restic_vss_backup.ps1

# Windows PowerShell Script to use restic to backup files using the Volume Shadow Copy Service, allowing
# that are in use to be backed up. The script must be run with elevated privileges.
# The Volume Shadow Copy Service must be enabled for the disk volume that contains the files to be backed up.
#
# credit: https://github.com/turnkey-commerce
#
# Parameters

# Config

function call_cmd() {
    $cwd = $PWD
    Set-Location $env:TEMP
    & cmd $MyInvocation.UnboundArguments
    Set-Location $cwd
}

$scriptPath = split-path -parent $MyInvocation.MyCommand.Definition
Set-Location $scriptPath

$ProgressPreference = "SilentlyContinue"

$IsAdmin = (New-Object Security.Principal.WindowsPrincipal([Security.Principal.WindowsIdentity]::GetCurrent())).IsInRole([Security.Principal.WindowsBuiltInRole]::Administrator)
$env:RESTIC_PASSWORD_COMMAND = "gopass show -o misc/Restic_Backup"
if ($IsAdmin -eq $false) {
    Write-Host "Running as admin!"
    Start-Process powershell.exe "-NoProfile -ExecutionPolicy Bypass -File `"$PSCommandPath`"" -Verb RunAs
    exit
}
# =========================

$env:RESTIC_REPOSITORY = '\\Server\RAID\Backups\restic\' + $env:COMPUTERNAME
$exclude_file = $env:RESTIC_REPOSITORY + '\exclude.txt'
$list_file = $env:TEMP + '\files_' + $env:COMPUTERNAME + '.txt'


$Volumes = @()
foreach ($part in (Get-Partition)) {
    $disk = (Get-Disk -Partition $part)
    If (($disk.Bustype -in ("SATA", "NVMe")) -and $part.DriveLetter) {
        $Volumes += $part.DriveLetter
    }
}

foreach ($sc in (Get-WmiObject Win32_ShadowCopy)) {
    $sc.Delete()
}

if ((Test-Path ($env:RESTIC_REPOSITORY + '\config')) -eq $false) {
    restic init
}

if (Test-Path "$env:TEMP\__shadowcopy__\") {
    call_cmd /c rmdir /s /q "$env:TEMP\__shadowcopy__\"
}

New-Item -ItemType Directory -Path "$env:TEMP\__shadowcopy__\" | Out-Null

$Files = @()
$ShadowVolumes = @()
$Mountpoints = @()
foreach ($rootVolume in ($Volumes | Sort-Object)) {
    Write-Host "Creating Snapshot for $rootVolume"
    $ShadowPath = $env:TEMP + '\__shadowcopy__\' + $rootVolume
    $s1 = (Get-WmiObject -List Win32_ShadowCopy).Create($rootVolume + ':\', "ClientAccessible")
    $s2 = Get-WmiObject Win32_ShadowCopy | Where-Object { $_.ID -eq $s1.ShadowID }
    $device = $s2.DeviceObject + "\"
    if (Test-Path $ShadowPath) {
        call_cmd /c rmdir $ShadowPath
    }
    call_cmd /c mklink /d $ShadowPath "$device"

    $ShadowVolumes += $s2
    $Mountpoints += $ShadowPath
}


$L = (Get-Location)

$Files = @()
Set-Location ($env:TEMP + '\__shadowcopy__\')
(Get-ChildItem -Force .).Name | ForEach-Object {
    $shadowPath = (Get-Item -LiteralPath ($env:TEMP + '\__shadowcopy__\')).FullName
    $Files += (Get-ChildItem -Force $_).FullName.Replace("[","?").Replace("]","?").Replace($shadowPath,"") # Fix paths so restic doesn't intepret them as Regex patterns
}
$Files | Out-File $list_file

"" | Out-File $env:TEMP\restic_exclude.txt

if (Test-Path $exclude_file) {
    (Get-Content $exclude_file) | ForEach-Object { 
        Write-Output ([Regex]::replace($_, "^([A-Z]):\\(.*)$", '$1\$2'))  # make path relative to shadowcopy
    } | Out-File $env:TEMP\restic_exclude.txt
}

restic cache --cleanup
restic backup --exclude-caches --exclude-file $env:TEMP\restic_exclude.txt --files-from $list_file

Set-Location $L

foreach ($vol in $ShadowVolumes) {
    $vol.Delete()
}

foreach ($mount in $Mountpoints) {
    call_cmd /c rmdir $mount
}

Remove-Item -Force $env:TEMP\restic_exclude.txt
Remove-Item -Force $list_file
Remove-Item -Force -Recurse $env:TEMP\__shadowcopy__

Write-Host "Done!"
Write-Host "Press enter to exit"
Read-Host