Why is the command in ScriptBlock not working? - powershell

Question

I want to measure elapsed time from a cmdlet
Invoke-ASCmd
I am using it the following way
$elapsedTime = [system.diagnostics.stopwatch]::StartNew()
$j = Start-Job -ScriptBlock {
Invoke-ASCmd –InputFile $XMLF -Server "$Server[-1]" >$output_file
}
do {
write-progress -activity "Syncing..." -status "$([string]::Format("Time Elapsed: {0:d2}:{1:d2}:{2:d2}", $elapsedTime.Elapsed.hours, $elapsedTime.Elapsed.minutes, $elapsedTime.Elapsed.seconds))"
#-percentcomplete ($_/10);
Start-Sleep -milliseconds 250
} while ($j.State -eq 'Running')
Receive-Job -Job $j
$elapsedTime.stop()
However, all i see on the console is a flashing blue progress bar that doesnt appear to be even elapsing the time at all...and frankly, i dont even think the scriptblock is being executed at all (the Invoke cmdlet)
why is that?
and it appears to last 1 second
I know that the scriptblock is not working because the syncing is supposed to take at least 20 seconds so something is wrong
Also, i would like to get the percentage (circles animation/prgress), this is not working
-percentcomplete ($_/10);
One last thing, i would like to save the final elapsed time to a variable $FinalTime, would i do it inside the loop or outside?
I am combining these two answers here and modifying for my needs:
https://stackoverflow.com/a/9813370/8397835
https://stackoverflow.com/a/8468024/8397835

Answer 1

Yes, the progress is quick because it takes PowerShell 1 second to load the module before erroring out. We can see the error message with Receive-Job:
PS C:\> Receive-Job $j
InputFile "" not found
+ CategoryInfo : InvalidData: (:) [Invoke-ASCmd], FileNotFoundException
+ FullyQualifiedErrorId : DataValidation,Microsoft.AnalysisServices.PowerShell.Cmdlets.ExecuteScriptCommand
+ PSComputerName : localhost
InputFile "" not found indicates that the variables were empty. They are empty because you can't reference variables directly inside of the Script Block. Using Start-Job, you must pass it into the Script Block as an argument, and receive it as a parameter inside the Script Block. Something like this:
$j = Start-Job -Arg $XMLF, $Server, $output_file -ScriptBlock {
Param($XMLF, $Server, $output_file)
Invoke-ASCmd –InputFile $XMLF -Server "$Server" >$output_file
}
As for progress, since there is no "Direct" way to measure how far the progress is to 100%, we "fake it". Since we know that it takes about 20 seconds to execute, we simply have our progress do some math using the time from 0 to 20 as our 0 to 100 progress:
[Math]::Min(100*($elapsedTime.Elapsed.Seconds / 20),100)
Essentially use $elapsedTime for 0 to 100 percent over 20 seconds. That 20 seconds can be changed to any number that is close to the approximate execution time. Using [Math]::Min we ensure that if it takes longer than 20 seconds, the progress will show 100 percent, but the status will continue to show the time. So it would look like this:
do {
write-progress -activity "Syncing..." -status "$($elapsedTime.Elapsed.ToString())" -percentcomplete ([Math]::Min(100*($elapsedTime.Elapsed.Seconds / 20),100));
Start-Sleep -Milliseconds 250
} while ($j.State -eq 'Running')