TFS2015 Powershell on Target Machine - Set a variable in the release process / Find a free port on a remote server - powershell

Question

I want to get a free port from my deployment server. To achieve this I run this powershell-script and I want to set the passed in variable in my release process. Is there a good solution to set a variable in my release process which was calculated on a remote server (the deployment target in this case).
I also tried to use write-host to set the variable but than the script crashed in my release process..
Param(
[string]$variableName
)
$port = 1000
for($i=1000;$i -le 65000;$i++){
$free = netstat -o -n -a | findstr ":$i"
IF([string]::IsNullOrEmpty($free)) {
$port = $i
break;
}
}
Write-Output "##vso[task.setvariable variable=$variableName]$port"
Or is there a better way to find a free port on a remote deployment target?

Answer 1

For anyone needing a solution to set a build/release variable from a "PowerShell on Target Machine" task this worked for me:
Write-Verbose ("##vso[task.setvariable variable=SomeVariable]{0}" -f $theValue) -verbose

Answer 2

Based on my test, set variable isn’t working in PowerShell On Target Machine task.
You can store variable value in a file, then read data from that file.

Answer 3

here is the correct script. I just use the normal powershell task and run the following script, than I can set the variable correctly.
Param(
[string]$remoteServer,
[string]$variableName
)
Write-Host "Parameters: Server: " $remoteServer
$port = 80
$usedPorts = invoke-command -ComputerName $remoteServer -ScriptBlock { return Get-WebBinding }
Write-Host "Got Ports: $usedPorts"
for($i=8000;$i -le 65000;$i++){
$free = $usedPorts | findstr ":$i"
IF([string]::IsNullOrEmpty($free)) {
$port = $i
break;
}
}
Write-Host "Found port: " $port
Write-Host "##vso[task.setvariable variable=$variableName;]$($port)"
exit 0