Examples of Fn::ForEach in the Conditions section - Amazon CloudFormation
Replicate a single condition
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Examples of Fn::ForEach in the Conditions section

These examples demonstrate using the Fn::ForEach intrinsic function in the Conditions section. For more information about this section, see Conditions in the Amazon CloudFormation User Guide.

Important

Conditions must be the second property listed, or later. Stack creation will fail if Conditions is the first property listed within the template fragment parameter of Fn::ForEach.

Resources:
  'Fn::ForEach::Topics':
    - LogicalId
    - !Ref TopicList
    - '${LogicalId}':
        Condition: !Sub 'TopicCondition${LogicalId}'
        Type: AWS::SNS::Topic
        Properties:
          TopicName: !Sub 'My${LogicalId}'

Conditions must be added as the second key, or later, for stack creation to succeed: 

Resources:
  'Fn::ForEach::Topics':
    - LogicalId
    - !Ref TopicList
    - '${LogicalId}':
        Type: AWS::SNS::Topic
        Condition: !Sub 'TopicCondition${LogicalId}'
        Properties:
          TopicName: !Sub 'My${LogicalId}'

Replicate a single condition

This example uses the Fn::ForEach intrinsic function in the Conditions section to replicate multiple similar conditions with different properties.

JSON

{
    "AWSTemplateFormatVersion": "2010-09-09",
    "Transform": "AWS::LanguageExtensions",
    "Parameters": {
        "ParamA": {
            "Type": "String",
            "AllowedValues": [
                "true",
                "false"
            ]
        },
        "ParamB": {
            "Type": "String",
            "AllowedValues": [
                "true",
                "false"
            ]
        },
        "ParamC": {
            "Type": "String",
            "AllowedValues": [
                "true",
                "false"
            ]
        },
        "ParamD": {
            "Type": "String",
            "AllowedValues": [
                "true",
                "false"
            ]
        }
    },
    "Conditions": {
        "Fn::ForEach::CheckTrue": [
            "Identifier",
            ["A", "B", "C", "D"],
            {
                "IsParam${Identifier}Enabled": {
                    "Fn::Equals": [
                        {"Ref": {"Fn::Sub": "Param${Identifier}"}},
                        "true"
                    ]
                }
            }
        ]
    },
    "Resources": {
        "WaitConditionHandle": {
            "Type": "AWS::CloudFormation::WaitConditionHandle"
        }
    }
}

YAML

AWSTemplateFormatVersion: 2010-09-09
Transform: 'AWS::LanguageExtensions'
Parameters:
  ParamA:
    Type: String
    AllowedValues:
      - 'true'
      - 'false'
  ParamB:
    Type: String
    AllowedValues:
      - 'true'
      - 'false'
  ParamC:
    Type: String
    AllowedValues:
      - 'true'
      - 'false'
  ParamD:
    Type: String
    AllowedValues:
      - 'true'
      - 'false'
Conditions:
  'Fn::ForEach::CheckTrue':
    - Identifier
    - [A, B, C, D]
    - 'IsParam${Identifier}Enabled': !Equals 
        - !Ref 
          'Fn::Sub': 'Param${Identifier}'
        - 'true'
Resources:
  WaitConditionHandle:
    Type: 'AWS::CloudFormation::WaitConditionHandle'

The transformed template will be equivalent to the following template:

AWSTemplateFormatVersion: 2010-09-09
Parameters:
  ParamA:
    Type: String
    AllowedValues:
      - 'true'
      - 'false'
  ParamB:
    Type: String
    AllowedValues:
      - 'true'
      - 'false'
  ParamC:
    Type: String
    AllowedValues:
      - 'true'
      - 'false'
  ParamD:
    Type: String
    AllowedValues:
      - 'true'
      - 'false'
Conditions:
  IsParamAEnabled: !Equals 
    - !Ref ParamA
    - 'true'
  IsParamBEnabled: !Equals 
    - !Ref ParamB
    - 'true'
  IsParamCEnabled: !Equals 
    - !Ref ParamC
    - 'true'
  IsParamDEnabled: !Equals 
    - !Ref ParamD
    - 'true'
Resources:
  WaitConditionHandle:
    Type: 'AWS::CloudFormation::WaitConditionHandle'