AWSTemplateFormatVersion: 2010-09-09
Description: This CloudFormation Template removes non-versioned files from an S3 Bucket. (qs-1sflpub3n)
Metadata:
  cfn-lint:
    config:
      ignore_checks:
        - W9002
        - W9003
        - W9006
Parameters:
  Bucket:
    Description: The Bucket required for the custom resource to function.
    Type: String
  QSTagKey:
    Type: String
    Description: Tag key to identify resources from this Quick Start.
  QSTagValue:
    Type: String
    Description: Tag value to identify resources from this Quick Start.
Resources:
  CleanupRole:
    Type: AWS::IAM::Role
    Properties:
      Path: /
      AssumeRolePolicyDocument:
        Version: 2012-10-17
        Statement:
        - Effect: Allow
          Principal:
            Service: lambda.amazonaws.com
          Action: sts:AssumeRole
      Policies:
      - PolicyName: DeletePolicy
        PolicyDocument:
          Version: 2012-10-17
          Statement:
          - Sid: CleanupBucket
            Effect: Allow
            Action:
            - s3:PutObject
            - s3:DeleteObject
            - s3:GetObject
            - s3:ListBucket
            - s3:ListBucketVersions
            - s3:DeleteObjectVersion
            - s3:GetObjectVersion
            - s3:GetBucketVersioning
            Resource:
            - !Sub arn:${AWS::Partition}:s3:::${Bucket}
            - !Sub arn:${AWS::Partition}:s3:::${Bucket}/*
  CleanUpS3Bucket:
    Properties:
      DestBucket: !Ref Bucket
      ServiceToken: !GetAtt CleanUpS3BucketFunction.Arn
    Type: AWS::CloudFormation::CustomResource
  CleanUpS3BucketFunction:
    Type: AWS::Lambda::Function
    Properties:
      Tags:
      - Key: !Ref QSTagKey
        Value: !Ref QSTagValue
      Code:
        ZipFile: |
          import json
          import logging
          import threading
          import boto3
          import cfnresponse
          client = boto3.client('s3')
          def delete_NonVersionedobjects(bucket):
              print("Collecting data from" + bucket)
              paginator = client.get_paginator('list_objects_v2')
              result = paginator.paginate(Bucket=bucket)
              objects = []
              for page in result:
                  try:
                      for k in page['Contents']:
                          objects.append({'Key': k['Key']})
                          print("deleting objects")
                          client.delete_objects(Bucket=bucket, Delete={'Objects': objects})
                          objects = []
                  except:
                      pass
                      print("bucket is already empty")
          def delete_versionedobjects(bucket):
              print("Collecting data from" + bucket)
              paginator = client.get_paginator('list_object_versions')
              result = paginator.paginate(Bucket=bucket)
              objects = []
              for page in result:
                  try:
                      for k in page['Versions']:
                          objects.append({'Key':k['Key'],'VersionId': k['VersionId']})
                      try:
                          for k in page['DeleteMarkers']:
                              version = k['VersionId']
                              key = k['Key']
                              objects.append({'Key': key,'VersionId': version})
                      except:
                          pass
                      print("deleting objects")
                      client.delete_objects(Bucket=bucket, Delete={'Objects': objects})
                  except:
                      pass
              print("bucket already empty")
          def timeout(event, context):
              logging.error('Execution is about to time out, sending failure response to CloudFormation')
              cfnresponse.send(event, context, cfnresponse.FAILED, {}, None)
          def handler(event, context):
              # make sure we send a failure to CloudFormation if the function is going to timeout
              timer = threading.Timer((context.get_remaining_time_in_millis() / 1000.00) - 0.5, timeout, args=[event, context])
              timer.start()
              print('Received event: %s' % json.dumps(event))
              status = cfnresponse.SUCCESS
              try:
                  dest_bucket = event['ResourceProperties']['DestBucket']
                  if event['RequestType'] == 'Delete':
                      CheckifVersioned = client.get_bucket_versioning(Bucket=dest_bucket)
                      print (CheckifVersioned)
                      if 'Status' in CheckifVersioned:
                          print (CheckifVersioned['Status'])
                          print ("This is a versioned bucket")
                          delete_versionedobjects(dest_bucket)
                      else:
                          print ("This is not a versioned bucket")
                          delete_NonVersionedobjects(dest_bucket)
                  else:
                      print("Nothing to do")
              except Exception as e:
                  logging.error('Exception: %s' % e, exc_info=True)
                  status = cfnresponse.FAILED
              finally:
                  timer.cancel()
                  cfnresponse.send(event, context, status, {}, None)
      Description: Empty the S3 Bucket
      Handler: index.handler
      Role: !GetAtt CleanupRole.Arn
      Runtime: python3.7
      Timeout: 600 # 10 min timeout