Nixery

What is this?

Nixery provides the ability to pull ad-hoc container images from a Docker-compatible registry server. The image names specify the contents the image should contain, which are then retrieved and built by the Nix package manager.

Nix is also responsible for the creation of the container images themselves. To do this it uses an interesting layering strategy described in this blog post.

How does it work?

Simply point your local Docker installation (or other compatible registry client) at Nixery and ask for an image with the contents you desire. Image contents are path separated in the name, so for example if you needed an image that contains a shell and emacs you could pull it as such:

nixery.appspot.com/shell/emacs25-nox

Image tags are currently ignored. Every package name needs to correspond to a key in the nixpkgs package set.

There are some special meta-packages which you must specify as the first package in an image. These are:

• shell: Provides default packages you would expect in an interactive environment
• builder: Provides the above as well as Nix's standard build environment

Hence if you needed an interactive image with, for example, htop installed you could run docker run -ti nixery.appspot.com/shell/htop bash.

FAQ

Technically speaking none of these are frequently-asked questions (because no questions have been asked so far), but I'm going to take a guess at a few anyways:

• Where is the source code for this?
  Not yet public, sorry. Check back later(tm).
• Which revision of nixpkgs is used?
  Nixery imports a Nix channel via builtins.fetchTarball. Currently the channel to which this instance is pinned is NixOS 19.03.
  One idea I've had is to let users specify tags on images that correspond to commits in nixpkgs, however there is some potential for abuse there (e.g. by triggering lots of builds on commits that have broken Hydra builds) and I don't want to deal with that yet.
• Who made this?
  @tazjin