VSTS: Pass build/release variables into Powershell script task

It is worth mentioning here, that secret variables are not passed into scripts as environment variables (env: in PS). So accessible only if passed as parameters for a script, eg. -MyPassword $(Password). See https://docs.microsoft.com/en-us/vsts/pipelines/build/variables?view=vsts&tabs=batch#secret-variables

The variables have already been passed to PowerShell script when the build start. If I understand your question correctly, you want to use these variables together instead of specifying them one by one like following:

PrepareAppSettings.ps1 -websiteName "MyWebApp" -appsettings $(AllVariables)

Then there isn't any way to do this.

If you want to reduce the strings passed to the PowerShell script, you can set the variable as following:

VariableName: MyRandomService | Value:"MyRandomService" = xxxxxxxx

Then you just need to call the PowerShell script with variable name passed.

Build Variables are automatically passed to all the PowerShell scripts as environment variables.

So if you have defined a variable myVar in the Variables section. You can access it as $env:myVar in your script. One thing to note here is that . is converted to a _. For eg. if your variable is myVar.config, you will access it in your script as $env:myVar_config.

The available variables also include variables such as branch name, build number etc. To see all the available variables, run a dummy build/release definition and add a PowerShell task with inline type and run Get-ChildItem Env:. This will show you all the available environment variables and you can see all your custom defined variables.

More details are available here