PSBackoff.ps1

# Simple backoff in PowerShell
# Executes a scriptblock - the Code parameter
# In case of a blocking error, retries - the number of retries and seconds to wait before each is the Intervals parameter (array)
# Returns the result of the code invocation of throws the last error if run out of the backoffs

function Invoke-WithBackoff {
    [CmdletBinding()]
    param (
        [Parameter()] [scriptblock]$Code,
        [Parameter()] [float[]]$Intervals
    )
    foreach ($t in $Intervals) {
        try {
            $res = &$Code
            return $res
        }
        catch {
            Write-Verbose "Backing off for $t seconds"
            Start-Sleep -Seconds $t
        }
    }
    throw (Get-Error)
}

$code = {
    $failprobability = 0.8
    if ((Get-Random 1.0) -gt $failprobability) { 
        "200" 
    } else { 
        throw "500" 
    }
}
$retries = @(1,1.5,2,3,5)

Invoke-WithBackoff -Intervals $retries -Code $code -Verbose