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Fn::FindInMap enhancements - AWS CloudFormation
DeclarationParametersExamplesSupported functionsRelated resources

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Fn::FindInMap enhancements

The AWS::LanguageExtensions transform enhances the functionality of the Fn::FindInMap intrinsic function in CloudFormation templates.

The standard Fn::FindInMap function supports only Fn::FindInMap and Ref as nested intrinsic functions. The AWS::LanguageExtensions transform removes this limitation, allowing you to use a wider range of intrinsic functions to define the parameters of Fn::FindInMap.

Note

The DefaultValue parameter for Fn::FindInMap no longer requires the AWS::LanguageExtensions transform. You can use DefaultValue in any CloudFormation template. For more information, see Fn::FindInMap.

Declaration

JSON

{ "Fn::FindInMap" : [ "MapName", "TopLevelKey", "SecondLevelKey"] }

If you want to specify a fallback value for when a key isn't found in the mapping, include a DefaultValue:

{ "Fn::FindInMap" : [ "MapName", "TopLevelKey", "SecondLevelKey", {"DefaultValue": "DefaultValue"}] }

YAML

Syntax for the full function name:

Fn::FindInMap: [ MapName, TopLevelKey, SecondLevelKey ]

Syntax for the short form:

!FindInMap [ MapName, TopLevelKey, SecondLevelKey ]

If you want to specify a fallback value for when a key isn't found in the mapping, include a DefaultValue:

Syntax for the full function name:

Fn::FindInMap:
  - MapName
  - TopLevelKey
  - SecondLevelKey
  - DefaultValue: DefaultValue

Syntax for the short form:

!FindInMap
  - MapName
  - TopLevelKey
  - SecondLevelKey
  - DefaultValue: DefaultValue

Parameters

With the AWS::LanguageExtensions transform, the parameters MapName, TopLevelKey, SecondLevelKey, and DefaultValue can each be an intrinsic function, as long as it resolves to a valid value during the transform.

Examples

The following examples demonstrate how to use intrinsic functions in the parameters of Fn::FindInMap when you add the AWS::LanguageExtensions transform.

Using intrinsic functions to define the top level key

The following is an example of using a Fn::FindInMap function with the Fn::Select and Fn::Split intrinsic functions embedded inside it to define the top level key.

JSON

{
  //...
  "Transform": "AWS::LanguageExtensions",
  //...
      "Fn::FindInMap": [
        "MyMap",
        {
          "Fn::Select": [
            0,
            {
              "Fn::Split": [
                "|",
                { "Ref": "InputKeys" }
              ]
            }
          ]
        },
        "SecondKey"
      ]
//...
}

YAML

Transform: 'AWS::LanguageExtensions'
#...
    !FindInMap: [MyMap, !Select [0, !Split [|, !Ref InputKeys]], SecondKey]
#...

Supported functions

You can use the following functions in the parameters of Fn::FindInMap with the AWS::LanguageExtensions transform:

Related resources

For more information and examples that show how to use the Fn::FindInMap intrinsic function, including the DefaultValue parameter, see Fn::FindInMap.

For more information about the AWS::LanguageExtensions transform, see AWS::LanguageExtensions transform.