添加到 $Error 变量时抑制 Powershell 错误

Question

我有一个正在执行的代码块，它设置了一个简单的 If/Else 块来捕获错误。我通常会使用 Try/Catch，但我正在使用的 Exchange 2010 PS 环境不允许我使用大多数 Try/Catch 功能（并且我无法以任何方式更新或更改它，因为它是客户的系统，他们不愿意）。

问题是，虽然当使用 -ErrorAction“Stop”设置 Add-DistributionGroupMember cmdlet 时代码将按预期运行，但它每次都会将错误输出到主机，这让客户（和我）感到烦恼，因为它实际上只是红噪声，因为所有可能的错误都通过详细的输出文件进行处理。

如果我将 cmdlet 设置为 -ErrorAction "SilentlyContinue"，错误文本将被抑制，但错误不会按照我的预期添加到 $Error[0] 位置。 -ErrorAction“忽略”也是如此。该代码要求每次出现错误时都将 Error 添加到 $Error 变量中。

这是代码：

$ListMembershipsIn | % {

        $Alias = $_.Alias
        $Member = $_.Member

        Add-DistributionGroupMember -Identity $Alias -Member $Member -Confirm:$false -ErrorAction Stop


        if($Error[0] -match "The recipient"){
            Write-Host -ForegroundColor Yellow "Already a member"
            Add-Content -Path $OutputPath -Value "$($Alias),$($Member),Group already contains Member"
        }
        elseif($Error[0] -match "couldn't be found"){
            Write-Host -ForegroundColor Yellow "not found"
            Add-Content -Path $OutputPath -Value "Group does not exist or cannot be found,$($Alias),N/A"
        }
        elseif($Error[0] -match "couldn't find"){
            Write-Host -ForegroundColor Yellow "not found"
            Add-Content -Path $OutputPath -Value "Member does not exist or cannot be found,$($Alias),$($Member)"
        }
        elseif($Error[0] -match "There are Multiple"){
            Add-Content -Path $OuputPath -Value "Member name matches too many recipient - Add Member Manually,$($Alias),$($Member)"
        }
        else{
            Add-Content -Path $OutputPath -Value "Member Successfully Added to Group,$($Alias),$($Member)"
            Write-Host -ForegroundColor Green "Throw Flag here"
        }
    }

Answer 1

您有两种追索选项，您可以利用

-ErrorVariable

通用参数，或

Try/Catch

块与特定错误进行交互。

---

错误变量

与

ErrorVariable

交互时，您可以在名称前面添加

+

以向其附加其他错误，就像

$Error

自动变量一样，例如：

-ErrorVariable '+MyError'

$ListMembershipsIn | ForEach-Object {
    $Alias = $_.Alias
    $Member = $_.Member
    Add-DistributionGroupMember -Identity $Alias -Member $Member -ErrorVariable 'MyError'

    ## No error = good, continue the next iteration of the loop
    If (-not $MyError)
    {
        Add-Content -Path $OutputPath -Value "Member Successfully Added to Group,$Alias,$Member"
        Write-Host -ForegroundColor Green "Throw Flag here"
        Continue
    }

    Switch -Regex ($MyError.Exception.Message)
    {
        'The recipient'
        {
            Write-Host -ForegroundColor Yellow "Already a member"
            Add-Content -Path $OutputPath -Value "$Alias,$Member,Group already contains Member"
        }
        "couldn't be found"
        {
            Write-Host -ForegroundColor Yellow "not found"
            Add-Content -Path $OutputPath -Value "Group does not exist or cannot be found,$Alias,N/A"
        }
        "couldn't find"
        {
            Write-Host -ForegroundColor Yellow "not found"
            Add-Content -Path $OutputPath -Value "Member does not exist or cannot be found,$Alias,$Member"
        }
        'There are Multiple'
        {
            Add-Content -Path $OuputPath -Value "Member name matches too many recipient - Add Member Manually,$Alias,$Member"
        }
    }
}

---

尝试/捕捉

$ListMembershipsIn | ForEach-Object {
    $Alias = $_.Alias
    $Member = $_.Member

    Try
    {
        Add-DistributionGroupMember -Identity $Alias -Member $Member -ErrorAction 'Stop'

        ## No error thrown = successful processing
        Add-Content -Path $OutputPath -Value "Member Successfully Added to Group,$Alias,$Member"
        Write-Host -ForegroundColor Green "Throw Flag here"
    }
    Catch
    {
        Switch -Regex ($_.Exception.Message)
        {
            'The recipient'
            {
                Write-Host -ForegroundColor Yellow "Already a member"
                Add-Content -Path $OutputPath -Value "$Alias,$Member,Group already contains Member"
            }
            "couldn't be found"
            {
                Write-Host -ForegroundColor Yellow "not found"
                Add-Content -Path $OutputPath -Value "Group does not exist or cannot be found,$Alias,N/A"
            }
            "couldn't find"
            {
                Write-Host -ForegroundColor Yellow "not found"
                Add-Content -Path $OutputPath -Value "Member does not exist or cannot be found,$Alias,$Member"
            }
            'There are Multiple'
            {
                Add-Content -Path $OuputPath -Value "Member name matches too many recipient - Add Member Manually,$Alias,$Member"
            }
        }
    }
}

Answer 2

Add-DistributionGroupMember 命令在指定时似乎未填充 ErrorVariable。 我发现没有办法避免不需要的输出，所以我用 Tristan 的技巧来处理错误，而不是通过异常处理（这绝对没问题，但不适合我自己的开发）：

$Error.clear()
Add-DistributionGroupMember -Identity $mySite.MailingList -Member $emailAddress
if ($Error.count -eq 0) {
    $script:logger["ldissue"] += "<li>Liste de diffusion $($mySite.MailingList) : La ressource <b>$($ADRecord.Name)</b> ($($ADRecord.SamAccountName) - $($BoondRecord.flags)) a été ajoutée à la liste</li>"
} else {
    $script:logger["ldissue"] += "<li>Liste de diffusion $($mySite.MailingList) : La ressource <b>$($ADRecord.Name)</b> ($($ADRecord.SamAccountName) - $($BoondRecord.flags)) n'a pas pu être ajoutée à la liste (<i>$($Error[0])</i>)</li>"
}

Answer 3

以下技术将抑制 Add-Type 命令生成的红色错误消息文本，并且仍会填充 $Error 变量，但我不确定这是否适用于 Add-DistributionGroupMember 命令，我无法测试该命令眼下。这是在 PowerShell 5.1 中测试的。

$Error.Clear()
.{Add-Type -Path 'NonExisting.dll' -ErrorAction Stop} 2>$Null
$Error[0]

Answer 4

使用“-ErrorAction Continue”这不会抑制错误，但会确保脚本继续并将错误放入 $Error 变量中。

您还可以使用 $Error.clear() 命令删除会话中任何存储的错误。