Wait for a service

$ErrorActionPreference = 'Stop'
Import-Module LibTmux

$session = $null
$failure = $null
try {
    $socket = 'libtmux-example-' + [Guid]::NewGuid().ToString('N')
    $server = New-TmuxServer -SocketName $socket -ConfigurationFile /dev/null

    $session = $server | New-TmuxSession -Name http `
        -Command 'exec python3 -u -m http.server 0 --bind 127.0.0.1'
    $pane = $session | Get-TmuxPane
    $ready = $pane | Wait-TmuxPaneText `
        -Pattern '^Serving HTTP on 127\.0\.0\.1 port [0-9]+' `
        -CaseSensitive -Timeout 10 -TailLines 4 -Confirm:$false
    if ($ready.Outcome -notin 'PresentAtEntry', 'Matched') {
        throw "HTTP readiness ended with $($ready.Outcome)."
    }
    $tail = $ready.Tail -join "`n"
    $port = [regex]::Match($tail, 'port ([0-9]+)').Groups[1].Value
    $response = Invoke-WebRequest "http://127.0.0.1:$port/" `
        -TimeoutSec 5 -NoProxy
    if ($response.StatusCode -ne 200) {
        throw "HTTP returned $($response.StatusCode)."
    }
    'readiness: observed'
    'HTTP status: {0}' -f $response.StatusCode
} catch {
    $failure = [InvalidOperationException]::new(
        "tmux example failed: $($_.Exception.Message)", $_.Exception)
    throw $failure
} finally {
    if ($session) {
        $cleanupErrors = @()
        $session | Remove-TmuxSession -Confirm:$false `
            -ErrorAction SilentlyContinue -ErrorVariable cleanupErrors
        if ($cleanupErrors) {
            if ($failure) {
                $errors = @($failure) + $cleanupErrors.Exception
                throw [AggregateException]::new(
                    'tmux operation and cleanup failed.',
                    [Exception[]]$errors)
            }
            throw $cleanupErrors[0]
        }
    }
}