将PowerShell命令记录到LogFile

Question

我有带有日志功能的基本PowerShell脚本和一些要运行的命令。我正在寻找一种登录日志文件命令的解决方案。

目前，我只知道这一点，但是复制+粘贴所有命令以被记录是非常烦人的：

$LogPath        = "C:\Logs"
$FileName       = (Get-Item $PSCommandPath).Basename                                                        
$LogFile        = $LogPath + "\" + $FileName + ".log"

Function WriteLog
{
Param ([string]$LogString)
$Stamp      = (Get-Date).toString("yyyy-MM-dd HH:mm:ss")
$LogMessage = "$Stamp $LogString"
Add-content $LogFile -value $LogMessage
}

WriteLog "***********************"
WriteLog ""

WriteLog "Command1"
Command1

WriteLog "Command2"
Command2

WriteLog "Command3"
Command3

WriteLog "Command4"
Command4

WriteLog "Command5"
Command5

WriteLog ""
WriteLog "***********************"

Answer 1

我建议如下：

• 修改函数以另一种方式接受表示要执行的命令的脚本块 ({ ... })。
• 如果给出一个脚本块，使用它的字符串表示作为日志消息，然后执行它。

# Create the logging function in a *dynamic module* (see below).
# Place this at the top of your script.
$null = New-Module {

  # Define the log-file path.
  $LogPath        = 'C:\Logs'
  $FileName       = (Get-Item $PSCommandPath).Basename                                                        
  $LogFile        = $LogPath + '\' + $FileName + '.log'
  
  # Create / truncate the file.
  New-Item -Force -ErrorAction Stop $LogFile

  function Add-LogMessage {
    [CmdletBinding(DefaultParameterSetName = 'String')]
    param(
      [Parameter(Position = 0, Mandatory, ParameterSetName = 'ScriptBlock')]
      [scriptblock] $ScriptBlock
      ,
      [Parameter(Position = 0, ParameterSetName = 'String')]
      [string] $String
    )

    # If a script block was given, use its string representation
    # as the log string.
    if ($ScriptBlock) {
      # Make the string representation single-line by replacing newlines
      # (and line-leading whitespace) with "; " 
      $String = $ScriptBlock.ToString().Trim() -replace '\r?\n *', '; '
    }

    # Create a timestamped message and append it to the log file.
    $stamp = (Get-Date).ToString("yyyy-MM-dd HH:mm:ss")
    $logMessage = "$stamp $String"
    Add-Content -LiteralPath $LogFile -Value $logMessage

    # If a script block was given, execute it now.
    if ($ScriptBlock) {
      # Because this function is defined in a (dynamic) module,
      # its invocation doesn't create a child scope of the *caller's* scope,
      # and invoking the given script block, which is bound to the caller's scope,
      # with . (dot-sourcing) runs it *directly in the caller's scope*.
      . $ScriptBlock
    }
  }
}

注意：

• 函数名遵循PowerShell的动词-名词惯例，使用的是Add，这是一个认可动词；但是，为了简洁起见，也执行执行的方面( Invoke将是已批准的动词)没有反映在名称中。

然后，您的脚本将如下所示：

Add-LogMessage "***********************"
Add-LogMessage ""

Add-LogMessage { Command1 }

Add-LogMessage { Command2 }

# ... 

Add-LogMessage "***********************"

注意：

• 通过将函数放置在通过模块创建的(动态的、瞬态的) New-Module中，它的调用不会创建调用方作用域的子作用域。
• 当传入调用方作用域中由文字({ ... })创建的脚本块时，可以使用.调用它，点源运算符直接在调用方的作用域中执行它，这意味着脚本块的代码可以自由地修改脚本的变量，就像将该代码直接放在脚本中一样。
• 如果您希望函数也记录给定脚本块的输出(同时仍将其打印到显示器)，您可以使用Tee-Object，如下所示(为了简单起见，我假设相同的目标日志文件，根据需要进行调整)： 。$ScriptBlock / Tee-Object -Append -FilePath $LogFile

- **Caveat**: As of PowerShell 7.2.x, `Tee-Object` uses a _fixed_ character encoding, namely UTF-16LE ("Unicode") in _Windows PowerShell_ and BOM-less UTF-8 in _PowerShell (Core) 7+_. [GitHub issue #11104](https://github.com/PowerShell/PowerShell/issues/11104) suggests adding an `-Encoding` parameter (which only future _PowerShell (Core)_ versions would benefit from).

- Therefore, if you're using _Windows PowerShell_ and you're targeting the _same_ log file for capturing the output, be sure to modify the `Add-Content` call with `-Encoding Unicode` as follows:

Add- -Encoding Unicode -LiteralPath $LogFile -Value $logMessage

- Alternatively, if you want to avoid UTF-16LE ("Unicode") files for their size (with all-ASCII characters, they're twice the size of ANSI and UTF-8 files), you can use one of the **workarounds** discussed in [this answer](https://stackoverflow.com/a/58922982/45375).