将值与前一个循环进行比较

Question

我制作了这个脚本来监控服务器分区的可用空间。现在我正在尝试将最新的循环与之前的循环进行比较，并将可用空间值存储到数组中，但我从未做过这样的事情。

我不知道如何使用数组——一个必须在循环开始时被擦除，第二个必须存储以前的值，然后它们必须进行比较。

能否请您至少给我一个提示？

#play star-wars imperial march
function play-alarm {    
    Start-Job {
        [Console]::Beep(440,500)
    }
}
$cred = Get-Credential domain\username

$hostname = "server1"

#if free space lower, then play alarm
$low_level = "10"

#get drives letters
$partitions = Get-WmiObject Win32_LogicalDisk -Computername $hostname -Credential $cred | foreach DeviceID

#create arrays
$old_values = New-Object System.Collections.ArrayList
$new_values = New-Object System.Collections.ArrayList

#noob loop
$repeat = "2"

while ($i -lt $repeat) {
    Write-Host "        ***        " -ForegroundColor Yellow
    Write-Host "        ***        " -ForegroundColor Yellow
    Write-Host "        ***        " -ForegroundColor Yellow
    Write-Host "Free space at server:" -BackgroundColor Black

    #backup previouse values and clear array for new ones
    $old_values = $new_values
    $new_values.Clear()

    foreach ($partition in $partitions) {
        $device = "DeviceID='" + $partition + "'"

        $size = Get-WmiObject Win32_LogicalDisk -Credential $cred -ComputerName $hostname -Filter $device |
                ForEach-Object {$_.Size}
        $size = [Math]::Round($size/1GB)
        $free = Get-WmiObject Win32_LogicalDisk -Credential $cred -ComputerName $hostname -Filter $device |
                ForEach-Object {$_.FreeSpace}
        $free = [Math]::Round($free/1GB)
        Write-Host $free
        #add value rounded to GB
        $new_values.Add($free)

        #if device is CD-ROM, the size or space is zero - this cause error when calculating percentage of free space
        if ($size -eq "0") {
            Write-Host "disk " $partition "is CD-ROM" -ForegroundColor Yellow
        } else {
            $perc = ($free/$size)*100
            $perc = [Math]::Round($perc, 3)

            if ($perc -le $low_level) {
                Write-Host "Not enough free space at partition " $partition "!!!" $perc "%" -BackgroundColor Red #| play-alarm
                Start-Sleep -s 15
            } else {
                Write-Host "disk " $partition "is OK - " $perc "%" -ForegroundColor Green
            }
        }
    }

    if ($old_values -eq $new_values) {
        Write-Host "no change..."
    } else {
        Write-Host "Attention - change!!!" -BackgroundColor Red
    }

    $time = $((Get-Date).ToString())
    Write-Host "Loop finished..." $time -BackgroundColor Black
    Write-Host "        ***        " -ForegroundColor Yellow
    Write-Host "        ***        " -ForegroundColor Yellow
    Write-Host "        ***        " -ForegroundColor Yellow
    Start-Sleep -s 300
}

Answer 1

复制以前的值

$old_values = $new_values
$new_values.Clear()

这个问题是 $old_values 现在引用 与 $new_values 相同的 数组。使用

$old_values = $new_values.Clone()

创建一个副本。

比较

您不想使用-eq 来比较容器对象的内容。您可以遍历数组并比较每个元素

for ($index=0;$index -lt $old_values.count;$index+=1) {
    if ($old_values[$index] -ne $new_values[$index]) {
        write-host "Changed!"
        break
    }
}

或者你可以使用Compare-Object

    if (Compare-Object $old_values $new_values) {
        write-host "No Change!"
    } else {
        write-host "Changed!"
    }

Compare-Object 返回差异列表。如果您比较的内容相同，则返回一个空值（并且布尔值为 false）。

Answer 2

如果要将当前值与之前运行的值进行比较，则需要将当前值存储在脚本末尾的某个位置（例如，在 CSV 文件中），并在脚本的开头。

$csv = 'C:\path\to\data.csv'

if (Test-Path -LiteralPath $csv) {
    $old_values = Import-Csv $csv
} else {
    # initialize $old_values as an empty array if the file doesn't exist (yet)
    $old_values = @()
}

...

$new_values | Export-Csv $csv -NoType

通过选择 WMI 数据的相关属性，将 $new_values 构建为自定义对象列表。避免格式化磁盘空间数据，除非它是为了输出给用户。

$new_values = Get-WmiObject Win32_LogicalDisk -Computer $hostname -Credential $cred |
              Select-Object DeviceID, Size, FreeSpace

您可以使用calculated properties 添加派生信息（如可用磁盘空间比率）：

... | Select-Object DeviceID, Size, FreeSpace, @{n='Ratio';e={$_.FreeSpace/$_.Size}}

使用Compare-Object 比较新旧数据：

Compare-Object -ReferenceObject $old_values -DifferenceObject $new_values -Property DeviceID, Size, FreeSpace