cloudformation.yml

---
AWSTemplateFormatVersion: '2010-09-09'
Metadata:
  'AWS::CloudFormation::Interface':
    ParameterGroups:
    - Label:
        default: ECR Settings
      Parameters:
      - RepositoryName
      - DaysToRetainUntaggedImages
Parameters: 
  RepositoryName:
    Description: The name of the ECR repository.
    Type: String
    Default: methyldackel
  DaysToRetainUntaggedImages:
    Description: The number of days to retain untagged images.
    Type: Number
    Default: 7
Resources:
  Repository: 
    Type: "AWS::ECR::Repository"
    Properties: 
      RepositoryName: !Ref RepositoryName
      LifecyclePolicy:
        LifecyclePolicyText: !Sub |
          {
            "rules": [
              {
                "rulePriority": 1,
                "description": "Only keep untagged images for ${DaysToRetainUntaggedImages} days",
                "selection": {
                  "tagStatus": "untagged",
                  "countType": "sinceImagePushed",
                  "countUnit": "days",
                  "countNumber": ${DaysToRetainUntaggedImages}
                },
                "action": { "type": "expire" }
              }
            ]
          }