Question

我有一个简单的问题。我一直在尝试使用Powershell DSC，我创建了一个自定义资源来更改客户端计算机的CD驱动器号。

我目前的代码有效，但我想看看它是否更有效率。请参阅下面的代码：

enum Ensure 
{ 
    Absent 
   Present 
}

[DscResource()]
class ChangeCDDriveLetter {

[DscProperty(Key)]
[string]$RequiredCDDriveLetter
[DscProperty(NotConfigurable)]
[string]$CurrentCDDriveLetter
[DscProperty(NotConfigurable)]
[string]$CurrentCDVolume

[ChangeCDDriveLetter] Get() {

    $This.CurrentCDDriveLetter = $This.CheckCurrentDriveLetter()
    $This.CurrentCDVolume = $This.CheckCurrentVolume($This.CurrentCDDriveLetter)

    Return $This

}

[Void] Set(){

    $This.CurrentCDDriveLetter = $This.CheckCurrentDriveLetter()
    $This.CurrentCDVolume = $This.CheckCurrentVolume($This.CurrentCDDriveLetter)

    mountvol $This.CurrentCDDriveLetter /d
    mountvol $This.RequiredCDDriveLetter $This.CurrentCDVolume

}

[bool] Test(){

    $This.CurrentCDDriveLetter = $This.CheckCurrentDriveLetter()
    $This.CurrentCDVolume = $This.CheckCurrentVolume($This.CurrentCDDriveLetter)

    Write-Verbose ("Current CD drive letter is: " + $This.CurrentCDDriveLetter)

    if ($This.CurrentCDDriveLetter -ne $This.RequiredCDDriveLetter){

        Write-Verbose ("The CD drive letter should be: " + $This.RequiredCDDriveLetter)
        Write-Verbose ("Setting the CD drive letter to: " + $This.RequiredCDDriveLetter)
        Return $False
    }
    else { 

        Write-Verbose "This is the correct drive letter."
        Return $True 

    }     
}

[string] CheckCurrentDriveLetter(){

    $CurrentDriveLetter = (Get-WmiObject win32_logicaldisk -filter 'DriveType=5').DeviceID
    return $CurrentDriveLetter

}

[string] CheckCurrentVolume($DriveLetter){

    $Volume = (mountvol $DriveLetter /l).Trim()
    Return $Volume

}

}

我的问题是关于以下重复的行：

$This.CurrentCDDriveLetter = $This.CheckCurrentDriveLetter()

如您所见，此信息在Set，Get和Test方法中收集。

是否可以收集此信息一次并在其他方法中共享此信息？

所以我会在Test方法中收集信息，并将此信息传递给Set方法？我想这样做不会对当前资源产生太大影响，但我仍然想知道它是否可行，以便我可以在将来的资源中使用它来使它们尽可能高效。

提前致谢！

亲切的问候， Bob Smienk

Answer 1

每次DSC运行资源时，您都不应该假设您将拥有相同的实例。因此，在执行之间保持实例字段或实例属性存在没有好方法。

如果该值对于机器是静态的，您可以尝试将其存储在静态字段中，但同样不应该假设调用这些方法的顺序。

Answer 2

我所做的和将要做的是基于OOP。在Test（）和Set（）方法的开头调用Get（），从而设置属性：

[DscResource()]
class ChangeCDDriveLetter {

[DscProperty(Key)]
[string]$RequiredCDDriveLetter
[DscProperty(NotConfigurable)]
[string]$CurrentCDDriveLetter
[DscProperty(NotConfigurable)]
[string]$CurrentCDVolume

[ChangeCDDriveLetter] Get() {

    $This.CurrentCDDriveLetter = $This.CheckCurrentDriveLetter()
    $This.CurrentCDVolume = $This.CheckCurrentVolume($This.CurrentCDDriveLetter)

    Return $This

}

[Void] Set(){

    $This.Get()

    # Replaced by $This.Get()
    # $This.CurrentCDDriveLetter = $This.CheckCurrentDriveLetter()
    # $This.CurrentCDVolume = $This.CheckCurrentVolume($This.CurrentCDDriveLetter)

    mountvol $This.CurrentCDDriveLetter /d
    mountvol $This.RequiredCDDriveLetter $This.CurrentCDVolume

}

[bool] Test(){

    $This.Get()

    # Replaced by $This.Get()
    # $This.CurrentCDDriveLetter = $This.CheckCurrentDriveLetter()
    # $This.CurrentCDVolume = $This.CheckCurrentVolume($This.CurrentCDDriveLetter)

    Write-Verbose ("Current CD drive letter is: " + $This.CurrentCDDriveLetter)

    if ($This.CurrentCDDriveLetter -ne $This.RequiredCDDriveLetter){

        Write-Verbose ("The CD drive letter should be: " + $This.RequiredCDDriveLetter)
        Write-Verbose ("Setting the CD drive letter to: " + $This.RequiredCDDriveLetter)
        Return $False
    }
    else { 

        Write-Verbose "This is the correct drive letter."
        Return $True 

    }     
}
}

我可以在自定义DSC资源中的get，set，test方法之间共享变量吗？

2 个答案: