Unable to pass variable to Invoke-command - powershell

Question

This is my first time using the workflow, could anyone explain me what is wrong with the code ?
Powershell version is 5.1
$Script = {
return(Get-Service WINRM).Status
}
workflow pushupdate{
##Select OUs
$OUs=
"OU=Workstations,DC=contoso,DC=com",
"OU=Notebooks,DC=contoso,DC=com"
foreach -parallel ($computer in ($Ous | foreach { Get-ADComputer -Filter {enabled -eq $true} -SearchBase $_} | Select Name)) {
if ((Test-Connection $computer.name -Quiet) -eq "True") {
Write-Output "Running update on:" $computer.name
InlineScript {
Invoke-Command -ComputerName $computer.name -Script $Script -Verbose
}
}
else{
Write-Output $computer.name "unreachable!"
}
}
}
pushupdate
I keep getting the error:
Invoke-Command : Cannot validate argument on parameter 'ScriptBlock'. The argument is null. Provide a valid value for
the argument, and then try running the command again.
At pushupdate:245 char:245

Answer 1

Variables defined outside the InlineScript block are unknown to the Invoke-Command cmdlet unless you use them as $using:<varname>.
It seems however that you cannot do that with a variable which is actually a scriptblock. That needs to be defined inside the InlineScript itself:
workflow pushupdate{
# Select OUs
$OUs = "OU=Workstations,DC=contoso,DC=com", "OU=Notebooks,DC=contoso,DC=com"
# get a string array of computerNames
$computers = ( $Ous | ForEach-Object { Get-ADComputer -Filter "Enabled -eq 'True'" -SearchBase $_ } ).Name
foreach -parallel ($computer in $computers) {
if (Test-Connection -ComputerName $computer -Quiet -Count 1) {
Write-Output "Running update on:" $computer
InlineScript {
# define the scriptblock here
$script = {(Get-Service WINRM).Status}
Invoke-Command -ComputerName $using:computer -ScriptBlock $Script -Verbose
}
}
else{
Write-Output "$computer unreachable!"
}
}
}
pushupdate