How to store s3 keys in database

Since my files are getting cleared off after every docker deploy/redeploy, I’m left with the option of using s3 bucket to store my files .the issue im having is how to store s3 keys in the database and using the (sign download url) later inorder to display the files to the user later…

I can’t see the option for the $key ,in the put file s3 option, even after using repeats…

How should i do it?