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在AWS cloudformation中,布尔值和布尔值串是否可以互换?

amazon-cloudformation amazon-web-services

Arel user3751769 · 技术社区 · 7 年前

我对AWS CloudFormation如何处理布尔值和串胸部。

例如,是 'true' 和 true (或) 'false' 和 false )就云形成而言,逻辑上是等价的?我在他们的快速启动模板中看到了这两种情况的例子,这让我觉得它们是(即使我没有找到这种或那种方式的文档)。

例如,在他们的模板中, quickstart-compliance-common/templates/vpc-production.template 它们定义了一个变量, pSupportsNatGateway ,类型为“string”(即使其默认值为 字面意义的 价值, 真 ):

Parameters:
  ...
  pSupportsNatGateway:
    Description: Specifies whether this region supports NAT Gateway (this value is
      determined by the main stack if it is invoked from there)
    Type: String
    Default: true

然后,在 condition 在模板的后面,将该参数(可能是字符串)与 字面意义的 价值, 真 .

Conditions:
  ...
  cSupportsNatGateway:
    !Equals
    - true
    - !Ref pSupportsNatGateway

我的问题是,cloudformation如何比较文本值和串这些价值观?AWS文件中对此作了何定义?

0 回复 | 直到 7 年前

Arel user3751769 7 年前

我不知道这是在哪里记录的,但是对 !就cloudformation而言,字面布尔值(或数字)及其字符串值似乎是等效的。

我创建了一个最小的cloudformation模板来测试:

---
AWSTemplateFormatVersion: 2010-09-09
Description: Test CloudFormation template

Parameters:

  pCreateCluster:
    Description: To create or not create?
    Type: String
    Default: 'true'
    AllowedValues:
    - 'true'
    - 'false'

Conditions:
  CreateClusterConditionTrue1:
    !Equals
    - !Ref pCreateCluster
    - 'true'

  CreateClusterConditionTrue2:
    !Equals
    - !Ref pCreateCluster
    - true

  CreateClusterConditionFalse1:
    !Equals
    - !Ref pCreateCluster
    - 'false'

  CreateClusterConditionFalse2:
    !Equals
    - !Ref pCreateCluster
    - false

Resources:

  rFargateCluster:
    Type: AWS::ECS::Cluster
    Condition: CreateClusterConditionTrue1
    Properties:
      ClusterName: "my-test-cluster"

Outputs:
  CreateClusterConditionTrue1:
    Value:
      !If
      - CreateClusterConditionTrue1
      - "The answer is True"
      - "The answer is False"
  CreateClusterConditionTrue2:
    Value:
      !If
      - CreateClusterConditionTrue2
      - "The answer is True"
      - "The answer is False"
  CreateClusterConditionFalse1:
    Value:
      !If
      - CreateClusterConditionFalse1
      - "The answer is True"
      - "The answer is False"
  CreateClusterConditionFalse2:
    Value:
      !If
      - CreateClusterConditionFalse2
      - "The answer is True"
      - "The answer is False"
...

结果表明,它们实际上是等效的:

Key                             Value
CreateClusterConditionTrue1     The answer is True      
CreateClusterConditionTrue2     The answer is True      
CreateClusterConditionFalse2    The answer is False     
CreateClusterConditionFalse1    The answer is False