AWSTemplateFormatVersion: 2010-09-09
Description: >-
  Template that uses existing S3 bucket as an event source for a Lambda function to transform squid proxy rules
Parameters:
  S3Bucket:
    Type: String
    Description: S3 bucket name that's used for uploading the squid domain list config file
    Default: test-squid-fw
  S3ObjectFile:
    Type: String
    Description: S3 file name that stores squid domain lists for squid
    Default: domain.txt
  RuleGroupName:
    Type: String
    Description: Provide the rule group name for the squid
    Default: squid-conversion-test
  DomainListKind:
    Type: String
    Description: Provide the type of domain list for the squid
    AllowedValues:
      - DENYLIST
      - ALLOWLIST
Resources:
  SquidLambdaFunction:
    Type: 'AWS::Lambda::Function'
    Properties:
      Code:
        S3Bucket: !Ref S3Bucket
        S3Key: squid.zip
      Handler: index.lambda_handler
      Role: !GetAtt LambdaIAMRole.Arn
      Runtime: python3.7
      Timeout: 5
      Environment:
        Variables:
          bucket: !Ref S3Bucket
          key: !Ref S3ObjectFile
          rg_name: !Ref RuleGroupName
          gen_rule_type: !Ref DomainListKind

  LambdaInvokePermission:
    Type: 'AWS::Lambda::Permission'
    Properties:
      FunctionName: !GetAtt SquidLambdaFunction.Arn
      Action: 'lambda:InvokeFunction'
      Principal: s3.amazonaws.com
      SourceAccount: !Ref 'AWS::AccountId'
      SourceArn: !Sub 'arn:aws:s3:::${S3Bucket}'

  LambdaIAMRole:
    Type: 'AWS::IAM::Role'
    Properties:
      AssumeRolePolicyDocument:
        Version: 2012-10-17
        Statement:
          - Effect: Allow
            Principal:
              Service:
                - lambda.amazonaws.com
            Action:
              - 'sts:AssumeRole'
      Path: /
      Policies:
        - PolicyName: root
          PolicyDocument:
            Version: 2012-10-17
            Statement:
              - Effect: Allow
                Action:
                  - 's3:*'
                  - 'logs:CreateLogGroup'
                  - 'logs:CreateLogStream'
                  - 'logs:PutLogEvents'
                Resource: 
                  - !Sub 'arn:aws:s3:::${S3Bucket}'
                  - 'arn:aws:logs:*:*:*'
                  - !Sub 'arn:aws:s3:::${S3Bucket}/*'
        - PolicyName: ec2
          PolicyDocument:
            Version: 2012-10-17
            Statement:  
              - Effect: Allow
                Action:
                  - 'ec2:*'
                Resource: '*'
        - PolicyName: network-firewall
          PolicyDocument:
            Version: 2012-10-17
            Statement:  
              - Effect: Allow
                Action:
                  - 'network-firewall:*'
                Resource: '*'

  CustomSquidResourceLambdaFunction:
    Type: 'AWS::Lambda::Function'
    Properties:
      Handler: index.lambda_handler
      Role: !GetAtt LambdaIAMRole.Arn
      Code:
        ZipFile: |
            from __future__ import print_function
            import json
            import boto3
            import cfnresponse
            SUCCESS = "SUCCESS"
            FAILED = "FAILED"
            print('Loading function')
            s3 = boto3.resource('s3')
            def lambda_handler(event, context):
                print("Received event: " + json.dumps(event, indent=2))
                responseData={}
                try:
                    if event['RequestType'] == 'Delete':
                        print("Request Type:",event['RequestType'])
                        Bucket=event['ResourceProperties']['Bucket']
                        delete_notification(Bucket)
                        print("Sending response to custom resource after Delete")
                    elif event['RequestType'] == 'Create' or event['RequestType'] == 'Update':
                        print("Request Type:",event['RequestType'])
                        LambdaArn=event['ResourceProperties']['LambdaArn']
                        Bucket=event['ResourceProperties']['Bucket']
                        add_notification(LambdaArn, Bucket)
                        responseData={'Bucket':Bucket}
                        print("Sending response to custom resource")
                    responseStatus = 'SUCCESS'
                except Exception as e:
                    print('Failed to process:', e)
                    responseStatus = 'FAILURE'
                    responseData = {'Failure': 'Something bad happened.'}
                cfnresponse.send(event, context, responseStatus, responseData)

            def add_notification(LambdaArn, Bucket):
                bucket_notification = s3.BucketNotification(Bucket)
                response = bucket_notification.put(
                  NotificationConfiguration={
                    'LambdaFunctionConfigurations': [
                      {
                          'LambdaFunctionArn': LambdaArn,
                          'Events': [
                              's3:ObjectCreated:*'
                          ]
                      }
                    ]
                  }
                )
                print("Put request completed....")
              
            def delete_notification(Bucket):
                bucket_notification = s3.BucketNotification(Bucket)
                response = bucket_notification.put(
                    NotificationConfiguration={}
                )
                print("Delete request completed....")


      Runtime: python3.7
      Timeout: 50

  LambdaTrigger:
    Type: 'Custom::LambdaTrigger'
    DependsOn: LambdaInvokePermission
    Properties:
      ServiceToken: !GetAtt CustomSquidResourceLambdaFunction.Arn
      LambdaArn: !GetAtt SquidLambdaFunction.Arn
      Bucket: !Ref S3Bucket