如何在不附带堆栈跟踪的情况下在PowerShell中显示“裸”错误消息？

Question

如何从PowerShell写入标准错误，或捕获错误，以便：

• 错误消息显示为错误(真正写入标准错误，以便TeamCity和八达通将其视为错误)。
• 没有堆栈跟踪垃圾干扰了我美丽而简洁的错误消息。

这些年来，我一直通过throw的错误或通过Write-Error进行写作而幸存下来，但我又累又老，在我的脚本中，我只想看到一条简明的错误消息。我一直在尝试trap、throw、Write-Error和-ErrorAction的每一个组合，但都没有结果：

try {
  throw "error" # Sample code for a stack overflow. In the theater
  # of your mind, imagine there is code here that does something real and useful
} catch {
  Write-Error "An error occurred attempting to 'do something.' Have you tried rebooting?"
}

下面是我想要看到的用户体验：

C:\> & .\Do-Something.ps1
An error occurred attempting to 'do something.' Have you tried rebooting?

C:\> ▏

相反，我得到了：

C:\> & .\Do-Something.ps1
An error occurred attempting to 'do something.' Have you tried rebooting?
At line:1 char:1
+ Do-RealWork
+ ~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (:) [Write-Error], WriteErrorException
    + FullyQualifiedErrorId : Microsoft.PowerShell.Commands.WriteErrorException,Do-RealWork

C:\> ▏

Answer 1

在前一个答案中的想法上构建时，可以使用自定义函数临时覆盖内置的写错误cmdlet .

# Override the built-in cmdlet with a custom version
function Write-Error($message) {
    [Console]::ForegroundColor = 'red'
    [Console]::Error.WriteLine($message)
    [Console]::ResetColor()
}

# Pretty-print "Something is wrong" on stderr (in red).
Write-Error "Something is wrong"

# Setting things back to normal 
Remove-Item function:Write-Error

# Print the standard bloated Powershell errors
Write-Error "Back to normal errors"

这样，您就可以利用Powershell函数优先于cmdlet这一事实。

https://technet.microsoft.com/en-us/library/hh848304.aspx

这是我想出的最优雅的方法，既可以显示漂亮而简洁的错误消息，也可以让TeamCity很容易地检测问题。

Answer 2

最近我需要自己解决这个问题，所以我编写了一个写错误消息函数，具体如下所示：https://intellitect.com/powershell-write-error-without-writing-stack-trace/

具体来说，我利用了

Write-Error -Message $err -ErrorAction SilentlyContinue
$Host.UI.WriteErrorLine($errorMessage)

Answer 3

在我看来，在PowerShell中捕获错误的最佳方法是使用以下方法：

$Error[0].Exception.GetType().FullName

下面是一个如何正确使用此方法的示例。基本上，用脚本失败的不同场景测试您在PowerShell中要做的事情。

下面是一条典型的PowerShell错误消息：

PS C:\> Stop-Process -Name 'FakeProcess'
Stop-Process : Cannot find a process with the name "FakeProcess". Verify the process name and call the cmdlet again.
At line:1 char:1
+ Stop-Process -Name 'FakeProcess'
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : ObjectNotFound: (FakeProcess:String) [Stop-Process], ProcessCommandException
    + FullyQualifiedErrorId : NoProcessFoundForGivenName,Microsoft.PowerShell.Commands.StopProcessCommand

接下来，您将得到错误消息的例外：

PS C:\> $Error[0].Exception.GetType().FullName
Microsoft.PowerShell.Commands.ProcessCommandException

您将设置代码以捕获错误消息，如下所示：

Try
{
    #-ErrorAction Stop is needed to go to catch statement on error
    Get-Process -Name 'FakeProcess' -ErrorAction Stop
}
Catch [Microsoft.PowerShell.Commands.ProcessCommandException]
{
    Write-Host "ERROR: Process Does Not Exist. Please Check Process Name"
}

输出将类似于下面的内容，而不是上面示例中的Powershell标准错误：

ERROR: Process Does Not Exist. Please Check Process Name

最后，还可以使用多个catch块来处理代码中的多个错误。您还可以包括一个“毯子”catch块，以捕获所有尚未处理的错误。示例：

Try
{
    Get-Process -Name 'FakeProcess' -ErrorAction Stop
}

Catch [Microsoft.PowerShell.Commands.ProcessCommandException]
{
    Write-Host "ERROR: Process Does Not Exist. Please Check Process Name"
}

Catch [System.Exception]
{
    Write-Host "ERROR: Some Error Message Here!"
}

Catch
{
    Write-Host "ERROR: I am a blanket catch to handle all unspecified errors you aren't handling yet!"
}