CloudFormation Template Example - Subscribe a Lambda to an SNS Topic

template.yaml

AWSTemplateFormatVersion: '2010-09-09'
Transform: AWS::Serverless-2016-10-31
Description: >
  example-lambda-sns

  Example CloudFormation template to subscribe a lambda to an SNS Topic.
Resources:
  ExampleTopic:
    Type: AWS::SNS::Topic
    Properties:
      DisplayName: !Sub 'example-sns-topic'
      TopicName: !Sub 'example-sns-topic'
      Subscription:
        - Protocol: lambda
          Endpoint: !GetAtt ExampleFunction.Arn
  
  ExampleFunction:
    Type: AWS::Serverless::Function
    Properties:
      CodeUri: ./
      Handler: index.handler
      Runtime: nodejs8.10

  ExampleFunctionInvokePermission:
    Type: 'AWS::Lambda::Permission'
    Properties:
      Action: 'lambda:InvokeFunction'
      FunctionName: !Ref ExampleFunction
      Principal: sns.amazonaws.com   

  ExampleTopicPolicy:
    Type: 'AWS::SNS::TopicPolicy'
    Properties:
      Topics:
        - !Ref ExampleTopic
      PolicyDocument:
        Version: '2012-10-17'
        Statement:
          - Effect: Allow
            Action: 'sns:Publish'
            Resource: !Ref ExampleTopic
            Principal:
              AWS: '*'
            Condition:
              ArnLike:
                AWS:SourceArn: !Sub 'arn:aws:*:*:${AWS::AccountId}:*'