# Check Backup State on Microsoft Exchange 2016
#
# This NSCP (former known as NSClient++) plugin checked the LastFullBackup information from an Exchange 2016 environment
# and if that isnīt in the given timeframe it will generate an warning inside nagios.
# 
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.

# Revision History
# 2015-09-14	Bastian W. [Bastian@gmx-ist-cool.de]		Created 0.4
# 2015-11-26	Bastian W. [Bastian@gmx-ist-cool.de]		Created 0.5:
#																- Fixed an issue if the full backup field is empty
# 2016-04-12	Bastian W. [Bastian@gmx-ist-cool.de]		Created 1.0:
#																- Released first offical version
# To execute from within NSClient++
#
# [NRPE Handlers]
# check_exchange_mailqueue=cmd /c echo C:\Scripts\Nagios\NagiosMonitoring_Exchange2010_BackupState.ps1 | PowerShell.exe -Command -
#
# On the check_nrpe command include the -t 30, since it takes some time to load the Exchange cmdlet's.
#
# Note:
# - This script assume your are running a full backup every week (7 days)
# - The script assume the full backup takes 8 hours!
# If this isnīt the case you can adjust the values below


# ToDos:
# - Change the monitoring script so that it checks also the daily incremental backups
# - Do Warning, Error, Critical States



# Config
$BackupFullRunTime = 8 # Hours it takes to perform a full backup; Default=8
$HoursUntilNewFullBackup = 168 # Hours which needs to pass until a new full backup is triggered; Default=168

# ============================================================================================================
# -------------------------------- DO NOT CHANGE ANYTHING BEHIND THIS LINE!!! --------------------------------

# Build with the help from the following URLS:
# http://blogs.technet.com/b/timmcmic/archive/2012/05/14/backup-dates-and-times-are-incorrect-even-though-data-has-been-committed-to-backup-media-successfully.aspx


# Internal Options
$bDebugScript = 0

# Reset / declare variables
[STRING]$strServer = ""
$ARRAYBackupFullDetails = ""
$intNagiosStatus = ""
$intHostActive = ""
$CalculatedLastBackupFullTime = ""
$CountedDBsWithBackupIssues=0
	
$Now = get-date
$strServer = $env:computername
$strServerShort = $env:computername

if ( (Get-PSSnapin -Name Microsoft.Exchange.Management.PowerShell.E2010 -ErrorAction:SilentlyContinue) -eq $null)
{
    Add-PSSnapin Microsoft.Exchange.Management.PowerShell.E2010 -EA SilentlyContinue
}
 
# In order to prevent recovery databases to pollute the open service problems each time a backup is restored

#$Status = Get-MailboxDatabase -server $strServer | ? {-not $_.Recovery} | Get-MailboxDatabaseCopyStatus | Where-Object {$_.mailboxserver -match $strServerShort}
#$Status = Get-MailboxDatabase -server $strServer | ? {-not $_.Recovery} | Get-MailboxDatabaseCopyStatus | Where-Object {$_.mailboxserver -match $strServer}

# Check last backup
#$ARRAYBackupFullDetails = @(Get-MailboxDatabase -server $strServer -status | Where-Object {-not $_.recovery -and $_.server -match $strServerShort} | Select-Object name, LastFullBackup )
#Get-MailboxDatabase -server $env:computername -status | Select-Object name, LastFullBackup, ServerName, MountedOnServer, LastIncrementalBackup 
#Get-MailboxDatabase -server $env:computername -status | Select-Object name, LastFullBackup, MountedOnServer, LastIncrementalBackup 
#Get-MailboxDatabase -Server $env:computername -Status | fl name,*BACKUP*
$ARRAYBackupFullDetails = @(Get-MailboxDatabase -server $strServer -status | Where-Object {-not $_.recovery -and $_.server -match $strServer} | Select-Object name, LastFullBackup)

$WarningList = @()
$CriticalErrorList = @()
#$CountMounted = 0
#$CountHealthy = 0
#$CountUnhealthy = 0
$OutputString = ''
 
# Compare last backup date with current date, only when $ARRAYBackupFullDetails is not empty
if ($ARRAYBackupFullDetails.count -gt 0) 
{

	if ($bDebugScript -eq 1){ Write-Host " Debug: We found some mounted DBs on server" -foregroundcolor Magenta}
	
	$CalculatedLastBackupFullTime = $HoursUntilNewFullBackup + $BackupFullRunTime
	
	#$ARRAYBackupFullDetails | Where-Object {$_.LastFullBackup -lt $Now.addhours(-168)} | % {
	$ARRAYBackupFullDetails | Where-Object {$_.LastFullBackup -lt $Now.addhours(-$CalculatedLastBackupFullTime)} | % {
	
		# We found a DB which do not have been backuped in the needed timeframe
		
		if ($bDebugScript -eq 1){ Write-Host " Debug: Found missing full backup for DB: $($_.name)" -foregroundcolor Magenta}
		
		$CurrentCalculatedTime = $Now.addhours(-$CalculatedLastBackupFullTime)
		
		if ($_.LastFullBackup -eq $null)
		{
			# The LastFullBackup is empty, so no full backup was performed
		
			if ($bDebugScript -eq 1){ Write-Host " Debug: No full backup for DB $($_.name) found!" -foregroundcolor Magenta}
			
			if ($CriticalErrorList)
			{
			$CriticalErrorList += ", No Backup for DB $($_.name) found"
			}
			else
			{
				$CriticalErrorList += "No Backup for DB $($_.name) found"
			}
			
			$CountedDBsWithBackupIssues += 1
			
		}
		#elseif ($_.LastFullBackup -lt $Now.addhours(-168))
		elseif ($_.LastFullBackup -lt $CurrentCalculatedTime)
		{
			# If last full backup is smaller (lt) as the callculated time
		
			$TempHours = $([Math]::floor(($now -  $_.LastFullBackup).totalHours))
			
			if ($TempHours -gt 8)
			{
				$TempHours = $TempHours / 8
				$TempHours = $TempHours.ToString() + " days"
			}
			else
			{
				$TempHours = $TempHours.ToString() + " hours"
			}
		
			#if ($bDebugScript -eq 1){ Write-Host " Debug: DB $($_.name) hasn't been backed up for $([Math]::floor(($now -  $_.LastFullBackup).totalHours)) hours" -foregroundcolor Magenta}
		
			if ($bDebugScript -eq 1){ Write-Host " Debug: DB $($_.name) hasn't been fully backed up for $TempHours" -foregroundcolor Magenta}
		
			#write-verbose 'error $($_.name)';
			#$CriticalErrorList += "DB $($_.name) hasn't been backed up for $([Math]::floor(($now -  $_.LastFullBackup).totalHours)) hours"
			if ($CriticalErrorList)
			{
				$CriticalErrorList += ", DB $($_.name) hasn't been backed up for $TempHours"
			}
			else
			{
				$CriticalErrorList += "DB $($_.name) hasn't been backed up for $TempHours"
			}
			
			$CountedDBsWithBackupIssues += 1
			
			$TempHours = 0
		}
		
	}
	
	#$TotalProblems = $WarningList.count + $CriticalErrorList.count
	$TotalProblems = $CriticalErrorList.count
	
	if ($TotalProblems -eq 0)
	{
		$OutputString = 'OK: All databases backups are ok.'
		$OutputString += " | 'Total DBs with Backup Problems'=0"
		Write-Host "$OutputString"
		exit 0 # Nagios Status = OK
	}
	else
	{
		#$OutputString = "CRITICAL: $CriticalErrorList" + ' - ' + "$WarningList
		$OutputString = "CRITICAL: $CriticalErrorList"
		#$OutputString += " | 'Total DBs with Backup Problems'=$TotalProblems"
		$OutputString += " | 'Total DBs with Backup Problems'=$CountedDBsWithBackupIssues"
	}

	if ($CriticalErrorList.count -ne 0)
	{
		Write-Host "$OutputString"
		exit 2 # Nagios Status = Critial
	}
	else
	{
		Write-Host "$OutputString"
		exit 1 # Nagios Status = Warning
	}

}
elseif ($ARRAYBackupFullDetails.count -eq 0) 
{

	if ($bDebugScript -eq 1){ Write-Host " Debug: No DBs mounted on current server" -foregroundcolor Magenta}

	# if we get a 0 counter here, it might be that no mailbox is mounted on that server!
	
	$OutputString = "OK: No mailbox databases mounted on $strServer!"
	$OutputString += " | 'Total DBs with Backup Problems'=0"
	Write-Host "$OutputString"
	exit 0 # Nagios Status = OK
	
}
else
{

	if ($bDebugScript -eq 1){ Write-Host " Debug: Unexpected error!" -foregroundcolor Magenta}

	# if we get something else as a counter here
	
	$OutputString = "CRITICAL: Unexpected error occoured"
	#$OutputString += " | 'Total DBs with Backup Problems'=$TotalProblems"
	Write-Host "$OutputString"
	exit 2 # Nagios Status = Critical
	
}