Creating PSSession-Based PowerShell Tools

            June 25, 2024

        Creating PSSession-Based PowerShell Tools

            Let's continue our exploration of creating and working with `PSSession` objects built from scratch. While I would normally use `New-PSSession`, using the .NET Framework shaves a few milliseconds off the process because I don't have the overhead of a cmdlet, and I can control the process more directly.

Today, I want to continue our exploration, including demonstrating how to make an SSH-based `PSSession`. And I want to give you a sample scripting project.

## Opening the Remote Runspace

Before we get to those topics, I want to briefly revisit working with the runspace that is part of the `PSSession` object. I shared this script sample that will create a `PSSession`.

#requires -version 7.4

#mkpssession.ps1

# You could modify to support credentials and/or SSL

Param([string]$ComputerName = $env:COMPUTERNAME)

$ci = [System.Management.Automation.Runspaces.WSManConnectionInfo]::new()

$ci.ComputerName = $ComputerName

$rs = [RunSpaceFactory]::CreateRunspace($ci)

$rs.ApartmentState = 'STA'

$rs.ThreadOptions = 'ReuseThread'

#script output

[System.Management.Automation.Runspaces.PSSession]::Create($rs, 'WSMan', $PSCmdlet)

When you run this, the connection to the remote computer is not open.

PS C:\> $a = c:\scripts\mkpssession.ps1 -computername dom1

PS C:\> $a

 Id Name            Transport ComputerName    ComputerType    State         ConfigurationName     Availability

 -- ----            --------- ------------    ------------    -----         -----------------     ------------

 13 Runspace13      WSMan     dom1            RemoteMachine   BeforeOpen    Microsoft.PowerShell          None

 PS C:\> $a.Runspace

 Id Name            ComputerName    Type          State         Availability

 -- ----            ------------    ----          -----         ------------

 19 Runspace19      dom1            Remote        BeforeOpen    None

 ```

Before I can invoke any code, the runspace must be opened. In the previous article I called the `Open()` method.

```powershell

$a.Runspace.Open()

This blocks your prompt while all the setup and authentication is happening. You can speed this process up by opening the runspace *asynchronously*.

$a.Runspace.OpenAsync()

This will make your code feel more responsive. I will demonstrate how I incorporate this into my PowerShell tooling a little bit later.

Because the code I'm using to create the `PSSession` requires PowerShell 7, we might as well see how to setup an SSH-based `PSSession`. I'm going to assume you've already configured PowerShell remoting with SSH in your environment.

Creating the SSH-based connection isn't that much different than using WSMan.

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Let's continue our exploration of creating and working with PSSession objects built from scratch. While I would normally use New-PSSession, using the .NET Framework shaves a few milliseconds off the process because I don't have the overhead of a cmdlet, and I can control the process more directly.
Today, I want to continue our exploration, including demonstrating how to make an SSH-based PSSession. And I want to give you a sample scripting project.
Opening the Remote Runspace

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Behind the PowerShell Pipeline

Creating PSSession-Based PowerShell Tools

Opening the Remote Runspace