---
AWSTemplateFormatVersion: '2010-09-09'
Description: >

  This Cloudformation Template deploys a Custom AMI Finder.

  Disclaimer: Not for production use. Demo and testing purposes only.

  Author: David Surey <suredavi@amazon.com>, Bastian Klein <basklein@amazon.com>

Parameters:
  BBBTurnInstanceOSVersion: 
    Description: Ubuntu Version to be deployed for Turn Instances 
    Default: focal-20.04
    Type: String
    AllowedValues:
      - bionic-18.04
      - focal-20.04
  BBBApplicationInstanceOSVersion: 
    Description: Ubuntu Version to be deployed for Application Instances 
    Default: bionic-18.04
    Type: String
    AllowedValues:
      - xenial-16.04
      - bionic-18.04
  BBBEnvironmentStage:
    Type: String
    Description: Select the appropriate environment
    AllowedValues:
      - stage
      - prod
      - dev

Resources:
  BBBGetLatestAMILambdaRole:
    Type: AWS::IAM::Role
    Properties:
      AssumeRolePolicyDocument:
        Version: '2012-10-17'
        Statement:
          - Action: sts:AssumeRole
            Effect: Allow
            Principal:
              Service: lambda.amazonaws.com
      Policies:
        - PolicyName: DescribeImages
          PolicyDocument:
            Version: '2012-10-17'
            Statement:
              - Action: ec2:DescribeImages
                Effect: Allow
                Resource: "*"
      ManagedPolicyArns:
        - arn:aws:iam::aws:policy/service-role/AWSLambdaBasicExecutionRole

  BBBGetLatestAMILogGroup:
    Type: AWS::Logs::LogGroup
    Properties:
      RetentionInDays: 7
      LogGroupName: !Join ["", ["/", !Ref "AWS::StackName", "/", !Ref BBBGetLatestAMI]]

  BBBGetLatestAMI:
    Type: AWS::Lambda::Function
    Properties:
      Runtime: python3.6
      Handler: index.handler
      Role: !Sub ${BBBGetLatestAMILambdaRole.Arn}
      Timeout: 60
      Code:
        ZipFile: |
          import boto3
          import cfnresponse
          import json

          def handler(event, context):
            try:
              response = boto3.client('ec2').describe_images(
                  Owners=[event['ResourceProperties']['Owner']],
                  Filters=[
                    {'Name': 'name', 'Values': [event['ResourceProperties']['Name']]},
                    {'Name': 'architecture', 'Values': [event['ResourceProperties']['Architecture']]},
                    {'Name': 'root-device-type', 'Values': ['ebs']},
                  ],
              )

              amis = sorted(response['Images'],
                            key=lambda x: x['CreationDate'],
                            reverse=True)
              id = amis[0]['ImageId']

              cfnresponse.send(event, context, cfnresponse.SUCCESS, {}, id)
            except:
              cfnresponse.send(event, context, cfnresponse.FAILED, {}, "ok")

  BBBApplicationAmiID:
    Type: Custom::FindAMI
    Properties:
      ServiceToken: !Sub ${BBBGetLatestAMI.Arn}
      Owner: "099720109477"
      Name: !Sub "ubuntu/images/hvm-ssd/ubuntu-${BBBApplicationInstanceOSVersion}-amd64-server*"
      Architecture: "x86_64"

  BBBTurnAmiID:
    Type: Custom::FindAMI
    Properties:
      ServiceToken: !Sub ${BBBGetLatestAMI.Arn}
      Owner: "099720109477"
      Name: !Sub "ubuntu/images/hvm-ssd/ubuntu-${BBBTurnInstanceOSVersion}-amd64-server-*"
      Architecture: "x86_64"

  BBBTurnAMIParameter:
    Type: AWS::SSM::Parameter
    Properties:
      Name: turniamgeamiid
      Type: String
      Value: !Ref BBBTurnAmiID
      Description: SSM Parameter for the variable part of the Turn Ubuntu AMI

  BBBApplicationAMIParameter:
    Type: AWS::SSM::Parameter
    Properties:
      Name: applicationimageamiid
      Type: String
      Value: !Ref BBBApplicationAmiID
      Description: SSM Parameter for the variable part of the Application Server Ubuntu AMI

Outputs:
  BBBGetLatestAMILambdaRole: 
    Description: Role for the Lambda to search for Image AMIs
    Value: !Ref BBBGetLatestAMILambdaRole
  BBBGetLatestAMI: 
    Description: Function to search for Image AMIs dynamically
    Value: !Ref BBBGetLatestAMI
  BBBTurnAMIParameter:
    Description: Parameter for the Turn AMI 
    Value: !Ref BBBTurnAMIParameter
  BBBApplicationAMIParameter:
    Description: Parameter for the Application AMI
    Value: !Ref BBBApplicationAMIParameter