PowerShell script to execute Docker maintenance, optionally non-interactively

periodic-docker-maintenance.ps1

<#
.Synopsis
    Runs periodic maintenance on Docker for Windows.
    It must be run as an Administrator!
.Description
    Intended to be run interactively or as a periodoc service, this will execute configurable docker prune
    within the VM and then stop and compact the virtual machine hard disk before restarting Docker.
    When run as a service, logs are sent to the Windows Event Log. Otherwise, progress is logged to the console.
.Parameter VHDX
    Required. The complete path to your DockerDesktop virtual hard disk file, i.e., 'F:\Docker\DockerDesktop.vhdx'
.Parameter FullSystem
    Optional. By default docker will prune unused images with 'docker image prune'.
    Add this flag to execute 'docker system prune -f'.
.Parameter Pull
    Optional (but recommended). Pull rebuilt base images from the internal HQ-DOCKER registry.
.Example
    periodic-maintenance.ps1 -VHDX "F:\Docker\DockerDesktop.vhdx" -FullSystem -Pull
    # Interactively run a full system prune, pull the latest internal base images, compact the VHDX.
.Example
    periodic-maintenance.ps1 -VHDX "F:\Docker\DockerDesktop.vhdx"
    # Run a minimal image prune and compact the VHDX.
#>

#Requires -RunAsAdministrator
#Requires -Modules Hyper-V

param(
    [Switch]$FullSystem,
    [Switch]$Pull,
    [String]$VHDX
)

if ([System.Diagnostics.EventLog]::SourceExists("DockerMaintenance") -eq $False) {
    New-EventLog -LogName Application -Source DockerMaintenance
}

function Write-ErrorLog($Message) {
    if (!$MyInvocation.scriptname) {
        Write-EventLog -LogName Application `
                    -Source DockerMaintenance `
                    -EventID 3001 `
                    -Category 1 `
                    -EntryType Error `
                    -Message $Message
    } else {
        Write-Host -ForegroundColor Red $Message
    }
}

function Write-InfoLog($Message) {
    if (!$MyInvocation.scriptname) {
        Write-EventLog -LogName Application `
        -Source DockerMaintenance `
        -EventID 3001 `
        -Category 1 `
        -EntryType Information `
        -Message $Message
    } else {
        Write-Host $Message
    }
}

if ($null -eq $VHDX) {
    $err = "The -VHDX parameter is missing! Please add it."
    Write-ErrorLog $err
    Exit -1
} elseif ((![System.IO.File]::Exists("${VHDX}")) -or ($VHDX -notlike "*\DockerDesktop.vhdx")){
    $err = "The path provided for -VHDX ""${VHDX}"" does not point to a 'DockerDesktop.vhdx'!"
    Write-ErrorLog $err
    Exit -2
}

function Invoke-Toast($Message, $Cancel) {
    $AppId = '{1AC14E77-02E7-4E5D-B744-2EB1AE5198B7}\WindowsPowerShell\v1.0\powershell.exe'
    $XmlString = @"
    <toast>
      <visual>
        <binding template="ToastGeneric">
          <text hint-maxLines="1">Docker Maintenance</text>
          <text>$Message</text>
        </binding>
      </visual>
      <audio src="ms-winsoundevent:Notification.Default" />
    </toast>
"@

    $ToastXml = [Windows.Data.Xml.Dom.XmlDocument]::new()
    $ToastXml.LoadXml($XmlString)
    $Toast = [Windows.UI.Notifications.ToastNotification]::new($ToastXml)
    [Windows.UI.Notifications.ToastNotificationManager]::CreateToastNotifier($AppId).Show($Toast)
}

function Invoke-ImagePrune() {
    Write-InfoLog "Pruning unused and dangling images"
    docker image prune -f
}

function Invoke-SystemPrune() {
    Write-InfoLog "Fully pruning docker system"
    docker system prune -f
}

function Invoke-DockerPull() {
    Write-InfoLog "Pulling HQ docker images"
    docker images --format "{{.Repository}}:{{.Tag}}" | Where-Object { $_ -like "hq-docker-*" } | ForEach-Object { docker pull $_ }
}

function Invoke-CompactDocker() {
    Write-InfoLog "Compacting ${VHDX}"
    Mount-VHD $VHDX -ReadOnly
    Optimize-VHD $VHDX -Mode Full
    Dismount-VHD $VHDX
}

function Stop-Docker() {
    $docker = Get-VM | Where-Object { $_.Name -eq 'DockerDesktopVM' }

    if ($docker.State -ne "Off") {
        Write-InfoLog "Docker is still running. Stopping..."
        Get-VM | Where-Object { $_.Name -eq 'DockerDesktopVM' } | Stop-VM
        Get-Process -Name "*Docker*" | Stop-Process -Force
    }
}

function Start-Docker() {
    Write-InfoLog "Restarting docker"
    Net Start "com.docker.service"
    & "C:\Program Files\Docker\Docker\Docker Desktop.exe"

    if ($MyInvocation.scriptname) {
        Write-Host "Docker for Windows is now starting up. Watch for the usual Toast notification."
    }
}

if ($MyInvocation.scriptname) {
    Invoke-Toast "Your Docker for Windows will be temporarily shut down for maintenance in 5 MINUTES. `
                  This process should take about 3 minutes."
    Start-Sleep -Seconds (60*5)
} else {
    Write-Host -ForegroundColor Green "Beginning maintenance in 5 seconds. Abort with [CTRL-C]."
    Start-Sleep -Seconds 5
}

if ($True -eq $Pull) {
    Invoke-DockerPull
}

if ($True -eq $FullSystem) {
    Invoke-SystemPrune
} else {
    Invoke-ImagePrune
}

Stop-Docker

Invoke-CompactDocker

Write-InfoLog "Maintenance Complete, restarting Docker..."

Start-Docker

This is also (currently) awaiting review on Code Review.SE, please feel free to contribute comments there https://codereview.stackexchange.com/questions/233370/powershell-script-to-execute-docker-maintenance-optionally-non-interactively