Visualizing PowerShell pipeline

View-Pipeline.ps1

<#
.Synopsis
    Visualize pipeline lifecycle and Begin/Process/End execution order for chained cmdlets.

.Description
    Provides grafical view of the Begin/Process/End blocks execution order for nested pipeline.

.Parameter Pipes
    Number of nested pipeleine functions.

.Parameter Items
    Number of items send through the pipeline. Controls how many times Process blocks will be executed.

.Parameter BreakAfter
    Stop pipeline processing after N's nested function. Simulates pipeline running out of items to process in the middle.
    In real life this could happen if the pipeline includes Where-Object in the middle and all items fail to meet the "true" criteria.

.Parameter NoBegin
    Generate functions without Begin block.

.Parameter NoProcess
    Generate functions without Process block.

.Parameter NoEnd
    Generate functions without End block.

.Example
    View-Pipeline

    Generate and execute single advanced function with Begin/Process/End blocks: View-Pipeline-1

.Example
    View-Pipeline -Pipes 3

    Generate and execute 3 advanced functions with Begin/Process/End blocks: View-Pipeline-1 | View-Pipeline-2 | View-Pipeline-3

.Example
    View-Pipeline -Items 2

    Generate and execute single advanced function with Begin/Process/End blocks.
    Process block will be executed twice, for each of the piped items.

.Example
    View-Pipeline -Pipes 2 -NoBegin

    Generate and execute 2 advanced functions with Process/End blocks only: View-Pipeline-1 | View-Pipeline-2

.Notes
	Author: beatcracker (http://beatcracker.wordpress.com, https://github.com/beatcracker)
	License: Microsoft Public License (http://opensource.org/licenses/MS-PL)

.Link
     https://beatcracker.wordpress.com/2017/02/04/visualizing-powershell-pipeline/
#>
function View-Pipeline {
    Param (
        [uint32]$Pipes = 1,
        [uint32]$Items = 1,
        [uint32]$BreakAfter = 0,
        [switch]$NoBegin,
        [switch]$NoProcess,
        [switch]$NoEnd
    )

    if ($BreakAfter) {++$BreakAfter}

    1..$Pipes | ForEach-Object -Begin {
        $Expression = @()
    } -Process {
        'function {3}-{0} {{
            [CmdletBinding()]
            Param (
                [Parameter(ValueFromPipeline = $true)]
                $InputObject
            )

        {4} Begin {{"[{{0}}]::Begin" -f $MyInvocation.MyCommand.Name | Write-Host -ForegroundColor Green}}
        {5}<#  
            Process {{
                if ({0} -eq {1}) {{return}}
                "{{0}}[{{1}}]::Process" -f ("`t"*{0}), $MyInvocation.MyCommand.Name | Write-Host -ForegroundColor Yellow
                "{{0}}In : `"{{1}}`"" -f ("`t  "*{0}), $InputObject | Write-Host -ForegroundColor DarkYellow
                "{{0}}Out: `"{{1}}`"" -f ("`t  "*{0}), $MyInvocation.MyCommand.Name | Write-Host -ForegroundColor DarkYellow
                @($MyInvocation.MyCommand.Name) * {2}
            }}
        #>
        {6} End {{"[{{0}}]::End" -f $MyInvocation.MyCommand.Name | Write-Host -ForegroundColor Red}}
        }}' -f $_, $BreakAfter, $Items, $MyInvocation.MyCommand.Name, ('#'*[bool]$NoBegin), ('#'*![bool]$NoProcess), ('#'*[bool]$NoEnd) | Invoke-Expression

        $Expression += $MyInvocation.MyCommand.Name + "-$_"
    } -End {
        ($Expression -join ' | ') | ForEach-Object {
            $_, ''| Write-Host -ForegroundColor Magenta
            $_ + ' > $null' | Invoke-Expression
        }
    }
}