Also I created this repo to create a reproducible sec environment for myself. I added other languages, but personally work mostly with python. It is basically resonating for handling all the boiler plate:

https://github.com/takeda/nix-cde

For packaging in docker I started to use nix2container project as it gives me a greater control over layers. So for example when I package my phyton app I typically use 3 layers:

python and it's dependencies
my application dependencies
my application, which is very tiny compared to other two, so there is great reuse of the layers

The algorithm mentioned in the video also helps a lot with reuse, but the above is more optimized by frequency of how things typically change.

BTW: today I discovered this https://github.com/astro/microvm.nix I haven't play with it yet, but in theory it would let me generate a microvm image (in similar fashion to generate a docker container) which would let me to run my app natively as a tiny VM on EC2 for example, and use only minimum necessary of a typical OS to run it.