PowerShell Core script to remove old files recursively, and in parallel, from a local file system or remote share, like Azure Storage File Share

Remove-OldFilesRecursively.ps1

param (
    $StartPath = "\\your_storage_account_name.file.core.windows.net\your_share_name\whatever"
)

Set-StrictMode -Version Latest

# Write a transcript to file.
$path = Get-Location
$scriptName = $MyInvocation.MyCommand.Name
$scriptLog = "$path\$scriptName.log"
Start-Transcript -Path $scriptLog -Force

$stopWatch = [System.Diagnostics.Stopwatch]::StartNew()

Write-Output "Started at $(Get-Date)"

$ErrorActionPreference = "Stop"
$ProgressPreference = "SilentlyContinue"

$foldersToPurge = @(
    [pscustomobject]@{Name = 'Folder1'; RetentionInDays = 180 }
    [pscustomobject]@{Name = 'Folder2'; RetentionInDays = 365 }
    [pscustomobject]@{Name = 'Folder3'; RetentionInDays = 30 }
)

# Thanks to https://stackoverflow.com/a/45472343/7752
function Retry-Command {
    [CmdletBinding()]
    Param(
        [Parameter(Position = 0, Mandatory = $true)]
        [scriptblock]$ScriptBlock,

        [Parameter(Position = 1, Mandatory = $false)]
        [int]$Maximum = 5,

        [Parameter(Position = 2, Mandatory = $false)]
        [int]$Delay = 100
    )

    Begin {
        $cnt = 0
    }

    Process {
        do {
            $cnt++
            try {
                $ScriptBlock.Invoke()
                return
            }
            catch {
                Write-Error $_.Exception.InnerException.Message -ErrorAction Continue
                Start-Sleep -Milliseconds $Delay
            }
        } while ($cnt -lt $Maximum)

        # Throw an error after $Maximum unsuccessful invocations. Doesn't need
        # a condition, since the function returns upon successful invocation.
        throw 'Execution failed.'
    }
}

$funcDef = ${function:Retry-Command}.ToString()

# Define a recursive function
function Remove-Files ($Path, $Days) {

    Write-Output "Processing folder $($Path)"

    # Get current date
    $CurrentDate = Get-Date

    # Calculate date to delete
    $DateToDelete = $CurrentDate.AddDays(-$Days)

    if (! ( Test-Path -Path $Path) ) {
        continue
    }

    # Delete files in parallel older than date
    Get-ChildItem -Path $Path -File | Where-Object { $_.LastWriteTime -lt $DateToDelete } | ForEach-Object -ThrottleLimit 10 -Parallel {
        $File = $_

        # Bring in out-of-scope function.
        ${function:Retry-Command} = $using:funcDef

        Write-Output "Removing $($File.FullName)"
        Retry-Command -Delay 1000 -ScriptBlock { Remove-Item -Path $File.FullName } -Maximum 5
    }

    # Get folders in current path
    $Folders = Get-ChildItem -Path $Path -Directory -ErrorAction SilentlyContinue

    # Call function for each subfolder
    $Folders | ForEach-Object {
        $Folder = $_
        Remove-Files -Path $Folder.FullName -Days $Days
        # Delete empty folder
        if ($null -eq (Get-ChildItem -Path $Folder.FullName)) {
            Write-Output "Removing empty folder $($Folder.FullName)"
            Remove-Item -Path $Folder.FullName
        }
    }
}


$folders = Get-ChildItem -Directory -Path $StartPath

foreach ($clientFolder in $folders) {
    foreach ($folder in $foldersToPurge) {

        $fullpath = $clientFolder.FullName + "\$($folder.Name)"

        Remove-Files -Path $fullpath -Days $folder.RetentionInDays
    }
}

$stopWatch.Stop()
$stopWatch.Elapsed.ToString()
Write-Output "Ended at $(Get-Date)"

# Stop Logging
Stop-Transcript