amazon-web-services - 将字符串转换为 CommaDelimitedList Cloudformation 模板

Question

我有以下 Cloudformation 模板:

AWSTemplateFormatVersion: '2010-09-09'

Parameters:
  serviceRoleArn:
    Type: String
    Description: The role that's used when the task is executed.
  AWSInstanceID:
    Type: String
  awsSSMMaintenanceWindowTargetId:
    Type: String
  awsSSMMaintenanceWindowId:
    Type: String
  automationSSMTaskRole:
    Type: String
  automationSSMTaskType:
    Type: String
  automationSSMTaskDescription:
    Type: String
  automationSSMTaskARN:
    Type: String

Resources:
  startInstanceTask:
    Type: 'AWS::SSM::MaintenanceWindowTask'
    Properties:
      MaxErrors: "2"
      Description: !Ref "automationSSMTaskDescription"
      ServiceRoleArn:
        Ref: serviceRoleArn
      Priority: 1
      MaxConcurrency: "1"
      Targets:
      - Values:
        - !Ref "awsSSMMaintenanceWindowTargetId"
        Key: WindowTargetIds
      Name: !Ref "automationSSMTaskType"
      TaskArn: !Ref "automationSSMTaskARN"
      WindowId: !Ref "awsSSMMaintenanceWindowId"
      TaskType: "AUTOMATION"
      TaskInvocationParameters:
        MaintenanceWindowAutomationParameters:
          DocumentVersion: "$DEFAULT"
          Parameters:
            InstanceId:
              - !Ref AWSInstanceID
            AutomationAssumeRole:
              - Ref: automationSSMTaskRole

但是，AWSInstanceID 正在转换为:

"InstanceId": ["i-0375357htn1a8ad40,i-0d0f0f724tytf4d37,i-0e61cc61hthf8c2b2"]

但这不是我想要的格式。如何获得以下输出？

"InstanceId": [
    "i-0375357htn1a8ad40",
    "i-0d0f0f724tytf4d37",
    "i-0e61cc61hthf8c2b2"
]

我想从 String 转换为 CommaDelimitedList。

Answer 1

CloudFormation 有一个名为 Fn::Split 的内部函数。从用户指南复制:

The following example splits a string at each vertical bar (|). The function returns ["a", "b", "c"].

!Split [ "|" , "a|b|c" ]

所以在你的例子中，我想它会转化为

!Split [ ",", !Ref AWSInstanceID ]

或者，您也可以尝试将 AWSInstanceID 指定为 CommaDelimitedList类型，例如

Parameters:
  AWSInstanceID:
    Type: CommaDelimitedList