Powershell script works interactively, not within a script

Question

Code works interactively, in a PS1 file it does not. to reproduce, open powershell, paste the function and then run get-job to see the task. type get-job | remove-job when done and then put code in a PS1 file, it only runs the first two, then exits.

function RunJobFromQueue
{

    if( $queue.Count -gt 0)

    {
        $cn = $queue.Dequeue()

        $j = Start-Job -name $cn -ScriptBlock {param($x); Start-Sleep -Seconds 10;"output - " + $x} -ArgumentList $cn

        Register-ObjectEvent -InputObject $j -EventName StateChanged -Action {RunJobFromQueue; Unregister-Event $eventsubscriber.SourceIdentifier; Remove-Job $eventsubscriber.SourceIdentifier } | Out-Null
    }

}

$maxConcurrentJobs = 2
$jobInput = "test1", "test2", "test3", "test4", "test5", "test6"
$queue = [System.Collections.Queue]::Synchronized( (New-Object System.Collections.Queue) )
foreach($item in $jobInput) {$queue.Enqueue($item)}

for( $i = 0; $i -lt $maxConcurrentJobs; $i++){RunJobFromQueue}

Answer 1

In my opinion: it fails in script because:

• you start script, define function and variables in script scope
• script exits once it defines 2 initial jobs
• job complete, registered action runs, but your function is not visible to it (defined in script scope) so it fails.

Two options to solve/ work around it:

• define RunJobFromQueue function in global scope (function Global:RunJobFromQueue, $global:queue)
• dot-source a script (. .\YourScript.ps1)

This works fine interactively, because in that case you define function/ variable in global scope, so -Action can find them just fine.