[benreesman]

Or just write a clean specification and get a docker image close to optimal, and if it’s not, you can prove cryptographically if by some chance you beat the defaults:

https://xeiaso.net/blog/i-was-wrong-about-nix-2020-02-10/

I’ve got plenty of gripes with nixlang, but being worse than Dockerfile-lang isn’t one of them.

[Cu3PO42]

Yes, you can use Nix to get extremely small Docker images. I have personally used it to that effect, but it's not a magic bullet. In this specific case, it gives pretty bad results even. I have written the simplest possible Nix derivation for ugit and the resulting Docker image is 158MB gzipped. I haven't explored fully why that is, but that's much worse than even the first effort from the OP.

[jbboehr]

I got it down to about 33M, gzipped with musl (completely untested, of course)[0].

Most of it seems to be from git:

$ nix path-info --closure-size --human-readable nixpkgs#legacyPackages.x86_64-linux.gitMinimal

/nix/store/f7b2yl226nbikiv6sbdhmaxg2452c8h5-git-minimal-2.42.0 112.9M

$ nix path-info --closure-size --human-readable nixpkgs#legacyPackages.x86_64-linux.pkgsMusl.gitMinimal

/nix/store/25807yw3143a94dpr3a3rffya7vg5r24-git-minimal-2.42.0 73.5M

Apparently "gitMinimal" is not all that minimal:

$ ls /nix/store/25807yw3143a94dpr3a3rffya7vg5r24-git-minimal-2.42.0/libexec/git-core/ | wc -l

172

[0]: https://gist.github.com/jbboehr/3a5d0dd52a0c1139ce88b76ab82a...