amazon-web-services - CloudFormation Fn::Transform 操作:较低 -> 语法错误

Question

我正在尝试创建一个具有云形成的 AWS S3 存储桶。

S3 存储桶名称需要小写，但我想使用参数来组合该名称。该参数为大写。

我找到了一条路。

我读过这篇文章。

• https://github.com/awslabs/aws-cloudformation-templates/tree/master/aws/services/CloudFormation/MacrosExamples/StringFunctions

这是我的代码:

Parameters:

# Global
  ServiceName:
    Type: String
    Description: 'Service Name'
    Default: content-input
   
  Environment:
    Type: String
    Description: 'Environment Name'

Resources:
  S3Bucket: 
    Type: AWS::S3::Bucket
    Properties:
      BucketName: !Join ['-',
      [ 
        content-input,
        'Fn::Transform':
          - Name: 'String'
          Parameters: 
            InputString: !Ref Environment
            Operation: Lower
      ]]

但我收到此错误。

while parsing a flow node
expected the node content, but found '-'
  in "<unicode string>", line 157, column 11:
              - Name: 'String'

我尝试了引用的其他语法 here

Parameters:

# Global
  ServiceName:
    Type: String
    Description: 'Service Name'
    Default: content-input
   
  Environment:
    Type: String
    Description: 'Environment Name'

Resources:
  S3Bucket: 
    Type: AWS::S3::Bucket
    Properties:
      BucketName: !Join ['-',
      [ 
        content-input,
        'Fn::Transform':
          Name: 'String'
          Parameters: 
            InputString: !Ref Environment
            Operation: Lower
      ]]

但我得到:

while parsing a flow sequence
  in "<unicode string>", line 154, column 7:
          [
          ^
expected ',' or ']', but got ':'
  in "<unicode string>", line 157, column 15:
              Name: 'String'
                  ^

当然，这工作得很好。

Parameters:

# Global
  ServiceName:
    Type: String
    Description: 'Service Name'
    Default: content-input
   
  Environment:
    Type: String
    Description: 'Environment Name'

Resources:
  S3Bucket: 
    Type: AWS::S3::Bucket
    Properties:
      BucketName: !Join ['-',
      [ 
        content-input,
        mytext
      ]]

正确的语法是怎样的？

Answer 1

要获得正确的语法，需要注意的重要一点是在使用多个 Intrinsic 函数时将 Json 与 Yaml 结合使用。下面更新了语法。对于环境值 DEV，这将创建一个名称为 content-input-dev

的存储桶

AWSTemplateFormatVersion: "2010-09-09"
Parameters:
  ServiceName:
    Type: String
    Description: "Service Name"
    Default: content-input
  Environment:
    Type: String
    Description: "Environment Name"
Resources:
  S3Bucket:
    Type: AWS::S3::Bucket
    Properties:
      BucketName:
        !Join [
          "-",
          [
            !Ref ServiceName,
            {
              "Fn::Transform":
                {
                  "Name": "String",
                  "Parameters":
                    { "InputString": !Ref Environment, "Operation": "Lower" },
                },
            },
          ],
        ]