Runspace Example

# Modified Example From : https://blogs.technet.microsoft.com/heyscriptingguy/2015/11/28/beginning-use-of-powershell-runspaces-part-3/
# Added import of all current session functions into the sessionstate for the runspacepool 


# --------------------------------------------------
#region - Setup custom functions
# --------------------------------------------------

# Create custom function to import into runspace session state
Function ConvertTo-Hex {
    Write-Output "Function Ran"
}
#endregion


# --------------------------------------------------
#region - Import Session Functions
# --------------------------------------------------
# Import functions from the current session into the RunspacePool sessionstate

# Create runspace session state
$InitialSessionState = [System.Management.Automation.Runspaces.InitialSessionState]::CreateDefault()

# Import all session functions into the runspace session state from the current one
Get-ChildItem Function:\ | Where-Object {$_.name -notlike "*:*"} |  select name -ExpandProperty name |
ForEach-Object {       

    # Get the function code
    $Definition = Get-Content "function:\$_" -ErrorAction Stop

    # Create a sessionstate function with the same name and code
    $SessionStateFunction = New-Object System.Management.Automation.Runspaces.SessionStateFunctionEntry -ArgumentList "$_", $Definition

    # Add the function to the session state
    $InitialSessionState.Commands.Add($SessionStateFunction)
}
#endregion



# --------------------------------------------------
#region - Runspace Pool Setup
# --------------------------------------------------

# Max runspace threads
$Limit = 10

# Create a Runspace Pool that uses the defined session state
$RunspacePool = [RunspaceFactory]::CreateRunspacePool($InitialSessionState)
$RunspacePool.SetMinRunspaces(1) | Out-Null
$RunspacePool.SetMaxRunspaces($Limit) | Out-Null

$PowerShell = [powershell]::Create()
$PowerShell.RunspacePool = $RunspacePool

$RunspacePool.Open()

#endregion


# --------------------------------------------------
#region - Perform Tasks in Background Threads
# --------------------------------------------------
$jobs = New-Object System.Collections.ArrayList

1..50 | ForEach {

    $PowerShell = [powershell]::Create() 

    $PowerShell.RunspacePool = $RunspacePool   

    # Set parameters and values to import into the runspace that will be used in the script
    $ParamList = @{
        Param1 = "Hello World"
        Param2 = "$_" 
    }    
    
    # Set the script to be run
    $MyScript = {

        Param (
            $Param1,
            $Param2
        )

        $ThreadID = [appdomain]::GetCurrentThreadId()

        write-output“ThreadID: $ThreadID” -Verbose             
        write-output“PID: $PID” -Verbose             

        [pscustomobject]@{

            Param1 = $param1
            Param2 = $param2
            ProcessID = $PID
            Thread = $ThreadID
            FunctionData = ConvertTo-Hex        
        }                                     
           
    }

    [void]$PowerShell.AddScript($MyScript)

    [void]$PowerShell.AddParameters($ParamList)

    $Handle = $PowerShell.BeginInvoke()

    $temp = '' | Select PowerShell,Handle

    $temp.PowerShell = $PowerShell

    $temp.handle = $Handle        

    [void]$jobs.Add($Temp)   

    <#
    write-output (“Available Runspaces in RunspacePool: {0}” -f $RunspacePool.GetAvailableRunspaces())

    write-output (“Remaining Jobs: {0}” -f @($jobs | Where {

        $_.handle.iscompleted -ne ‘Completed’

    }).Count)     

    #>
}
#endregion


# --------------------------------------------------
#region - Clean Up
# --------------------------------------------------
#Verify completed
<#write-output (“Available Runspaces in RunspacePool: {0}” -f $RunspacePool.GetAvailableRunspaces())
write-output (“Remaining Jobs: {0}” -f @($jobs | Where {
    $_.handle.iscompleted -ne ‘Completed’

}).Count)#>

# Empty the jobs
$return = $jobs | ForEach {

    $_.powershell.EndInvoke($_.handle)

    $_.PowerShell.Dispose()

}

$jobs.clear()

#endregion

# --------------------------------------------------
#region - Return data
# --------------------------------------------------

$return 

#endregion