Add asynchronous variant function on Invoke-Command with the help of Runspaces.

PowerShell/function_Invoke-CommandInRunspace.ps1

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+function Invoke-CommandInRunspace { 
+	<#
+	.SYNOPSIS
+	Invoke a command on multiple computers asynchronously
+	.DESCRIPTION
+	To save time run a command on several computers at the same time
+	Written by Floris van Enter | EnterMI
+	.PARAMETER ComputerName
+	The name of the computer(s) to run the code on.
+	.PARAMETER ScriptBlock
+	The block of code to run against the machines
+	.PARAMETER ScriptFile
+	The scriptfile to run against the machines
+	.PARAMETER Throttle
+	How many threads can run simultaniously
+	.EXAMPLE
+	Invoke-CommandInRunspace -Computername 'DC01','DC02','FILE01' -ScriptFile '.\testCopy.ps1'
+	.EXAMPLE
+	Invoke-CommandInRunspace -Computername 'FILE01','SQL01','MAIL01' -ScriptBlock { Get-Process }
+	.LINK
+	https://www.entermi.nl
+	.NOTES
+	This function does nothing with any error handling. So if you write bad code and pass it to the parameters with you will not get the red text. It will just fail.
+	In the future I want to add the error stream of the runspaces. Here I help myself with some notes to have a quick start;
+	* In $Thread(s).Runspace you can find the property 'HadErrors' to check if there were any errors.
+	* Check $Thread(s).Runspace.Streams to get to Error, Verbose etc.
+
+	Tip: Catch the result of this function in a variable so you can check what comes from which computer without having to run it again.
+	#>
+	[CmdletBinding()]
+	Param(
+		[Parameter(Mandatory=$True,
+				   ValueFromPipeline=$True)]
+		[string[]]$ComputerName,
+		[Parameter(Mandatory=$False,
+				   ValueFromPipeline=$False)]
+		[striptblock]$ScriptBlock = $null,
+		[Parameter(Mandatory=$False,
+				   ValueFromPipeline=$False)]
+		[sring]$ScriptFile = $null,
+		[Parameter(Mandatory=$False,
+				   ValueFromPipeline=$True)]
+		[int]$Throttle = 20
+	)
+
+	$Stopwatch = New-Object System.Diagnostics.Stopwatch
+    $Stopwatch.start()
+	Write-Verbose -Message "Begin Invoke-CommandInRunspace"
+	
+	$RunspacePool = [runspacefactory]::CreateRunspacePool(1,$Throttle)
+	$RunspacePool.ApartmentState = "MTA"
+	$RunspacePool.Open()
+
+	$CodeContainer = {
+		Param(
+			[string] $Computer,
+			[scriptblock] $ScriptBlock = $null,
+			[string] $ScriptFile = $null
+		)
+
+		if($ScriptBlock) {
+			Write-Verbose -Message "Run Invoke-Command on $Computer with scriptblock"
+			return (Invoke-Command -ComputerName $Computer -ScriptBlock $ScriptBlock)
+		} elseif($ScriptFile) {
+			Write-Verbose -Message "Run Invoke-Command on $Computer with scriptfile; $ScriptFile"
+			return (Invoke-Command -ComputerName $Computer -FilePath $ScriptFile)
+		} else {
+			return $null
+		}
+	}
+
+	$Threads = @()
+
+	ForEach ($Computer in $ComputerName) {
+        $ParamContainer = @{
+            Computer = $Computer
+            ScriptBlock = $ScriptBlock
+            ScriptFile = $ScriptFile
+        }
+
+		$RunspaceObject = [PSCustomObject]@{
+			Runspace = [PowerShell]::Create()
+			Invoker = $null
+		}
+		$RunspaceObject.Runspace.RunspacePool = $RunspacePool
+		$RunspaceObject.Runspace.AddScript($CodeContainer) | Out-Null
+		$RunspaceObject.Runspace.AddParameters($ParamContainer) | Out-Null
+		$RunspaceObject.Invoker = $RunspaceObject.Runspace.BeginInvoke()
+
+		$Threads += $RunspaceObject
+		Write-Verbose -Message "Finished creating runspace for $Computer. Elapsed time: $($Stopwatch.Elapsed)"
+	}
+	Write-Verbose -Message "Finished creating runspaces for all computers. Elapsed time: $($Stopwatch.Elapsed)"
+	
+	While ($Threads.Invoker.IsCompleted -contains $false) {
+		Write-Host "Waiting for all threads to complete"
+		Start-Sleep -Seconds 3
+	}
+	Write-Host "All threads are completed, time elapsed: $($Stopwatch.Elapsed)"
+
+	ForEach($Thread in $Threads) {
+		$ThreadResults += $Thread.Runspace.EndInvoke($Thread.Invoker)
+		$Thread.Runspace.Dispose()
+	}
+
+	$RunspacePool.Close()
+	$RunspacePool.Dispose()
+
+	Write-Verbose -Message "End Invoke-CommandInRunspace, time elapsed: $($Stopwatch.Elapsed)"
+}