Nix at Mozilla

Jan 2017

London Nixos Usergroup

@garbas

What is Nix?

a build tool
a language
a package manager
extends to whole Linux distro

How to introduce Nix at work?

Solve your own problem first (eg. your own development environment)
Teach nix
Start to package projects as you come by them
Put infrastructure in place (Travis + S3 bucket is enough)
Teach nix
Volunteer to solve hard problems only Nix can solve
Teach nix
Point out problems (laud) which other tools are not considering

Create default.nix for all your projects
Time to create first PRs to share default.nix with others
Talk with coworkers about Nix (to remove the fear)
In worse case you can keep you default.nix and people will eventually look at it.

Solve your own problems first

Start to package other projects

create an overlay repository (eg. nixpkgs-<company>)
https://github.com/mozilla/nixpkgs-mozilla
https://garbas.si/2016/updating-your-nix-sources.html#extending-nixpkgs
show that you coulud improve current situation of your tooling. best to do it is by example. eg. automatic security checks using vulnix (per project), automatic updating of sources/version

Put infrastructure in place

This is needs to help the future growth. you want your coworkers to get binaries and not to compile.
Travis + S3 bucket is all you need
https://github.com/mozilla-releng/services/blob/master/.taskcluster.sh
Do not use Hydra! It is not bad, but switching to many thing scares people. Be patient and move step by step.

Volunteer to solve hard problems

Package old projects
https://github.com/NixOS/nixpkgs/pull/21355
Build reproducible docker images (no other tool can do this)
Reproducibility as a productivity tool
https://garbas.si/2016/reproducible-builds-summit-in-berlin.html
Create Nix recipe for puppet/chef/ansible/... and when time comes (we need a X version which is not packaged for a distro) step in to solve it with nix

Teach Nix

No idea how best to do it. There are no good resources. With attention that Nix is getting this should get fixed soon.
Pair programming session, write down questions and make sure you document the answers.
Nix + Python + Docker session: https://docs.google.com/document/d/1d66PQmsFgJLn9Dck4e1d_2yvmIoDLUsws4vDMOh7RDA/edit?usp=sharing
https://docs.mozilla-releng.net/prerequirements.html

Bonus: Updating sources

(coming soon to nixpkgs - partially is already in)

{ stdenv, ... }:

stdenv.mkDerivation {
  name
  src = fetchFromGithubWithUpdate {
    owner = "gutschke";
    repo = "pdf2odt";
    branch = "master";
    path = "pkgs/tools/typesetting/pdf2odt/src.json";
  };
  ... or ...
  src = fetchFromGitHub (stdenv.lib.importJSON ./src.json);
  passthru.updateScript = updateFromGitHub {
    owner = "gutschke";
    repo = "pdf2odt";
    branch = "master";
    path = "pkgs/tools/typesetting/pdf2odt/src.json";
  };
}

----

nix-shell maintainers/scripts/update.nix --argstr package pdf2odt