Question

I’ve written a Powershell script that would periodically delete folders on my machine.
The algorithm is as follows:

• Drill down into each directory structure to the lowest subfolders
• Check the creation date of the subfolder
• If it’s 14 days old, or older, delete it
• LOG EVERYTHING (not part of the algorithm, just good practise)

When running, it operates exactly as expected…

… Except it throws the following, non-terminating exception:

Get-ChildItem : Could not find a part of the path 'C:\foo\baz'.
At C:\src\CoreDev\Trunk\Tools\BuildClean script\buildclean.ps1:55 char:15
+     Get-ChildItem <<<<  -recurse -force |
    + CategoryInfo          : ReadError: (C:\foo\baz:String) [Get-ChildItem],
   DirectoryNotFoundException
    + FullyQualifiedErrorId : DirIOError,Microsoft.PowerShell.Commands.GetChil
   dItemCommand

Why is this happening? More importantly, how can I remove it, and will it cause an issue?

The script is as follows:

# folderclean.ps1

# This script will remove each leaf node of a directory, provided that leaf is over
# 14 days old.

# CONSTANT DECLARATIONS
# testing (run on my local machine)
$proj_loc = "C:\foo", "C:\bar"
$logpath = "C:\Logs\BuildClean\$(Get-Date -format yyyyMMdd).log"

function Write-ToLogFile {
    param ([string]$stringToWrite)

    Add-Content $logpath -value $stringToWrite
}

# Function to check if a folder is a leaf folder.
#   First, retrieve the directory $item is pointing to
#   Then, create a list of children of $item that are folders
#   If this list is either empty or null, return $true
#   Otherwise, return $false
function Folder-IsLeaf($item) {
    $ary = Get-ChildItem $item -force | ?{ $_.PSIsContainer }
    if (($ary.length) -eq 0 -or $ary -eq $null) {
        return $true
    }

    return $false
}

# Deletes leaf folders that are older than a certain threshhold.
#   Get a list of children of the folder, where each child is a folder itself and 
#       was created over 14 days ago and the folder is a leaf
#   For each of these children, delete them and increment $folderCount
#   Get a list of children of the folder, where each child is a folder itself and 
#       was last modified over 14 days ago and the folder is a leaf
#   For each of these children, delete them and increment $folderCount
function Remove-LeafFolders($path) {
    $createdCount = 0
    $modifiedCount = 0

    Write-ToLogFile "Operation started at $(Get-Date -format "dd/MM/yyyy hh:mm:ss.fff")"
    Write-ToLogFile "Looking in $proj_loc"
    Write-ToLogFile ""
    $start = $(Get-Date)

    $proj_loc | 
    Get-ChildItem -recurse -force | 
    ?{
        $_.PSIsContainer -and ($_.CreationTime).AddDays(15) -lt $(Get-Date) -and $(Folder-IsLeaf $_.FullName) -eq $true
    } | %{
        $formattedDate = $($_.CreationTime).ToString("dd/MM/yyyy hh:mm:ss");
        Write-ToLogFile "Folder $($_.FullName) is being removed; created: $formattedDate"
        Remove-Item $_.FullName -recurse;
        $createdCount += 1
    }

    $end = $(Get-Date)
    $elapsed = $end - $start
    Write-ToLogFile "Operation completed at $(Get-Date -format "dd/MM/yyyy hh:mm:ss.fff")."
    Write-ToLogFile "Folders removed: $createdCount"
    Write-ToLogFile "Time elapsed: $(($elapsed).TotalMilliseconds) ms"
    Write-ToLogFile "-------------------------------"
}

Remove-LeafFolders($proj_loc)

Answer 1

I found this other StackOverflow question, and, after looking through the answer, I realised that the problem was the pipeline. So, I changed my code as follows:

...
$leafList = $proj_loc | 
    Get-ChildItem -recurse -force | 
    ?{

        $_.PSIsContainer -and ($_.CreationTime).AddDays(15) -lt $(Get-Date) -and $(Folder-IsLeaf $_.FullName) -eq $true
    }

    Foreach ($folder in $leafList)
    {
        $formattedDate = $($folder.CreationTime).ToString("dd/MM/yyyy hh:mm:ss");
        Write-ToLogFile "Folder $($folder.FullName) is being removed; created: $formattedDate"
        Remove-Item $folder.FullName -recurse;
        $createdCount += 1
    }
...

I created a few local folders and screwed around with them. No exceptions cropped up, so this appears to have worked:

Operation started at 10/12/2012 05:16:18.631
Looking in C:\foo C:\bar

Folder C:\foo\baz is being removed; created: 09/01/2010 02:00:00
Folder C:\bar\baz3\recursion is being removed; created: 01/01/2008 01:00:00
Operation completed at 10/12/2012 05:16:18.748.
Folders removed: 2
Time elapsed: 33.0033 ms
-------------------------------
Operation started at 10/12/2012 05:41:59.246
Looking in C:\foo C:\bar

Folder C:\foo\baz2\NewFolder is being removed; created: 10/10/2010 10:10:10
Folder C:\bar\baz3\barbar is being removed; created: 20/11/2012 05:37:38
Operation completed at 10/12/2012 05:41:59.279.
Folders removed: 2
Time elapsed: 21.0021 ms
-------------------------------