Using Get-Variable to retrieve variables from library in Azure Pipelines-CodePudding

I have a HelloWorld variable library in Azure DevOps containing the variable $foo=bar.

I want to read it in my pipeline using Get-Variable but regardless of the scope I give to my search, the variable is nowhere to be found. It is however, accessible "directly" (as shown below):

variables:
  - group: HelloWorld

stages:
  - stage: test
    jobs:
    - job:
      displayName: Retrieve variables
      steps:
        - task: Powershell@2
          displayName: Variable retrieval
          inputs:
            targetType: inline
            verbose: true
            script: |
              # This works
              Write-Host "Direct access: $(foo)"
              # All of the following returns nothing
              $indirectAccess = Get-Variable -Name "foo" -ValueOnly -ErrorAction SilentlyContinue
              $indirectAccess = Get-Variable -Name "foo" -ValueOnly -ErrorAction SilentlyContinue -Scope Global
              $indirectAccess = Get-Variable -Name "foo" -ValueOnly -ErrorAction SilentlyContinue -Scope Script
              Write-Host "Indirect access: $indirectAccess"

Can I in any way retrieve library variables with Get-Variable?

The reason it's so important for me to know whether it's possible is because I need to retrieve values with variables which name is a variable itself... And so far I haven't found a way to do it except than with Get-Variable.

CodePudding user response：

$(foo) is Azure's macro expansion syntax, meaning that the value of the variable is injected into the script, so the script doesn't know the name of the variable whose value was used.
From what I understand, Azure also defines variables as environment variables, with the original name transformed to all-uppercase, with . replaced with _, if applicable. Thus, try accessing the variable as:
- $env:FOO (direct access)
- $name = 'FOO'; Get-Content env:$name (indirect access)

Note that Get-Variable only works for regular (PowerShell-only) variables, not for environment variables; the latter must be accessed via the env: drive, as shown above.