Is there a way to run a Google App engine cron task without hitting an endpoint but rather pointing cron.yaml at a python script?
A cron job in GAE has to hit a URL, there's no other way to do it. That's just how the system is designed.
But since you have control over app.yaml anyway, you can easily assign your script to a URL there.
my end goal is to update Google cloud storage with some json data and I would rather it run a script rather than hitting a url endpoint. What would be the proper configuration of cron.yaml if, let's say the script were to sit right next to app.yaml?