Public/Intrinisic Functions/Add-FnImportValue.ps1
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function Add-FnImportValue { <# .SYNOPSIS Adds the intrinsic function "Fn::ImportValue" to a resource property .DESCRIPTION The intrinsic function Fn::ImportValue returns the value of an output exported by another stack. You typically use this function to create cross-stack references. In the following example template snippets, Stack A exports VPC security group values and Stack B imports them. Note: The following restrictions apply to cross-stack references: * For each AWS account, Export names must be unique within a region. * You can't create cross-stack references across regions. You can use the intrinsic function Fn::ImportValue to import only values that have been exported within the same region. * For outputs, the value of the Name property of an Export can't use Ref or GetAtt functions that depend on a resource. * Similarly, the ImportValue function can't include Ref or GetAtt functions that depend on a resource. * You can't delete a stack if another stack references one of its outputs. * You can't modify or remove an output value that is referenced by another stack. .LINK http://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/intrinsic-function-reference-importvalue.html .PARAMETER ValueToImport The stack output value that you want to import. .EXAMPLE Add-FnImportValue -ValueToImport (Add-FnSub -String "`${NetworkStackNameParameter}-SubnetID") # When the template is exported, this will convert to: {"Fn::ImportValue":{"Fn::Sub":"${NetworkStackNameParameter}-SubnetID"}} .NOTES You can use the following functions in the Fn::ImportValue function. The value of these functions can't depend on a resource. Fn::Base64 Fn::FindInMap Fn::If Fn::Join Fn::Select Fn::Split Fn::Sub Ref .FUNCTIONALITY Vaporshell #> [OutputType('Vaporshell.Function.ImportValue')] [cmdletbinding()] Param ( [parameter(Mandatory = $true,Position = 0)] [ValidateScript({ $allowedTypes = "Vaporshell.Condition.If","Vaporshell.Function.Base64","Vaporshell.Function.FindInMap","Vaporshell.Function.Join","Vaporshell.Function.Select","Vaporshell.Function.Split","Vaporshell.Function.Sub","Vaporshell.Function.Ref","System.String" if ([string]$($_.PSTypeNames) -match "($(($allowedTypes|ForEach-Object{[RegEx]::Escape($_)}) -join '|'))") { $true } else { throw "The ValueToImport parameter only accepts the following types: $($allowedTypes -join ", "). The current types of the value are: $($_.PSTypeNames -join ", ")." } })] $ValueToImport ) $obj = [PSCustomObject][Ordered]@{ "Fn::ImportValue" = $ValueToImport } $obj | Add-ObjectDetail -TypeName 'Vaporshell.Function','Vaporshell.Function.ImportValue' Write-Verbose "Resulting JSON from $($MyInvocation.MyCommand): `n`n`t$($obj | ConvertTo-Json -Depth 5 -Compress)`n" } |