为什么传入脚本块的参数无法工作?

充分披露:我的问题可能是基于对Citrix PowerShell module for Xen Desktop的不完全理解。

我有下面的脚本块。它在循环中被调用,对于列表中的每个VM调用一次。我在用 PowerShell Jobs 因为我想让UI线程保持自由,以便在作业运行时更新UI。

代码“A”

$j = Start-Job -Name $jobName -ScriptBlock {
    param($url, $uuid, $cred, $snapshotName)
    $ErrorActionPreference = "Stop" 
    try
    {
        $error.clear()
        $xSS = $cred | Connect-XenServer -url $url -NoWarnCertificates -SetDefaultSession -PassThru; 
        $vm = (Get-XenVM -SessionOpaqueRef $xss.opaque_ref -uuid $uuid)
        #Create snapshot
        Invoke-XenVM -Async -SessionOpaqueRef $xss.opaque_ref -VM $vm -XenAction Snapshot -NewName $snapshotName
        return "OK"
    }
    catch
    {
        return ("ERROR: "+$error)
    }
} -ArgumentList $global:configFileVmMetaData.poolUrl, $xenVm.key, $global:cred, $snapshotName

代码“A” Connect-XenServer 每次调用脚本块时使用cmdlet。

所以,我试着打电话 连接XenServer 一旦跳出循环并传入session变量,如中所示 代码“B” . 结果是错误 Could not find open sessions to any XenServers 在脚本块中抛出。我假设$xss会话变量在传递到脚本块时受到了某种影响。

代码“B”

$xSS = $cred | Connect-XenServer -url $global:configFileVmMetaData.poolUrl -NoWarnCertificates -SetDefaultSession -PassThru; 

loop
{

    $j = Start-Job -Name $jobName -ScriptBlock {
        param($xss, $uuid, $snapshotName)
        $ErrorActionPreference = "Stop" 
        try
        {
            $error.clear()
            $vm = (Get-XenVM -SessionOpaqueRef $xss.opaque_ref -uuid $uuid)
            #Create snapshot
            Invoke-XenVM -Async -SessionOpaqueRef $xss.opaque_ref -VM $vm -XenAction Snapshot -NewName $snapshotName
            return "OK"
        }
        catch
        {
            return ("ERROR: "+$error)
        }
    } -ArgumentList $xss, $xenVm.key, $snapshotName

}

受 Robert Cotterman 回答

Could not find open sessions to any XenServers

仅供参考-使用PowerShell 5.1

示例使用 $using . 变量内容按预期传入和传出

cls

$aLocal = "AAA"
$bLocal = "BBB"

$j = Start-Job -Name "TestJob" -ScriptBlock {
    return ($using:aLocal + " *** " + $using:bLocal)
    }

while ($true)
{
    $g = get-job -name "TestJob"

    write-host ("get-job " + $g.Name + " is " + $g.State)

    if ($g.State -ne "Running")
    {
        break
    }

    start-sleep -Seconds 1
}

write-host ("receive-Job='" + (receive-Job -Name "TestJob") +"'")

$g = get-Job -Name "TestJob"
Write-Host ("get-Job "+$g.name + " " + $g.state + " " + $g.HasMoreData + " " + $g.id)

if($g)
{
    Remove-Job -Name "TestJob"
}

输出

get-job TestJob is Running
get-job TestJob is Completed
receive-Job='AAA *** BBB'
get-Job TestJob Completed False 45
Remove-Job

cls

$aLocal = "AAA"
$bLocal = "BBB"

$j = Start-Job -Name "TestJob" -ScriptBlock {
    return ($args[0] + " *** " + $args[1])
    } -ArgumentList ($aLocal, $bLocal)

while ($true)
{
    $g = get-job -name "TestJob"

    write-host ("get-job " + $g.Name + " is " + $g.State)

    if ($g.State -ne "Running")
    {
        break
    }

    start-sleep -Seconds 1
}

write-host ("receive-Job='" + (receive-Job -Name "TestJob") +"'")

$g = get-Job -Name "TestJob"
Write-Host ("get-Job "+$g.name + " " + $g.state + " " + $g.HasMoreData + " " + $g.id)

if($g)
{
    Remove-Job -Name "TestJob"
}

输出

get-job TestJob is Running
get-job TestJob is Completed
receive-Job='AAA *** BBB'
get-Job TestJob Completed False 49

使用命名参数的示例。变量内容按预期传入和传出

cls

$aLocal = "AAA"
$bLocal = "BBB"

$j = Start-Job -Name "TestJob" -ScriptBlock {
    param($a, $b)
    return ($a + " *** " + $b)
    } -ArgumentList ($aLocal, $bLocal)

while ($true)
{
    $g = get-job -name "TestJob"

    write-host ("get-job " + $g.Name + " is " + $g.State)

    if ($g.State -ne "Running")
    {
        break
    }

    start-sleep -Seconds 1
}

write-host ("receive-Job='" + (receive-Job -Name "TestJob") +"'")

$g = get-Job -Name "TestJob"
Write-Host ("get-Job "+$g.name + " " + $g.state + " " + $g.HasMoreData + " " + $g.id)

if($g)
{
    Remove-Job -Name "TestJob"
}

输出

get-job TestJob is Running
get-job TestJob is Completed
receive-Job='AAA *** BBB'
get-Job TestJob Completed False 55