Example custom Discovery probe and sensor: populate a CI with text file values

This custom Discovery probe helps you if you need to read a text file from a Windows computer and populate a CI in the CMDB with the values from the file.

About this task

In this example the user wanted to read files created by BGinfo.
Note: When you have completed the probe and sensor, place the probe in the appropriate Windows classifier at Discovery Definition > CI Classification > Windows.


  1. Navigate to Discovery Definition > Probes, and then click New.
  2. Complete the following fields:
    • Name: Unique and descriptive name for the probe
    • Probe type: Select Probe.
    • Description: Describe the function of this probe.
    • Used by Discovery: Select this check box
    • ECC queue topic: This is name of the probe the MID server is to run. In this example, we use WMIRunner.
    • ECC queue name: In this example, we use the descriptive name WMI: BGInfo files.
  3. Right-click in the header bar and select Save from the context menu.
  4. Select the Probe Parameters tab in the Probe form, and then click New.
  5. Enter WMI_GetFiles.js as the Name of this parameter.
  6. Copy the script below into the Script field and edit as needed.
  7. Click Submit.
     // Use ServiceNow WMIAPI to gather stats
     var CMD_RETRIES = 3;
     var scanner = getScanner();
     if (scanner) {
       var output = "";
       for(var i = 0; i < CMD_RETRIES; i++) {
          output = scanner.winExec("%SystemRoot%\\system32\\cmd.exe /C type \\\"C:\\Information Systems\\BgInfo\\*.txt\\\"");
          if (output)
       scanner.appendToRoot("output", output);
  8. Navigate to Discovery Definition > Sensors, and then click New.
    Complete the following fields:
    • Name: Use the same name as the matching probe. In this example, we use Windows - Get BGInfo files.
    • Reacts to probe: The name of the probe created in the previous procedure: Windows - Get BGInfo files
    • Sensor type: Select the type of sensor to create - in this example Sensor.
    • Description: Describes the function of this sensor.
    • Script: Copy the script below into the Script field and edit as needed.
    • Sensor type: Determines how the answer from the probe is processed - in this example JavaScript.
  9. Click Submit.
    new DiscoverySensor({ data: {}, process: function(result) { 
     parseOutput: function(output) {
            var currentFile;
            var files = {};
     if (output.startsWith("<wmi")) {
                var bgout = new XMLHelper(output).toObject();
                if (!bgout)
     output = bgout.output;
     var lines = output.split(/\n/);
     for(var i = 0; i < lines.length; i++) {
                var line = lines[i];
                if (line.startsWith("C:\\Information Systems\\BgInfo\\")) {
                    currentFile = line.substr(30);
                    files[currentFile] = "";
                } else if (currentFile) {
                    var newLine = line.trim();
                    if (newLine)
                        files[currentFile] += (files[currentFile]? "\n"&nbsp;: "") + newLine;
     this.data['u_jack_id'] = files['JackID.txt'];
     this.data['warranty_expiration'] = files['Warranty.txt'];
     this.data['po_number'] = files['Ponum.txt'];},
     type: "DiscoverySensor"