Execute code if a PowerShell script is terminated - powershell

Question

Is it possible to force the execution of some code if a PowerShell script is forcefully terminated? I have tried try..finally and Traps, but they both don't seem to work, at least when I press Ctrl-C from PowerShell ISE.
Basically, I have a Jenkins build that executes a PowerShell script. If for any reason I want to stop the build from within Jenkins, I don't want any subprocess to lock the files, hence keeping my build project in a broken state until an admin manually kill the offending processes (nunit-agent.exe in my case). So I want to be able to force the execution of a code that terminates nunit-agent.exe if this happens.
UPDATE: As #Frode suggested below, I tried to use try..finally:
$sleep = {
try {
Write-Output "In the try block of the job."
Start-Sleep -Seconds 10
}
finally {
Write-Output "In the finally block of the job."
}
}
try {
$sleepJob = Start-Job -ScriptBlock $sleep
Start-Sleep -Seconds 5
}
finally {
Write-Output "In the finaly block of the script."
Stop-Job $sleepJob
Write-Output "Receiving the output from the job:"
$content = Receive-Job $sleepJob
Write-Output $content
}
Then when I executed this and broke the process using Ctrl-C, I got no output. I thought that what I should got is:
In the finally block of the script.
Receiving the output from the job:
In the try block of the job.
In the finally block of the job.

Answer 1

I use try {} finally {} for this. The finally-block runs when try is done or if you use ctrl+c, so you need to either run commands that are safe to run either way, ex. it doesn't matter if you kill a process that's already dead..
Or you could add a test to see if the last command was a success using $?, ex:
try {
Write-Host "Working"
Start-Sleep -Seconds 100
} finally {
if(-not $?) { Write-Host "Cleanup on aisle 5" }
Write-Host "Done"
}
Or create your own test (just in case the last command in try failed for some reason):
try {
$IsDone = $false
Write-Host "Working"
Start-Sleep -Seconds 100
#.....
$IsDone = $true
} finally {
if(-not $IsDone) { Write-Host "Cleanup on aisle 5" }
Write-Host "Done"
}
UPDATE: The finally block will not work for output as the pipeline is stopped on CTRL+C.
Note that pressing CTRL+C stops the pipeline. Objects that are sent to
the pipeline will not be displayed as output. Therefore, if you
include a statement to be displayed, such as "Finally block has run",
it will not be displayed after you press CTRL+C, even if the Finally
block ran.
Source: about_Try_Catch_Finally
However, if you save the output from Receive-Job to a global variable like $global:content = Receive-Job $sleepJob you can read it after the finally-block. The variable is normally created in a different local scope and lost after the finally-block.