Retry-TestCommand

Retry-TestCommand.ps1

function Retry-TestCommand
{
    param (
    [Parameter(Mandatory=$true)][string]$Test,
    [Parameter(Mandatory=$false)][hashtable]$Args = @{},
    [Parameter(Mandatory=$false)][string]$TestProperty,
    [Parameter(Mandatory=$false)][int]$Tries = 5,
    [Parameter(Mandatory=$false)][int]$SecondsDelay = 2,
    [Parameter(Mandatory=$false)][switch]$ExpectNull
    )
    $TryCount = 0
    $Completed = $false
    $MsgFailed = "Command [{0}] failed" -f $Test
    $MsgSucceeded = "Command [{0}] succeeded." -f $Test

    while (-not $Completed)
    {
        try
        {
            $Result = & $Test @Args
            $TestResult = if ($TestProperty) { $Result.$TestProperty } else { $Result }
            if (-not $TestResult -and -not $ExpectNull)
            {
                throw $MsgFailed
            }
            else
            {
                Write-Verbose $MsgSucceeded
                Write-Output $TestResult
                $Completed = $true
            }
        }
        catch
        {
            $TryCount++
            if ($TryCount -ge $Tries)
            {
                $Completed = $true
                Write-Output $null
                Write-Warning ($PSItem | Select -Property * | Out-String)
                Write-Warning ("Command [{0}] failed the maximum number of {1} time(s)." -f $Test, $Tries)
                $PSCmdlet.ThrowTerminatingError($PSItem)
            }
            else
            {
                $Msg = $PSItem.ToString()
                if ($Msg -ne $MsgFailed) { Write-Warning $Msg }
                Write-Warning ("Command [{0}] failed. Retrying in {1} second(s)." -f $Test, $SecondsDelay)
                Start-Sleep $SecondsDelay
            }
        }
    }
}