On February 22. and 23. Oslo NixOS User Group hosted a mini conference at Hackeriet. We had a variety of talks about different parts of the Nix ecosystem.

DAY 1

The Nix ecosystem

Elis Hirwing (etu) talked about the Nix ecosystem! This was a great overview of the different Nix components and tools.

Some take-aways from this talk:

• The Nix pkgs repository on Github is huge, over 49 000 packages! So this is a very active community. According to Repology it’s the most up-to-date repo right now!
• The community works to keep packages as up to date as possible, and it is relatively easy to become a contributor.
• They try to remove unmaintained or EOL packages (unless too many other packages depend on it….looking at you Python 2!).
• You don’t have to use NixOS to take advantage of Nix packages, they can be used on basically any Linux or Darwin (macOS) distribution.

With tools like direnv and nix-shell, Nix is also great for setting up development environments. There is also a lot of tooling for different languages. This slide is an example of how Etu uses nix-shell to get the dependencies needed for generating the slides of this presentation. Nix has grown a lot in the last five years, and it is pretty exciting to follow that development further down the road.

Watch the talk

The slides are available on Github

NixOps

Then Kim Lindberger (talyz) gave a great presentation on NixOps. We even got treated to some demos!

Some things to note about NixOps:

• NixOps can be used to deploy NixOS systems to machines and non-machine resources (DNS, S3 buckets, etc.). All configuration is build locally before being shipped.
• There are plugins for a few cloud providers, for instance Amazon EC2 and Google Cloud Engine.
• If a deploy fails for some reason, you are never stuck with a system that is in a half-updated state. If the config doesn’t build, it won’t get pushed upstream and applied at all.
• NixOps is unfortunately still Python 2, but there are efforts on the way to port it to a modern Python.
• Backends will be split into separate plugins in an upcoming release!

Watch the talk

You can find the slides and the examples used in the demos on Github

Nix expressions

Last talk of the day was Adam Höse (Adisbladis) giving us an intro to reading Nix expressions. This is perhaps the most daunting aspect of NixOS for beginners.

A few things to consider:

• It’s not an imperative language, it is functional! A description that was mentioned is “a little bit like a weird Lisp without all the parents”
• Using the nix repl can be useful if you want to debug expressions or just play around with the language.
• Nix configurations can have different weights. Meaning that if you duplicate expressions, you can assign a weight to one of them that determines what will actually be built. Nix will merge all config together and that way decide what takes precedence.
• The key take-away: Learning the language will take your Nix journey further!

Lots of questions were asked by the audience during this talk, and hopefully some light was shed on the mysteries of the Nix language by the end.

Watch the talk

Then we ate some pizza and hung out Hackeriet style!

DAY 2

Building Docker containers with Nix

On the last day we got an overview of how to build Docker containers using Nix by Adam Höse.

• Normally a Docker build is an imperative process that might have different outcomes at different points in time (mostly because of the use of base images). Building a Docker image “Nix style” makes it reproducible, it will build the same way every time.
• Docker layers are content-addressed paths that are ordered; they are not sequential.
• buildLayeredImage is great for minimizing the amount of dependencies that are pulled into the final Docker image.
• Nixery is a project where you can get ad-hoc Docker images with a specific set of packages. The way to do this is to put the package names in the image name, like this: docker pull nixery.dev/shell/git/htop. Then you will get a custom docker image with bash, git and htop. Really cool!

Watch the talk

After this talk we had a informal session of hacking on Nix things and socializing.

The organizers (fnords & sgo) want to thank the speakers and everyone else that came to the mini-con! Special thanks to NUUG Foundation for sponsoring this event! If you want to get notified of any future events in Oslo NixOS User Group, you can join our Meetup group.