Building a Nix Project

What This Guide Covers #

This guide covers build environment and configuration topics specific to Nix projects. Please make sure to read our Tutorial and general build configuration guides first.

Community-Supported Warning #

Travis CI support for Nix is contributed by the community and may be removed or altered at any time. If you run into any problems, please report them in the Travis CI issue tracker and cc @domenkozar @garbas @matthewbauer and @grahamc.

Overview #

To install the Nix store and set up a basic single-user profile, set the language key in .travis.yml to nix.

language: nix

The default channel for nixpkgs will be nixpkgs-unstable.

Provided Tools #

The following command line tools are available in the Nix environment:

  • nix
  • nix-build
  • nix-channel
  • nix-collect-garbage
  • nix-copy-closure
  • nix-daemon
  • nix-env
  • nix-instantiate
  • nix-prefetch-url
  • nix-shell
  • nix-store

Default Nix Version #

This installs Nix 2.0.4 using https://nixos.org/releases/nix/nix-2.0.4/install. You may specify a different version of Nix installer with the nix: key in your .travis.yml:

language: nix
nix: 2.0.4

Note: This option supports all Nix releases, starting with version 1.11.16.

Default Target #

The default build script is nix-build which builds everything in the default.nix file of the repository root. This can be overridden by setting the script key in the .travis.yml file. For example,

language: nix
script: nix-build -A tarball release.nix

The above configuration will attempt to build the attribute “tarball” from the Nix expression in release.nix.

Nix manual #

More information on writing Nix expressions and how each of the above tools works is available in the Nix manual.