do-while loop with timeout

Question

I have the following loop:

$output = (command)
do {
something
} while ($output -match "some string")

Which works fine. I want to add a timeout to the loop, how do I do that? The expectation is that at some point the output won't match the string but I don't want it to run forever if the output matches the string forever.

Answer 1

Although using the Get-Date Cmdlet is valid, a cleaner approach would be to use the System.Diagnostics.Stopwatch class, which is available in .NET Core >= 1.0.

$timeout = New-TimeSpan -Seconds 5
$stopwatch = [System.Diagnostics.Stopwatch]::StartNew()
do {
    # do stuff here
} while ($stopwatch.elapsed -lt $timeout)

Sources:

1. https://mjolinor.wordpress.com/2012/01/14/making-a-timed-loop-in-powershell/
2. https://mcpmag.com/articles/2017/10/19/using-a-stopwatch-in-powershell.aspx
3. https://docs.microsoft.com/en-us/dotnet/api/system.diagnostics.stopwatch?view=netframework-4.8
4. https://docs.microsoft.com/en-us/powershell/module/microsoft.powershell.utility/new-timespan?view=powershell-6

Answer 2

Just use the Get-Date cmdlet and check for that in your while condition. Example:

$startDate = Get-Date

$output = (command)
do {
something
} while ($output -match "some string" -and $startDate.AddMinutes(2) -gt (Get-Date))