How to trigger a Google Apps Script using Knime?

Hi, I have a google apps script which I access in my GSheet using the dropdowns. Whenever Knime updates my GSheet, I want the attached Apps Script to run exactly once. I tried setting up a trigger in Apps Script but the onEdit trigger works only if the spreadsheet is manually updated. The onChange trigger results in the Apps Script running twice whenever my workflow dumps data into the GSheet. Help?