這是新的 *CloudFormation 範本參考指南*。請更新您的書籤和連結。如需 CloudFormation 入門的說明，請參閱 [AWS CloudFormation 使用者指南](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/Welcome.html)。
本文為英文版的機器翻譯版本，如內容有任何歧義或不一致之處，概以英文版為準。
# `Condition` 屬性
若要根據條件在 CloudFormation 中建立資源，請先在範本的 `Conditions` 區段中宣告條件。然後，使用 `Condition` 金鑰以及條件的邏輯 ID 作為資源屬性。只有當條件評估為 true 時，CloudFormation 才會建立資源。這可讓您根據範本中定義的特定條件或參數來控制資源建立。
如果您是第一次在範本中使用條件，建議您先檢閱《*AWS CloudFormation 使用者指南*》中的 [CloudFormation 範本條件語法](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/conditions-section-structure.html)主題。
**注意**
如果未建立具有條件的資源，則不會建立任何依賴該資源的資源，無論其自身條件為何。
## 範例
下列範本包含具有 `Condition` 屬性的 Amazon S3 儲存貯體資源。只有在 `CreateBucket` 條件評估為 `true` 時，才會建立儲存貯體。
### JSON
```
{
"AWSTemplateFormatVersion" : "2010-09-09",
"Parameters" : {
"EnvType" : {
"Type" : "String",
"AllowedValues" : ["prod", "dev"],
"Default" : "dev",
"Description" : "Environment type"
}
},
"Conditions" : {
"CreateBucket" : {"Fn::Equals" : [{"Ref" : "EnvType"}, "prod"]}
},
"Resources" : {
"MyBucket" : {
"Type" : "AWS::S3::Bucket",
"Condition" : "CreateBucket",
"Properties" : {
"BucketName" : {"Fn::Join" : ["-", ["mybucket", {"Ref" : "EnvType"}]]}
}
}
}
}
```
### YAML
```
1. AWSTemplateFormatVersion: 2010-09-09
2. Parameters:
3. EnvType:
4. Type: String
5. AllowedValues:
6. - prod
7. - dev
8. Default: dev
9. Description: Environment type
10. Conditions:
11. CreateBucket: !Equals [!Ref EnvType, prod]
12. Resources:
13. MyBucket:
14. Type: AWS::S3::Bucket
15. Condition: CreateBucket
16. Properties:
17. BucketName: !Sub mybucket-${EnvType}
```
## 使用多個條件
可以使用 [`Fn::And`](intrinsic-function-reference-conditions.md#intrinsic-function-reference-conditions-and)、[`Fn::Or`](intrinsic-function-reference-conditions.md#intrinsic-function-reference-conditions-or) 和 [`Fn::Not`](intrinsic-function-reference-conditions.md#intrinsic-function-reference-conditions-not) 等內建函數來組合多個條件，以建立更複雜的條件式邏輯。
### JSON
```
{
"AWSTemplateFormatVersion" : "2010-09-09",
"Parameters" : {
"EnvType" : {
"Type" : "String",
"AllowedValues" : ["prod", "test", "dev"],
"Default" : "dev",
"Description" : "Environment type"
},
"CreateResources" : {
"Type" : "String",
"AllowedValues" : ["true", "false"],
"Default" : "true",
"Description" : "Create resources flag"
}
},
"Conditions" : {
"IsProd" : {"Fn::Equals" : [{"Ref" : "EnvType"}, "prod"]},
"IsTest" : {"Fn::Equals" : [{"Ref" : "EnvType"}, "test"]},
"CreateResourcesFlag" : {"Fn::Equals" : [{"Ref" : "CreateResources"}, "true"]},
"CreateProdResources" : {"Fn::And" : [{"Condition" : "IsProd"}, {"Condition" : "CreateResourcesFlag"}]},
"CreateTestOrDevResources" : {"Fn::And" : [{"Fn::Or" : [{"Condition" : "IsTest"}, {"Fn::Not" : [{"Condition" : "IsProd"}]}]}, {"Condition" : "CreateResourcesFlag"}]}
},
"Resources" : {
"ProdBucket" : {
"Type" : "AWS::S3::Bucket",
"Condition" : "CreateProdResources",
"Properties" : {
"BucketName" : {"Fn::Join" : ["-", ["prod-bucket", {"Ref" : "AWS::StackName"}]]}
}
},
"TestDevBucket" : {
"Type" : "AWS::S3::Bucket",
"Condition" : "CreateTestOrDevResources",
"Properties" : {
"BucketName" : {"Fn::Join" : ["-", [{"Ref" : "EnvType"}, "bucket", {"Ref" : "AWS::StackName"}]]}
}
}
}
}
```
### YAML
```
1. AWSTemplateFormatVersion: 2010-09-09
2. Parameters:
3. EnvType:
4. Type: String
5. AllowedValues:
6. - prod
7. - test
8. - dev
9. Default: dev
10. Description: Environment type
11. CreateResources:
12. Type: String
13. AllowedValues:
14. - 'true'
15. - 'false'
16. Default: 'true'
17. Description: Create resources flag
18. Conditions:
19. IsProd: !Equals [!Ref EnvType, prod]
20. IsTest: !Equals [!Ref EnvType, test]
21. CreateResourcesFlag: !Equals [!Ref CreateResources, 'true']
22. CreateProdResources: !And
23. - !Condition IsProd
24. - !Condition CreateResourcesFlag
25. CreateTestOrDevResources: !And
26. - !Or
27. - !Condition IsTest
28. - !Not [!Condition IsProd]
29. - !Condition CreateResourcesFlag
30. Resources:
31. ProdBucket:
32. Type: AWS::S3::Bucket
33. Condition: CreateProdResources
34. Properties:
35. BucketName: !Sub prod-bucket-${AWS::StackName}
36. TestDevBucket:
37. Type: AWS::S3::Bucket
38. Condition: CreateTestOrDevResources
39. Properties:
40. BucketName: !Sub ${EnvType}-bucket-${AWS::StackName}
```
## 在條件中使用 `AWS::AccountId`
您可以使用 條件`AWS::AccountId`中的虛擬參數，根據要部署堆疊 AWS 帳戶 的 來建立資源。對於多帳戶部署或需要阻止特定帳戶接收某些資源時，這非常有用。如需虛擬參數的詳細資訊，請參閱*AWS CloudFormation 《 使用者指南*》中的[使用虛擬參數取得 AWS 值](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/pseudo-parameter-reference.html)。
### JSON
```
{
"AWSTemplateFormatVersion" : "2010-09-09",
"Conditions" : {
"ExcludeAccount1" : {"Fn::Not" : [{"Fn::Equals" : [{"Ref" : "AWS::AccountId"}, "111111111111"]}]},
"ExcludeAccount2" : {"Fn::Not" : [{"Fn::Equals" : [{"Ref" : "AWS::AccountId"}, "222222222222"]}]},
"ExcludeBothAccounts" : {"Fn::And" : [{"Condition" : "ExcludeAccount1"}, {"Condition" : "ExcludeAccount2"}]}
},
"Resources" : {
"StandardBucket" : {
"Type" : "AWS::S3::Bucket",
"Properties" : {
"BucketName" : {"Fn::Join" : ["-", ["standard-bucket", {"Ref" : "AWS::StackName"}]]}
}
},
"RestrictedResource" : {
"Type" : "AWS::SNS::Topic",
"Condition" : "ExcludeBothAccounts",
"Properties" : {
"TopicName" : {"Fn::Join" : ["-", ["restricted-topic", {"Ref" : "AWS::StackName"}]]}
}
}
}
}
```
### YAML
```
1. AWSTemplateFormatVersion: 2010-09-09
2. Conditions:
3. ExcludeAccount1: !Not [!Equals [!Ref 'AWS::AccountId', '111111111111']]
4. ExcludeAccount2: !Not [!Equals [!Ref 'AWS::AccountId', '222222222222']]
5. ExcludeBothAccounts: !And
6. - !Condition ExcludeAccount1
7. - !Condition ExcludeAccount2
8. Resources:
9. StandardBucket:
10. Type: AWS::S3::Bucket
11. Properties:
12. BucketName: !Sub standard-bucket-${AWS::StackName}
13. RestrictedResource:
14. Type: AWS::SNS::Topic
15. Condition: ExcludeBothAccounts
16. Properties:
17. TopicName: !Sub restricted-topic-${AWS::StackName}
```