How to setup ec2 on costomer's aws environment

I have a saas product in my company where a user needs to upload his stl file. And we take that stl file and we do operations on it like finding blender-wall-thickness, material-anlaysis, complexity -analysis and save the stl in our database. Our server is hosted in ec2 and we are storing stls in s3. We are making docker containers then running this container in the ec2 while exposing one specific to each service. Now one of our costomer does not want to upload his stl files in our s3 and ec2 instead they want to use their ec2 and s3 due to confidentiality reasons. How can we setup a system in their environment where their stl files does not leave their environment still uses our service. But We don't have to share our code .