system_b.yml

AWSTemplateFormatVersion: '2010-09-09'
Description: System B

Resources:
  Queue:
    Type: AWS::SQS::Queue
    # Properties:
    #   RedrivePolicy:
    #     deadLetterTargetArn: !GetAtt DLQueue.Arn
    #     maxReceiveCount: 3

  # DLQueue:
  #   Type: AWS::SQS::Queue

  SnsSubscription:
    Type: AWS::SNS::Subscription
    Properties:
      Protocol: sqs
      Endpoint: !GetAtt Queue.Arn
      TopicArn: !ImportValue SystemASnsTopicArn

  QueuePolycy:
    Type: AWS::SQS::QueuePolicy
    Properties:
      PolicyDocument:
        Version: 2012-10-17
        Id: AllowSnsTopicToSendMessage
        Statement:
          - Sid: 1
            Effect: Allow
            Principal: "*"
            Action:
              - sqs:SendMessage
            Resource: "*"
            Condition:
              ArnEquals:
                aws:SourceArn:
                  !ImportValue SystemASnsTopicArn
      Queues:
        - !Ref Queue