AWS SAM 模板 - 錯誤：無法解析模板：解析塊映射時

Question

我有這個模板：

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

Parameters:
  EnvironmentPrefix:
    Type: String
    Default: "test-"

Resources:
  S3JsonLoggerFunction:
    Type: AWS::Serverless::Function
    Properties:
      Handler: src/handlers/s3-json-logger.s3JsonLoggerHandler
      Runtime: nodejs18.x
      Architectures:
        - x86_64
      MemorySize: 128
      Timeout: 60
      Policies:
        - S3ReadPolicy:
            BucketName:
              !Fn::ImportValue:
                !Sub "${EnvironmentPrefix}example-bucket"
      Events:
        S3NewObjectEvent:
          Type: S3
          Properties:
            Bucket:
              !Fn::ImportValue:
                !Sub "${EnvironmentPrefix}example-bucket"
            Events: s3:ObjectCreated:*
            Filter:
              S3Key:
                Rules:
                  - Name: prefix
                    Value: "changelog/"

為什么會失敗並出現此錯誤？？？

Error: Failed to parse template: while parsing a block mapping
  in "<unicode string>", line 23, column 13:
                BucketName:
                ^
expected <block end>, but found '<tag>'
  in "<unicode string>", line 25, column 17:
                    !Sub "${EnvironmentPrefix}example-b ...
                    ^

我一直盯着這個並將其與https://docs.aws.amazon.com/serverless-application-model/latest/developerguide/serverless-policy-templates.html上的示例進行比較，但無法弄清楚是什么不同的！！！

Answer 1

我認為您的:Fn::ImportValue:語法是錯誤的。

它應該只是Fn::ImportValue:沒有! ，作為! 是Fn::的簡稱。

Policies:
  - S3ReadPolicy:
     BucketName:
       Fn::ImportValue:
         !Sub "${EnvironmentPrefix}example-bucket"

文檔在這里： https ://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/intrinsic-function-reference-importvalue.html