template.yml

Parameters:
  SNSEndpoint: 
    Description: Email address for sns topic subscription
    Type: String

Resources:
  LambdaRole:
    Type: AWS::IAM::Role
    Properties:
      AssumeRolePolicyDocument:
        Version: "2012-10-17"
        Statement:
          - Effect: Allow
            Principal:
              Service:
                - lambda.amazonaws.com
            Action: 
              - 'sts:AssumeRole'
      Path: /
      Policies:
        - PolicyName: S3GetObject
          PolicyDocument: 
            Version: "2012-10-17"
            Statement: 
              - Effect: Allow
                Action: 
                  - 's3:GetObject'
                Resource: 'arn:aws:s3:::*'
                    
        - PolicyName: AllowLogging
          PolicyDocument: 
            Version: "2012-10-17"
            Statement:
              - Effect: Allow
                Action:  
                  - 'logs:*'
                Resource: 'arn:aws:logs:*'
        
        - PolicyName: AllowSNS
          PolicyDocument: 
            Version: "2012-10-17"
            Statement:
              - Effect: Allow
                Action:
                  - 'sns:Publish'
                Resource: 'arn:aws:sns:*'
  
  LambdaFunction:
    Type: AWS::Lambda::Function
    Properties:
      FunctionName: s3-get-object-function
      Role: !GetAtt LambdaRole.Arn
      Runtime: python3.8
      Code:
        ZipFile: |
          import json
          import urllib.parse
          import boto3

          print('Loading function')

          s3 = boto3.client('s3')


          def lambda_handler(event, context):

              # Get the object from the event and show its content type
              bucket = event['Records'][0]['s3']['bucket']['name']
              key = urllib.parse.unquote_plus(event['Records'][0]['s3']['object']['key'], encoding='utf-8')
              try:
                  response = s3.get_object(Bucket=bucket, Key=key)
                  print("CONTENT TYPE: " + response['ContentType'])
                  return response['ContentType']
              except Exception as e:
                  print(e)
                  print('Error getting object {} from bucket {}. Make sure they exist and your bucket is in the same region as this function.'.format(key, bucket))
                  raise e
      Handler: index.lambda_handler
        
  
  LambdaSNS:
    Type: AWS::SNS::Topic
    Properties:
      TopicName: Lambda-success

  SnsSubscription:
    Type: AWS::SNS::Subscription
    Properties: 
      Protocol: email
      Endpoint: !Ref SNSEndpoint
      TopicArn: !Ref LambdaSNS

  LambdaInvokeSNS:
    Type: AWS::Lambda::EventInvokeConfig
    Properties:
      DestinationConfig:
        OnSuccess:
          Destination: !Ref LambdaSNS
      FunctionName: !Ref LambdaFunction
      Qualifier: $LATEST


Outputs:
  LambdaFunction:
    Description: Name of the lambda function
    Value:
      Fn::GetAtt:
        - LambdaFunction
        - Arn
    Export:
      Name: LambdaFunctionArn