custom-capacity-provider.yml

Resources:
    CustomResourceRole:
        Type: AWS::IAM::Role
        Properties:
            AssumeRolePolicyDocument:
                Version: '2012-10-17'
                Statement:
                    - Effect: Allow
                      Principal:
                          Service: 'lambda.amazonaws.com'
                      Action: 'sts:AssumeRole'
            Policies:
                - PolicyName: 'customresource'
                  PolicyDocument:
                      Statement:
                          - Effect: Allow
                            Action:
                                - 'autoscaling:DescribeAutoScalingGroups'
                            Resource: '*'
                          - Effect: Allow
                            Action:
                                - 'logs:CreateLogGroup'
                                - 'logs:CreateLogStream'
                                - 'logs:PutLogEvents'
                            Resource: '*'

    AutoScalingGroupARNFunction:
        Type: AWS::Lambda::Function
        Properties:
            Code:
                ZipFile: |
                    const aws = require('aws-sdk')
                    const response = require('cfn-response')
                    const autoscaling = new aws.AutoScaling({apiVersion: '2011-01-01'})
                    const ecs = new aws.ECS({apiVersion: '2014-11-13'})
                    exports.handler = function(event, context) {
                      console.log(`AWS SDK Version: ${aws.VERSION}`)
                      console.log(`Request received: ${JSON.stringify(event)}`)
                      if (event.RequestType === 'Create') {
                        autoscaling.describeAutoScalingGroups({AutoScalingGroupNames: [event.ResourceProperties.ASGName]})
                          .promise()
                          .then(asgResponse => {
                            console.log(`ASG found: ${asgResponse.AutoScalingGroups[0].AutoScalingGroupARN}`)
                            response.send(event, context, response.SUCCESS, {}, asgResponse.AutoScalingGroups[0].AutoScalingGroupARN)
                          })
                          .catch(err => {
                            console.error(err)
                            response.send(event, context, response.FAILED)
                          })
                      } else {
                          response.send(event, context, response.SUCCESS)
                      }
                    }
            Handler: 'index.handler'
            MemorySize: 128
            Role: !GetAtt 'CustomResourceRole.Arn'
            Runtime: 'nodejs12.x'
            Timeout: 30

    AutoScalingGroupARN:
        Type: Custom::AutoScalingGroupARN
        Properties:
            ServiceToken: !GetAtt AutoScalingGroupARNFunction.Arn
            ASGName: !Ref AsgEcsHosts

    EcsCapacityProvider:
        Type: AWS::ECS::CapacityProvider
        Properties:
            AutoScalingGroupProvider:
                AutoScalingGroupArn: !Ref AutoScalingGroupARN
                ManagedScaling:
                    Status: ENABLED