AWSTemplateFormatVersion: 2010-09-09
Description: >-
  AWS Cloudformation template to create an EC2 instance, installs and starts
  GitLab Runner. **WARNING** This template creates an Amazon EC2 instance. You
  will be billed for the AWS resources used if you create a stack from this
  template.
Parameters:
  GitLabServer:
    Description: Address of GitLab Web Server application
    Type: String
    Default: 'https://gitlab.com'
  GitLabRunnerToken:
    Description: >-
      Registration token for GitLab Runner. Registration token must contain
      exactly 20 alphanumeric characters
    AllowedPattern: '^[-_a-zA-Z0-9]*$'
    Type: String
    MinLength: '20'
    MaxLength: '20'
    NoEcho: true
  GitLabApiToken:
    Description: >-
      Access token for GitLab API for removal of the runner registration from
      GitLab upon EC2 instance termination.
    AllowedPattern: '^[-_a-zA-Z0-9]*$'
    Type: String
    NoEcho: true
  DockerVersion:
    Description: The Docker CE version number.
    Type: String
    Default: '18.02'
  InstanceType:
    Description: The EC2 instance type for GitLab Runner server
    Type: String
    Default: t2.micro
    AllowedValues:
      - t2.nano
      - t2.micro
      - t2.small
      - t2.medium
      - t2.large
      - m3.large
      - m3.xlarge
      - m3.2xlarge
      - m4.large
      - m4.xlarge
      - m4.2xlarge
      - m4.4xlarge
    ConstraintDescription: must be a valid EC2 instance type
  InstanceStorageSize:
    Description: GitLab Runner server storage size (in GBs)
    Type: Number
    Default: '40'
  KeyName:
    Description: Name of an existing EC2 KeyPair to enable SSH access to the instance
    Type: 'AWS::EC2::KeyPair::KeyName'
    ConstraintDescription: Can contain only ASCII characters.
  VpcId:
    Description: GitLab Runner server VPC
    Type: 'AWS::EC2::VPC::Id'
  Subnet1ID:
    Description: GitLab Runner server private subnet 1
    Type: 'AWS::EC2::Subnet::Id'
  Subnet2ID:
    Description: GitLab Runner server private subnet 2
    Type: 'AWS::EC2::Subnet::Id'
  Subnet3ID:
    Description: GitLab Runner server private subnet 3
    Type: 'AWS::EC2::Subnet::Id'
  NumInstances:
    Description: Number of Runner server instances in Auto scaling group
    Type: Number
    Default: 1
Conditions:
  HasKeyName: !Not 
    - !Equals 
      - ''
      - Ref: KeyName
  HasGitLabApiToken: !Not 
    - !Equals 
      - ''
      - Ref: GitLabApiToken
Mappings:
  RegionMap:
    us-east-1:
      AMI: ami-cd0f5cb6
    us-east-2:
      AMI: ami-10547475
    us-west-1:
      AMI: ami-09d2fb69
    us-west-2:
      AMI: ami-6e1a0117
    ca-central-1:
      AMI: ami-9818a7fc
    eu-west-1:
      AMI: ami-785db401
    eu-central-1:
      AMI: ami-1e339e71
    eu-west-2:
      AMI: ami-996372fd
    ap-southeast-1:
      AMI: ami-6f198a0c
    ap-southeast-2:
      AMI: ami-e2021d81
    ap-northeast-2:
      AMI: ami-d28a53bc
    ap-northeast-1:
      AMI: ami-ea4eae8c
    ap-south-1:
      AMI: ami-099fe766
    sa-east-1:
      AMI: ami-10186f7c
Resources:
  RunnerIamRole:
    Type: 'AWS::IAM::Role'
    Properties:
      RoleName: GitlabRunnerRole
      AssumeRolePolicyDocument:
        Version: 2012-10-17
        Statement:
          - Effect: Allow
            Principal:
              Service:
                - ec2.amazonaws.com
            Action:
              - 'sts:AssumeRole'
      Path: /
      Policies:
        - PolicyName: GitLabRunnerPolicy
          PolicyDocument:
            Version: 2012-10-17
            Statement:
              - Effect: Allow
                Action:
                  - 'sts:AssumeRole'
                Resource: 
                  - 'arn:aws:iam::*:role/TerraformRole'
                  - 'arn:aws:iam::*:role/S3BackendRole'
    Metadata:
      'AWS::CloudFormation::Designer':
        id: 294bb1e8-9c8f-41eb-9c34-e37d348993a0
  RunnerInstanceProfile:
    Type: 'AWS::IAM::InstanceProfile'
    Properties:
      InstanceProfileName: GitlabRunnerProfile
      Roles:
        - !Ref RunnerIamRole
    Metadata:
      'AWS::CloudFormation::Designer':
        id: 8431b43e-a91e-4a42-a3f2-3e19e8408683
  RunnerAutoScalingGroup:
    Type: 'AWS::AutoScaling::AutoScalingGroup'
    Properties:
      LaunchConfigurationName: !Ref RunnerLaunchConfiguration
      VPCZoneIdentifier:
        - !Ref Subnet1ID
        - !Ref Subnet2ID
        - !Ref Subnet3ID
      MinSize: !Ref NumInstances
      MaxSize: !Ref NumInstances
      Cooldown: '300'
      NotificationConfigurations: !If
        - HasGitLabApiToken
        - - NotificationTypes:
              - 'autoscaling:EC2_INSTANCE_TERMINATE'
            TopicARN: !Ref RunnerLifecycleTopic
        - !Ref 'AWS::NoValue'
      DesiredCapacity: !Ref NumInstances
      Tags:
        - Key: Name
          Value: GitLabRunner
          PropagateAtLaunch: 'true'
    CreationPolicy:
      ResourceSignal:
        Count: !Ref NumInstances
        Timeout: PT15M
    Metadata:
      'AWS::CloudFormation::Designer':
        id: 43142532-0cf7-41bc-8c0f-891d886aee8d
  RunnerLaunchConfiguration:
    Type: 'AWS::AutoScaling::LaunchConfiguration'
    Metadata:
      Comment: Install GitLab Runner
      'AWS::CloudFormation::Init':
        config:
          packages: {}
          files: {}
          commands:
            1-Register-Docker-Runner:
              command: !Sub >-
                gitlab-runner register --non-interactive --name
                Docker-Runner-$(ec2metadata --instance-id) --url ${GitLabServer}
                --executor docker --docker-image docker:${DockerVersion}
                --docker-volumes /var/run/docker.sock:/var/run/docker.sock
                --registration-token ${GitLabRunnerToken} --locked=false
            2-Register-Shell-Runner:
              command: !Sub >-
                gitlab-runner register --non-interactive --name
                Shell-Runner-$(ec2metadata --instance-id) --url ${GitLabServer}
                --executor shell --registration-token ${GitLabRunnerToken}
                --locked=false --tag-list terraform,awscli
            3-Start-Runner:
              command: gitlab-runner start
      'AWS::CloudFormation::Designer':
        id: aece8c9d-d225-49d9-a729-14ec4a45ceea
    Properties:
      KeyName: !If
        - HasKeyName
        - !Ref KeyName
        - !Ref 'AWS::NoValue'
      ImageId: !FindInMap
        - RegionMap
        - !Ref 'AWS::Region'
        - AMI
      InstanceType: !Ref InstanceType
      IamInstanceProfile: !GetAtt
        - RunnerInstanceProfile
        - Arn
      BlockDeviceMappings:
        - DeviceName: /dev/sda1
          Ebs:
            VolumeSize: !Ref InstanceStorageSize
      UserData: !Base64
        'Fn::Join':
          - |+

          - - '#!/bin/bash'
            - set -x -e
            - apt-get update
            - >-
              apt-get -y install apt-transport-https ca-certificates curl
              software-properties-common
            - >-
              curl -fsSL https://download.docker.com/linux/ubuntu/gpg | apt-key
              add -
            - >-
              add-apt-repository "deb [arch=amd64]
              https://download.docker.com/linux/ubuntu $(lsb_release -cs)
              stable"
            - apt-get update
            - apt-get -y install docker-ce awscli unzip
            - >-
              wget
              https://releases.hashicorp.com/terraform/0.11.7/terraform_0.11.7_linux_amd64.zip
            - unzip terraform_0.11.7_linux_amd64.zip
            - rm terraform_0.11.7_linux_amd64.zip
            - mv terraform /usr/local/bin/
            - >-
              curl -L
              https://packages.gitlab.com/install/repositories/runner/gitlab-runner/script.deb.sh
              | bash
            - apt-get -y install gitlab-runner
            - apt-get -y install python-setuptools
            - >-
              easy_install
              https://s3.amazonaws.com/cloudformation-examples/aws-cfn-bootstrap-latest.tar.gz
            - !Sub >-
              cfn-init --stack ${AWS::StackName} --resource
              RunnerLaunchConfiguration --region ${AWS::Region}
            - !Sub >-
              cfn-signal -e $? --stack ${AWS::StackName} --resource
              RunnerAutoScalingGroup --region ${AWS::Region}
  ScaleDownAtNight:
    Type: 'AWS::AutoScaling::ScheduledAction'
    Properties:
      AutoScalingGroupName: !Ref RunnerAutoScalingGroup
      DesiredCapacity: 0
      MaxSize: 0
      MinSize: 0
      Recurrence: 0 22 * * *
    Metadata:
      'AWS::CloudFormation::Designer':
        id: d16f00fe-10db-4d20-bc66-0664546b8f33
  ScaleUpInMorning:
    Type: 'AWS::AutoScaling::ScheduledAction'
    Properties:
      AutoScalingGroupName: !Ref RunnerAutoScalingGroup
      DesiredCapacity: 1
      MaxSize: 1
      MinSize: 1
      Recurrence: 0 14 * * 1-5
    Metadata:
      'AWS::CloudFormation::Designer':
        id: 928e53f3-5cb6-495e-a0af-6aea93a04c80
  RunnerLifecycleTopic:
    Type: 'AWS::SNS::Topic'
    Condition: HasGitLabApiToken
    Properties:
      Subscription:
        - Protocol: lambda
          Endpoint: !GetAtt 
            - RunnerUnregisterFunction
            - Arn
    Metadata:
      'AWS::CloudFormation::Designer':
        id: 5acf3eaa-8aae-4d88-a6b8-0b4201d8bd03
  RunnerUnregisterFunction:
    Type: 'AWS::Lambda::Function'
    Condition: HasGitLabApiToken
    Properties:
      Handler: index.handler
      MemorySize: 128
      Timeout: 15
      Runtime: nodejs6.10
      Role: !GetAtt 
        - RunnerUnregisterRole
        - Arn
      Environment:
        Variables:
          GITLAB_API_TOKEN: !Ref GitLabApiToken
      Code:
        ZipFile: !Sub |-
          const https = require('https');
          var extractInstanceIdFromEvent = function(event) {
            console.log('Event received: ' + event);

            var message = event.Records[0].Sns.Message;
            console.log('SNS Message: ' + message);

            var regex = /Terminating EC2 instance: (i-[0-9a-z]+)/g;
            var match = regex.exec(message);
            var instanceId = match[1];
            console.log('EC2 Instance ID: ' + instanceId);

            return instanceId;
          };
          const optionsForRequestAllRunners = {
            hostname: 'gitlab.com',
            method: 'GET',
            path: '/api/v4/runners',
            headers: {
              'PRIVATE-TOKEN': process.env.GITLAB_API_TOKEN
            },
            timeout: 5000
          };
          const optionsForRunnerDelete = function(runnerId) {
            return {
              hostname: 'gitlab.com',
              method: 'DELETE',
              path: '/api/v4/runners/'+runnerId,
              headers: {
                'PRIVATE-TOKEN': process.env.GITLAB_API_TOKEN
              },
              timeout: 5000
            };
          };
          exports.handler = function(event, context) {
            var ec2InstanceId = extractInstanceIdFromEvent(event);

            const req = https.request(optionsForRequestAllRunners, (res) => {
              console.log('statusCode:', res.statusCode);

              let rawData = '';
              res.on('data', (chunk) => { rawData += chunk; });
              res.on('end', () => {
                try {
                  const parsedData = JSON.parse(rawData);
                  //console.log(parsedData);
                  parsedData.forEach((elem) => {
                    if (elem.description && elem.description.endsWith(ec2InstanceId)) {
                      console.log("About to delete runner: "+elem.description);
                      const deleteReq = https.request(optionsForRunnerDelete(elem.id));
                      deleteReq.end();
                    }
                  });
                } catch (e) {
                  console.error(e.message);
                }
              });
            });

            req.on('error', (e) => {
              console.error(e);
            });

            req.end();
          };
    Metadata:
      'AWS::CloudFormation::Designer':
        id: f898ddfa-41c5-4382-aebb-02c12666dead
  RunnerLifecycleRole:
    Type: 'AWS::IAM::Role'
    Condition: HasGitLabApiToken
    Properties:
      AssumeRolePolicyDocument:
        Version: 2012-10-17
        Statement:
          - Action: 'sts:AssumeRole'
            Principal:
              Service: ec2.amazonaws.com
            Effect: Allow
            Sid: ''
    Metadata:
      'AWS::CloudFormation::Designer':
        id: 91e172ec-6c5e-4ee0-99b8-730a2194aad5
  RunnerLifecyclePolicy:
    Type: 'AWS::IAM::Policy'
    Condition: HasGitLabApiToken
    Properties:
      PolicyName: RunnerLifecyclePolicy
      Roles:
        - Ref: RunnerLifecycleRole
      PolicyDocument:
        Version: 2012-10-17
        Statement:
          - Effect: Allow
            Action:
              - 'sns:publish'
            Resource: !Ref RunnerLifecycleTopic
    Metadata:
      'AWS::CloudFormation::Designer':
        id: bcf4f765-f8b0-44a3-b937-ccfa8c5622ea
  RunnerUnregisterPermission:
    Type: 'AWS::Lambda::Permission'
    Condition: HasGitLabApiToken
    Properties:
      Action: 'lambda:InvokeFunction'
      FunctionName: !GetAtt 
        - RunnerUnregisterFunction
        - Arn
      Principal: sns.amazonaws.com
      SourceArn: !Ref RunnerLifecycleTopic
    Metadata:
      'AWS::CloudFormation::Designer':
        id: 7c9ae8c0-95d5-43bf-ad14-ec2ce473dc34
  RunnerUnregisterRole:
    Type: 'AWS::IAM::Role'
    Condition: HasGitLabApiToken
    Properties:
      AssumeRolePolicyDocument:
        Version: 2012-10-17
        Statement:
          - Action: 'sts:AssumeRole'
            Principal:
              Service: lambda.amazonaws.com
            Effect: Allow
            Sid: ''
    Metadata:
      'AWS::CloudFormation::Designer':
        id: c236e2d0-2cdd-447c-9dba-ca60e7c8fb24
  RunnerUnregisterPolicy:
    Type: 'AWS::IAM::Policy'
    Condition: HasGitLabApiToken
    Properties:
      PolicyName: RunnerUnregisterPolicy
      Roles:
        - Ref: RunnerUnregisterRole
      PolicyDocument:
        Version: 2012-10-17
        Statement:
          - Effect: Allow
            Action:
              - 'logs:CreateLogGroup'
              - 'logs:CreateLogStream'
              - 'logs:DescribeLogGroups'
              - 'logs:PutLogEvents'
            Resource: 'arn:aws:logs:*:*:*'
    Metadata:
      'AWS::CloudFormation::Designer':
        id: 6eace77b-cc29-4fb7-b324-ae3e623e0df3
Outputs:
  StackName:
    Value: !Ref 'AWS::StackName'
  AwsRegion:
    Value: !Ref "AWS::Region"
  AwsAccountId:
    Value: !Ref "AWS::AccountId"
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