template.yml

AWSTemplateFormatVersion: "2010-09-09"
Transform: AWS::Serverless-2016-10-31
Description: SAM template to create sample messaging architechture

Parameters:
  SNSTopicName:
    Type: String
    Description: Name of the SNS Topic
    MinLength: 0
  SQSQueueName:
    Type: String
    Description: Name of the Subscriber Queue
    MinLength: 0

Conditions:
  SNSTopicNameGenerated:
    Fn::Equals:
      - Ref: SNSTopicName
      - false
  SQSQueueNameGenerated:
    Fn::Equals:
      - Ref: SQSQueueName
      - false

Resources:
  FirstSNSTopic:
    Type: AWS::SNS::Topic
    Properties:
      TopicName:
        Fn::If:
          - SNSTopicNameGenerated
          - Ref: AWS::NoValue
          - Ref: SNSTopicName

  FirstSQSQueue:
    Type: AWS::SQS::Queue
    Properties:
      QueueName:
        Fn::If:
          - SQSQueueNameGenerated
          - Ref: AWS::NoValue
          - Ref: SQSQueueName

  FirstSNSTopicSubscription:
    Type: AWS::SNS::Subscription
    Properties:
      Endpoint: !GetAtt FirstSQSQueue.Arn
      Protocol: sqs
      TopicArn:
        Ref: FirstSNSTopic

  SQSQueuePolicy:
    Type: AWS::SQS::QueuePolicy
    Properties:
      PolicyDocument:
        {
          "Version": "2012-10-17",
          "Statement":
            [
              {
                "Effect": "Allow",
                "Principal": { "AWS": "*" },
                "Action": "SQS:SendMessage",
                "Resource": { "Fn::GetAtt": ["FirstSQSQueue", "Arn"] },
                "Condition":
                  {
                    "ArnEquals":
                      { "aws:SourceArn": { "Ref": "FirstSNSTopic" } },
                  },
              },
              {
                "Effect": "Allow",
                "Principal": { "AWS": "*" },
                "Action": ["SQS:ReceiveMessage", "SQS:DeleteMessage", "SQS:GetQueueAttributes"],
                "Resource": "*",
              },
            ],
        }
      Queues:
        - Ref: FirstSQSQueue

Outputs:
  SNSTopicARN:
    Description: ARN of the SNS Topic
    Value:
      Ref: FirstSNSTopic
  SNSTopicName:
    Description: Name of the topic
    Value: !GetAtt FirstSNSTopic.TopicName
  SQSQueueARN:
    Description: ARN of the SQS Queue
    Value: !GetAtt FirstSQSQueue.Arn
  SQSQueueName:
    Description: Name of the topic
    Value: !GetAtt FirstSQSQueue.QueueName
  SQSQueueURL:
    Description: URL of the SQS Queue
    Value:
      Ref: FirstSQSQueue