NeophyteThere's a really good course in the "Training" section of your portal called "Using Groovy in LogicMonitor". Unfortunately, direct linking to a course isn't possible, so you'll have to go search for it yourself. You can go to "All Courses" then filter by "LogicModules" using the checkbox on the left. Should be the last one listed.
This is the documentation on doing scripted data collection. However, this will be the last thing you do in your script. The first thing you'll need to do in your script is connect to the remote system from your Collector, fetch the contents of the log file, then parse through the log file to count all the things you want to count. Then you should reference the documentation to output the data in the proper format. Then you'll create the datasource with your script at the heart.