Attempts at different versions of the "smallest" image for Binder

Try it out:

• use alpine linux for base image (not the alpine-based python images!)

• two-stage builds to avoid installer files in runtime image (runtime has no pip)

• PYTHONOPTIMIZE=2

• pyc-wheel to include only .pyc files in installed packages

• remove .dist-info package metadata (small savings)

• remove __pycache__ for stdlib (ideally, we would keep only .opt-2, but I haven't figured that out yet) Result (analyzed dive): 81MB total

• 5.6MB for alpine base image

• 27MB for apk-installed python, pyzmq

• 48MB for pip-installed packages

A much simpler version can be found in the simple branch, which only does the simplest version of installation based on alpine. This version has:

• 48MB to install python from api (not post-slimmed)
• 52MB to install notebook with pip ()

totalling out to 105MB, so the slimming strategy saves ~20MB at the expense of being much more complicated and actually slower to build and slower at runtime.

The main reason to make a tiny image is launch time, but the removal of __pycache__ for the stdlib should actually greatly increase launch time of everything after image pull, in exchange for an only slightly reduced image size (~20-25MB saved).