This article applies to PRTG Network Monitor 14 or later

Using PRTG to Monitor Nginx Status

You can monitor the status page of nginx and see the corresponding values by creating an EXE/Script Advanced sensor which uses the PowerShell script given below.

Note: The script might not properly work with newer versions of Nginx and probably requires some modifications. As an alternative, you can try the REST Custom sensor with an appropriate template.

Set up Monitoring of Nginx Status

• Open a text editor.
• Copy the following code and paste it into the editor:

Param([string]$url)
$warningpreference = "silentlyContinue"


    $global:resultText = "OK"

# create a table to store the information 
    $table = New-Object system.Data.DataTable "result"
    $col1 = New-Object system.Data.DataColumn channel,string
    $col2 = New-Object system.Data.DataColumn value,string
    $col3 = New-Object system.Data.DataColumn unit,string
    $col4 = New-Object system.Data.DataColumn customUnit,string
    $col5 = New-Object system.Data.DataColumn warning,string
    $col6 = New-Object system.Data.DataColumn float,string
    $col7 = New-Object system.Data.DataColumn mode, string
    
    $table.columns.add($($col1))
    $table.columns.add($($col2))
    $table.columns.add($($col3))
    $table.columns.add($($col4))
    $table.columns.add($($col5))
    $table.columns.add($($col6))
    $table.columns.add($($col7))
    
# To get this script running with PRTGNetworkMonitor you need to enable RemoteSigned-scripting for 32bit-processes. 
# This can be done with running 'c:\Windows\SysWOW64\WindowsPowerShell\v1.0\powershell.exe "Set-ExecutionPolicy RemoteSigned"' on a system with default paths

# this function produces a well-formated xml-output out of a given table
function New-Xml
{
    param($RootTag="ROOT",$ItemTag="ITEM", $ChildItems="*", $TextTag="OK", $Attributes=$Null)

    Begin {
        $xml = "<$RootTag>`n"
    }

    Process {
        $xml += "  <$ItemTag>`n"
        
    foreach ($child in $_ | Get-Member -Type *Property $childItems)
    {
        $Name = $child.Name
        if (-not "$($_.$name)" -eq "")  {
            $xml += "    <$Name>$($_.$Name)</$Name>`n"
        }
    }
        $xml += "  </$ItemTag>`n"
    }

    End {
        $xml += "  <text>$TextTag</text>`n" 
        $xml += "</$RootTag>`n"
        $xml
    }
} 


    $web = New-Object Net.WebClient
    Try {
        $response = $web.DownloadString($url)
    } 
    Catch {
        Write-Warning "$($error[0])"
    }
    # Stubbing input for development:
    #$response="Active connections: 291`r`n
#server accepts handled requests`r`n
#  16630948 16630949 31070465`r`n
#Reading: 6 Writing: 179 Waiting: 106"

    $responseArray = $response.split(“`r`n”)

    ForEach ($responseLine in $responseArray){
      if ($responseLine.startswith('Active')) {
        $keyval = $responseLine.split(":") 
        $row = $table.NewRow();
        $row.channel = "$($keyval[0])";
        $row.value = $keyval[1]
        $row.unit  = "Count"
        $row.mode  = "absolute"
        $table.Rows.Add($row)
      }
      if ($responseLine.startswith('Reading:')) {
        ($responseLine -match "Reading: [0-9]+") | out-null 
          $keyval = $matches[0].split(": ")
          $row = $table.NewRow();
          $row.channel = "$($keyval[0])";
          $row.value = $keyval[2]
          $row.unit  = "Count"
          $row.mode  = "absolute"
          $table.Rows.Add($row)
        ($responseLine -match "Writing: [0-9]+") | out-null 
          $keyval = $matches[0].split(": ")
          $row = $table.NewRow();
          $row.channel = "$($keyval[0])";
          $row.value = $keyval[2]
          $row.unit  = "Count"
          $row.mode  = "absolute"
          $table.Rows.Add($row)
        ($responseLine -match "Waiting: [0-9]+") | out-null 
          $keyval = $matches[0].split(": ")
          $row = $table.NewRow();
          $row.channel = "$($keyval[0])";
          $row.value = $keyval[2]
          $row.unit  = "Count"
          $row.mode  = "absolute"
          $table.Rows.Add($row)
      }
      if (!$responseLine.length -eq 0 -and ! $responseLine.startswith('Active connections:') -and ! $responseLine.startswith('server') -and ! $responseLine.startswith('Reading:')) {
        $values = $responseLine.trim().split(" ")
        $row = $table.NewRow();
          $row.channel = "Accepts";
          $row.value = "$($values[0])"
          $row.unit  = "Count"
          $row.mode  = "difference"
          $table.Rows.Add($row)
        $row = $table.NewRow();
          $row.channel = "Handled";
          $row.value = $values[1]
          $row.unit  = "Count"
          $row.mode  = "difference"
          $table.Rows.Add($row)
          $row = $table.NewRow();
        $row.channel = "Requests";
          $row.value = $values[2]
          $row.unit  = "Count"
          $row.mode  = "difference"
          $table.Rows.Add($row)
      }
    }

# forward the generated table to xml-generator and store the result
    $retval = $table | New-Xml -RootTag prtg -ItemTag result -ChildItems Channel,Value,Unit,CustomUnit,Warning,Float,Mode -TextTag $resultText

# return the result
    write-host $retval

• Save the file and name it, e.g., nginx_status.ps1
• Place the script in the \Custom Sensors\EXEXML sub-directory of your PRTG installation to ensure that the EXE/Script Advanced sensor can pick up the same.
• Create a new EXE/Script Advanced Sensor .
  • Choose nginx_status.ps1 as executable.
  • As Parameter, pass the URL to the nginx status page to the sensor.

The sensor will now read the status page and you should see the values reflected in the sensor's channels.

Best regards