Ecosyste.ms: Awesome

An open API service indexing awesome lists of open source software.

Awesome Lists | Featured Topics | Projects

https://github.com/yaxitech/nix-install-pkgs-action

A GitHub Action to install flake packages using an ephemeral Nix profile
https://github.com/yaxitech/nix-install-pkgs-action

actions nix

Last synced: about 1 month ago
JSON representation

A GitHub Action to install flake packages using an ephemeral Nix profile

Awesome Lists containing this project

README 

        
# nix-install-pkgs-action



![Coverage](https://github.com/yaxitech/nix-install-pkgs-action/blob/gh-pages/coverage.svg)



A GitHub Action to install [Nix][nixos] packages into an ephemeral profile.



The action is particularly useful if you use a self-hosted [GitHub Actions Runner

on NixOS][nixos-runner]. Third-party actions frequently require certain tools to be installed

which are by default not available to the runner. With this action, you can install

Nix packages easily making them available to following actions.



As soon as the action terminates—no matter if successfully or unsuccessfully—the profile is purged to

allow garbage collection of all installed derivations.



[nixos]: https://nixos.org

[nixos-runner]: https://search.nixos.org/options?channel=unstable&query=services.github-runner.



## Usage



The action supports installing derivations from Flake packages and by evaluating a given expression.

Installation happens through `nix profile`.



You may call this action multiple times within the same job. Following steps will reuse the profile.

The path of the profile is also available with the step output `nix_profile_path`.



### Packages



Install `packages` by giving a comma-separated string of packages from a flake.

If no flake reference is given, `nixpkgs` is assumed. Example:



```yaml

name: 'nix-install-pkgs-action packages'

on:

  - pull_request

  - push

jobs:

  tests:

    runs-on: self-hosted

    steps:

      - uses: actions/checkout@v4

      - uses: yaxitech/nix-install-pkgs-action@v4

        with:

          packages: "nixpkgs#hello, figlet"

      - run: |

          hello

          figlet "Hello nix-install-pkgs-action!"



```



When installing flakes which reference a registry entry, the action resolves them as follows:



- If the input `inputs-from` is given, the action invokes `nix profile install --inputs-from`.

   As a result, `nixpkgs#hello` will look up `nixpkgs` using the inputs of the flake given in

   `inputs-from`. 

- `inputs-from` defaults to `.`, i.e., the current working directory of the process. If this

   directory (or a parent) contains a valid flake, `nix profile install` is invoked with this

   flake.

- If `inputs-from` is unset (i.e., `""`), `nix profile` resolves tokens using the registry.



### Expressions



On some occasions, you need to compose a custom derivation from a Nix expression, for example,

to install Python 3 with specific packages. This can be done with the `expr` input.

The action evaluates the passed string through `nix profile install --expr`.

Within your expression, the actions provides an imported `nixpkgs` as `pkgs` using the same

resolution strategy as outlined for the `packages` input.

In the following example, `pkgs` references `inputs.nixpkgs` from the flake `github:yaxitech/ragenix`:



```yaml

name: 'nix-install-pkgs-action expr'

on:

  - pull_request

  - push

jobs:

  tests:

    runs-on: self-hosted

    steps:

      - uses: actions/checkout@v4

      - uses: yaxitech/nix-install-pkgs-action@v4

        with:

          expr: 'pkgs.python3.withPackages(ps: with ps; [toml pyyaml])'

          inputs-from: 'github:yaxitech/ragenix'

      - run: |

          python3 ...

```



Within your expression, the action also introduces `let` bindings for a flake in the current

working directory (`repoFlake`) and for the flake referenced by `inputs-from` (`inputsFromFlake`).



## Prerequisites



This action requires a Flake-enabled Nix with support for

[profiles](https://nixos.org/manual/nix/stable/command-ref/new-cli/nix3-profile.html).



### NixOS



```nix

{

  nix.settings.experimental-features = [ "nix-command" "flakes" ];

}

```



### Non-NixOS



Use [`cachix/install-nix-action`](https://github.com/cachix/install-nix-action#usage-with-flakes)

to install Nix with flake support.



## Development notes



After you changed `package.json`, you also need to update `npmDepsHash` in `flake.nix`.

You can acquire the hash by running: `nix develop -c prefetch-npm-deps package-lock.json`.



Some of the TypeScript tests invoke `nix` during test execution. That means if

you invoke the tests through `nix`, for example as part of `nix build`, a nix

that has the `recursive-nix` feature enabled is required. You can put the

following snippet into your `configuration.nix`:



```nix

{

  nix.settings = {

    experimental-features = [ "nix-command" "flakes" "recursive-nix" ];

    system-features = [ "recursive-nix" ];

  };

}

```