在 AWS SAM 模板中獲取 Fn::GetAtt 錯誤

Question

我已經在我的 AWS 無服務器應用程序 Model 模板中聲明了如下所示的 SNS 主題和訂閱：-

MyTopic:
    Type: AWS::SNS::Topic
    Properties:
      DisplayName: !Sub 'test-${Environment}-${AWS::AccountId}-${AWS::Region}'
      Tags:
       - Key: Environment
         Value: !FindInMap [Environment, FullForm, !Ref Environment]
      TopicName: !Sub 'test-${Environment}-${AWS::AccountId}-${AWS::Region}'

  MySubscription:
    Type: AWS::SNS::Subscription
    Properties:
      Endpoint: !Ref SubscriptionEndPoint
      Protocol: !Ref SubscriptionProtocol
      Region: !Ref 'AWS::Region'
      TopicArn: !Ref MyTopic

然后在我的 Lambda 函數環境中使用 SNS 主題 ARN，如下所示在同一模板文件中：-

MyLambda:
    Type: AWS::Serverless::Function
    Properties:
      Environment:
        Variables:
          RUNTIME_SNS_TOPIC_ARN: !GetAtt MyTopic.Arn

輸出（在 SAM 模板中）：-

MyTopic:
    Description: SNS Topic for the Ingest to send notification to
    Export:
      Name: !Sub
        - ${ExportPrefix_}:${AWS::Region}:MyTopic
        - ExportPrefix_: !If
          - HasExportPrefix
          - !Join ['-', [!Ref ExportPrefix, !Ref Environment]]
          - !Join ['-', [!Select [0, !Split ["-", !Ref "AWS::StackName"]], !Ref Environment]]
      Value: !Sub "${MyTopic.Arn}:${MyTopic.Version.Version}"
  MySubscription:
    Description: Subscription to get messages from a topic
    Export:
      Name: !Sub
        - ${ExportPrefix_}:${AWS::Region}:MySubscription
        - ExportPrefix_: !If
          - HasExportPrefix
          - !Join ['-', [!Ref ExportPrefix, !Ref Environment]]
          - !Join ['-', [!Select [0, !Split ["-", !Ref "AWS::StackName"]], !Ref Environment]]
      Value: !Sub "${MySubscription.Arn}:${MySubscription.Version.Version}"

但是，我收到以下錯誤：-

13:30:30 錯誤：無法為堆棧創建變更集：my-stack，例如：服務員 ChangeSetCreateComplete 失敗：服務員遇到終端故障 state 狀態：失敗。 原因：模板錯誤：資源 MyTopic 不支持 Fn::GetAtt 中的屬性類型 Arn

Answer 1

AWS::SNS:Topic在您使用Ref時返回 ARN

查看有關返回值的文檔。

試試

MyLambda:
    Type: AWS::Serverless::Function
    Properties:
      Environment:
        Variables:
          RUNTIME_SNS_TOPIC_ARN: !Ref MyTopic  # Using !Ref

Answer 2

建議在VSCode中嘗試使用CloudFormation Linter，以在編寫模板時查看其中的一些內聯錯誤：

[cfn-lint] E1010: Invalid GetAtt MyTopic.Arn for resource MyLambda
[cfn-lint] E1019: Parameter MyTopic.Arn for Fn::Sub not found at Outputs/MyTopic/Value/Fn::Sub
[cfn-lint] E1019: Parameter MyTopic.Version.Version for Fn::Sub not found at Outputs/MyTopic/Value/Fn::Sub
[cfn-lint] E1019: Parameter MySubscription.Arn for Fn::Sub not found at Outputs/MySubscription/Value/Fn::Sub
[cfn-lint] E1019: Parameter MySubscription.Version.Version for Fn::Sub not found at Outputs/MySubscription/Value/Fn::Sub

它還會指出Value需要在Outputs中減少縮進

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AWS::SNS::Topic返回值

AWS::SNS::Subscription