Caching The Python World: guix shell --container

[jgart]

Hi Guixers, 

I've been developing an app[0] that launches jupyter notebooks in "the
cloud" in guix containers[1]. In other words, the user submits a url for a
git repo containing the jupyter notebook and the app runs the notebook
in a guix container serving it to the user's browser tab.

The app auto-detects a manifest.scm in the root of the jupyter notebook's
project repository. The app then builds the container and all the
dependencies for the notebook specified by the manifest.scm.

The issue is the following: 

Sometimes a manifest with 10 notebook dependencies or even less will take
a long time (> 3 minutes) for Guix to build the container with everything
specified by the manifest.

For example, this repository containing a guix manifest caused the
browser to timeout out today after minutes of waiting for guix to build
the container.

https://github.com/BonfaceKilz/tsaf-analysis-of-bxd-mouse-colonies/blob/main/manifest.scm

Is there a way to pre-cache all the guix packaged binaries or a
subset thereof *ahead of time* so that if the user needs a particular
package/library they can get it near instantaneously[2]/on demand when
the app calls guix shell?

In other words, I am interested in pre-caching "the python world"
packaged by GNU Guix upstream. 

Is there currently a convenient way to tell Guix to build "all python-*
packages" and cache them? One way that comes to mind is dumping all
the python packages to a manifest and regularly updating that manifest
as new packages are added by maintainers. 

Does this sound like a sane way to solve this container build waiting issue?

Any thoughts/advice is much appreciated.

all best,

jgart

[0]: https://git.genenetwork.org/jgart/binderlite
[1]: https://guix.gnu.org/en/blog/2015/container-provisioning-with-guix/
[2]: https://guix.gnu.org/en/blog/2021/from-guix-environment-to-guix-shell/
"hot cache, in 0.1 seconds"