1. docker container providing toolchain for projects that can build with nix
2. could instead use docker container provided by nixos:

docker run -ti ghcr.io/nixos/nix

That container provides nix, bashInteractive, coreutils-full, gnutar, gzip, gnugrep, which, curl, less, wget, man, cacert.out, findutils.

build/update

0. if changed any foo.nix files, then

$ cd ~/proj/docker-nix-builder
$ nix flake check

1. compile if necessary

$ cd ~/proj/docker-nix-builder  # directory containing this file
$ nix build -L --print-build-logs .#docker-nix-builder

2. upload to docker

$ docker load <./result  # i.e. docker load < ~/proj/docker-nix-builder/result

2a. Note: to publish container to github, need a personal access token:

• on github.com/${myusername}:
  • visit profile (upper rhs or github.com)
    • developer settings (bottom of sidebar)
      • personal access tokens

        • tokens (classic) 'generate a personal access token'

          scopes needed:

          • read:packages
          • write:packages
          • delete:packages

2b.

$ export CR_PAT=${token}
$ echo $CR_PAT | docker login ghcr.io -u rconybea --password-stdin
Login Succeeded

Docker keeps secret in ~/.docker/config.json, so don't need to remember token separately unless want to use for something besides docker.

tag image the way github expects, i.e. format ghcr.io/${username}/${imagename}:${tag} (tag should match tag argument to dockerTools.buildLayeredImage in pkgs/docker-nix-image.nix)

$ docker image tag docker-nix-builder:v1 ghcr.io/rconybea/docker-nix-builder:v1

push to github container registry:

$ docker image push ghcr.io/rconybea/docker-nix-builder:v1
The push refers to repository [ghcr.io/rconybea/docker-nix-builder]
...omitted...
v1: digest: sha256:e1aad3df64c1ea2ed6674b354e22e3807a831bb8229fa3be399c21f87ea72cb6 size: 6192

verify it's arrived by inspecting the gihub 'packages' tab [https://github.com/Rconybea?tab=packages]

image (github package) is initially private; make it public from the package's 'setting' link

for example workflow using this image, see [https://github.com/rconybea/docker-action-example3]

miscellaneous

operate container locally

To test container locally:

$ docker run -i docker-nix-builder:v1 bash

list available images

list available docker images

$ docker image ls
REPOSITORY                            TAG       IMAGE ID       CREATED         SIZE
docker-nix-builder                    v1        ce3fdf8fa87f   5 minutes ago   750MB
...

delete old containers+images

$ docker container prune
$ docker image prune