Nix Quick Install Action

This GitHub Action installs Nix in single-user mode, and adds almost no time at all to your workflow's running time.

The Nix installation is deterministic – for a given release of this action the resulting Nix setup will always be identical, no matter when you run the action.

• Supports all Linux and MacOS runners

• Single-user installation (no nix-daemon)

• Installs in ≈ 1 second on Linux, ≈ 5 seconds on MacOS

• Allows selecting Nix version via the nix_version input

• Allows specifying nix.conf contents via the nix_conf input

Details

The main motivation behind this action is to install Nix as quickly as possible in your GitHub workflow. If that isn't important, you should probably use the Install Nix action instead, which sets up Nix in multi-user mode (daemon mode) using the official Nix installer.

To make this action as quick as possible, the installation is minimal: no nix-daemon, no nix channels and no NIX_PATH. The nix store (/nix/store) is owned by the unprivileged runner user.

The action provides you with a fully working Nix setup, but since no NIX_PATH or channels are setup you need to handle this on your own. Nix Flakes is great for this, and works perfectly with this action (see below). niv should also work fine, but has not been tested yet.

Inputs

See action.yml for documentation of the available inputs. The available Nix versions are listed in the release notes.

Usage

Minimal example

The following workflow installs Nix and then just runs nix-build --version:

name: Examples
on: push
jobs:
  minimal:
    runs-on: ubuntu-latest
    steps:
      - uses: nixbuild/nix-quick-install-action@v28
      - run: nix build --version
      - run: nix build ./examples/flakes-simple
      - name: hello
        run: ./result/bin/hello

Flakes

For nix > 2.13, these settings are always set by default:

experimental-features = nix-command flakes
accept-flake-config = true

This variant will also automatically set up the environment to bridge the configuration from the nixConfig flake attribute for old-style (nix-build, nix-store etc) Nix commands.

To disable that convenience bridge, you can specify:

name: Examples
on: push
jobs:
  flakes-simple:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v3
      - uses: nixbuild/nix-quick-install-action@v28
        with: {load_nixConfig: false}

You can see the flake definition for the above example in examples/flakes-simple/flake.nix.

Using Cachix

You can use the Cachix action together with this action, just make sure you put it after this action in your workflow.

Using specific Nix versions locally

Locally, you can use this repository's Nix flake to build or run any of the versions of Nix that this action supports. This is very convenient if you quickly need to compare the behavior between different Nix versions.

Build a specific version of Nix like this (requires you to use a version of Nix that supports flakes):

$ nix build github:nixbuild/nix-quick-install-action#nix-2_3_16

$ ./result/bin/nix --version
nix (Nix) 2.3.16

With nix shell -c you can also directly run Nix like this:

$ nix shell github:nixbuild/nix-quick-install-action#nix-2_2_2 -c nix --version
nix (Nix) 2.2.2

List all available Nix versions like this:

$ nix flake show --all-systems github:nixbuild/nix-quick-install-action
github:nixbuild/nix-quick-install-action/60e9c39264d4714139af3cdf15f691b19eec3530
├───apps
│   ├───x86_64-darwin
│   │   └───release: app
│   └───x86_64-linux
│       └───release: app
├───defaultApp
│   ├───x86_64-darwin: app
│   └───x86_64-linux: app
├───overlays
│   ├───x86_64-darwin: Nixpkgs overlay
│   └───x86_64-linux: Nixpkgs overlay
└───packages
    ├───x86_64-darwin
    │   ├───nix-2_18_2: package 'nix-2.18.2'
    │   ├───nix-2_19_3: package 'nix-2.19.3'
    │   ├───nix-2_20_5: package 'nix-2.20.5'
    │   ├───nix-2_21_0: package 'nix-2.21.0'
    │   ├───nix-2_3_17: package 'nix-2.3.17'
    │   ├───nix-archives: package 'nix-archives'
    │   └───release: package 'release'
    └───x86_64-linux
        ├───nix-2_18_2: package 'nix-2.18.2'
        ├───nix-2_19_3: package 'nix-2.19.3'
        ├───nix-2_20_5: package 'nix-2.20.5'
        ├───nix-2_21_0: package 'nix-2.21.0'
        ├───nix-2_3_17: package 'nix-2.3.17'
        ├───nix-archives: package 'nix-archives'
        └───release: package 'release'

If you want to make sure that the version of Nix you're trying to build hasn't been removed in the latest revision of nix-quick-install-action, you can specify a specific release of nix-quick-install-action like this:

$ nix build github:nixbuild/nix-quick-install-action/v12#nix-2_3_7

Note that we've added /v12 to the flake url above.