garm/internal/templates/userdata/windows_wrapper.tmpl

$ErrorActionPreference="Stop"

function Start-ExecuteWithRetry {
    [CmdletBinding()]
    param(
        [Parameter(Mandatory=$true)]
        [ScriptBlock]$ScriptBlock,
        [int]$MaxRetryCount=10,
        [int]$RetryInterval=3,
        [string]$RetryMessage,
        [array]$ArgumentList=@()
    )
    PROCESS {
        $currentErrorActionPreference = $ErrorActionPreference
        $ErrorActionPreference = "Continue"
        $retryCount = 0
        while ($true) {
            try {
                $res = Invoke-Command -ScriptBlock $ScriptBlock -ArgumentList $ArgumentList
                $ErrorActionPreference = $currentErrorActionPreference
                return $res
            } catch [System.Exception] {
                $retryCount++

                if ($_.Exception -is [System.Net.WebException]) {
                    $webResponse = $_.Exception.Response
					# Skip retry on Error: 4XX (e.g. 401 Unauthorized, 404 Not Found etc.)
                    if ($webResponse -and $webResponse.StatusCode -ge 400 -and $webResponse.StatusCode -lt 500) {
                        # Skip retry on 4xx errors
                        Write-Output "Encountered non-retryable error (4xx): $($_.Exception.Message)"
                        $ErrorActionPreference = $currentErrorActionPreference
                        throw
                    }
                }

                if ($retryCount -gt $MaxRetryCount) {
                    $ErrorActionPreference = $currentErrorActionPreference
                    throw
                } else {
                    if ($RetryMessage) {
                        Write-Output $RetryMessage
                    } elseif ($_) {
                        Write-Output $_
                    }
                    Start-Sleep -Seconds $RetryInterval
                }
            }
        }
    }
}

$installScript = (Join-Path $env:TMP, "garm-install.ps1")
Start-ExecuteWithRetry -ScriptBlock {
	wget -UseBasicParsing -Headers @{"Accept"="application/json"; "Authorization"="Bearer {{ .CallbackToken }}"} -Uri {{ .MetadataURL }}/install-script/ -OutFile $installScript
} -MaxRetryCount 5 -RetryInterval 5 -RetryMessage "Retrying download of runner install script..."

$installScript