_stream_name\": \"${EnvironmentName}/{instance_id}/$MASTER_ID/replication_log\",
                      \"timezone\": \"UTC\"
                      },
                      {\"file_path\": \"/var/lib/docker/volumes/gerrit-logs-$MASTER_ID/_data/httpd_log\",
                      \"log_group_name\": \"${LogGroupName}\",
                      \"log_stream_name\": \"${EnvironmentName}/{instance_id}/$MASTER_ID/httpd_log\",
                      \"timezone\": \"UTC\"
                      },
                      {\"file_path\": \"/var/lib/docker/volumes/gerrit-logs-$MASTER_ID/_data/sshd_log\",
                      \"log_group_name\": \"${LogGroupName}\",
                      \"log_stream_name\": \"${EnvironmentName}/{instance_id}/$MASTER_ID/sshd_log\",
                      \"timezone\": \"UTC\"
                      },
                      {\"file_path\": \"/var/lib/docker/volumes/gerrit-logs-$MASTER_ID/_data/gc_log\",
                      \"log_group_name\": \"${LogGroupName}\",
                      \"log_stream_name\": \"${EnvironmentName}/{instance_id}/$MASTER_ID/gc_log\",
                      \"timezone\": \"UTC\"
                      },
                      {\"file_path\": \"/var/lib/docker/volumes/gerrit-logs-$MASTER_ID/_data/sharedref_log\",
                      \"log_group_name\": \"${LogGroupName}\",
                      \"log_stream_name\": \"${EnvironmentName}/{instance_id}/$MASTER_ID/sharedref_log\",
                      \"timezone\": \"UTC\"
                      },
                      {\"file_path\": \"/var/lib/docker/volumes/gerrit-logs-$MASTER_ID/_data/message_log\",
                      \"log_group_name\": \"${LogGroupName}\",
                      \"log_stream_name\": \"${EnvironmentName}/{instance_id}/$MASTER_ID/message_log\",
                      \"timezone\": \"UTC\"
                      },
                      {\"file_path\": \"/var/lib/docker/volumes/gerrit-logs-$MASTER_ID/_data/websession_log\",
                      \"log_group_name\": \"${LogGroupName}\",
                      \"log_stream_name\": \"${EnvironmentName}/{instance_id}/$MASTER_ID/websession_log\",
                      \"timezone\": \"UTC\"
                      },
                      {\"file_path\": \"/var/lib/docker/volumes/gerrit-logs-$MASTER_ID/_data/audit_log\",
                      \"log_group_name\": \"${LogGroupName}\",
                      \"log_stream_name\": \"${EnvironmentName}/{instance_id}/$MASTER_ID/audit_log\",
                      \"timezone\": \"UTC\"
                      }
                    ]
                  }
                }
              }
            }" >> /home/ec2-user/gerritlogsaccess.json

          # Install the CloudWatch Logs agent
          wget https://s3.amazonaws.com/amazoncloudwatch-agent/centos/amd64/latest/amazon-cloudwatch-agent.rpm
          rpm -U ./amazon-cloudwatch-agent.rpm
          /opt/aws/amazon-cloudwatch-agent/bin/amazon-cloudwatch-agent-ctl -a fetch-config -m ec2 -c file:/home/ec2-user/gerritlogsaccess.json -s

          # Signal to CloudFormation aws-cfn-bootstrap has been correctly updated
          /opt/aws/bin/cfn-signal -e $? --stack ${AWS::StackName} --resource MasterECSAutoScalingGroup --region ${AWS::Region}

Outputs:
  MasterLaunchConfiguration:
    Value: !Ref MasterLaunchConfiguration
    Export:
      Name: !Join [ '-', [ !Ref 'AWS::StackName', 'MasterLaunchConfiguration', !Ref GerritInstanceNumber ] ]

  MasterECSAutoScalingGroup:
    Value: !Ref MasterECSAutoScalingGroup
    Export:
      Name: !Join [ '-', [ !Ref 'AWS::StackName', 'MasterECSAutoScalingGroup', !Ref GerritInstanceNumber ] ]