samueldr / action-nix-build

nix-build action

This GitHub Action will run nix-build, using the latest nixos/nix docker image.

It will build one of, in order or preference:

• "$@" if arguments are set
• nix-build release.nix if release.nix exists
• nix-build default.nix if default.nix exists

/nix/store

Given that this executes in a single-use Docker container, the Nix store is not persistent, and will be lost once the action is over.

The results from running nix-build [release|default].nix will be automatically resolved from their symlinks and copied in place in a non- recursive manner.

This means that release.nix is expected to not keep reference to the store.

Environment

Channel

By default, it will use nixos-unstable as a channel. This is meant to keep the action "always up to date" even on new NixOS releases.

To configure another channel, set NIX_PATH accordingly

action "samueldr/action-nix-build@master" {
  uses = "samueldr/action-nix-build@master"
  env = {
    NIX_PATH = "nixpkgs=channel:nixos-18.09"
  }
}

See the Nix manual for more information about NIX_PATH.

Unfree

The easiest way to handle this is to use the environment variable that Nixpkgs looks at.

action "samueldr/action-nix-build@master" {
  uses = "samueldr/action-nix-build@master"
  env = {
    NIXPKGS_ALLOW_UNFREE = "1"
  }
}