Fn::FindInMap enhancements - AWS CloudFormation
DeclarationParametersExampleSupported functions

Fn::FindInMap enhancements

When you add the AWS::LanguageExtensions transform in a AWS CloudFormation template, you can use intrinsic functions to define the fields of Fn::FindInMap. You can also use a new optional field to return a default value if a mapping is not found.

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

For more information about the Fn::FindInMap intrinsic function, see Fn::FindInMap.

Declaration

JSON

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

YAML

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

DefaultValue

The value that Fn::FindInMap will resolve to if the TopLevelKey and/or SecondLevelKey can not be found from the MapName map. This field is optional.

All parameters MapName, TopLevelKey, SecondLevelKey, and DefaultValue can be an intrinsic function as long as it's able to resolve to a valid value during the transform.

Example

The following is an example of using intrinsic functions 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]
#...

The following is an example of using default values:

JSON

{
  //...
    "Transform": "AWS::LanguageExtensions",
    //...
    "Fn::FindInMap": [
      "InstanceConfiguration",
      { "Ref": "AWS::Region" },
      "Type",
      { "DefaultValue": "m5.small" }
    ]
  //...
}

YAML

Transform: 'AWS::LanguageExtensions'
#...
    !FindInMap 
        - 'InstanceConfiguration'
        - !Ref 'AWS::Region'
        - 'Type'
        - DefaultValue: m5.small
#...

Supported functions

You can use the following functions in the parameters of Fn::FindInMap: enhancements: