Examples of Fn::ForEach in the Outputs section - Amazon CloudFormation
Reference replicated AWS::S3::Bucket resources Reference replicated AWS::EC2::Instance resources
Services or capabilities described in Amazon Web Services documentation might vary by Region. To see the differences applicable to the China Regions, see Getting Started with Amazon Web Services in China (PDF).

This is the new Amazon CloudFormation Template Reference Guide. Please update your bookmarks and links. For help getting started with CloudFormation, see the Amazon CloudFormation User Guide.

Examples of Fn::ForEach in the Outputs section

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

Reference replicated AWS::S3::Bucket resources

This example uses nested Fn::ForEach loops in the Outputs section to reduce the template length.

JSON

{
  "AWSTemplateFormatVersion": "2010-09-09",
  "Transform": "AWS::LanguageExtensions",
  "Resources": {
    "Fn::ForEach::Buckets": [
      "Identifier",
      [ "A", "B", "C" ],
      {
        "S3Bucket${Identifier}": {
          "Type": "AWS::S3::Bucket",
          "Properties": {
            "AccessControl": "PublicRead",
            "MetricsConfigurations": [
              {
                "Id": {"Fn::Sub": "EntireBucket${Identifier}"}
              }
            ],
            "WebsiteConfiguration": {
              "IndexDocument": "index.html",
              "ErrorDocument": "error.html",
              "RoutingRules": [
                {
                  "RoutingRuleCondition": {
                    "HttpErrorCodeReturnedEquals": "404",
                    "KeyPrefixEquals": "out1/"
                  },
                  "RedirectRule": {
                    "HostName": "ec2-11-22-333-44.compute-1.amazonaws.com",
                    "ReplaceKeyPrefixWith": "report-404/"
                  }
                }
              ]
            }
          },
          "DeletionPolicy": "Retain",
          "UpdateReplacePolicy": "Retain"
        }
      }
    ]
  },
  "Outputs": {
    "Fn::ForEach::BucketOutputs": [
      "Identifier",
      [ "A", "B", "C" ],
      {
        "Fn::ForEach::GetAttLoop": [
          "Property",
          [ "Arn", "DomainName", "WebsiteURL" ],
          {
            "S3Bucket${Identifier}${Property}": {
              "Value": {
                "Fn::GetAtt": [
                  {"Fn::Sub": "S3Bucket${Identifier}"},
                  {"Ref": "Property"}
                ]
              }
            }
          }
        ]
      }
    ]
  }
}

YAML

AWSTemplateFormatVersion: 2010-09-09
Transform: 'AWS::LanguageExtensions'
Resources:
  'Fn::ForEach::Buckets':
    - Identifier
    - [A, B, C]
    - 'S3Bucket${Identifier}':
        Type: 'AWS::S3::Bucket'
        Properties:
          AccessControl: PublicRead
          MetricsConfigurations:
            - Id: !Sub 'EntireBucket${Identifier}'
          WebsiteConfiguration:
            IndexDocument: index.html
            ErrorDocument: error.html
            RoutingRules:
              - RoutingRuleCondition:
                  HttpErrorCodeReturnedEquals: '404'
                  KeyPrefixEquals: out1/
                RedirectRule:
                  HostName: ec2-11-22-333-44.compute-1.amazonaws.com
                  ReplaceKeyPrefixWith: report-404/
        DeletionPolicy: Retain
        UpdateReplacePolicy: Retain
Outputs:
  'Fn::ForEach::BucketOutputs':
    - Identifier
    - [A, B, C]
    - 'Fn::ForEach::GetAttLoop':
        - Property
        - [Arn, DomainName, WebsiteURL]
        - 'S3Bucket${Identifier}${Property}':
            Value: !GetAtt [!Sub 'S3Bucket${Identifier}', !Ref Property]

The transformed template will be equivalent to the following template:

AWSTemplateFormatVersion: 2010-09-09
Transform: 'AWS::LanguageExtensions'
Resources:
  S3BucketA:
    Type: 'AWS::S3::Bucket'
    Properties:
      AccessControl: PublicRead
      MetricsConfigurations:
        - Id: EntireBucketA
      WebsiteConfiguration:
        IndexDocument: index.html
        ErrorDocument: error.html
        RoutingRules:
          - RoutingRuleCondition:
              HttpErrorCodeReturnedEquals: '404'
              KeyPrefixEquals: out1/
            RedirectRule:
              HostName: ec2-11-22-333-44.compute-1.amazonaws.com
              ReplaceKeyPrefixWith: report-404/
    DeletionPolicy: Retain
    UpdateReplacePolicy: Retain
  S3BucketB:
    Type: 'AWS::S3::Bucket'
    Properties:
      AccessControl: PublicRead
      MetricsConfigurations:
        - Id: EntireBucketB
      WebsiteConfiguration:
        IndexDocument: index.html
        ErrorDocument: error.html
        RoutingRules:
          - RoutingRuleCondition:
              HttpErrorCodeReturnedEquals: '404'
              KeyPrefixEquals: out1/
            RedirectRule:
              HostName: ec2-11-22-333-44.compute-1.amazonaws.com
              ReplaceKeyPrefixWith: report-404/
    DeletionPolicy: Retain
    UpdateReplacePolicy: Retain
  S3BucketC:
    Type: 'AWS::S3::Bucket'
    Properties:
      AccessControl: PublicRead
      MetricsConfigurations:
        - Id: EntireBucketC
      WebsiteConfiguration:
        IndexDocument: index.html
        ErrorDocument: error.html
        RoutingRules:
          - RoutingRuleCondition:
              HttpErrorCodeReturnedEquals: '404'
              KeyPrefixEquals: out1/
            RedirectRule:
              HostName: ec2-11-22-333-44.compute-1.amazonaws.com
              ReplaceKeyPrefixWith: report-404/
    DeletionPolicy: Retain
    UpdateReplacePolicy: Retain
Outputs:
  S3BucketAArn:
    Value: !GetAtt [S3BucketA, Arn]
  S3BucketADomainName:
    Value: !GetAtt [S3BucketA, DomainName]
  S3BucketAWebsiteURL:
    Value: !GetAtt [S3BucketA, WebsiteURL]
  S3BucketBArn:
    Value: !GetAtt [S3BucketB, Arn]
  S3BucketBDomainName:
    Value: !GetAtt [S3BucketB, DomainName]
  S3BucketBWebsiteURL:
    Value: !GetAtt [S3BucketB, WebsiteURL]
  S3BucketCArn:
    Value: !GetAtt [S3BucketC, Arn]
  S3BucketCDomainName:
    Value: !GetAtt [S3BucketC, DomainName]
  S3BucketCWebsiteURL:
    Value: !GetAtt [S3BucketC, WebsiteURL]

Reference replicated AWS::EC2::Instance resources

This example references replicated resources in the Resources section using the generated logical IDs.

JSON

{
  "AWSTemplateFormatVersion": "2010-09-09",
  "Transform": "AWS::LanguageExtensions",
  "Mappings": {
    "Instances": {
      "InstanceType": {
        "B": "m5.4xlarge",
        "C": "c5.2xlarge"
      },
      "ImageId": {"A": "ami-id1"}
    }
  },
  "Resources": {
    "Fn::ForEach::Instances": [
      "Identifier",
      [ "A", "B", "C" ],
      {
        "Instance${Identifier}": {
          "Type": "AWS::EC2::Instance",
          "Properties": {
            "InstanceType": {
              "Fn::FindInMap": [
                "Instances",
                "InstanceType",
                {"Ref": "Identifier"},
                {"DefaultValue": "m5.xlarge"}
              ]
            },
            "ImageId": {
              "Fn::FindInMap": [
                "Instances",
                "ImageId",
                {"Ref": "Identifier"},
                {"DefaultValue": "ami-id-default"}
              ]
            }
          }
        }
      }
    ]
  },
  "Outputs": {
    "SecondInstanceId": {
      "Description": "Instance Id for InstanceB",
      "Value": {"Ref": "InstanceB"}
    },
    "SecondPrivateIp": {
      "Description": "Private IP for InstanceB",
      "Value": {
        "Fn::GetAtt": [
          "InstanceB",
          "PrivateIp"
        ]
      }
    }
  }
}

YAML

AWSTemplateFormatVersion: 2010-09-09
Transform: 'AWS::LanguageExtensions'
Mappings:
  Instances:
    InstanceType:
      B: m5.4xlarge
      C: c5.2xlarge
    ImageId:
      A: ami-id1
Resources:
  'Fn::ForEach::Instances':
    - Identifier
    - [A, B, C]
    - 'Instance${Identifier}':
        Type: 'AWS::EC2::Instance'
        Properties:
          InstanceType: !FindInMap [Instances, InstanceType, !Ref Identifier, DefaultValue: m5.xlarge]
          ImageId: !FindInMap [Instances, ImageId, !Ref Identifier, DefaultValue: ami-id-default]
Outputs:
  SecondInstanceId:
    Description: Instance Id for InstanceB
    Value: !Ref InstanceB
  SecondPrivateIp:
    Description: Private IP for InstanceB
    Value: !GetAtt [InstanceB, PrivateIp]

The transformed template will be equivalent to the following template:

AWSTemplateFormatVersion: 2010-09-09
Transform: 'AWS::LanguageExtensions'
Resources:
  InstanceA:
    Type: 'AWS::EC2::Instance'
    Properties:
      InstanceType: m5.xlarge
      ImageId: ami-id1
  InstanceB:
    Type: 'AWS::EC2::Instance'
    Properties:
      InstanceType: m5.4xlarge
      ImageId: ami-id-default
  InstanceC:
    Type: 'AWS::EC2::Instance'
    Properties:
      InstanceType: c5.2xlarge
      ImageId: ami-id-default
Outputs:
  SecondInstanceId:
    Description: Instance Id for InstanceB
    Value: !Ref InstanceB
  SecondPrivateIp:
    Description: Private IP for InstanceB
    Value: !GetAtt [InstanceB, PrivateIp]