How to reference Script Arguments in DSC Script Resource - ms-release-management

Question

I'm using TFS 2015 Update 2 to create a release. One of my release steps is a "PowerShell on Target Machines" task that I'm using to apply a DSC configuration.
I'd like to use the Script Arguments field to pass in parameters from TFS to the DSC script.
My script looks like this:
Param(
[string]$data
)
configuration ApplyConfig
{
Script Backup {
SetScript = {
#do some stuff with $data
}
TestScript = {
Write-Output "Print param"
Write-Output $data
return $true
}
GetScript = {
return #{"Test" = "test data"}
}
}
}
ApplyConfig
The Script Arguments field contains this:
-Destination "$(ApplicationPath)"
However, at this point, $data seems to always be null. How can I get the argument defined in the Script Arguments field into my Script Resource?

Answer 1

When you reference $data in the TestScript you need the 'using' scope:
TestScript = {
Write-Output "Print param"
Write-Output $using:data
return $true
}
The TestScript executes on a different PowerShell context; 'using' allows you to copy the value of $data across those contexts.

Answer 2

My recommendation for flexibility is to declare a configuration hash table in your DSC script and pass parameters in to configure it. My Continuous Delivery with TFS / VSTS – Server Configuration and Application Deployment with Release Management blog post has a complete walkthrough of how to use DSC and Release Management in TFS 2015 Update 2.
Getting the parameters in then becomes a case of declaring your parameters as follows:
param(
[Parameter(Position=1)]
[string]$myFirstParameter,
[Parameter(Position=2)]
[string]$mySecondParameter
)
and then passing in the value in either directly:
Script Arguments field contains 'myFirstValue' 'mySecondValue'
or better as variables:
Script Arguments field contains $(myFirstValue) $(mySecondValue)