functions/ComputerManagement/Invoke-PSFCommand.ps1

function Invoke-PSFCommand
{
<#
    .SYNOPSIS
        An Invoke-Command wrapper with integrated session management.
     
    .DESCRIPTION
        This wrapper command around Invoke-Command allows conveniently calling remote calls.
     
        - It uses the PSFComputer parameter class, and is thus a lot more flexible in accepted input
        - It automatically reuses sessions specified for input
        - It automatically establishes new sessions, tracks usage and retires sessions that have timed out.
     
        Using this command, it is no longer necessary to first establish a connection and then manually handle the session object.
        Just point the command at the computer and it will remember.
        It also reuses sessions across multiple commands that call it.
     
        Note:
        Special connection conditions (like a custom application name, alternative authentication schemes, etc.) are not supported and require using New-PSSession to establish the connection.
        Once that session has been established, the session object can be used with this command and will be used for command invocation.
     
    .PARAMETER ComputerName
        The computer(s) to invoke the command on.
        Accepts all kinds of things that legally point at a computer, including DNS names, ADComputer objects, IP Addresses, SQL Server connection strings, CimSessions or PowerShell Sessions.
        It will reuse PSSession objects if specified (and not include them in its session management).
     
    .PARAMETER ScriptBlock
        The code to execute.
     
    .PARAMETER ArgumentList
        The arguments to pass into the scriptblock.
     
    .PARAMETER Credential
        Credentials to use when establishing connections.
        Note: These will be ignored if there already exists an established connection.
     
    .PARAMETER HideComputerName
        Indicates that this cmdlet omits the computer name of each object from the output display. By default, the name of the computer that generated the object appears in the display.
     
    .PARAMETER ThrottleLimit
        Specifies the maximum number of concurrent connections that can be established to run this command. If you omit this parameter or enter a value of 0, the default value, 32, is used.
     
    .EXAMPLE
        PS C:\> Invoke-PSFCommand -ScriptBlock $ScriptBlock
     
        Runs the $scriptblock against the local computer.
     
    .EXAMPLE
        PS C:\> Invoke-PSFCommand -ScriptBlock $ScriptBlock (Get-ADComputer -Filter "name -like 'srv-db*'")
     
        Runs the $scriptblock against all computers in AD with a name that starts with "srv-db".
#>

    [Diagnostics.CodeAnalysis.SuppressMessageAttribute("PSPossibleIncorrectUsageOfAssignmentOperator", "")]
    [CmdletBinding()]
    param (
        [PSFComputer[]]
        [Alias('Session')]
        $ComputerName = $env:COMPUTERNAME,
        
        [Parameter(Mandatory = $true)]
        [scriptblock]
        $ScriptBlock,
        
        [object[]]
        $ArgumentList,
        
        [System.Management.Automation.CredentialAttribute()]
        [System.Management.Automation.PSCredential]
        $Credential,
        
        [switch]
        $HideComputerName,
        
        [int]
        $ThrottleLimit = 32
    )
    
    begin
    {
        Write-PSFMessage -Level InternalComment -Message "Bound parameters: $($PSBoundParameters.Keys -join ", ")" -Tag 'debug', 'start', 'param'
        
        #region Clean up broken sessions
        [array]$broken = $psframework_pssessions.GetBroken()
        foreach ($sessionInfo in $broken)
        {
            Write-PSFMessage -Level Debug -Message "Removing broken session to $($sessionInfo.ComputerName)"
            Remove-PSSession -Session $sessionInfo.Session -ErrorAction Ignore
            $null = $psframework_pssessions.Remove($sessionInfo.ComputerName)
        }
        #endregion Clean up broken sessions
        
        #region Invoke Command Splats
        $paramInvokeCommand = @{
            ScriptBlock           = $ScriptBlock
            ArgumentList       = $ArgumentList
            HideComputerName   = $HideComputerName
            ThrottleLimit       = $ThrottleLimit
        }
        
        $paramInvokeCommandLocal = @{
            ScriptBlock            = $ScriptBlock
            ArgumentList        = $ArgumentList
        }
        #endregion Invoke Command Splats
    }
    process
    {
        #region Collect list of sessions to process
        $sessionsToInvoke = @()
        $managedSessions = @()
        
        foreach ($computer in $ComputerName)
        {
            if ($computer.Type -eq "PSSession") { $sessionsToInvoke += $computer.InputObject }
            else
            {
                #region Handle localhost
                if ($computer.IsLocalHost)
                {
                    Write-PSFMessage -Level Verbose -Message "Executing command against localhost" -Target $computer
                    Invoke-Command @paramInvokeCommandLocal
                    continue
                }
                #endregion Handle localhost
                
                #region Already have a cached session
                if ($session = $psframework_pssessions[$computer.ComputerName])
                {
                    $sessionsToInvoke += $session.Session
                    $managedSessions += $session
                    $session.ResetTimestamp()
                }
                #endregion Already have a cached session
                
                #region Establish new session and add to management
                else
                {
                    Write-PSFMessage -Level Verbose -Message "Establishing connection to $computer" -Target $computer
                    try
                    {
                        if ($Credential) { $pSSession = New-PSSession -ComputerName $computer -Credential $Credential -ErrorAction Stop}
                        else { $pSSession = New-PSSession -ComputerName $computer -ErrorAction Stop }
                    }
                    catch
                    {
                        Write-PSFMessage -Level Warning -Message "Failed to connect to $computer" -ErrorRecord $_ -Target $computer 3>$null
                        Write-Error -ErrorRecord $_
                        continue
                    }
                    
                    $session = New-Object PSFramework.ComputerManagement.PSSessioninfo($pSSession)
                    $psframework_pssessions[$session.ComputerName] = $session
                    $sessionsToInvoke += $session.Session
                    $managedSessions += $session
                }
                #endregion Establish new session and add to management
            }
        }
        #endregion Collect list of sessions to process
        
        if ($sessionsToInvoke)
        {
            Write-PSFMessage -Level VeryVerbose -Message "Invoking command against $($sessionsToInvoke.ComputerName -join ', ' )"
            Invoke-Command -Session $sessionsToInvoke @paramInvokeCommand
        }
        
        #region Refresh timestamp
        foreach ($session in $managedSessions)
        {
            $session.ResetTimestamp()
        }
        #endregion Refresh timestamp
    }
    end
    {
        #region Cleanup expired sessions
        [array]$expired = $psframework_pssessions.GetExpired()
        foreach ($sessionInfo in $expired)
        {
            Write-PSFMessage -Level Debug -Message "Removing expired session to $($sessionInfo.ComputerName)"
            Remove-PSSession -Session $sessionInfo.Session -ErrorAction Ignore
            $null = $psframework_pssessions.Remove($sessionInfo.ComputerName)
        }
        #endregion Cleanup expired sessions
    }
}