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https://github.com/cachix/install-nix-action
Installs Nix on GitHub Actions for the supported platforms: Linux and macOS.
https://github.com/cachix/install-nix-action
actions nix
Last synced: about 1 month ago
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Installs Nix on GitHub Actions for the supported platforms: Linux and macOS.
- Host: GitHub
- URL: https://github.com/cachix/install-nix-action
- Owner: cachix
- License: apache-2.0
- Created: 2019-10-02T09:31:59.000Z (about 5 years ago)
- Default Branch: master
- Last Pushed: 2024-10-03T10:19:48.000Z (about 1 month ago)
- Last Synced: 2024-10-06T02:01:58.562Z (about 1 month ago)
- Topics: actions, nix
- Language: Shell
- Homepage:
- Size: 15.7 MB
- Stars: 520
- Watchers: 12
- Forks: 80
- Open Issues: 23
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# install-nix-action
Installs [Nix](https://nixos.org/nix/) on GitHub Actions for the supported platforms: Linux and macOS.
By default it has no nixpkgs configured, you have to set `nix_path`
by [picking a channel](https://status.nixos.org/)
or [pin nixpkgs yourself](https://nix.dev/reference/pinning-nixpkgs)
(see also [pinning tutorial](https://nix.dev/tutorials/towards-reproducibility-pinning-nixpkgs)).
# Features
- Quick installation (~4s on Linux, ~20s on macOS)
- Multi-User installation (with sandboxing enabled only on Linux)
- [Self-hosted GitHub runner](https://docs.github.com/en/actions/hosting-your-own-runners/about-self-hosted-runners) support
- Allows specifying Nix installation URL via `install_url` (the oldest supported Nix version is 2.3.5)
- Allows specifying extra Nix configuration options via `extra_nix_config`
- Allows specifying `$NIX_PATH` and channels via `nix_path`
- Share `/nix/store` between builds using [cachix-action](https://github.com/cachix/cachix-action) for simple binary cache setup to speed up your builds and share binaries with your team
- Enables KVM on supported machines: run VMs and NixOS tests with full hardware-acceleration
## Usage
Create `.github/workflows/test.yml` in your repo with the following contents:
```yaml
name: "Test"
on:
pull_request:
push:
jobs:
tests:
runs-on: ubuntu-latest
steps:
- uses: actions/checkout@v4
- uses: cachix/install-nix-action@v27
with:
nix_path: nixpkgs=channel:nixos-unstable
- run: nix-build
```
## Usage with Flakes
```yaml
name: "Test"
on:
pull_request:
push:
jobs:
tests:
runs-on: ubuntu-latest
steps:
- uses: actions/checkout@v4
- uses: cachix/install-nix-action@v27
with:
github_access_token: ${{ secrets.GITHUB_TOKEN }}
- run: nix build
- run: nix flake check
```
To install Nix from any commit, go to [the corresponding installer_test action](https://github.com/NixOS/nix/runs/2219534360) and click on "Run cachix/install-nix-action@XX" step and expand the first line.
## Inputs (specify using `with:`)
- `extra_nix_config`: append to `/etc/nix/nix.conf`
- `github_access_token`: configure Nix to pull from GitHub using the given GitHub token. This helps work around rate limit issues. Has no effect when `access-tokens` is also specified in `extra_nix_config`.
- `install_url`: specify URL to install Nix from (useful for testing non-stable releases or pinning Nix, for example https://releases.nixos.org/nix/nix-2.3.7/install)
- `install_options`: additional installer flags passed to the installer script.
- `nix_path`: set `NIX_PATH` environment variable, for example `nixpkgs=channel:nixos-unstable`
- `enable_kvm`: whether to enable KVM for hardware-accelerated virtualization on Linux. Enabled by default if available.
## Differences from the default Nix installer
Some settings have been optimised for use in CI environments:
- `nix.conf` settings. Override these defaults with `extra_nix_config`:
- The experimental `flakes` and `nix-command` features are enabled. Disable by overriding `experimental-features` in `extra_nix_config`.
- `max-jobs` is set to `auto`.
- `show-trace` is set to `true`.
- `$USER` is added to `trusted-users`.
- `$GITHUB_TOKEN` is added to `access_tokens` if no other `github_access_token` is provided.
- `always-allow-substitutes` is set to `true`.
- `ssl-cert-file` is set to `/etc/ssl/cert.pem` on macOS.
- KVM is enabled on Linux if available. Disable by setting `enable_kvm: false`.
- `$TMPDIR` is set to `$RUNNER_TEMP` if empty.
---
## FAQ
### How do I print nixpkgs version I have configured?
```yaml
- name: Print nixpkgs version
run: nix-instantiate --eval -E '(import {}).lib.version'
```
### How do I run NixOS tests?
With the following inputs:
```yaml
- uses: cachix/install-nix-action@vXX
with:
enable_kvm: true
extra_nix_config: "system-features = nixos-test benchmark big-parallel kvm"
```
### How do I install packages via nix-env from the specified `nix_path`?
```
nix-env -i mypackage -f ''
```
### How do I add a binary cache?
If the binary cache you want to add is hosted on [Cachix](https://cachix.org/) and you are
using [cachix-action](https://github.com/cachix/cachix-action), you
should use their `extraPullNames` input like this:
```yaml
- uses: cachix/cachix-action@vXX
with:
name: mycache
authToken: '${{ secrets.CACHIX_AUTH_TOKEN }}'
extraPullNames: nix-community
```
Otherwise, you can add any binary cache to nix.conf using
install-nix-action's own `extra_nix_config` input:
```yaml
- uses: cachix/install-nix-action@v27
with:
extra_nix_config: |
trusted-public-keys = hydra.iohk.io:f/Ea+s+dFdN+3Y/G+FDgSq+a5NEWhJGzdjvKNGv0/EQ= cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY=
substituters = https://hydra.iohk.io https://cache.nixos.org/
```
### How do I pass environment variables to commands run with `nix develop` or `nix shell`?
Nix runs commands in a restricted environment by default, called `pure mode`.
In pure mode, environment variables are not passed through to improve the reproducibility of the shell.
You can use the `--keep / -k` flag to keep certain environment variables:
```yaml
- name: Run a command with nix develop
run: nix develop --ignore-environment --keep MY_ENV_VAR --command echo $MY_ENV_VAR
env:
MY_ENV_VAR: "hello world"
```
Or you can disable pure mode entirely with the `--impure` flag:
```
nix develop --impure
```