How do I kill main\parent task through background job? - powershell

Question

I have a requirement where I need to kill\stop main task if it has been running for a long time. I am thinking of creating a background job that monitors the time and kills the main job after timeout with proper message but I'm not sure how to do that.
Something like this..
function Kill-MainTask{
$sb = {
Start-Sleep -Seconds 5
throw "main task should end"
}
$job1 = Start-Job -ScriptBlock $sb
Write-Host "main task running"
Start-Sleep -Seconds 10
#This statement should not run
Write-Host "main task not finished"
}
Kill-MainTask
When I call Kill-MainTask function it should print "mian task running" but after 5 seconds should throw.

Answer 1

There are several existing samples that show how to use this main and child job monitoring use case. See the below sample and resource links.
Monitoring the Progress of a PowerShell Job
Quick Tip To Find Out What Your Background Jobs Are Doing
Example:
This is a simple script that create 5 background jobs (as
defined by $Num). After submitting we’ll begin monitoring the
progress of the job. We define $TotProg as 0 to start, then query the
StatusDescription–
and since this returns an array we only want the
last element, hence the -1 element reference–and add it to our
$TotProg. After that we check if $TotProg is greater than 0
(otherwise you’ll get a divide by zero error), display our progress
bar, wait a few seconds and loop again. Go ahead and run the code
(don’t step through it in an ISE, to really see what I mean you have
to just run it).
$Num = 5
$Jobs = #()
ForEach ($Job in (1..$Num))
{ $Jobs += Start-Job -ScriptBlock {
$Count = 1
Do {
Write-Progress -Id 2 -Activity "Background Job" -Status $Count -PercentComplete 1
$Count ++
Start-Sleep -Seconds 4
} Until ($Count -gt 5)
}
}
$Total = $Num * 5
Write-Progress -Id 1 -Activity "Watching Background Jobs" -Status "Waiting for background jobs to started" -PercentComplete 0
Do {
$TotProg = 0
ForEach ($Job in $Jobs)
{ Try {
$Info =
$TotProg += ($Job | Get-Job).ChildJobs[0].Progress.StatusDescription[-1]
}
Catch {
Start-Sleep -Seconds 3
Continue
}
}
If ($TotProg)
{ Write-Progress -Id 1 -Activity "Watching Background Jobs" -Status "Waiting for background jobs to complete: $TotProg of $Total" -PercentComplete (($TotProg / $Total) * 100)
}
Start-Sleep -Seconds 3
} Until (($Jobs | Where State -eq "Running").Count -eq 0)
$Jobs | Remove-Job -Force
Write-Progress -Id 1 -Activity "Watching Background Jobs" -Status "Completed! $Total of $Total" -PercentComplete 100
Start-Sleep -Seconds 1
Write-Progress -Id 1 -Activity "Watching Background Jobs" -Status "Completed! $Total of $Total" -Completed
Or this approach
Creating A Timeout Feature In Your PowerShell Scripts
# define a timeout
$Timeout = 10 ## seconds
# Code for the scriptblock
$jobs = Get-Job
$Condition = {param($jobs) 'Running' -notin $jobs.State }
$ConditionArgs = $jobs
# define how long in between checks
$RetryInterval = 5
# Start the timer
$timer = [Diagnostics.Stopwatch]::StartNew()
# Invoke code actions
while (($timer.Elapsed.TotalSeconds -lt $Timeout) -and (& $Condition $ConditionArgs)) {
## Wait a specific interval
Start-Sleep -Seconds $RetryInterval
## Check the time
$totalSecs = [math]::Round($timer.Elapsed.TotalSeconds,0)
Write-Verbose -Message "Still waiting for action to complete after [$totalSecs] seconds..."
}
# The action either completed or timed out. Stop the timer.
$timer.Stop()
# Return status of what happened
if ($timer.Elapsed.TotalSeconds -gt $Timeout)
{ throw 'Action did not complete before timeout period.' }
else
{ Write-Verbose -Message 'Action completed before the timeout period.' }