VSTS validate and warn user if task requires SYSTEM_ACCESSTOKEN - azure-devops

Question

Is there any way I can warn my user when they are configuring their task that this particular task requires use of the SYSTEM_ACCESSTOKEN variable? I have added a check in my task:
if($env:SYSTEM_ENABLEACCESSTOKEN -eq $false){throw "OAuth Token Access not enabled! Set in the Agent Phase Options."}
That is ok, but the user won't find out until they have already kicked off a release which in this cause would fail. I didn't see anything in the extension manifest.

Answer 1

Tasks don't need explicit access to the OAuth token. Tasks are always privileged and can request the access token through the VSTS Task SDK.
To access the REST APIs use:
$vssCredentials = Get-VstsVssCredentials
$collectionUrl = New-Object System.Uri((Get-VstsTaskVariable -Name 'System.TeamFoundationCollectionUri'
-Require))
Add-Type -LiteralPath "$PSScriptRoot\Microsoft.TeamFoundation.Core.WebApi.dll"
$projectHttpClient = New-Object Microsoft.TeamFoundation.Core.WebApi.ProjectHttpClient($collectionUrl,
$vssCredentials)
$projectHttpClient.GetProjects().Result
See also:
https://github.com/Microsoft/vsts-task-lib/blob/master/powershell/Docs/FullHelp/Get-VstsTfsClientCredentials.md
https://github.com/Microsoft/vsts-task-lib/blob/master/powershell/Docs/FullHelp/Get-VstsVssCredentials.md
If needed, you can also extract the token from the returned credential.
The Access to OAuth token checkbox is only required when a custom script needs access to the Build's user token.