check_ms_iis_application_pool.ps1

# Script name:      check_ms_iis_application_pool.ps1
# Version:          v1.03.170218
# Created on:       10/03/2016
# Author:           Willem D'Haese
# Purpose:          Checks Microsoft Windows IIS application pool cpu and memory usage
# On Github:        https://github.com/willemdh/check_ms_iis_application_pool
# On OutsideIT:     https://outsideit.net/monitoring-iis-application-pools/
# Recent History:
#   06/04/16 => Added Run AppPoolOnDemand option - WRI
#   09/06/16 => Cleanup and formatting for release
#   27/01/17 => AppCmd method as workaround for hanging gci
#   28/01/16 => appcount to the back
#   18/02/17 => Cleanup and PSSharpening
# Copyright:
#   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 3 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, see <http://www.gnu.org/licenses/>.

#Requires -Version 2.0

$DebugPreference = 'SilentlyContinue'
$VerbosePreference = 'SilentlyContinue'

$IISStruct = New-Object -TypeName PSObject -Property @{
    StopWatch = [Diagnostics.Stopwatch]::StartNew()
    ApplicationPool = ''
    ProcessId = ''
    Process = ''
    PoolCount = ''
    PoolState = ''
    SitesCount = ''
    WarningMemory = ''
    CriticalMemory = ''
    WarningCpu = ''
    CriticalCpu = ''
    CurrentMemory = ''
    CurrentCpu = ''
    Duration = ''
    Exitcode = 3
    AppPoolOnDemand = 0
    AppCmd = 0
    AppCmdList = ''
    ReturnString = 'UNKNOWN: Please debug the script...'
}

#region Functions

Function Write-Log {
    Param (
        [parameter(Mandatory=$true)][string]$Log,
        [parameter(Mandatory=$true)][ValidateSet('Debug', 'Info', 'Warning', 'Error', 'Unknown')][string]$Severity,
        [parameter(Mandatory=$true)][string]$Message
    )
    $Now = Get-Date -Format 'yyyy-MM-dd HH:mm:ss,fff'
    $LocalScriptName = Split-Path -Path $myInvocation.ScriptName -Leaf
    If ( $Log -eq 'Undefined' ) {
        Write-Debug -Message "${Now}: ${LocalScriptName}: Info: LogServer is undefined."
    }
    ElseIf ( $Log -eq 'Verbose' ) {
        Write-Verbose -Message "${Now}: ${LocalScriptName}: ${Severity}: $Message"
    }
    ElseIf ( $Log -eq 'Debug' ) {
        Write-Debug -Message "${Now}: ${LocalScriptName}: ${Severity}: $Message"
    }
    ElseIf ( $Log -eq 'Output' ) {
        Write-Host "${Now}: ${LocalScriptName}: ${Severity}: $Message"
    }
    ElseIf ( $Log -match '^(([a-zA-Z0-9]|[a-zA-Z0-9][a-zA-Z0-9\-]*[a-zA-Z0-9])\.)*([A-Za-z0-9]|[A-Za-z0-9][A-Za-z0-9\-]*[A-Za-z0-9])(?::(?<port>\d+))$' -or $Log -match '^(([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\.){3}([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])$' ) {
        $IpOrHost = $log.Split(':')[0]
        $Port = $log.Split(':')[1]
        If ( $IpOrHost -match '^(([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\.){3}([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])$' ) {
            $Ip = $IpOrHost
        }
        Else {
            $Ip = [Net.Dns]::GetHostAddresses($IpOrHost)[0].IPAddressToString
        }
        Try {
            $LocalHostname = ([Net.Dns]::GetHostByName((hostname.exe)).HostName).tolower()
            $JsonObject = (New-Object -TypeName PSObject | 
                Add-Member -PassThru NoteProperty logsource $LocalHostname | 
                Add-Member -PassThru NoteProperty hostname $LocalHostname | 
                Add-Member -PassThru NoteProperty scriptname $LocalScriptName | 
                Add-Member -PassThru NoteProperty logtime $Now | 
                Add-Member -PassThru NoteProperty severity_label $Severity | 
                Add-Member -PassThru NoteProperty message $Message ) 
            If ( $psversiontable.psversion.major -ge 3 ) {
                $JsonString = $JsonObject | ConvertTo-Json
                $JsonString = $JsonString -replace "`n",' ' -replace "`r",' '
            }
            Else {
                $JsonString = $JsonObject | ConvertTo-Json2
            }               
            $Socket = New-Object -TypeName System.Net.Sockets.TCPClient -ArgumentList ($Ip,$Port) 
            $Stream = $Socket.GetStream() 
            $Writer = New-Object -TypeName System.IO.StreamWriter -ArgumentList ($Stream)
            $Writer.WriteLine($JsonString)
            $Writer.Flush()
            $Stream.Close()
            $Socket.Close()
        }
        Catch {
            Write-Host "${Now}: ${LocalScriptName}: Error: Something went wrong while trying to send message to logserver `"$Log`"."
        }
        Write-Verbose -Message "${Now}: ${LocalScriptName}: ${Severity}: Ip: $Ip Port: $Port JsonString: $JsonString"
    }
    ElseIf ($Log -match '^((([a-zA-Z]:)|(\\{2}\w+)|(\\{2}(?:(?:25[0-5]|2[0-4]\d|[01]\d\d|\d?\d)(?(?=\.?\d)\.)){4}))(\\(\w[\w ]*))*)') {
        If (Test-Path -Path $Log -pathType container){
            Write-Host "${Now}: ${LocalScriptName}: Error: Passed Path is a directory. Please provide a file."
            Exit 1
        }
        ElseIf (!(Test-Path -Path $Log)) {
            Try {
                $null = New-Item -Path $Log -Type file -Force	
            } 
            Catch { 
                $Now = Get-Date -Format 'yyyy-MM-dd HH:mm:ss,fff'
                Write-Host "${Now}: ${LocalScriptName}: Error: Write-Log was unable to find or create the path `"$Log`". Please debug.."
                exit 1
            }
        }
        Try {
            "${Now}: ${LocalScriptName}: ${Severity}: $Message" | Out-File -filepath $Log -Append   
        }
        Catch {
            Write-Host "${Now}: ${LocalScriptName}: Error: Something went wrong while writing to file `"$Log`". It might be locked."
        }
    }
}

Function ConvertTo-JSON2 {
    param (
        $MaxDepth = 4,
        $ForceArray = $false
    )
    Begin {
        $Data = @()
    }
    Process{
        $Data += $_
    }
    End{
        If ($Data.length -eq 1 -and $ForceArray -eq $false) {
            $Value = $Data[0]
        } 
        Else {
            $Value = $Data
        }
        If ($Value -eq $null) {
            Return 'null'
        }
        $DataType = $Value.GetType().Name
        Switch -Regex ($DataType) {
            'String'                { Return  "`"{0}`"" -f (Format-JSONString $Value ) }
            '(System\.)?DateTime'   { Return  "`"{0:yyyy-MM-dd}T{0:HH:mm:ss}`"" -f $Value }
            'Int32|Double'          { Return  "$Value" }
            'Boolean'               { Return  "$Value".ToLower() }
            '(System\.)?Object\[\]' {
                If ($MaxDepth -le 0) {
                    Return "`"$value`""
                }
                $JsonResult = ''
                ForEach ($Elem in $Value) {
                    If ($JsonResult.Length -gt 0) {
                        $JsonResult +=', '
                    }
                    $JsonResult += ($Elem | ConvertTo-JSON -MaxDepth ($MaxDepth -1))
                }
               Return '[' + $jsonResult + ']'
            }
            '(System\.)?Hashtable' {
                $JsonResult = ''
                ForEach ($Key in $Value.Keys) {
                    If ($JsonResult.Length -gt 0) {
                        $JsonResult +=', '
                    }
                $jsonResult += 
@'
    "{0}": {1}
'@ -f $Key , ($Value[$Key] | ConvertTo-JSON2 -MaxDepth ($MaxDepth -1) )
                }
                Return '{' + $jsonResult + '}'
            }
            default {
                If ($MaxDepth -le 0) {
                    Return  "`"{0}`"" -f (Format-JSONString $Value)
                }
                Return '{' +(($value | Get-Member -MemberType *property | ForEach-Object { 
@'
	"{0}": {1}
'@ -f $_.Name , ($value.($_.Name) | ConvertTo-JSON2 -maxDepth ($maxDepth -1))
                }) -join ', ') + '}'
            }
        }
    }
}

Function Initialize-Args {
    Param ( 
        [Parameter(Mandatory=$true)]$Args
    )
    try {
        For ( $i = 0; $i -lt $Args.count; $i++ ) { 
            $CurrentArg = $Args[$i].ToString()
            if ($i -lt $Args.Count-1) {
                $Value = $Args[$i+1];
                If ($Value.Count -ge 2) {
                    foreach ($Item in $Value) {
                        $null = Test-Strings -String $Item
                    }
                }
                else {
                    $Value = $Args[$i+1];
                    $null = Test-Strings -String $Value
                }
            } 
            else {
                $Value = ''
            }
            switch -regex -casesensitive ($CurrentArg) {
                '^(-A|--ApplicationPool)$' {
                    if ($value -match '^[a-zA-Z0-9. _-]+$') {
                        $IISStruct.ApplicationPool = $Value
                    }
                    else {
                        throw "Application Pool `"$value`" does not meet regex requirements."
                    }
                    $i++
                }
                '^(-WM|--WarningMemory)$' {
                    if ($value -match '^[0-9]{1,10}$') {
                        $IISStruct.WarningMemory = $Value
                    }
                    else {
                        throw "Method `"$value`" does not meet regex requirements."
                    }
                    $i++
                }
                '^(-CM|--CriticalMemory)$' {
                    if ($value -match '^[0-9]{1,10}$') {
                        $IISStruct.CriticalMemory = $Value
                    }
                    else {
                        throw "Method `"$value`" does not meet regex requirements."
                    }
                    $i++
                }
                '^(-WC|--WarningCpu)$' {
                    if ($value -match '^[0-9]{1,10}$') {
                        $IISStruct.WarningCpu = $Value
                    }
                    else {
                        throw "Method `"$value`" does not meet regex requirements."
                    }
                    $i++
                }
                '^(-CC|--CriticalCpu)$' {
                    if ($value -match '^[0-9]{1,10}$') {
                        $IISStruct.CriticalCpu = $Value
                    }
                    else {
                        throw "Method `"$value`" does not meet regex requirements."
                    }
                    $i++
                }
                '^(-APOD|--AppPoolOnDemand)$' {
                    if ($value -match '^[0-1]{1,2}$') {
                        $IISStruct.AppPoolOnDemand = $Value
                    }
                    else {
                        throw "Method `"$value`" does not meet regex requirements."
                    }
                    $i++
                }
               '^(-Appcmd|-AppCmd|-appcmd|-APPCMD)$' {
                    if ($value -match '^[0-1]{1,2}$') {
                        $IISStruct.Appcmd = $Value
                    }
                    else {
                        throw "Method `"$value`" does not meet regex requirements."
                    }
                    $i++
                }
                '^(-h|--Help)$' {
                    Write-Help
                }
                default {
                    throw "Illegal arguments detected: $_"
                 }
            }
        }
    } 
    catch {
        Write-Host "CRITICAL: Argument: $CurrentArg Value: $Value Error: $_"
        Exit 2
    }
}
Function Test-Strings {
    Param ( [Parameter(Mandatory=$true)][string]$String )
    $BadChars=@("``", '|', ';', "`n")
    $BadChars | ForEach-Object {
        If ( $String.Contains("$_") ) {
            Write-Host "Error: String `"$String`" contains illegal characters."
            Exit $IISStruct.ExitCode
        }
    }
    Return $true
} 

Function Invoke-CheckIISApplicationPool {
    Try {
        Import-Module -Name WebAdministration
        If (Get-ChildItem -Path IIS:\AppPools | Where-Object {$_.Name -eq "$($IISStruct.ApplicationPool)"}) {
            $IISStruct.PoolState = Get-ChildItem -Path IIS:\AppPools | Where-Object {$_.Name -eq "$($IISStruct.ApplicationPool)"} | Select-Object -Property State -ExpandProperty State
            If ( $IISStruct.PoolState -eq 'Started') {
                $IISStruct.ProcessId = Get-WmiObject -NameSpace 'root\WebAdministration' -class 'WorkerProcess' | Where-Object {$_.AppPoolName -match $IISStruct.ApplicationPool}  | Select-Object -Expand ProcessId
                If ( $IISStruct.ProcessId ) {
                    $IISStruct.Process = Get-Wmiobject -Class Win32_PerfFormattedData_PerfProc_Process | Where-Object { $_.IdProcess -eq $IISStruct.ProcessId } 
                    $IISStruct.CurrentCpu = $IISStruct.Process.PercentProcessorTime
                    Write-Log Verbose Info "Application pool $($IISStruct.ApplicationPool) process id: $($IISStruct.ProcessId) Percent CPU: $($IISStruct.CurrentCpu)"
                    $IISStruct.CurrentMemory = [Math]::Round(($IISStruct.Process.workingSetPrivate / 1MB),2)
                    Write-Log Verbose Info "Application pool $($IISStruct.ApplicationPool) process id: $($IISStruct.ProcessId) Private Memory: $($IISStruct.CurrentMemory)"
                    $Sites = Get-WebConfigurationProperty "/system.applicationHost/sites/site/application[@applicationPool='$($IISStruct.ApplicationPool)' and @path='/']/parent::*" machine/webroot/apphost -name name
                    $Apps = Get-WebConfigurationProperty "/system.applicationHost/sites/site/application[@applicationPool='$($IISStruct.ApplicationPool)' and @path!='/']" machine/webroot/apphost -name path
                    $IISStruct.SitesCount = ($Sites,$Apps | ForEach-Object {$_.value}).count
                    $IISStruct.ExitCode = 0
                    $IISStruct.ReturnString = "OK: Application Pool `"$($IISStruct.ApplicationPool)`" with $($IISStruct.SitesCount) Applications. {CPU: $($IISStruct.CurrentCpu) %}{Memory: $($IISStruct.CurrentMemory) MB}"
                    $IISStruct.ReturnString += " | 'pool_cpu'=$($IISStruct.CurrentCpu)%, 'pool_memory'=$($IISStruct.CurrentMemory)MB, 'app_count'=$($IISStruct.SitesCount)"
                }
                Else {
                    If ( $IISStruct.AppPoolOnDemand = 1 ) {
                        $IISStruct.Process = 0
                        $IISStruct.CurrentCpu  = 0
                        $IISStruct.CurrentMemory = 0
                        $Sites = 0
                        $Apps = 0
                        $IISStruct.SitesCount = 0
                        $IISStruct.ExitCode = 0
                        $IISStruct.ReturnString = "OK:  Application Pool Started but no process is assigned yet `"$($IISStruct.ApplicationPool)`" with 0 Applications. {CPU: 0%}{Memory: 0MB}"
                        $IISStruct.ReturnString += " | 'pool_cpu'=0%, 'pool_memory'=0MB, 'app_count'=0"
                    }
                    Else {
                        Throw "Application Pool `"$($IISStruct.ApplicationPool)`" not found in WMI."
                    }
                }
            }
            Else {
                Throw "Application Pool `"$($IISStruct.ApplicationPool)`" is $($IISStruct.PoolState)."       
            }
        }
        Else {
            Throw "Application Pool `"$($IISStruct.ApplicationPool)`" does not exist."
        }
    }
    Catch {
        $IISStruct.ExitCode = 2
        $IISStruct.ReturnString = "CRITICAL: $_"
    }
}
Function Invoke-CheckIISWithAppCmd {
    Try {
        [xml]$AppCmdXml = & "$env:windir\system32\inetsrv\appcmd.exe" list apppools /xml
        $IISStruct.PoolCount = $AppCmdXml.appcmd.APPPOOL.Count
        If ( ! $IISStruct.PoolCount ) {
             $IISStruct.PoolState = $AppCmdXml.appcmd.APPPOOL.'state'
             if ( $AppCmdXml.appcmd.APPPOOL.'APPPOOL.NAME' -eq $IISStruct.ApplicationPool ) {
                 $Found = $True
             }
             Else {
                 $IISStruct.ReturnString = "CRITICAL: NO IIS application pool with name $($IISStruct.ApplicationPool) found. "
                 $IISStruct.ExitCode = 2
             }
        }
        Else {
            $Found = $False
            $i = 0
            while ( ! $found -and $i -lt $IISStruct.PoolCount ) {
                If ( $AppCmdXml.appcmd.APPPOOL[$i].'APPPOOL.NAME' -eq $IISStruct.ApplicationPool ) {
                     Write-Log Verbose Info "Application pool found: $($IISStruct.ApplicationPool)"
                     $IISStruct.PoolState = $AppCmdXml.appcmd.APPPOOL[$i].'state'
                     $Found = $True
                 }
                 Write-Log Verbose Info "Pool: $($AppCmdXml.appcmd.APPPOOL[$i].'APPPOOL.NAME')"
                 $i++
            }
        }
        If ( $Found ) {
            If ( $IISStruct.PoolState -eq 'Started') {
                $IISStruct.ProcessId = Get-WmiObject -NameSpace 'root\WebAdministration' -class 'WorkerProcess' | Where-Object {$_.AppPoolName -match $IISStruct.ApplicationPool}  | Select-Object -Expand ProcessId
                If ( $IISStruct.ProcessId ) {
                    $IISStruct.Process = get-wmiobject Win32_PerfFormattedData_PerfProc_Process | Where-Object { $_.IdProcess -eq $IISStruct.ProcessId } 
                    $IISStruct.CurrentCpu = $IISStruct.Process.PercentProcessorTime
                    Write-Log Verbose Info "Application pool $($IISStruct.ApplicationPool) process id: $($IISStruct.ProcessId) Percent CPU: $($IISStruct.CurrentCpu)"
                    $IISStruct.CurrentMemory = [Math]::Round(($IISStruct.Process.workingSetPrivate / 1MB),2)
                    Write-Log Verbose Info "Application pool $($IISStruct.ApplicationPool) process id: $($IISStruct.ProcessId) Private Memory: $($IISStruct.CurrentMemory)"
                    $Sites = Get-WebConfigurationProperty "/system.applicationHost/sites/site/application[@applicationPool='$($IISStruct.ApplicationPool)' and @path='/']/parent::*" machine/webroot/apphost -name name
                    $Apps = Get-WebConfigurationProperty "/system.applicationHost/sites/site/application[@applicationPool='$($IISStruct.ApplicationPool)' and @path!='/']" machine/webroot/apphost -name path
                    $IISStruct.SitesCount = ($Sites,$Apps | ForEach-Object {$_.value}).count
                    $IISStruct.ExitCode = 0
                    $IISStruct.ReturnString = "OK: Application Pool `"$($IISStruct.ApplicationPool)`" with $($IISStruct.SitesCount) Applications. {CPU: $($IISStruct.CurrentCpu) %}{Memory: $($IISStruct.CurrentMemory) MB}"
                    $IISStruct.ReturnString += " | 'pool_cpu'=$($IISStruct.CurrentCpu)%, 'pool_memory'=$($IISStruct.CurrentMemory)MB, 'app_count'=$($IISStruct.SitesCount)"
                }
                Else {
                    If ( $IISStruct.AppPoolOnDemand = 1 ) {
                        $IISStruct.Process = 0
                        $IISStruct.CurrentCpu  = 0
                        $IISStruct.CurrentMemory = 0
                        $Sites = 0
                        $Apps = 0
                        $IISStruct.SitesCount = 0
                        $IISStruct.ExitCode = 0
                        $IISStruct.ReturnString = "OK:  Application Pool Started but no process is assigned yet `"$($IISStruct.ApplicationPool)`" with 0 Applications. {CPU: 0%}{Memory: 0MB}"
                        $IISStruct.ReturnString += " | 'pool_cpu'=0%, 'pool_memory'=0MB, 'app_count'=0"
                    }
                    Else {
                        Throw "Application Pool `"$($IISStruct.ApplicationPool)`" not found in WMI."
                    }
                }
            }
            Else {
                Throw "Application Pool `"$($IISStruct.ApplicationPool)`" is $($IISStruct.PoolState)."       
            }
        }
        Else {
            Throw "NO IIS application pool with name $($IISStruct.ApplicationPool) found. "
        }
    }   
    Catch {
        $IISStruct.ExitCode = 2
        $IISStruct.ReturnString = "CRITICAL: $_"
    }            
}

#endregion Functions

#region Main

If ( $Args ) {
    If ( ! ( $Args[0].ToString()).StartsWith('$') ) {
        If ( $Args.count -ge 1 ) {
            Initialize-Args $Args
        }
    }
    Else {
        $IISStruct.ReturnString = 'CRITICAL: Script needs mandatory parameters to work.'
        $IISStruct.ExitCode = 2
    }
}
If ( $IISStruct.AppCmd -eq 0 ) {
    Invoke-CheckIISApplicationPool
}
else {
    Invoke-CheckIISWithAppCmd
}
Write-Host $IISStruct.ReturnString
Exit $IISStruct.ExitCode

#endregion Main