Best Practices #

1. Search for and install updates a few times in a loop #

Some packages and updates depend on others already being installed, so they might not show up during the first search for updates. If you want to make sure “everything” has been installed and/or updated it is best to re-run Get-LSUpdate and Install-LSUpdate a few times or until no more updates are found.

Example

This is a minimal example implementation of this best practice for demonstration purposes:

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$MaxRounds = 3
for ($Round = 1; $Round -le $MaxRounds; $Round++) {
    Write-Host "Starting round $Round"
    $updates = Get-LSUpdate
    Write-Host "$($updates.Count) updates found"

    if ($updates.Count -eq 0) {
        break;
    }

    $updates | Install-LSUpdate -Verbose
}

2. Download all packages before starting to install any #

Installing a network (NIC, WiFi adapter) driver can cause a short loss of network connectivity. When you feed packages found by Get-LSUpdate directly to Install-LSUpdate they will each be individually downloaded and then installed, therefore a network driver installation can cause the following package downloads to fail (see GitHub issue #41). Downloading all packages you intend to install beforehand with Save-LSUpdate will prevent this potential problem.

Example

This is a minimal example implementation of this best practice for demonstration purposes:

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# Find updates
$updates = Get-LSUpdate

# Download them all to the local disk
$updates | Save-LSUpdate

# Then install
$updates | Install-LSUpdate

If you download packages to a custom location with Save-LSUpdate -Path you have to pass that same path to Install-LSUpdate -Path in order for it to find the previously downloaded files. If Install-LSUpdate cannot find the expected files locally, it will still attempt to fetch them from the repository.

3. Write a logfile #

Especially when running unattended or remotely, it is crucial to have a good logfile that details what happened and allows you to find the cause of a problem in retrospect.

If you don’t know where to start, start with Start-Transcript to log whatever is being output to the console. If you would like more insight into what LSUClient is doing, add the common -Verbose parameter to the cmdlets you run. If you are intimately familiar with Lenovos package XML format, perhaps even the output of Get-LSUpdate -Verbose -Debug will be useful to you.

Example

This is a minimal example implementation of this best practice for demonstration purposes:

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Start-Transcript -LiteralPath "$env:TEMP\lsuclient_$(Get-Date -Format 'yyyyMMdd-HHmmss').log"

$updates = Get-LSUpdate -Verbose
Write-Host "$($updates.Count) updates found"

$i = 1
foreach ($update in $updates) {
    Write-Host "Installing update $i of $($updates.Count): $($update.Title)"
    Install-LSUpdate -Package $update -Verbose
    $i++
}

Stop-Transcript

4. Keep $ErrorActionPreference set to Continue #

Not every internal operation LSUClient carries out will and must neccesarily always succeed. Sometimes a file is in use by another process or just missing from Lenovos servers.

Errors like these often only affect a single package out of many, and if they are severe enough that a particular package cannot be processed further then it will be skipped, but all other packages can still be processed normally. This is the behavior of PowerShells’ default ErrorActionPreference setting: Continue. LSUClient does not attempt to silence or hide errors because they contain useful information about what went wrong and why. Particularly if you host your own package repository, any repository-related failures for example are important to know about so you can address them.

So while it is a common best practice for PowerShell scripts, with ErrorActionPreference set to Stop one of these “small” errors will always halt your entire script. Because of this I recommend against setting the ErrorActionPreference to Stop in your LSUClient scripts.