DNS backup script with logging and error handling

Backup-DNSZoneData.ps1

<#
.SYNOPSIS
    DNS Backup Script.

.DESCRIPTION
    This script connects to a specified DNS server, retrieves DNS zone and forwarder information, exports the zones and forwarders to files,
    compresses the files, and performs cleanup operations. It logs all actions and sends an email notification if an error occurs.

.PARAMETER LogFilePath
    The path to the log file where script actions and messages will be recorded. If run from ISE script pane with "Run selection", log file will be saved to C:\Temp\Backup

.PARAMETER DNSServer
    The name of the DNS server to connect to and retrieve zone information from.

.PARAMETER BackupFolder
    The directory where backup files will be stored.

.EXAMPLE
    .\DNSBackupScript.ps1

.NOTES
    Author: Sebastian Rock
    Date: 31/05/2024
    Modified and extended script from https://gist.github.com/compwiz32
#>

# Define the global variable for the log file path
if ($PSScriptRoot) {
    $Global:LogFilePath = Join-Path -Path $PSScriptRoot -ChildPath ("$(Get-Date -Format 'yyyy-MM-dd_HH-mm-ss').log")
} else {
    New-Item -Path "C:\Temp\DNSBackup" -ItemType Directory -Force
    $Global:LogFilePath = "C:\Temp\DNSBackup\DNSBackup_$(Get-Date -Format 'yyyy-MM-dd_HH-mm-ss').log"
}

# If you want to set a custom log file name path, uncomment the line below
# $Global:LogFilePath = "C:\Your\Custom\Path\DNSBackup_$(Get-Date -Format 'yyyy-MM-dd_HH-mm-ss').log"

Function Log-Message {
    param (
        [Parameter(Mandatory=$true)] [string] $Message,
        [switch] $Warning,
        [switch] $Error
    )
 
    Try {
        # Add Content to the Log File
        $TimeStamp = (Get-Date).ToString("yyyy/MM/dd HH:mm:ss:fff")
        $Line = "$TimeStamp - $Message"
        
        Add-Content -Path $Global:LogFilePath -Value $Line

        # Set the default color and prefix
        $Color = "Green"
        $Prefix = "Message"

        # Change color and prefix based on the parameters
        if ($Warning.IsPresent) {
            $Color = "Yellow"
            $Prefix = "Warning"
        } elseif ($Error.IsPresent) {
            $Color = "Red"
            $Prefix = "Error  "
        }

        Write-Host "$Prefix : '$Line'" -ForegroundColor $Color
    } Catch {
        Write-Host "Error: $_.Exception.Message" -ForegroundColor Red
    }
}

Function Send-ErrorEmail {
    param (
        [Parameter(Mandatory=$true)] [string] $LogFilePath
    )
    $SmtpServer = "" # smtp.your.company
    $From = "" # Sender
    $To = "" # Reciever
    $Subject = "DNS Backup Script Failed"
    $Body = @"

Example body:

The DNS backup script encountered an error. Please find the log file attached for more details.

The script and job is automatically paused on error, it will try to run again in three days.

Actions to take:

1. Troubleshoot
2. Fix problem
3. Stop the task in Task Manager
4. Run manual test in Task Manager


Backupatron 4000 signing off
God speed


"@
    
    Try {
        Send-MailMessage -SmtpServer $SmtpServer -From $From -To $To -Subject $Subject -Body $Body -Attachments $LogFilePath
        Log-Message "Error email sent to $To."
    } Catch {
        Log-Message "Failed to send error email: $_" -Warning
    }
}

#Set file paths
$BackupFolder = "" # use a valid path like "\\Server01\Path\" or "C:\Backup\"
$DNSServer = ""

#Date variable
$LongDate = Get-Date -Format "yyyy-MM-dd_HH-mm"

#Log Start Time of the Script
$StartTime = (Get-Date)
Log-Message "Script Started at: $(Get-date -format 'yyyy/MM/dd HH:mm:ss')"

# Main try-catch block for the script
Try {
    # Connect to DC
    Try {
        $CIMSession = New-CimSession -ComputerName $DNSServer
        Log-Message "Successfully connected to DNS server $DNSServer."
    } Catch {
        Log-Message "Failed to connect to DNS server $DNSServer $_" -Error
        throw
    }

    # Read DNS info from DC
    Try {
        $ZoneInfo = Get-DnsServerZone -CimSession $CIMSession
        Log-Message "Successfully retrieved DNS zone information. Total zones: $($ZoneInfo.Count)"
    } Catch {
        Log-Message "Failed to retrieve DNS zone information: $_. Exiting script." -Error
        throw
    }

    # Create temporary ps drive
    Try {
        New-PSDrive -Name DC -PSProvider FileSystem -Root \\$DNSServer\c$\windows\system32\dns
        Log-Message "Temporary PSDrive created."
    } Catch {
        Log-Message "Failed to create temporary PSDrive: $_" -Error
        throw
    }

    # Filter out the forward zones, reverse zones, and conditional forwarders
    $ForwardZones = $ZoneInfo | Where-Object { $_.ZoneName -notlike "*.arpa" -and $_.ZoneType -eq "Primary" } | Select-Object -ExpandProperty ZoneName
    $ReverseZones = $ZoneInfo | Where-Object { $_.ZoneName -like "*.arpa" -and $_.ZoneName -notin @("0.in-addr.arpa", "127.in-addr.arpa", "255.in-addr.arpa") } | Select-Object -ExpandProperty ZoneName
    $ConditionalForwarder = $ZoneInfo | Where-Object { $_.ZoneType -eq "Forwarder" } | Select-Object -ExpandProperty ZoneName

    # Check if ForwardZones, ReverseZones, and ConditionalForwarders are populated
    if ($ForwardZones) {
        Log-Message "ForwardZones are populated: $($ForwardZones.Count) zones"
        Log-Message "$ForwardZones"
    } else {
        Log-Message "No ForwardZones found." -Warning
    }

    if ($ReverseZones) {
        Log-Message "ReverseZones are populated: $($ReverseZones.Count) zones"
        Log-Message "$ReverseZones"
    } else {
        Log-Message "No ReverseZones found." -Warning
    }

    if ($ConditionalForwarder) {
        Log-Message "ConditionalForwarders are populated: $($ConditionalForwarder.Count) zones"
        Log-Message "$ConditionalForwarder"
    } else {
        Log-Message "No ConditionalForwarders found." -Warning
    }

    # Throw an error if any of the collections are empty
    $EmptyCollections = @()
    if (-not $ForwardZones) {
        $EmptyCollections += "ForwardZones"
    }
    if (-not $ReverseZones) {
        $EmptyCollections += "ReverseZones"
    }
    if (-not $ConditionalForwarder) {
        $EmptyCollections += "ConditionalForwarder"
    }

    if ($EmptyCollections.Count -gt 0) {
        $ErrorMessage = "The following collection(s) are empty: $($EmptyCollections -join ', ')"
        Log-Message $ErrorMessage -Error
        throw $ErrorMessage
    }

    # Export data for each forward lookup zone
    foreach ($DNSZone in $ForwardZones) {
        $JobScope = "DNSBackup_ForwardZone"
        $FileName = -join ($JobScope, "_", $($DNSZone.Replace(".", "_")), "_", $LongDate, ".dns")

        Try {
            Export-DnsServerZone -Name $DNSZone -FileName $FileName -CimSession $CIMSession
            Log-Message "Successfully exported forward lookup zone $DNSZone to $FileName."
        } Catch {
            Log-Message "Failed to export zone $DNSZone $_" -Error
        }
    }

    # Export data for each reverse lookup zone
    foreach ($DNSZone in $ReverseZones) {
        $JobScope = "DNSBackup_ReverseZone"
        $FileName = -join ($JobScope, "_", $($DNSZone.Replace(".", "_")), "_", $LongDate, ".dns")

        Try {
            Export-DnsServerZone -Name $DNSZone -FileName $FileName -CimSession $CIMSession
            Log-Message "Successfully exported reverse lookup zone $DNSZone to $FileName."
        } Catch {
            Log-Message "Failed to export zone $DNSZone $_" -Error
        }
    }

    # Export data for each conditional forwarder
    foreach ($DNSZone in $ConditionalForwarder) {
        $JobScope = "DNSBackup_ConditionalForwarder"
        $FileName = -join ($JobScope, "_", $($DNSZone.Replace(".", "_")), "_", $LongDate, ".csv")

        Try {
            Get-DnsServerZone -Name $DNSZone -ComputerName $DNSServer | Export-Csv -NoTypeInformation -Path DC:\$FileName
            Log-Message "Successfully exported conditional forwarder $DNSZone to $FileName."
        } Catch {
            Log-Message "Failed to export forwarder $DNSZone $_" -Error
        }
    }

    # Compress and copy the files
    $ZipFileName = "DNSBackup_$LongDate.zip"
    $ZipFilePath = Join-Path -Path "$BackupFolder" -ChildPath $ZipFileName
    Try {
        Compress-Archive -Path DC:\DNSBackup* -DestinationPath $ZipFilePath
        Log-Message "Successfully compressed backup files to $ZipFilePath."
    } Catch {
        Log-Message "Failed to compress backup files: $_" -Error
        throw
    }

    # Cleanup files, drives, and CIM sessions
    Get-ChildItem DC: | Where-Object Name -Like "DNSBackup*" | Remove-Item
    Log-Message "Temporary files removed."
    
    Remove-PSDrive -Name DC -ErrorAction Stop
    Log-Message "PSDrive DC removed."

    Remove-CimSession -CimSession $CIMSession -ErrorAction Stop
    Log-Message "CIM session removed."

    #Log End Time
    $EndTime = (Get-Date)
    Log-Message "Script Ended at: $(Get-date -format 'yyyy/MM/dd HH:mm:ss')"

    #Get Elapsed Time
    $ElapsedTime = ($EndTime - $StartTime).Seconds
    Log-Message "Script Execution Time: $ElapsedTime Seconds"
} Catch {
    Log-Message "Script encountered a fatal error: $_" -Error
    Send-ErrorEmail -LogFilePath $Global:LogFilePath
    Read-Host -Prompt "Script paused until manual input"
}