如何让PowerShell导出Azure防火墙规则时无数据仍保留CSV表头

修改后的完整脚本 #

function create($path) {
    $exists = Test-Path -path $path
    Write-Host "tried the following path: $path, it" $(If ($exists) {"Exists"} Else {"Does not Exist!"}) 
    if (!($exists)) { New-Item $path -itemType Directory }
}

# reading file contents 
$subs_file =  "C:\script\Subscriptions.xlsx"
$azSubs = Import-Excel $subs_file
$azSubs
$output_folder = "C:\audit-automation"
# creating folder for outputing data 
create("$output_folder")

# 定义CSV表头属性（与Select-Object中的label对应）
$csvHeaders = @(
    'NSG Name', 
    'NSG Location', 
    'Rule Name', 
    'Source', 
    'Source Application Security Group',
    'Source Port Range', 
    'Access', 
    'Priority', 
    'Direction', 
    'Destination', 
    'Destination Application Security Group', 
    'Destination Port Range', 
    'Resource Group Name',
    'Subscription Name'
)

# iterating over subscriptions 
ForEach ( $sub in $azSubs ) {
    $azsub = $sub.Subscription
    $app = $sub.Application
    $azsub
    $app
    
    # setting config for azure 
    Set-AzContext -SubscriptionName $azsub
        
    # FIREWALL RULES
    $azNsgs = Get-AzNetworkSecurityGroup
    # iterating over retrieved NSGs 
    $Output = ForEach ( $azNsg in $azNsgs ) {
        #Export custom rules
        Get-AzNetworkSecurityRuleConfig -NetworkSecurityGroup $azNsg | `
            Select-Object @{label = 'NSG Name'; expression = { $azNsg.Name } }, `
            @{label = 'NSG Location'; expression = { $azNsg.Location } }, `
            @{label = 'Rule Name'; expression = { $_.Name } }, `
            @{label = 'Source'; expression = { $_.SourceAddressPrefix } }, `
            @{label = 'Source Application Security Group'; expression = { if ($_.SourceApplicationSecurityGroups) { $_.SourceApplicationSecurityGroups.id.Split('/')[-1] } else { $null } } },
            @{label = 'Source Port Range'; expression = { $_.SourcePortRange } }, Access, Priority, Direction, `
            @{label = 'Destination'; expression = { $_.DestinationAddressPrefix } }, `
            @{label = 'Destination Application Security Group'; expression = { if ($_.DestinationApplicationSecurityGroups) { $_.DestinationApplicationSecurityGroups.id.Split('/')[-1] } else { $null } } }, `
            @{label = 'Destination Port Range'; expression = { $_.DestinationPortRange } }, `
            @{label = 'Resource Group Name'; expression = { $azNsg.ResourceGroupName } },
            @{label = 'Subscription Name'; expression = { $azsub } } 
    }
    
    # creating folder to save 
    create("$output_folder\$app")
    $csvPath = "$output_folder\$app\$app-firewall_rules_data$((Get-Date).ToString("yyyy-MM-dd")).csv"

    # 处理无数据情况：生成带表头的空CSV
    if (-not $Output) {
        # 创建包含所有表头属性的空对象
        $emptyRow = New-Object PSObject
        foreach ($header in $csvHeaders) {
            Add-Member -InputObject $emptyRow -MemberType NoteProperty -Name $header -Value $null
        }
        $emptyRow | Export-Csv -Path $csvPath -NoTypeInformation -Append
    } else {
        $Output | Export-Csv -Path $csvPath -NoTypeInformation -Append
    }
}

关键改动说明 #

1. 定义表头数组：提前声明所有CSV列名，确保空数据场景下表头与有数据时完全一致
2. 空数据处理逻辑：检查$Output是否为空，若为空则创建包含所有表头的空对象并导出，保证CSV文件生成完整表头
3. 空值安全处理：优化安全组的取值逻辑，避免空值时执行拆分操作导致的报错
4. 添加-NoTypeInformation参数：移除CSV文件开头多余的类型信息行，让输出更简洁规范

内容的提问来源于stack exchange，提问作者Rav