PS_Threading

##AH - AdilHindistan - Multi-Threading with PowerShell
Ref: http://bits_video.s3.amazonaws.com/022012-SUPS01_archive.f4v by Tobias Weltner

## Run new thread synchronously
$scriptBlock = {some code here}
$newThread = [Powershell]::Create().AddScript($Code)
$newThread.Invoke() # does not help much, as it stops foreground processing until its job is complete


## Run new thread asynchronously (as if sending a job to the background)
$scriptBlock = {some code here}
$newThread = [Powershell]::Create().AddScript($Code)
$handle = $newThread.BeginInvoke() ##does not wait for code to finish, you just get a handle
while (!$handle.IsCompleted) {
  # wait, show-progress, or do something else
}
$newThread.EndInvoke($handle)  # Get the job results back

# Cleanup
$newThread.Runspace.Close()
$newThread.Dispose()

## Running (background)a thread in STA mode
$scriptBlock1 = {some code here}
$scriptBlock2 = {some other code here}

$Runspace = [RunSpaceFactory]::CreateRunspace()
$Runspace.ApartmentState= 'STA'
$RunSpace.Open()

$newThread = [PowerShell]::Create()
$newThread.RunSpace= $RunSpace
[void]$newThread.AddScript($ScriptBlock1).AddScript($ScriptBlock2).AddArgument("Some arg").AddArgument("Some other args")
$newThread.Invoke()

## MultiThreading

$scriptBlock = {
  
}

$throttleLimit = 10  # 10 at a time
$iss = [System.Management.Automation.RunSpaces.InitialSessionState]::CreateDefault()
$pool = [RunSpaceFactory]::CreateRunSpacePool(1,$throttleLimit, $iss, $Host)
$pool.Open()

## Basic, when you need to get results to console, or do something but do not need the data back
For ($i=1; $i -le 100; $i++) {
  $newThread = [PowerShell]::Create().AddScript($scriptBlock).AddArgument($i)
  $newThread.RunSpacePool = $pool
  $handle = $newThread.BeginInvoke()
}

## More useful, you get the handles back so you can do something with the data
$threads = @()
$handles = for ($i=1 ; $i -lt 100; $i++){
  $newThread=[PowerShell]::Create().AddScript($scriptBlock).AddArgument($i)
  $newThread.RunspacePool = $pool
  $newThread.BeginInvoke()
  $thread += $newThread
}

## loop while waiting for all threads to complete. Clean up the ones done.
do {
  $i = 0
  $done = $true
  foreach ($handle in $handles){
    if ($handle.isCompleted){
      $threads[$i].EndInvoke($handle)
      $threads[$i].Dispose()
      $handles[i] = $null
    } else {
      $done = $false
    }
    $i++
  }
  
  if (!$done) { start-sleep -sec 1}
} until ($done)