Powershell Progress Counter Scope Issue - Remote Session resetting progress tracker - powershell

Question

I'm trying to track progress and I think it's a scope issue. The two functions are located in Functions.ps1 and are called from another script main.ps1. The progress is tracked fine until it gets the the invoke-command in Function 1. Why is the remote session resetting progress tracker? Here is what the code and output look like:
main.ps1
. "C:\Functions.ps1" #dot source so functions available
$steps = 10
Write-ProgressHelper -stepTotal $steps -Status "reset"
Functions.ps1
Function Write-ProgressHelper {
param (
[int]$stepTotal,
[string]$Status
)
Switch ($Status)
{
"run" {
$global:Counter++
Write-Host "$Counter"
Write-Progress -Activity "STIG" -PercentComplete (($Counter / $stepTotal) * 100)
}
"reset" {
$Counter = 0
Write-Host "Counter Reset"
}
}
}
Function 1 {
Write-Host "StepNumber:1"
Write-ProgressHelper -stepTotal $steps -Status "run"
#some code here
Write-Host "StepNumber:2"
$sysinfo = {
. "C:\Functions.ps1" #dot source so write-progresshelper is available within invoke-command
#more code
Write-Host "StepNumber:3"
Write-ProgressHelper -stepTotal $using:steps -Status "run"
Write-Host "StepNumber:4"
#more code
Write-ProgressHelper -stepTotal $using:steps -Status "run"
}#end sysinfo
Invoke-Command -ComputerName $Servers -ScriptBlock $sysinfo
Write-Host "StepNumber:10"
Write-ProgressHelper -stepTotal $using:steps -Status "run"
}#end Function 1
There are 10 Steps to track in Function 1 and then I output the $counter variable. Step 1,2, and 10 are within Function 1. Steps 3-9 are in invoke-command session. I tried declaring the counter as global and that didn't work (I had it declare with script scope in order for it to increment at all). Here is the output:
StepNumber:1
1
StepNumber:2
2
StepNumber:3
1
StepNumber:4
2
StepNumber:5
3
StepNumber:6
4
StepNumber:7
5
StepNumber:8
6
StepNumber:9
7
StepNumber:10
3

Answer 1

Remote variables don't get saved back to local variables (See: about_Remote_Variables). So even though you define $counter as a $global variable, it is only global within that PowerShell session. It is not available on the remote computer. When the Invoke-Command is called, a new PowerShell session is created on that computer, and $counter is reset to 0. It will increment and return. The existing value of the $counter variable on the local computer is retained, and continues on.
When we look at what the value of $global:Counter is, we have to realize that the variable is only available on the computer that the script is executing:
Local Computer Server1
----------------- -------------------
$global:Counter $global:Counter
_________________ ___________________
StepNumber:1 1 (0)
1
StepNumber:2 2 (0)
2
Invoke-Command -Computer Server1
|---------------->
StepNumber:3 (2) 1
1
StepNumber:4 (2) 2
2
StepNumber:5 (2) 3
3
StepNumber:6 (2) 4
4
StepNumber:7 (2) 5
5
StepNumber:8 (2) 6
6
StepNumber:9 (2) 7
7
<-----------------|
StepNumber:10 3
3
See how the value of $global:Counter is incremented for step 1 and 2. When the Invoke-Computer is run, PowerShell creates a new PowerShell session on the remote computer, where the value of $global:Counter is 0. That is why you see the value apparently "reset". After steps 3-9 execute, the process returns to the local computer, where the value of $global:Counter is still 2. That is why you see for Step 10, it returns 3.
To have an effective counter, you will have to pass the counter value to the Invoke-Command as an AgrumentList and return the value back.